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onsemi andand other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates and/or
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product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. onsemi reserves the right to make changes at any time to any products or information herein, without
notice. The information herein is provided “as-is” and onsemi makes no warranty, representation or guarantee regarding the accuracy of the information, product features, availability, functionality,or suitability of its products for any particular purpose, nor does onsemi assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all
liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using onsemi products, including compliance with all laws,
regulations and safety requirements or standards, regardless of any support or applications information provided by onsemi. “Typical” parameters which may be provided in onsemi data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application
by customer’s technical experts. onsemi does not convey any license under any of its intellectual property rights nor the rights of others. onsemi products are not designed, intended, or authorized
for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for
implantation in the human body. Should Buyer purchase or use onsemi products for any such unintended or unauthorized application, Buyer shall indemnify and hold onsemi and its officers, employees,
subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or deathassociated with such unintended or unauthorized use, even if such claim alleges that onsemi was negligent regarding the design or manufacture of the part. onsemi is an Equal Opportunity/Affirmative
Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. Other names and brands may be claimed as the property of others.

30 W Automotive 2 MHz
Pre-Regulator, Non-Isolated,
Synchronous Buck,
NCV891930-Based
Reference Designwww.onsemi.com

TND6287/D

REFERENCE DESIGN

Overview

This reference design describes the operation and performance of
the NCV891930 automotive synchronous buck controller witha NVMFD5C478NL 40 V dual N−channel FET. The design
demonstrates the NCV891930 controller capabilities as well as
a complete designed for an automotive pre-regulator for broad range
of applications.
It is intended for the power supply designer to adopt the circuit
directly into a typical system design, making only minimal component
changes based on system requirements.
The design is meant to be a complete solution, but it also provides
access to key features of the NCV891930. These include integrated
compensation, low IQ and continuous synchronous mode, wide input
range, overcurrent protection, external synchronization, adaptive
non-overlap drivers, integrated spread-spectrum and undervoltage
lockout.
Key Features• Complete Automotive Reference Design• Synchronous Buck Converter with an Input Voltage Range of 5.0

Figure 1. Reference Design
Board Image

to 16.0 V, Handles Peaks up to 40 V

• 2 MHz Switching Frequency to Minimize Inductor Size
• NCV891930 Low Quiescent Current Automotive Synchronous Buck
Converter and NVMFD5C478NL 40 V Dual N-channel FET• Small Form Factor PCB with Four Layers
Specifications
Table 1. SPECIFICATIONS TABLE
Device

NCV891930

Application

Automotive Pre-Regulator

Input Voltage

6 V to 16 V DC, 40 V Peak

Output Power

Up to 15 W Average,
Up to 30 W Peak

Topology

Synchronous Buck

Isolation

Non-Isolated

Output Voltage

5.0 V

Nominal Current

3.0 A Average
6.0 A Peak

© Semiconductor Components Industries, LLC, 2019

September, 2020 − Rev. 1

1

Publication Order Number:
TND6287/D

www.onsemi.com

2

TP6

1.00

R3

Figure 2. NCV891930 Synchronous Buck Schematic

C15
1μF

GND

EN

R13
open

10.0k

R11

SYNCI

TP5

GND

C20
0.1μF

GND

C19
0.1μF

GND

* Low/Open: 3.3V Output Voltage* High: 5.0V Output Voltage

VSEL

GND

C18
0.1μF

2.2V

DBIAS

R8
10.0k

VOUT

VIN

GND

24

SSC
ROSC
GND

9
8
10

GND

4
19
1
18
5
7

VOUT
VCCEXT
V_CS
VDRV
NC
NC
20

3

CSN

PGND

2

21

CSP

22

23

GL

GH

BST

VSW

fswitch = 2 MHz

V_SO

DBIAS

16

14

VSEL

RSTB

11
15

SYNCI

SYNCO

EN

VIN

12

13

6

17

C8

R7

GND

C21
1μF

GND

5.0V

68.1

C17 68.1
100pF R9

0.1μF

TP7

C23
1μF

0

R6

GND

C22
0.1μF

GND

4

0

R12

10.0

R10

2

Q1A
NVMFD5C478NL

0* Ext. Sync. Input
U1
NCV891930

R1

Q1B
NVMFD5C478NL* Low: Low Iq Mode

GND

SYNCI

* High: Continuous Synchronous Mode123

* Low: Off

J3

SYNCI

GND

EN

* High: On

1
2
3

EN

J2

DBIAS

EPAD
25

VIN

GND

50V

GND

VOUT

C16
470pF

GND

Separate Traces!

VOUT

GND

TP9

TP8

GND

50V

L2
1μH

0.018

R4

0.018

R2

GND

C4
0.1μF

L1
160nH

GND

* Output Capacitance: 0.5A rms* Inductor: 6.9A peak, 6.0A rms* Low−Side FET: 6.9A peak, 5.0A rms* High−Side FET: 6.9A peak, 5.5A rms* Input Capacitance: 3.0A rms

C5
0.1μF

C12
0.1μF

GND

Current Stress (6 .. 16V input)

35V

C7
150μF

GND

C1
4.7μF

GND

C6
4.7μF

R5
5.6

GND

C3
0.1μF

D1
NRVTS260ESFT1G

5,6

3
7,8

1

VIN

6.3V

10V

GND

C10
10μF

GND

C9
120μF

GND

VOUT

GND

50V

C2
4.7μF

2
1

1
2

J4

TP4

GND

VOUT

TP3

5.0V @ 3.0A / 6.0A peak

Output

6 .. 16V, 40V peak

GND

TP2

Input
VIN

TP1
J1

TND6287/D

SCHEMATICSTND6287/D
BOARD LAYOUT
Figure 3, 4, 5 and 6 shows the top and bottom assembly
and the four layers of the PCB. The PCB is 47 mm × 44 mm(length × width) where the height of the PCB isapproximately 11 mm.

Figure 3. Top Layer and Assembly Drawing

Figure 4. Bottom Layer and Assembly Drawing

Figure 5. Inner 1 Layer

Figure 6. Inner 2 Layer

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TND6287/D
PERFORMANCE SUMMARY
Output Voltage

Efficiency

NCV891930 has two fixed output voltage options, 3.3 V
and 5.0 V. By pulling pin VSEL to DBIAS by a 10 kW
resistor, the output voltage is set to 5.0 V. Leaving VSEL
floating or connecting to GND, the output voltage is set to
3.3 V.
Dependent on the output current, a modification of thepower stage (inductor, shunt, output capacitance) might benecessary. Please consult therefore Table 1 in the datasheet.

The efficiency for continuous synchronous mode isshown in Figure 7. This measurement doesn’t take into
account losses of the input filter (inductor L1).

Efficiency − Continuous Synchronous Mode
96.0

4.5
4.0

94.0

3.5
92.0

8.0 V in

90.0

2.5
2.0

88.0

1.5
86.0
1.0
84.0

0.5

82.0

0.0
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Output Current [A]Figure 7. Efficiency for 8.0, 12.0 and 16.0 V Input Voltage

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4

Losses [W]

Efficiency [%]3.0

12.0 V in
16.0 V in
8.0 V in12.0 V in
16.0 V inTND6287/D
Thermal Image

The thermal image (Figure 8) shows the circuit at an
ambient temperature of 21°C with an input voltage of 12.0 V
and 3.0 A load.

3.0 A Load
♦ FET Q1: 69°C
♦ Inductor L2: 57°C

Figure 8. Thermal Image at 3.0 A Load
Transient Response

The response to a load step from 3.0 A to 6.0 A and viceversa at 12.0 V input voltage is shown in Figure 9.

Channel 1♦ Output current, load step 3.0 to 6.0 A♦ 2 A/div, 1 ms/div
Channel 2♦ Output voltage, −120 mV (−2.4%) undershoot,+117 mV (2.3%) overshoot♦ 100 mV/div, 1 ms/div, AC coupled

Figure 9. Transient Response on 3.0 A Load Step

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TND6287/D
Frequency Response

The frequency response at 12.0 V input voltage and 6.0 A
load is shown in Figure 10.

Trace 1
♦ 31.5 kHz bandwidth♦ −22 dB gain margin
Trace 2
♦ 82° phase margin

Figure 10. Frequency Response at 6.0 A Load
Impact of Output Capacitance Configuration on
Performance

OutcomeThe datasheet of NCV891930 gives detailed
recommendations for the output filter configuration(inductance, shunt resistance, output capacitance)
dependent on the output voltage and current. A detailed test
series with different output capacitance configurations
showed, that different configurations are possible without
decreasing performance or causing stability issues.
Table 2 shows the measurement results for various output
capacitor configurations and their corresponding
performance regarding ripple, transient response andphase/gain margin.
Different sets of high capacitance ceramic and polymer
capacitors were used for the measurements.
• 1x 100 nF, 50 V, 0603, X7R, always populated
muRata GCJ188R71H104KA12D• 10 mF ceramic, 10 V, 0805, X7R
muRata GCM21BR71A106KE22L
6 mF @ 5.0 V DC, 4 mW ESR @ 2 MHz• 22 mF ceramic, 16 V, 1210, X7R
muRata GCM32ER71C226ME19L
18 mF @ 5.0 V DC, 2 mW ESR @ 410 kHz• 100 mF polymer
Nichicon PCJ0J101MCL1GS
24 mW ESR @ 100 kHz• 120 mF polymer
Nichicon PCJ0J121MCL1GS
24 mW ESR @ 100 kHz• 220 mF polymer
Nichicon PCJ0J221MCL1GS
15 mW ESR @ 100 kHz

output voltage ripple around 90...100 mV (2 %).
Adding a single high capacitance ceramic capacitor(10 mF or more) in parallel reduces the output voltage
ripple heavily by a factor of almost ten.
• The phase and gain margin shows very good values overa broad range of output capacitance and is independent of
the type of capacitor (ceramic, polymer or a mix).
Basically any value between 54 mF (3x 22 mF ceramic
taking DC−biasing into account) and 274 mF (1x 220 mF
polymer + 3x 22 mF ceramic) can be used.
Even higher output capacitance should be no problem,
lower capacitance will degrade phase and gain margin too
much.
• The transient response is almost identical for all
measurements and independent of the output capacitance.
The voltage drop/overshoot is between 118 mV (2.4%)
and 163 mV (3.3%).
With low output capacitance the bandwidth increases andwith higher output capacitance it decreases. Therefore
a lower bandwidth is compensated by larger capacitanceand vice versa.
As the device is internally compensated, the reason forthat behavior is the shift of the load pole:• Using only a polymer capacitor results in relatively highf Polewww.onsemi.com
6

Load

+

1
+
2 @ p @ C out @ R load

1
2 @ p @ C out @

V out
I out

(eq. 1)

TND6287/D
Output Ripple, Transient Response & Frequency
Response Measurements
Table 2. MEASUREMENT RESULTS FOR VARIOUS OUTPUT CAPACITOR CONFIGURATIONSPolymer: 220 mF, 6.3 V

1

1

1

1

# of caps

Ceramic: 10 mF, 10 V

0

1

2

3

# of caps

Output Ripple, peak-peak

107

8

5

3

[mV]

Output Ripple, peak-peak

2.1

0.2

0.1

0.1

[%]

Transient Response, peak-peak

324

258

255

253

[mV]

Transient Response, peak

162

129

128

127

[mV]

3.2

2.6

2.6

2.5

[%]

Bandwidth

16.7

17.0

16.0

15.3

[kHz]

Phase Margin

92

92

91

90

[deg]

Gain margin

−26

−21

−20

−20

[dB]

Polymer: 120 mF, 6.3 V

1

1

1

1

# of caps

Ceramic: 10 mF, 10 V

0

1

2

3

# of caps

Output Ripple, peak-peak

89

11

6

5

[mV]

Output Ripple, peak-peak

1.8

0.2

0.1

0.1

[%]

Transient Response, peak-peak

313

246

236

244

[mV]

Transient Response, peak

157

123

118

122

[mV]

3.1

2.5

2.4

2.4

[%]

Bandwidth

32.3

31.5

31.0

30.2

[kHz]

Phase Margin

82

82

82

82

[deg]

Gain margin

−27

−22

−22

−22

[dB]

Polymer: 100 mF, 6.3 V

1

1

1

1

# of caps

Ceramic: 10 mF, 10 V

0

1

2

3

# of caps

Output Ripple, peak-peak

92

11

7

5

[mV]

Output Ripple, peak-peak

1.8

0.2

0.1

0.1

[%]

Transient Response, peak-peak

325

259

277

262

[mV]

Transient Response, peak

163

130

139

131

[mV]

3.3

2.6

2.8

2.6

[%]

33.2

31.4

30.2

30.0

[kHz]

Bandwidth
Phase Margin

80

81

80

80

[deg]

Gain margin

−27

−22

−22

−22

[dB]

Ceramic: 22 mF, 16 V

3

4

5

6

# of caps

Output Ripple, peak-peak

8

6

5

4

[mV]

Output Ripple, peak-peak

0.2

0.1

0.1

0.1

[%]

Transient Response, peak-peak

275

265

265

258

[mV]

Transient Response, peak

138

133

133

129

[mV]

2.8

2.7

2.7

2.6

[%]

Bandwidth

59.0

49.3

40.7

35.6

[kHz]

Phase Margin

49

54

60

64

[deg]

Gain margin

−14

−17

−21

−24

[dB]

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7

TND6287/D
BILL OF MATERIALS (BOM)
Table 3. BILL OF MATERIALS
Designator

Qty.

Value

Part Number

Manufacturer

Description

Package

C1, C2, C6

3

4.7 mF

GCM32ER71H475KA55

MuRataCAP, CERM, 4.7 mF,
50 V, 10%, X7R, 1210

1210

C3, C4, C5,
C8, C12,
C18, C19,
C20, C2290.1 mF

GCM155R71H104KE02D

MuRataCAP, CERM, 0.1 mF,
50 V, ±10%, X7R,
AEC−Q200 Grade 1,
0402

0402

C7

1

150 mF

GYA1V151MCQ1GS

Nichicon

CAP, Hybrid Polymer,
150 mF, 35 V, ±20%,0.027 W, SMD

D8xL10mmC9

1

120 mF

PCJ0J121MCL1GS

Nichicon

CAP, Aluminum Polymer,
120 mF, 6.3 V, ±20%,0.024 W, SMD

D5.0xL6.0mm

C10

1

10 mF

GCM21BR71A106KE22L

MuRataCAP, CERM, 10 mF, 10 V,
10%, X7R, AEC−Q200
Grade 1, 0805

0805

C15

1

1 mF

GCM21BR71H105KA03

MuRataCAP, CERM, 1 mF, 50 V,
10%, X7R, 0805

0805

C16

1

470 pF

GCM155R71H471KA37D

MuRataCAP, CERM, 470 pF,
50 V, 10%, X7R,
AEC−Q200 Grade 1,
0402

0402

C17

1

100 pF

GCM1555C1H101JA16

MuRataCAP, CERM, 100 pF,
50 V, 5%, C0G/NP0,
0402

0402

C21, C23

2

1 mF

GCM188R71E105KA64D

MuRataCAP, CERM, 1 mF, 25 V,±10%, X7R, AEC−Q200
Grade 1, 0603

0603

D1

1

60 V

NRVTS260ESFT1G

ON Semiconductor

Diode, Schottky, 60 V,
2 A, AEC−Q101,
SOD−123FL

SOD−123FL

FID1, FID2,
FID3

3

N/A

N/A

Fiducial mark. There isnothing to buy or mount.

N/A

J1, J4

2

ED555/2DS

On−Shore
Technology

Terminal Block, 3.5 mm
Pitch, 2x1, TH

7.0x8.2x6.5mm

J2, J3261300311121

Wurth Elektronik

Header, 2.54 mm, 3x1,
Gold, TH

Header,2.54mm,3x1, TH

L1

1

160 nH

XAL7030−161MEB

CoilcraftInductor, Shielded,
Composite, 160 nH,
32.5 A, 0.00115 W, SMD

7.5x7.5x3.1mm

L2

1

1 mH

XAL7030−102MEB

CoilcraftInductor, Shielded,
Composite, 1 mH, 21.8 A,
0.00455 W, SMD

7.5x7.5x3.1mm

Q1

1

40 V

NVMFD5C478NLWFT1G

ON Semiconductor

MOSFET, 2-CH, N-CH,
40 V, 29 A, DFN8 5x6

DFN8, 5x6

R1, R6, R12

30W

CRCW06030000Z0EA

Vishay−Dale

RES, 0 W, 5%, 0.1 W,
0603

0603

R2, R42

0.018 W

ERJ−8CWFR018V

Panasonic

RES, 0.018 W, 1%, 1 W,
AEC−Q200 Grade 0,
1206

1206

R3

1

1.00 W

CRCW06031R00FKEA

Vishay−Dale

RES, 1.00 W, 1%, 0.1 W,
0603

0603

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8

TND6287/D
Table 3. BILL OF MATERIALS (continued)
Designator

Qty.

Value

Part Number

Manufacturer

Description

Package

R5

1

5.6 W

CRCW12065R60JNEA

Vishay−Dale

RES, 5.6 W, 5%, 0.25 W,
1206

1206

R7, R92

68.1 W

CRCW060368R1FKEA

Vishay−Dale

RES, 68.1 W, 1%, 0.1 W,
0603

0603

R8, R11,R133

10.0 kWCRCW060310K0FKEA

Vishay−Dale

RES, 10.0 kW, 1%,
0.1 W, 0603

0603

R10

1

10.0 W

CRCW060310R0FKEA

Vishay−Dale

RES, 10.0 W, 1%, 0.1 W,
0603

0603

TP1, TP3

2

5000

Keystone

Test Point, Miniature,
Red, TH

Red Miniature
Testpoint

TP2, TP4,
TP9

3

5001

Keystone

Test Point, Miniature,
Black, TH

Black Miniature
Testpoint

TP5, TP6,
TP7, TP8

45002

Keystone

Test Point, Miniature,
White, TH

White Miniature
Testpoint

U1

1

NCV891930MW00R2G

ON Semiconductor

Low Quiescent Current
2 MHz Automotive
Synchronous Buck
Controller

ON Semiconductor andare trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent
coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.
ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,
regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer
application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are notdesigned, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, andexpenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if suchclaim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This
literature is subject to all applicable copyright laws and is not for resale in any manner.

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Phone: 011 421 33 790 2910

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