S-8590AA/8590AB/8591AA/8591AB Series
18 V INPUT, 600 mA SYNCHRONOUS
STEP-DOWN SWITCHING REGULATOR

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Rev.2.1_00© ABLIC Inc., 2019-2021

The S-8590/8591 Series is a step-down switching regulator developed using high withstand voltage CMOS process
technologies.
This IC has high maximum operation voltage of 18 V and maintains high-accuracy FB pin voltage at ±1.5%. As suitable
packages for high-density mounting, such as small-sized HSNT-6(2025), are adopted, this IC contributes to miniaturizationof electronic equipment.
PWM control (S-8590 Series) or PWM / PFM switching control (S-8591 Series) can be selected as an option.
Since the S-8591 Series, which features PWM / PFM switching control, operates with PWM control under heavy load andautomatically switches to PFM control under light load, it achieves high-efficiency operation in accordance with thedevice's status. Furthermore, our distinctive PWM / PFM switching control technology suppresses the ripple voltage to begenerated in VOUT while PFM control is in operation.
Since the S-8590/8591 Series has the built-in synchronous circuit, it achieves high efficiency easier compared withconventional step-down switching regulators. In addition, it has the built-in overcurrent protection circuit which protects the
IC and coils from excessive load current as well as a thermal shutdown circuit which prevents damage from heatgeneration.

 Features

 Applications
4.0 V to 18.0 V
1.0 V to 12.0 V
600 mA±1.5%
91%
2.2 MHz typ.
1.2 A typ. (pulse-by-pulse method)
170°C typ. (detection temperature)Hiccup control, Latch control
5.8 ms typ.
3.35 V typ. (detection voltage)
Ceramic capacitor compatible
Ta = −40°C to +85°C

 Typical Application Circuit
VIN

VIN

VEN

EN
CIN
4.7 μFSW

L
3.3 μH

VOUT
3.3 V
CFB
33 pF

FB

VREG
VSS

CREG
1 μF

• Constant-voltage power supply
for industrial equipment• Constant-voltage power supply
for home electric appliance Packages• HTMSOP-8(4.0 mm × 2.9 mm × t0.8 mm max.)• HSNT-8(2030)(3.0 mm × 2.0 mm × t0.5 mm max.)• HSNT-6(2025)(2.46 mm × 1.96 mm × t0.5 mm max.) Efficiency

COUT
10 μF

RFB1
46.9 kΩ

VIN = 12.0 V, VOUT = 3.3 V

100

S-8591 Series

80
η [%]

• Input voltage:• Output voltage (externally set):• Output current:• FB pin voltage accuracy:• Efficiency:• Oscillation frequency:• Overcurrent protection function:• Thermal shutdown function:• Short-circuit protection function:• 100% duty cycle operation:• Soft-start function:• Under voltage lockout function (UVLO):• Input and output capacitors:• Operation temperature range:• Lead-free (Sn 100%), halogen-free

60
40
20

RFB2
15 kΩ

S-8590 Series

0
0.1

1

10
IOUT [mA]

100

1000

1

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Block Diagrams
1.

S-8590 Series (PWM control)
VIN
*1
*1

EN

VIN

Enablecircuit

CIN

*1

VREG

Regulator*1

UVLO circuit

Soft-start
circuit

VREG
*1

FB

*1

SW

+

Error
amplifier

−
*1

CREG

PWM
control
circuit

−

+

VOUT
L
COUT

*1

CFB

RFB1
RFB2

Oscillation circuit
VREF
Short-circuit
protection circuit
VSS*1. Parasitic diodeFigure 1

2.

S-8591 Series (PWM / PFM switching control)
VIN
*1

VIN

*1

EN
CIN

Enablecircuit*1

VREG

Regulator*1

UVLO circuit

Soft-start
circuit

VREG
FB

*1

−
*1

Error
amplifier

+

*1

SW
+
−

VOUT
L

switching

*1

COUT

CFB

RFB1
RFB2

Oscillation circuit
VREF
Short-circuit
protection circuit
VSS*1. Parasitic diodeFigure 2

2

CREG

Reversecurrent
detection
circuit18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Product Name Structure
1.

Product nameS-859 x

A x

-

xxxx

U

7
Environmental codeU:
Lead-free (Sn 100%), halogen-free
Package name abbreviation and packing specification*1
S8T1: HTMSOP-8, Tape
A8T1: HSNT-8(2030), Tape
A6T8: HSNT-6(2025), Tape
Product type*2
A, B
Control method
0:
PWM control
1:
PWM / PFM switching control

*1.
*2.

2.

Refer to the tape drawing.
Refer to "2. Function list of product types".

Function list of product types
Table 1

3.

Product Type

Oscillation Frequency

AB

2.2 MHz
2.2 MHz

Short-circuit Protection Function
Hiccup control
Latch control

Packages
Table 2

Package NameHTMSOP-8
HSNT-8(2030)
HSNT-6(2025)

Dimension
FP008-A-P-SD
PP008-A-P-SD
PJ006-B-P-SD

Package Drawing Codes

Tape
FP008-A-C-SD
PP008-A-C-SD
PJ006-B-C-SD

Reel
FP008-A-R-SD
PP008-A-R-SD
PJ006-B-R-SD

Land
FP008-A-L-SD
PP008-A-L-SD
PJ006-B-LM-SD

Stencil Opening−−
PJ006-B-LM-SD

3

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Pin Configurations
1.

HTMSOP-8
Table 3Top view

Pin No.

1
2
3
4

8
7
6
5
Bottom view
1
2
3
4

8
7
6
5

1
2
3
4
5
6
7
8

Symbol
VIN
FB
EN
NC*2
NC*2
VREG*3VSS
SW

Description
Power supply pin
Feedback pin
Enable pin (active "H")No connection
No connection
Internal power supply pin
GND pin
External inductor connection pin*1

Figure 3
*1.
*2.
*3.

2.

Connect the heat sink of backside at shadowed area to the board, and set electric potential GND.
However, do not use it as the function of electrode.
The NC pin is electrically open.
The NC pin can be connected to the VIN pin or the VSS pin.
The VREG pin cannot supply load current outside.

HSNT-8(2030)
Table 4
Pin No.

Top view
1

8

4

5

Bottom view
8

1

5

4

1
2
3
4
5
6
7
8

Symbol
VIN
FB
EN
NC*2
NC*2
VREG*3VSS
SW

Description
Power supply pin
Feedback pin
Enable pin (active "H")No connection
No connection
Internal power supply pin
GND pin
External inductor connection pin*1

Figure 4
*1.
*2.
*3.

4

Connect the heat sink of backside at shadowed area to the board, and set electric potential GND.
However, do not use it as the function of electrode.
The NC pin is electrically open.
The NC pin can be connected to the VIN pin or the VSS pin.
The VREG pin cannot supply load current outside.

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
3.

HSNT-6(2025)
Table 5
Pin No.

Top view
1
2
3

6
5
4

Bottom view
6
5
4

1
2
3

1
2
3
4
5
6

SymbolVIN
FBEN
VREG*2VSS
SW

Description
Power supply pin
Feedback pin
Enable pin (active "H")Internal power supply pin
GND pin
External inductor connection pin*1

Figure 5*1.
*2.

Connect the heat sink of backside at shadowed area to the board, and set electric potential GND.
However, do not use it as the function of electrode.
The VREG pin cannot supply load current outside.

5

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Absolute Maximum Ratings
Table 6
(Unless otherwise specified: Ta = +25°C, VSS = 0 V)
VIN pin voltage
EN pin voltage
FB pin voltage
VREG pin voltage

Item

Symbol
VIN
VEN
VFB
VREG

SW pin voltage

VSW

Junction temperature
Operation ambient temperature
Storage temperature

Tj
Topr
Tstg

Absolute Maximum Ratings
VSS − 0.3 to VSS + 22
VSS − 0.3 to VSS + 22
VSS − 0.3 to VREG + 0.3 ≤ VSS + 6.0
VSS − 0.3 to VIN + 0.3 ≤ VSS + 6.0
VSS − 2 to VIN + 2 ≤ VSS + 22 (< 20 ns)
VSS − 0.3 to VIN + 0.3 ≤ VSS + 22
−40 to +125
−40 to +85−40 to +125

Unit
V
V
V
V
V
°C
°C
°C

Caution The absolute maximum ratings are rated values exceeding which the product could suffer physicaldamage. These values must therefore not be exceeded under any conditions.

 Thermal Resistance Value
Table 7
Item
SymbolCondition
Board A
Board BHTMSOP-8
Board C
Board D
Board E
Board A
Board B
Junction-to-ambient thermal resistance*1 θJA
HSNT-8(2030)
Board C
Board D
Board E
Board A
Board B
HSNT-6(2025)
Board C
Board D
Board E
*1. Test environment: compliance with JEDEC STANDARD JESD51-2A
Remark Refer to " Power Dissipation" and "Test Board" for details.

6

Min.
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−

Typ.
159
113
39
40
30
181
135
40
42
32
180
128
43
44
36

Max.
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−

Unit
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series Electrical Characteristics
Table 8(VIN = 12 V, Ta = +25°C unless otherwise specified)
Item
Operating input voltage
Current consumption
during shutdown
Current consumption
during switching off
UVLO detection voltage
UVLO release voltage

SymbolCondition

Min.

Typ.

Max.

Unit

−

4.0

−

18.0

V

−

0

1

μA

−
−
3.1
3.2

175
68
3.35
3.45

260
120
3.6
3.7

μA
μA
V
V

VIN
ISSS

VEN = 0 V

ISS

VFB = 1.0 V

VUVLOVUVLO+

VREG pin voltage
VREG pin voltage

S-8590 Series
S-8591 Series

FB pin voltage

VFB

−

0.788

0.8

0.812

V

Oscillation frequency

fOSC

−

1.98

2.2

2.42

MHz

Minimum ON time
Maximum duty ratio

tON_MIN
MaxDuty

−
100

60
−

−
−

ns
%

Soft-start wait time

tSSW

0.30

0.58

0.90

ms

Soft-start time

tSS

−
−
Time until VOUT starts rising,
CREG = 1 μF
Time until VFB reaches 90% after it starts
rising

3.0

5.8

8.5

ms

High side power
MOS FET on-resistanceLow side power
MOS FET on-resistanceHigh side power
MOS FET leakage current
Low side power
MOS FET leakage current
Limit current
Thermal shutdown
detection temperature
Thermal shutdown
release temperature
High level input voltage
Low level input voltage

RHFET

ISW = 50 mA

−

0.85

1.75

Ω

RLFET

ISW = −50 mA

−

0.35

0.65

Ω

IHSW

VIN = 18.0 V, VEN = 0 V, VSW = 0 V

−

0.01

1

μA

ILSW

VIN = 18.0 V, VEN = 0 V, VSW = 18.0 V

−

0.01

1

μA

1.0

1.2

1.4

A

−

ILIM
TSD

Junction temperature

−

170

−

°C

TSR

Junction temperature

−

150

−

°C

VSH
VSL

EN pinEN pin

2.0
−

−
−

−
0.8

V
V

High level input current

ISH

EN pin, VEN = 2.0 V

−

−

1

μA

Low level input current
FB pin current

ISL
IFB

EN pin, VEN = 0 V
FB pin, VFB = 1.0 V

−0.5
−0.06

−
−

0.5
0.06

μA
μA

7

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Operation
1.

Overview of operation
The S-8590/8591 Series adopts the current mode control. By comparing the current feedback signal which hasslope compensation added to the current flows through high side power MOS FET with the output signal of error
amplifier, the Duty ratio of the SW pin is determined. Using the negative feedback loop configured, the error
amplifier output signal is maintained at the value that VREF and FB pin voltage (VFB) will be equalized.

2.

PWM control (S-8590 Series)
The S-8590 Series operates with the pulse width modulation method (PWM) regardless of the extent of load current
and allows the switching frequency to stabilize.

3.

PWM / PFM switching control (S-8591 Series)
The S-8591 Series automatically switches between PWM and pulse frequency modulation method (PFM) according
to the load current. PFM control is selected when under light load, and the pulse will skip according to the load
current. This reduces self-current consumption and improves efficiency when under light load.
In PFM control, the peak current, flows through an inductor, is set to 125 mA typ. in the IC. In addition, ourdistinctive PWM / PFM switching control technology suppresses the ripple voltage to be generated in VOUT while
PFM control is in operation.

4.

Minimum ON time
ON time (tON) of the SW pin during current continuous mode can be calculated by the following expression.
VOUT
1tON = V × f
IN
OSCtON will be small when VIN is high and VOUT is low. Set the use conditions to realize tON > minimum ON time (tON_MIN).
Although the maximum value of tON_MIN varies according to inductance, load current, and the conditions of VIN and
VOUT, the value is 80 ns. When tON < tON_MIN, the ripple voltage (ΔVOUT) in VOUT may increase by skipping a pulse
during current continuous mode. In addition, when the S-8590/8591 Series changes to an overload status, the limit
current (ILIM) to protect the IC from overcurrent may increase. Sufficient evaluations under actual conditions are
required.

5.

100% duty cycle operation
The high side power MOS FET allows for 100% duty cycle operation. Even when the input voltage is lowered up to
the output voltage value set using the external output voltage setting resistor, the high side power MOS FET is kept
on and current can be supplied to the load. The output voltage at this time is the input voltage from which thevoltage drop due to the direct resistance of the inductor and the on-resistance of the high side power MOS FET are
subtracted.

6.

Under voltage lockout function (UVLO)The S-8590/8591 Series has a built-in UVLO circuit to prevent the IC from malfunctioning due to a transient status at
power-on or a momentary drop in the supply voltage. When UVLO status is detected, the high side power MOS FET
and low side power MOS FET will turn off, and the SW pin will change to "High-Z". For this reason, switching
operation will stop. The soft-start function is reset if UVLO status is detected once and is restarted by releasing the
UVLO status.
Note that the other internal circuits operate normally, and the status is different from the disabled status.
Also, there is a hysteresis width for avoiding malfunctions due to generation of noise etc. in the input voltage.

8

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
7.

EN pinThis pin starts and stops switching operation. When the EN pin is set to "L", the operation of all internal circuits,
including the high side power MOS FET, is stopped, reducing current consumption. When not using the EN pin,connect it to the VIN pin. Since the EN pin is neither pulled down nor pulled up internally, do not use it in the floating
status. The structure of the EN pin is shown in Figure 6, and the clamp circuit is internally connected. Refer to "3. 1High level input current (ISH) vs. EN pin voltage (VEN)" in " Characteristics (Typical Data)" for the input currentof EN pin.

EN Pin
"H"
"L"
*1.
*2.

Table 9Internal Circuit
Enable (normal operation)
Disable (standby)

VOUT
Constant value*1
Pulled down to VSS*2

The constant value is output due to the regulating based on the output voltage setting resistors(RFB1 and RFB2).
VOUT is pulled down to VSS due to the output voltage setting resistors (RFB1 and RFB2) and a load.

EN
Clamp
circuitFigure 6

8.

Thermal shutdown function
The S-8590/8591 Series has a built-in thermal shutdown circuit to limit overheating. When the junction temperature
increases to 170°C typ., the thermal shutdown circuit becomes the detection status, and the switching operation is
stopped. When the junction temperature decreases to 150°C typ., the thermal shutdown circuit becomes the releasestatus, and the switching operation is restarted.
If the thermal shutdown circuit becomes the detection status due to self-heating, the switching operation is stopped
and output voltage (VOUT) decreases. For this reason, the self-heating is limited and the temperature of the IC
decreases. The thermal shutdown circuit becomes release status when the temperature of the IC decreases, andthe switching operation is restarted, thus the self-heating is generated again. Repeating this procedure makes the
waveform of VOUT into a pulse-like form. Note that the product may suffer physical damage such as deterioration if
the above phenomenon occurs continuously. Switching operation stopping and starting can be stopped by either
setting the EN pin to "L", lowering the output current (IOUT) to reduce internal power consumption, or decreasing theambient temperature.
Table 10
Thermal Shutdown Circuit

VOUT

Release: 150°C typ.*1
Constant value*2*1
Detection: 170°C typ.
Pulled down to VSS*3*1. Junction temperature*2. The constant value is output due to the regulating based on the output voltage setting resistors(RFB1 and RFB2).
*3. VOUT is pulled down to VSS due to the output voltage setting resistors (RFB1 and RFB2) and a load.

918 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
9.

Overcurrent protection function
The overcurrent protection circuit monitors the current that flows through the high side power MOS FET and limits
current to prevent thermal destruction of the IC due to an overload, magnetic saturation in the inductor, etc.
When a current exceeding the limit current (ILIM) flows through the high side power MOS FET, the high side power
MOS FET is turned off. When the next switching cycle starts, the high side power MOS FET is turned on. If thecurrent value continues to remain at ILIM or higher, the high side power MOS FET is turned off again, repeating thisseries of operation.
Meanwhile, when the current, which flows through the high side power MOS FET, falls to ILIM or lower, theS-8590/8591 Series will return to the normal operation.
When the slope of inductor current is large, ILIM may appear to increase due to the delay time of overcurrent
protection circuit. This phenomenon tends to occur when low-inductance inductor is used or when the voltage
different between VIN and VOUT is large.

10.

Frequency foldback function

The frequency foldback function has FB pin voltage (VFB) and oscillation frequency (fOSC) to have a proportional
relation when VFB is 0.7 V typ. or lower. Refer to "11. Short-circuit protection function" for details.
The frequency foldback function in the S-8590 Series is set to invalid at start-up.

10

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
11.

Short-circuit protection function

11. 1 Hiccup control
The S-8590/8591 Series A type has a built-in short-circuit protection function for Hiccup control.
Hiccup control is a method for periodically carrying out automatic recovery when the IC detects overcurrent andstops the switching operation.
11. 1. 1 When overload status is released<1> Overcurrent detection<2> After detection of the FB pin voltage (VFB) < 0.7 V typ., frequency foldback function becomes valid.
<3> Detection of VFB < 0.5 V typ.
<4> 0.3 ms elapse<5> Switching operation stop (for 21 ms typ.)<6> Overload status release<7> The IC restarts, soft-start function starts.
In this case, it is unnecessary to input an external reset signal for restart.
<8> VFB reaches 0.72 V typ. after 5.8 ms typ. elapses.
<1><6>Overload status
Normal load status
1.2 A typ.
*1

IL

0.6 A
0A

VSW

VFB

0V
0.8 V typ.
0.7 V typ.
0.5 V typ.

<2>
<4>
<8>
0.3 ms typ. 21 ms typ. 5.8 ms typ.
<3>
<5>
<7>

*1.

0V

Inductor current
Figure 7

11. 1. 2 When overload status continues<1> Overcurrent detection<2> After detection of VFB < 0.7 V typ., frequency foldback function becomes valid.
<3> Detection of VFB < 0.5 V typ.
<4> 0.3 ms elapse<5> Switching operation stop (for 21 ms typ.)<6> The IC restarts, soft-start function starts.
<7> The status returns to <3> when overload status continues after 8.6 ms typ. elapses.

*1.

Inductor current
Figure 81118 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
11. 2

Latch control

The S-8590/8591 Series B type has a built-in short-circuit protection function for Latch control.
Latch control is a method for maintaining the Latch status when the IC detects overcurrent and stops the switching
operation.
<1> Overcurrent detection<2> After detection of VFB < 0.7 V typ., frequency foldback function becomes valid.
<3> Detection of VFB < 0.5 V typ.
<4> 0.3 ms elapse<5> Switching operation stop
<1>

Overload status
1.2 A typ.

*1

IL

0.6 A
0A

VSW
0V
0.8 V typ.
0.7 V typ.
VFB

<2>

0.5 V typ.
<4>
0.3 ms typ.
<3>
<5>

*1. Inductor current
Figure 9
In addition, Latch status is reset under the following conditions.
• At UVLO detection• When the EN pin changes from "H" to "L".

120V

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
12.

Pre-bias compatible soft-start function

The S-8590/8591 Series has a built-in pre-bias compatible soft-start circuit.
If the pre-bias compatible soft-start circuit starts when electrical charge remains in the output voltage (VOUT) as aresult of power supply restart, etc., or when VOUT is biased beforehand (pre-bias status), switching operation is
stopped until the soft-start voltage exceeds the FB pin voltage (VFB), and then VOUT is maintained. If the soft-start
voltage exceeds VFB, switching operation will restart and VOUT will rise to the output voltage setting value (VOUT(S)).
This allows VOUT(S) to be reached without lowering the pre-biased VOUT.
In soft-start circuits which are not pre-bias compatible, a large current flows as a result of the discharge of theresidual electric charge through the low side power MOS FET when switching operation starts, which could cause
damage, however in a pre-bias compatible soft-start circuit, the IC is protected from the large current when switching
operation starts, and it makes power supply design for the application circuit simpler.
In the S-8590/8591 Series, VOUT reaches VOUT(S) gradually due to the soft-start circuit.
In the following cases, rush current and VOUT overshoot are reduced.
• When the EN pin changes from "L" to "H".
• When UVLO operation is released.*1• When thermal shutdown is released.*1• At short-circuit recovery*1*1. In this case, the soft-start wait time is eliminated.
The soft-start circuit starts operating after "H" is input to the EN pin and the soft-start wait time (tSSW) = 0.58 ms typ.
elapses. The soft-start time (tSS) is set to 5.8 ms typ.
Soft-start
wait time(tSSW)

Soft-start operation
during pre-bias

Soft-start time
(tSS)

VEN

VOUT

VSW

Figure 10

13.

Internal power supply (VREG)

Some of the circuits in the IC operate using the VREG pin voltage (VREG) as the power supply. To stabilize thisinternal power supply, a ceramic capacitor with 1 μF needs to be connected between the VREG pin and the VSS pin.
To achieve low impedance, this capacitor should be placed as close to the IC as possible. Additionally, note that any
external parts other than CREG or any load must not connect to the VREG pin.

13

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Typical Circuit
VIN
L
EN

VIN

CIN

VOUT

SW
CFB

FB

VREG
VSS

RFB1

COUT
CREG
RFB2

Figure 11
Caution The above connection diagram will not guarantee successful operation. Perform thorough evaluation
using an actual application to set the constants.

14

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 External Parts Selection
The recommended values for each external part are shown in Table 11, and the recommended parts are shown in
Table 12 to Table 16. When selecting an input capacitor (CIN), output capacitor (COUT), and internal power supply
stabilized capacitor (CREG), take into consideration the temperature range and DC bias characteristics of the capacitor
to be used.
Table 11
VOUT
CIN
COUT
CFB
CREG
L
RFB1
RFB2
1.0 V
33 pF
4.7 μF
10 μF
1 μF
2.2 μH
3.75 kΩ
15 kΩ
2.5 V
33 pF
4.7 μF
10 μF
1 μF
3.3, 4.7 μH
31.9 kΩ
15 kΩ
3.3 V
33 pF
4.7 μF
10 μF
1 μF
3.3, 4.7 μH
46.9 kΩ
15 kΩ
5.0 V
33 pF
4.7 μF
10 μF
1 μF
4.7, 6.8 μH
84 kΩ
16 kΩ
12.0 V33 pF
4.7 μF
10 μF
1 μF
6.8, 10 μH
210 kΩ
15 kΩ
Table 12Manufacturer
TDK Corporation
TDK Corporation
TDK Corporation
Murata ManufacturingCo., Ltd.

Recommended Capacitors (CIN) List
Withstanding
Part Number
Capacitance
Voltage
C2012X7R1E475K125AB
25 V
4.7 μF
C2012X7R1H475K125AC
50 V
4.7 μF
CGA5L3X7R1H475K160AB
50 V
4.7 μF
GRM219R61E475KA73

4.7 μF25 V

2.0 mm × 1.25 mm × 1.25 mm
2.0 mm × 1.25 mm × 1.25 mm
3.2 mm × 1.6 mm × 1.6 mm
2.0 mm × 1.25 mm × 1.25 mm

Table 13

Manufacturer
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
Murata ManufacturingCo., Ltd.

Recommended Capacitors (COUT) List
Withstanding
Part Number
Capacitance
Voltage
C2012X7R0J106K125AB
6.3 V
10 μF
CGA4J3X7S1A106K125AB
10 V
10 μF
CGA5L1X7R1C106K160AC
16 V
10 μF
C2012X7S1E106K125AC
25 V
10 μF
CGA4J1X7S1E106K125AC
25 V
10 μF

Dimensions (L × W × H)

GRM188R60J106KE47

10 μF

6.3 V

2.0 mm × 1.25 mm × 1.25 mm
2.0 mm × 1.25 mm × 1.25 mm
3.2 mm × 1.6 mm × 1.6 mm
2.0 mm × 1.25 mm × 1.25 mm
2.0 mm × 1.25 mm × 1.25 mm
1.6 mm × 0.8 mm × 0.8 mm

Table 14

Manufacturer
TDK Corporation

Recommended Capacitor (CFB) List
Withstanding
Part Number
Capacitance
Voltage
CGA1A2C0G1H330J030BA
33 pF
50 V

Dimensions (L × W × H)

0.6 mm × 0.3 mm × 0.3 mm

Table 15

Manufacturer
TDK Corporation
TDK Corporation
Murata ManufacturingCo., Ltd.

Recommended Capacitors (CREG) List
Withstanding
Part Number
Capacitance
Voltage
CGA3E1X7R1C105K080AC
16 V
1 μF
C1608X7R1E105K080AE
25 V
1 μF

Dimensions (L × W × H)

GRM155C71A105KE11

1 μF

10 V

1.6 mm × 0.8 mm × 0.8 mm
1.6 mm × 0.8 mm × 0.8 mm
1.0 mm × 0.5 mm × 0.5 mm

Table 16

Manufacturer
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
TDK Corporation
Murata ManufacturingCo., Ltd.
Murata ManufacturingCo., Ltd.
Würth Elektronik GmbH & Co. KG
Würth Elektronik GmbH & Co. KG

Recommended Inductors (L) List
Withstanding
Part Number
Inductance
Voltage
VLS201610HBX-2R2M-1
2.2 μH−
VLS201612HBX-3R3M-1
3.3 μH−
TFM252012ALMA3R3MTAA
20 V
3.3 μH
CLF5030NIT-3R3N-D
3.3 μH−
VLS252012HBX-4R7M-1
4.7 μH−
CLF5030NIT-4R7N-D
4.7 μH−
CLF5030NIT-6R8N-D
6.8 μH−
CLF5030NIT-100M-D
10 μH−

Dimensions (L × W × H)

Dimensions (L × W × H)
2.0 mm × 1.6 mm × 1.0 mm
2.0 mm × 1.6 mm × 1.2 mm
2.5 mm × 2.0 mm × 1.2 mm
5.0 mm × 5.3 mm × 2.7 mm
2.5 mm × 2.0 mm × 1.2 mm
5.0 mm × 5.3 mm × 2.7 mm
5.0 mm × 5.3 mm × 2.7 mm
5.0 mm × 5.3 mm × 2.7 mm

DFE201210S-2R2M

2.2 μH20 V

2.0 mm × 1.2 mm × 1.0 mm

DFE252012F-3R3M

3.3 μH20 V

2.5 mm × 2.0 mm × 1.2 mm

74404024033
74438335047

3.3 μH4.7 μH−−

2.5 mm × 2.0 mm × 1.2 mm
3.0 mm × 3.0 mm × 1.5 mm

1518 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
1.

Input capacitor (CIN)
CIN, which has an effect to suppress the ripple voltage and switching noise to be generated in the power supply line,
is used for the stable operation of IC. A ceramic capacitor with 4.7 μF or higher is recommended.

2.

Output capacitor (COUT)
COUT is used to smooth output voltage. The ripple voltage (ΔVOUT) to be generated in VOUT is inversely proportional
to COUT. When selecting a capacitor whose ESR is sufficiently small, ΔVOUT during current continuous mode iscalculated by the following expression.
ΔVOUT =

ΔIL
8 × fOSC × COUT

In addition, since COUT contributes to the stability of feedback loop, a ceramic capacitor with 10 μF or higher isrecommended. When selecting a capacitor whose capacitance is extremely large, the overcurrent protection
function may start the operation and cause a start-up failure. Therefore, select a capacitor with 200 μF or lower.

3.

Inductor (L)To suppress the intrinsic subharmonic oscillation in current mode control, the optimal L value needs to be selected.
Considering the slope compensation in the IC, select an inductor from the range of 2.2 μH to 10 μH depending on
VOUT.
When selecting L, note the allowable current. If a current exceeding the allowable current flows through the inductor,
magnetic saturation may occur, and there may be risks which substantially lower efficiency and damage the IC as aresult of large current.
The ripple current (ΔIL) and peak current (IPK) flow through the inductor during current continuous mode arecalculated by the following expressions respectively. Make sure IPK will not exceed the allowable current of inductor.
ΔIL =VOUT × (VIN − VOUT)
fOSC × L × VINΔILIPK = IOUT + 2
In order to maintain the allowable current of inductor even in cases VOUT shorts to VSS or other fault conditions occur,
an inductor with 1.4 A or higher, the maximum value of ILIM, needs to be selected.

4.

Internal power supply stabilized capacitor (CREG)
CREG is used to stabilize the operation of IC's internal power supply (VREG = 4.5 V typ.) A ceramic capacitor with
1 μF is recommended.

16

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
5.

Output voltage setting resistors (RFB1, RFB2), capacitor for phase compensation (CFB)
VOUT can be set to any value using RFB1 and RFB2. VOUT can be calculated by the following expression substituting
VFB = 0.8 V typ. Note that if the RFB1 and RFB2 values are increased, the FB pin will more likely to be affected bynoise. A resistor with approximately 15 kΩ is recommended for RFB2.
VOUT =(RFB1 + RFB2)
× 0.8
RFB2

CFB connected in parallel with RFB1 is a capacitor for phase compensation. Using RFB1 and CFB to set the zero point(the phase feedback) allows the feedback loop to gain larger phase margin.
When selecting CFB, refer to the following expressions. In addition, perform thorough evaluations with the actual
applications to set the constants.
First, calculate the zero point frequency (fz) by the following expression.
fZ = 3.94 × C

1
OUT

VFB
× V

OUT

Next, substitute RFB1 and fZ gained by the above expression into the below expression to calculate CFB value.
CFB =1
2 × π× RFB1 × fZ

Caution Generally a switching regulator may cause oscillation depending on the selection of external parts.
Perform thorough evaluations including the temperature characteristics with actual applications toconfirm no oscillation occurs.

1718 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series Board Layout Guidelines
Note the following cautions when determining the board layout for the S-8590/8591 Series.
• Place CIN as close to the VIN pin and the VSS pin as possible. Prioritize the layout of CIN.
• Place CREG as close to the VREG pin and the VSS pin as possible.
• Mount CIN and CREG on the same surface layer as the IC. If they are connected through thermal vias, theimpedance of the thermal vias may influence the operation, resulting in unstable condition.
• Make the wiring of the FB pin as short as possible. The parasitic capacitance of FB pin may affect the phase marginof feedback loop.
• Do not place the FB pin close to noise sources such as the wiring of SW pin to avoid unstable operations.
• Make the GND pattern as wide as possible.
• Place thermal vias in the GND pattern to ensure sufficient heat dissipation.
• Large current flows through the SW pin. Make the wiring area of the pattern to be connected to the SW pin small tominimize parasitic capacitance and emission noise.
• Make a short loop wiring of the SW pin → L → COUT → VSS pin. This is effective to reduce emission noise.
• Do not wire the SW pin pattern under the IC.

Total size

7.9 mm × 3.9 mm = 30.81 mm2Figure 12

Reference Board Pattern

Caution The above pattern diagram does not guarantee successful operation. Perform thorough evaluation
using the actual application to determine the pattern.

1818 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Precautions•

Mount external capacitors and inductors as close as possible to the IC, and make single GND.

•

Characteristic ripple voltage and spike noise occur in the IC containing switching regulators. Moreover rush current
flows at the time of a power supply injection. Because these largely depend on the inductor, the capacitor and
impedance of power supply to be used, fully check them using an actually mounted model.

•

The 4.7 μF capacitor connected between the VIN pin and the VSS pin is a bypass capacitor. It stabilizes the power
supply in the IC, and thus effectively works for stable switching regulator operation. Allocate the bypass capacitor
as close to the IC as possible, prioritized over other parts.

•

Although the IC contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of
the protection circuit should not be applied.

•

The power dissipation of the IC greatly varies depending on the size and material of the board to be connected.
Perform sufficient evaluation using an actual application before designing.

•

ABLIC Inc. assumes no responsibility for the way in which this IC is used on products created using this IC or forthe specifications of that product, nor does ABLIC Inc. assume any responsibility for any infringement of patents or
copyrights by products that include this IC either in Japan or in other countries.

1918 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
 Characteristics (Typical Data)
Example of major power supply dependence characteristics (Ta = +25°C)
1. 1

Current consumption during switching off (ISS) vs. Input voltage (VIN)

ISS [μA]

1. 1. 1

S-8590 Series

1. 1. 2

150

225

125

200

100

175
150
100
6

8

10 12
VIN [V]

14

16

18

Current consumption during shutdown (ISSS)
vs. Input voltage (VIN)

4

6

8

10 12
VIN [V]

14

16

18

1. 3 FB pin voltage (VFB) vs. Input voltage (VIN)

100

0.810

80

0.805
VFB [V]ISSS [nA]

50
0

4

60
40

0.800
0.795

20
0

75
25

125

1. 2

S-8591 Series

250

ISS [μA]

1.

4

6

8

10 12
VIN [V]

14

16

0.790

18

4

6

8

10 12
VIN [V]

14

16

18

1. 4 Oscillation frequency (fOSC) vs. Input voltage (VIN)

2.3
2.2
2.1
2.0

tSSW [ms]1. 5

4

10 12 14 16 18
VIN [V]
Soft-start wait time (tSSW) vs. Input voltage (VIN)
68Soft-start time (tSS) vs. Input voltage (VIN)

1.0

10

0.8

8

0.6
0.4
0.2

6
4
2

0.0

0
4

20

1. 6

tSS [ms]

fOSC [MHz]

2.4

6

8

10 12
VIN [V]

14

16

18

4

6

8

10 12
VIN [V]

14

16

18

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series

1. 7High side power MOS FET on-resistance (RHFET) 1. 8
vs. Input voltage (VIN)

1.0
0.8

1.5

RLFET [Ω]RHFET [Ω]

2.0

1.0
0.5
6

8

10 12
VIN [V]

14

16

18

High side power MOS FET leakage current (IHSW)
vs. Input voltage (VIN)

4
1. 10

1000

80

800

60
40
20
0

6

8

10 12
VIN [V]

14

16

18

Low side power MOS FET leakage current (ILSW)
vs. Input voltage (VIN)

100
ILSW [nA]

IHSW [nA]

0.4

0.0
4

1. 11

0.6

0.2

0.0

1. 9

Low side power MOS FET on-resistance (RLFET)
vs. Input voltage (VIN)

600
400
200

4

6

8

10 12
VIN [V]

14

16

0

18

4

6

8

10 12
VIN [V]

14

16

18

Limit current (ILIM) vs. Input voltage (VIN)

1.4

ILIM [A]

1.3
1.2
1.1
1.0
4

6

8

10 12
VIN [V]14

16

18
1. 13 Low level input voltage (VSL) vs. Input voltage (VIN)

3.0

3.0

2.5

2.5

2.0

2.0

VSL [V]

VSH [V]

1. 12 High level input voltage (VSH) vs. Input voltage (VIN)

1.5
1.0
0.5

1.5
1.0
0.5

0.0

0.0
4

6

8

10 12
VIN [V]

14

16

18

4

6

8

10 12
VIN [V]

14

16

18

21

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
2.

Example of major temperature characteristics (Ta = −40°C to +85°C)
2. 1

Current consumption during switching off (ISS) vs. Temperature (Ta)2. 1. 1

S-8590 Series

2. 1. 2
VIN = 12 V

225

125

200

100

175
150
125
100

2. 2

−40 −25

50
0

0

25
Ta [°C]

50

75 85
2. 3

−40 −25025Ta [°C]50

75 85

FB pin voltage (VFB) vs. Temperature (Ta)
VIN = 12 V

0.810

80

0.805

60

VFB [V]ISSS [nA]7525

Current consumption during shutdown (ISSS)
vs. Temperature (Ta)
VIN = 12 V
100

40

0.800
0.795

20
0

VIN = 12 V

150

ISS [μA]

ISS [μA]

250

S-8591 Series−40 −25

0.790
0

25
Ta [°C]50

75 85−40 −25025Ta [°C]50

75 85

2. 4 Oscillation frequency (fOSC) vs. Temperature (Ta)
VIN = 12 V

fOSC [MHz]

2.4
2.3
2.2
2.1
2.0

−

−

3.6

3.6

3.5

3.5

3.4
3.3
3.2

22

2. 6 UVLO release voltage (VUVLO+) vs. Temperature (Ta)VUVLO+ [V]VUVLO− [V]Ta [°C]
2. 5 UVLO detection voltage (VUVLO−) vs. Temperature (Ta)−40 −25

3.4
3.3
3.2

0

25
Ta [°C]50

75 85−40 −25025Ta [°C]50

75 85

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
2. 7

Soft-start wait time (tSSW) vs. Temperature (Ta)

2. 8

VIN = 12 V

1.0

8tSS [ms]tSSW [ms]0.6
0.4−40 −2525
Ta [°C]

50

75 85
2. 10

VIN = 4 V

RLFET [Ω]RHFET [Ω]025Ta [°C]50

75 85

Low side power MOS FET on-resistance (RLFET)
vs. Temperature (Ta)

0.8

1.5
1.0
0.5
−40 −2525
Ta [°C]50

VIN = 4 V

0.4

0.0

0

VIN = 12 V

0.6

0.2

VIN = 12 V

75 85

2. 11 High side power MOS FET leakage current (IHSW)
vs. Temperature (Ta)
VIN = 12 V
200

150
100
50

−40 −25025Ta [°C]50

75 85

2. 12 Low side power MOS FET leakage current (ILSW)
vs. Temperature (Ta)
VIN = 12 V
200

ILSW [nA]

IHSW [nA]−40 −25

1.0

2.0

2. 13

4

0
0

2. 9 High side power MOS FET on-resistance (RHFET)
vs. Temperature (Ta)

0

6

2

0.2

0.0

VIN = 12 V

10

0.8

0.0

Soft-start time (tSS) vs. Temperature (Ta)

150
100
50

−40 −250025Ta [°C]50

75 85−40 −25025Ta [°C]50

75 85

Limit current (ILIM) vs. Temperature (Ta)
VIN = 12 V

1.4

ILIM [A]

1.3
1.2
1.1
1.0

−40 −25025Ta [°C]

50

75 85

23

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series

2. 14 High level input voltage (VSH) vs. Temperature (Ta)

2. 15 Low level input voltage (VSL) vs. Temperature (Ta)
VIN = 12 V

3.0

2.5

2.5

2.0

2.0

VSL [V]

VSH [V]

VIN = 12 V

3.0

1.5
1.0
0.5
0.0

1.5
1.0
0.5

−40 −250.0025Ta [°C]50

75 85−40 −25025Ta [°C]50

75 85

EN pin characteristics (Ta = +25°C)

3.

3. 1

High level input current (ISH) vs. EN pin voltage (VEN)60

ISH [μA]

45
30
15
0
3

0

9
12
VEN [V]

15

18

Transient response characteristics

The external parts shown in Table 17 are used in "4.

Element Name

Constant
4.7 μH4.7 μF
10 μF

Inductor
Input capacitor
Output capacitor

10

12

0

8

VIN

−10

4
VOUT
0

5

10
Time [ms]15

20

4. 1. 2 IOUT = 600 mA
20

16

10

12

0

8

VIN

−10

0

−20

−4

−30

4
0

VOUT
0

5

10
Time [ms]

15

20

−4

VOUT [V]16

VIN [V]

VIN [V]

Part Number
CLF5030NIT-4R7N-D
CGA5L3X7R1H475K160AB
CGA5L1X7R1C106K160AC

TDK Corporation
TDK Corporation
TDK Corporation

4. 1. 1 IOUT = 1 mA
20

−20

24

Table 17
Manufacturer

Power-on (VOUT = 5.0 V, VIN = VEN =0 V → 12 V, Ta = +25°C)

4. 1

−30

Transient response characteristics".

VOUT [V]4.

6

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series

4. 2

Transient response characteristics of EN pin(VOUT = 5.0 V, VIN = 12 V, VEN = 0 V → 2 V, Ta = +25°C)
4. 2. 2 IOUT = 600 mA
3

25

2

20

1

15

1

15

0

−3

10

VEN

−1

5

VOUT
5

0

10

15

20

VEN [V]

20

−2

0

0

−2

−5

−3

10

VEN

−1

5
0

VOUT
5

0

10

Time [ms]VIN [V]IOUT = 1 mA

0.08

0.04
0.02

9
VOUT = 5 V

6
3

0.0

4. 3. 2 IOUT = 600 mA
18

0.06

VIN

12

0.2

0.4

0.6

0.8

1.0

0.06

12

VIN

0.04
0.02

9

0.00

6

−0.02

3

VOUT = 5 V

0.0

0.2

−800
−1200

0.4

0.6

0.8

1.0

−0.02

Time [ms]IOUT = 10 mA → 200 mA → 10 mA

0.8

4. 4. 2 IOUT = 10 mA → 600 mA → 10 mA
800

0.6
IOUT

0.4
0.2

VOUT = 5 V

0.0

0.2

0.4

0.6

Time [ms]

0.8

1.0

0.8
0.6

400

IOUT [mA]

400

−400

0.00

Load fluctuation (VOUT = 5.0 V, Ta = +25°C)

4. 4. 1
800

0

−5

0.08

15

Time [ms]4. 420Power supply fluctuation (VOUT = 5.0 V, VIN = 12 V → 16 V → 12 V, Ta = +25°C)

4. 3. 118

15

15Time [ms]VIN [V]

4. 3

IOUT [mA]25

2

VOUT [V]IOUT = 1 mA

VOUT [V]VEN [V]4. 2. 1
3

0
−400

0.0

−800

−0.2

−1200

IOUT

0.4
0.2

VOUT = 5 V

0.0

0.2

0.0
0.4

0.6

0.8

1.0

−0.2

Time [ms]2518 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series Reference Data
The external parts shown in Table 18 are used in " Reference Data".

Condition
<1>
<2>

1.

Inductor (L)
CLF5030NIT-4R7N-D (4.7 μH)
TDK Corporation
CLF5030NIT-3R3N-D (3.3 μH)
TDK Corporation

Table 18
Input Capacitor (CIN)
CGA5L3X7R1H475K160AB (4.7 μF)
TDK Corporation
CGA5L3X7R1H475K160AB (4.7 μF)
TDK Corporation

VOUT = 5.0 V (External parts: Condition<1>)
1. 1

Efficiency (η) vs. Output current (IOUT)

1. 1. 1

S-8590 Series

1. 1. 2100

VIN = 8 V

40

1

10
IOUT [mA]

100

1000

0.1

1

10
IOUT [mA]

100

1000

Output voltage (VOUT) vs. Output current (IOUT)

1. 2. 1

S-8590 Series

1. 2. 2

5.20

S-8591 Series

5.20
VIN = 8 V

5.10

VOUT [V]

VOUT [V]VIN = 16 V
VIN = 12 V

40

0
0.1

5.00
4.90

VIN = 8 V

5.10
5.00
4.90

VIN = 16 V

VIN = 12 V

4.80

VIN = 12 V

VIN = 16 V

4.80
0.1

1

10
IOUT [mA]

100

1000

0.1

1

10
IOUT [mA]

100

1000

Ripple voltage (ΔVOUT) vs. Output current (IOUT)

1. 3. 1

S-8590 Series

1. 3. 2

100

100

80

80

60

ΔVOUT [mV]ΔVOUT [mV]60

20

VIN = 16 V

0

1. 3

VIN = 8 V

80
η [%]

η [%]

60

20

1. 2

S-8591 Series

100
VIN = 12 V

80

VIN = 12 V

40

VIN = 8 V

20

VIN = 16 V

0S-8591 Series

60
40

VIN = 8 V

VIN = 12 V
VIN = 16 V

20
0

0.1

26

Output Capacitor (COUT)
CGA5L1X7R1C106K160AC (10 μF)
TDK Corporation
CGA5L1X7R1C106K160AC (10 μF)
TDK Corporation

1

10
IOUT [mA]

100

1000

0.1

1

10
IOUT [mA]

100

1000

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series
VOUT = 3.3 V (External parts: Condition<2>)
2. 1

Efficiency (η) vs. Output current (IOUT)

2. 1. 1

S-8590 Series

2. 1. 2

VIN = 8 V

60

VIN = 6 V

40

VIN = 16 V

20

VIN = 16 V
VIN = 12 V
VIN = 8 V

40

0
0.1

1

10
IOUT [mA]

100

0.1

1000

1

10
IOUT [mA]

100

1000

Output voltage (VOUT) vs. Output current (IOUT)

2. 2. 1

S-8590 Series

2. 2. 2

3.50

S-8591 Series

3.50
VIN = 6 V

3.40

VIN = 12 V

VOUT [V]

VOUT [V]60

20

VIN = 12 V

0

3.30
3.20

3.40

VIN = 6 V

VIN = 12 V

VIN = 8 V

VIN = 16 V

3.30
3.20

VIN = 16 V

VIN = 8 V

3.10

3.10
0.1

1

10
IOUT [mA]

100

1000

0.1

1

10
IOUT [mA]

100

1000

Ripple voltage (ΔVOUT) vs. Output current (IOUT)

2. 3. 1

S-8590 Series

2. 3. 2

100

100

80

80

60

VIN = 16 V

VIN = 8 V

40

VIN = 6 V

20

ΔVOUT [mV]2. 3

VIN = 6 V

80
η [%]

η [%]

80

2. 2

S-8591 Series

100

100

ΔVOUT [mV]2.

VIN = 12 V

0S-8591 Series

60

VIN = 16 V

VIN = 8 V

40

VIN = 6 V

20

VIN = 12 V

0
0.1

1

10
IOUT [mA]

100

1000

0.1

1

10
IOUT [mA]

100

1000

27

18 V INPUT, 600 mA SYNCHRONOUS STEP-DOWN SWITCHING REGULATOR
Rev.2.1_00
S-8590AA/8590AB/8591AA/8591AB Series Power Dissipation
HSNT-8(2030)

HTMSOP-8
Tj = +125°C max.

4
E
3 C
D

2

1 B

Tj = +125°C max.

5
Power dissipation (PD) [W]Power dissipation (PD) [W]

5

4
E
3

C

2 D
1 B

A
0

0

A
25

50

75

100

125

150

175

0

0

25

Ambient temperature (Ta) [°C]
Board
A
B
C
D
E

Board
A
B
C
D
E

HSNT-6(2025)
Tj = +125°C max.

Power dissipation (PD) [W]

4
3 E
C
2 D
1 B
A
0

0

25

50

75

100

125

150

Ambient temperature (Ta) [°C]

28

Board

Power Dissipation (PD)A

0.56 WB

0.78 WC

2.33 W

DE

2.27 W
2.78 W

75

100

125

150

Ambient temperature (Ta) [°C]Power Dissipation (PD)
0.63 W
0.88 W
2.56 W
2.50 W
3.33 W550

175Power Dissipation (PD)
0.55 W
0.74 W
2.50 W
2.38 W
3.13 W

175

HTMSOP-8 Test Board
IC Mount Area

(1) Board A
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
2Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.070-(2) Board B
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-(3) Board C
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]Thermal via

1
2
3
4

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070
Number: 4
Diameter: 0.3 mm

No. HTMSOP8-A-Board-SD-1.0

enlarged view

ABLIC Inc.

HTMSOP-8 Test Board
IC Mount Area
(4) Board D
Item
Size [mm]Material
Number of copper foil layer

Specification
114.3 x 76.2 x t1.6
FR-4
4

Thermal via

2
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-

Item
Size [mm]Material
Number of copper foil layer

Specification
114.3 x 76.2 x t1.6
FR-4
4

Copper foil layer [mm]

1
2
3
4

enlarged view

(5) Board E

Copper foil layer [mm]Thermal via

1
2
3
4

2
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070

Number: 4
Diameter: 0.3 mm

enlarged viewNo. HTMSOP8-A-Board-SD-1.0

ABLIC Inc.

HSNT-8(2030) Test Board
IC Mount Area
(1) Board A
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
2Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.070-(2) Board B
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-(3) Board C
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]Thermal via

1
2
3
4

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070
Number: 4
Diameter: 0.3 mm

enlarged viewNo. HSNT8-A-Board-SD-2.0

ABLIC Inc.

HSNT-8(2030) Test Board
IC Mount Area
(4) Board D
Item
Size [mm]Material
Number of copper foil layer

Specification
114.3 x 76.2 x t1.6
FR-4
4

Thermal via

2
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-

Item
Size [mm]Material
Number of copper foil layer

Specification
114.3 x 76.2 x t1.6
FR-4
4

Copper foil layer [mm]

1
2
3
4

enlarged view

(5) Board E

Copper foil layer [mm]Thermal via

1
2
3
4

2
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070

Number: 4
Diameter: 0.3 mm

enlarged viewNo. HSNT8-A-Board-SD-2.0

ABLIC Inc.

HSNT-6(2025) Test Board
IC Mount Area

(1) Board A
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
2Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.070-(2) Board B
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-(3) Board C
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]Thermal via

1
2
3
4

Specification
114.3 x 76.2 x t1.6
FR-4
4Land pattern and wiring for testing: t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070
Number: 4
Diameter: 0.3 mm

No. HSNT6-B-Board-SD-1.0
enlarged view

ABLIC Inc.

HSNT-6(2025) Test Board
IC Mount Area

(4) Board D
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]

1
2
3
4

Thermal via

Specification
114.3 x 76.2 x t1.6
FR-4
42
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070-

enlarged view

(5) Board E
Item
Size [mm]Material
Number of copper foil layer

Copper foil layer [mm]Thermal via

1
2
3
4

Specification
114.3 x 76.2 x t1.6
FR-4
42
Pattern for heat radiation: 2000mm t0.070
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.035
74.2 x 74.2 x t0.070

Number: 4
Diameter: 0.3 mm

enlarged viewNo. HSNT6-B-Board-SD-1.0

ABLIC Inc.

2.90±0.2
1.85
8

5

1

4

0.13±0.1

0.2±0.1
0.65±0.1

No. FP008-A-P-SD-2.0

TITLE

HTMSOP8-A-PKG Dimensions

No.

FP008-A-P-SD-2.0

ANGLE
UNIT

mm

ABLIC Inc.

2.00±0.05
4.00±0.1

4.00±0.1

1.00±0.1+0.1

1.5 -01.05±0.05

0.30±0.05

3.25±0.05

4

1

5

8

Feed direction

No. FP008-A-C-SD-1.0

TITLE

HTMSOP8-A-Carrier Tape

No.

FP008-A-C-SD-1.0

ANGLE
UNIT

mm

ABLIC Inc.

16.5max.

13.0±0.3

Enlarged drawing in the central part13±0.2

(60°)

(60°)

No. FP008-A-R-SD-1.0

TITLE

HTMSOP8-A-ReelNo.

FP008-A-R-SD-1.0

ANGLE

QTY.

UNIT

mm

ABLIC Inc.

4,000

0.35

1.90

0.65

0.65

0.65

No. FP008-A-L-SD-2.0

TITLE

HTMSOP8-A-Land Recommendation

No.

FP008-A-L-SD-2.0

ANGLE
UNIT

mm

ABLIC Inc.

2.0±0.185(1.70)

1

4

+0.05

0.08 -0.02

0.5

0.23±0.1

The heat sink of back side has different electric
potential depending on the product.
Confirm specifications of each product.
Do not use it as the function of electrode.

No. PP008-A-P-SD-2.0

TITLE

HSNT-8-A-PKG Dimensions

No.

PP008-A-P-SD-2.0

ANGLE
UNIT

mm

ABLIC Inc.

+0.1

ø1.5 -0

2.0±0.05

4.0±0.1

0.25±0.05+0.1

ø1.0 -00.60±0.05

4.0±0.1

2.3±0.05

4 321

5 6 78Feed direction

No. PP008-A-C-SD-1.0

TITLE

HSNT-8-A-Carrier TapeNo.

PP008-A-C-SD-1.0

ANGLE
UNIT

mm

ABLIC Inc.

+1.0

9.0 - 0.0
11.4±1.0

Enlarged drawing in the central part

ø13±0.2

(60°)

(60°)

No. PP008-A-R-SD-1.0

TITLE

HSNT-8-A-ReelNo.

PP008-A-R-SD-1.0

ANGLE

QTY.

UNIT

mm

ABLIC Inc.

5,000

1.6

0.30

0.50

No. PP008-A-L-SD-1.0

TITLE
No.

HSNT-8-A-Land Recommendation
PP008-A-L-SD-1.0

ANGLE
UNIT

mm

ABLIC Inc.

1.96±0.05
1.78±0.1
6

5

4

2

3

0.5

0.5

0.5
1

0.12±0.04

0.48±0.02

0.22±0.05
The heat sink of back side has different electric
potential depending on the product.
Confirm specifications of each product.
Do not use it as the function of electrode.

No. PJ006-B-P-SD-1.0

TITLE

HSNT-6-C-PKG Dimensions

No.

PJ006-B-P-SD-1.0

ANGLE
UNIT

mm

ABLIC Inc.

+0.1

2.0±0.05

ø1.5 -0

4.0±0.1

ø0.5±0.1

0.25±0.05

0.65±0.05

4.0±0.1

2.25±0.05

3 21

0.5
0.5

0.5

0.5

0.5

0.5

4 5 6

Feed direction

No. PJ006-B-C-SD-1.0

TITLE

HSNT-6-C-Carrier Tape

No.

PJ006-B-C-SD-1.0

ANGLE
UNIT

mm

ABLIC Inc.

+1.0

9.0 - 0.0
11.4±1.0

Enlarged drawing in the central part

ø13±0.2

(60°)

(60°)

No. PJ006-B-R-SD-1.0

TITLE

HSNT-6-C-Reel

No.

PJ006-B-R-SD-1.0
QTY.

ANGLE
UNIT

mm

ABLIC Inc.

5,000

Land Recommendation
0.50

0.35

0.50

1.44
1.78
2.10

Caution It is recommended to solder the heat sink to a board in order to ensure the heat radiation.
PKG

Stencil Opening

1.40
0.50

0.50

No. PJ006-B-LM-SD-1.0

0.35

CautionMask aperture ratio of the lead mounting part is 100~120%.
Mask aperture ratio of the heat sink mounting part is 30%.
Mask thickness: t0.12 mm
Reflow atmosphere: Nitrogen atmosphere is recommended.
(Oxygen concentration: 1000ppm or less)100~120%30%
t0.12 mm

TITLE

HSNT-6-C-Land &Stencil Opening

No.

PJ006-B-LM-SD-1.0

ANGLE
UNIT

mm

1000ppm

ABLIC Inc.

Disclaimers (Handling Precautions)1.

All the information described herein (product data, specifications, figures, tables, programs, algorithms andapplication circuit examples, etc.) is current as of publishing date of this document and is subject to change without
notice.

2.

The circuit examples and the usages described herein are for reference only, and do not guarantee the success ofany specific mass-production design.
ABLIC Inc. is not liable for any losses, damages, claims or demands caused by the reasons other than the products
described herein (hereinafter "the products") or infringement of third-party intellectual property right and any otherright due to the use of the information described herein.

3.

ABLIC Inc. is not liable for any losses, damages, claims or demands caused by the incorrect information describedherein.

4.

Be careful to use the products within their ranges described herein. Pay special attention for use to the absolute
maximum ratings, operation voltage range and electrical characteristics, etc.
ABLIC Inc. is not liable for any losses, damages, claims or demands caused by failures and / or accidents, etc. due tothe use of the products outside their specified ranges.

5.

Before using the products, confirm their applications, and the laws and regulations of the region or country where they
are used and verify suitability, safety and other factors for the intended use.

6.

When exporting the products, comply with the Foreign Exchange and Foreign Trade Act and all other export-relatedlaws, and follow the required procedures.

7.

The products are strictly prohibited from using, providing or exporting for the purposes of the development of
weapons of mass destruction or military use. ABLIC Inc. is not liable for any losses, damages, claims or demands
caused by any provision or export to the person or entity who intends to develop, manufacture, use or store nuclear,biological or chemical weapons or missiles, or use any other military purposes.

8.

The products are not designed to be used as part of any device or equipment that may affect the human body, human
life, or assets (such as medical equipment, disaster prevention systems, security systems, combustion control
systems, infrastructure control systems, vehicle equipment, traffic systems, in-vehicle equipment, aviation equipment,
aerospace equipment, and nuclear-related equipment), excluding when specified for in-vehicle use or other uses by
ABLIC, Inc. Do not apply the products to the above listed devices and equipments.
ABLIC Inc. is not liable for any losses, damages, claims or demands caused by unauthorized or unspecified use of
the products.

9.

In general, semiconductor products may fail or malfunction with some probability. The user of the products should
therefore take responsibility to give thorough consideration to safety design including redundancy, fire spread
prevention measures, and malfunction prevention to prevent accidents causing injury or death, fires and social
damage, etc. that may ensue from the products' failure or malfunction.
The entire system in which the products are used must be sufficiently evaluated and judged whether the products areallowed to apply for the system on customer's own responsibility.

10. The products are not designed to be radiation-proof. The necessary radiation measures should be taken in the
product design by the customer depending on the intended use.
11. The products do not affect human health under normal use. However, they contain chemical substances and heavy
metals and should therefore not be put in the mouth. The fracture surfaces of wafers and chips may be sharp. Be
careful when handling these with the bare hands to prevent injuries, etc.
12. When disposing of the products, comply with the laws and ordinances of the country or region where they are used.
13. The information described herein contains copyright information and know-how of ABLIC Inc. The information
described herein does not convey any license under any intellectual property rights or any other rights belonging to
ABLIC Inc. or a third party. Reproduction or copying of the information from this document or any part of thisdocument described herein for the purpose of disclosing it to a third-party is strictly prohibited without the express
permission of ABLIC Inc.
14. For more details on the information described herein or any other questions, please contact ABLIC Inc.'s sales
representative.
15. This Disclaimers have been delivered in a text using the Japanese language, which text, despite any translations into
the English language and the Chinese language, shall be controlling.
2.4-2019.07

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