LTM2884
Isolated USB Transceiverwith Isolated Power
Features

Description

Isolated USB Transceiver: 2500VRMS for 1 Minuten USB 2.0 Full Speed and Low Speed Compatiblen Integrated Isolated DC/DC Converter, External or
Bus Poweredn Auto-Configuration of Bus Speed
n 2.5W (500mA at 5V) Output Power from External
Input Supply (VCC = 8.6V to 16.5V)
n 1W (200mA at 5V) Output Power from USB Bus
Supply (VBUS)
n 3.3V LDO Output Supply Signal References V , V
LO LO2n High Common Mode Transient Immunity: 30kV/μs
n ESD: ±15kV HBM on USB Interface Pinsn 15mm × 15mm × 5mm Surface Mount BGA Package

The LTM®2884 is a complete galvanically isolated USB
2.0 compatible μModule® (micromodule) transceiver.
An upstream supply powers both sides of the interface
through an integrated, isolated DC/DC converter.

n

Applications
Isolated USB Interfaces
Host, Hub, or Device Isolationn Industrial/Medical Data AcquisitionnnL, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks ofLinear Technology Corporation. All other trademarks are the property of their respective owners.

The LTM2884 is ideal for isolation in host, hub, bus splitter or peripheral device applications. It is compatible withUSB 2.0 full speed (12Mbps) and low speed (1.5Mbps)
operation. Automatic speed selection configures integrated
pull-up resistors on the upstream port to match thosesensed on the downstream device.
The isolator µModule technology uses coupled inductors
and an isolated power transformer to provide 2500VRMS
of isolation between the upstream and downstream USB
interface. This device is ideal for systems requiring isolated
ground returns or large common mode voltage variations.
Uninterrupted communication is guaranteed for common
mode transients greater than 30kV/μs.
Enhanced ESD protection allows this part to withstandup to ±15kV (human body model) on the USB transceiverinterface pins to local supplies and ±15kV through theisolation barrier to supplies without latch-up or damage.

Typical Application
Powered 2.5W Isolated Hub Port
VBUS

8.6V TO 16.5V
VCC

VBUS

LTM2884
VCC2

VLO
PWR
ISOLATION BARRIERON
SPNDPWR
HUB
µC
D1+

15k

+

D2+

VCC

LTM2884
VCC2

VLO
PWR

ON

100µF

VLO2
DOWNSTREAM
USB PORT

D2–

GND

VBUS

VBUS2

SPNDPWR

D1–

15k

200mA AT 5V

500mA AT 5V

D1+
UPSTREAM
USB PORTPERIPHERALISOLATION BARRIER

4.4V TO 16.5V

Bus Powered 1W Isolated Peripheral Device

VLO2
1.5k
D2+

D1–

GND2

D2–

GND
GND

GND2
2884 TA01b

2884 TA01a

2884f

For more information www.linear.com/LTM2884

1

LTM2884
Absolute Maximum Ratings

Pin Configuration(Note 1)TOP VIEW

Supply Voltages
VCC to GND............................................. –0.3V to 18V
VBUS to GND........................................... –0.3V to 18V
VCC2 to GND2........................................ –0.3V to 10V
VLO to GND................................................... –0.3V to 4V
VLO2 to GND2................................................ –0.3V to 4V
ON, SPNDPWR to GND..................–0.3V to (VLO + 0.3V)
D1+, D1– to GND......................................... –0.3V to 5.3V
D2+, D2– to GND2...................................... –0.3V to 5.3V
Operating Ambient Temperature Range (Note 3)
LTM2884C................................................ 0°C to 70°C
LTM2884I.............................................–40°C to 85°C
LTM2884H.......................................... –40°C to 105°C
Storage Temperature Range................... –40°C to 125°C
Maximum Internal Operating Temperature............. 125°C
Peak Body Reflow Temperature............................. 245°C

1
A

2

3

4

5

6

7

8

9

SPNDD1– D1+ PWR ON VLO GND VBUS

10

11

VCC

B
GND

C
D
E
F
G
H
J

GND2

K
L
D2– D2+

GND2

VLO2

GND2

VCC2

BGA PACKAGE
44-LEAD (15mm × 15mm × 5mm)
TJMAX = 125°C,
PCB = JESD51-9 2s2p: θJA = 18.7°C/W, θJCtop = 16°C/W, θJCbottom = 5.7°C/W, θJB = 5.6°C/W
PCB = DC1746A: θJA = 33.5°C/W, θJCtop = 15.7°C/W, θJCbottom = 6.1°C/W, θJB = 5.3°C/W
HEAT FLOW: θJA = NORMAL, θJCtop = 100%, θJCbottom = 100%, θJB = 100%
WEIGHT = 2.4g

Order Information
PART MARKINGPART NUMBERPAD OR BALL FINISH

DEVICEFINISH CODE

PACKAGETYPE

MSL
RATING

LTM2884CY#PBF
LTM2884IY#PBF

TEMPERATURE RANGE
0°C to 70°C

SAC305 (RoHS)

LTM2884Y

e1

BGA

LTM2884HY#PBF

4–40°C to 85°C
–40°C to 105°C• Device temperature grade is indicated by a label on the shipping
container.

• Recommended BGA PCB Assembly and Manufacturing Procedures:www.linear.com/BGA-assy• Pad or ball finish code is per IPC/JEDEC J-STD-609.

• BGA Package and Tray Drawings: www.linear.com/packaging• Terminal Finish Part Marking: www.linear.com/leadfree• This product is moisture sensitive. For more information, go to:www.linear.com/BGA-assy• This product is not recommended for second side reflow. For more
information, go to: www.linear.com/BGA-assy

2

2884f

For more information www.linear.com/LTM2884

LTM2884
Electrical Characteristics The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VBUS = 5V, GND = GND2 = 0V, ON = VLO, unless otherwise noted.
SYMBOLPARAMETERCONDITIONS

MIN

TYP

MAX

UNITS

12

16.5

V

5

16.5

V

100

500

µA

Power Supply
VCC

Operating Supply Range (Isolated Power Input)

l

4.4

VBUS

Operating Supply Range (USB Bus Power Input)l

4.4

VCC Supply Current Power Off
ICC
IBUS

VCC2

ON = 0V, VCC = 4.4V to 16.5Vl

VCC Supply Current Power On

ICC2 = 0mA, Figure 1

l

50

100

mA

VBUS Supply Current Power Off

ON = 0V

l

10

100

µA

VBUS Supply Current Power On

IVLO = 0mA, Figure 1

l

6

9

mA

VBUS Supply Current Suspend Mode

SPNDPWR = 3.3V
USB Suspend Timeout
SPNDPWR = 0,
USB Suspend Timeout

500

µA

1.5

2.0

mA

5
5

5.25
5.25

V
V

l
l

Regulated VCC2 Output Voltage, Loaded

VCC = 4.4V, ICC2 = 200mA, Figure 1
VCC = 8.6V, ICC2 = 500mA, Figure 1

l
l

4.75
4.75

VCC2 Source Current High Power Mode

VCC = 8.6V, Figure 1

l

500

mA

VCC2 Source Current Bus Power Mode

VCC = VBUS = 4.4V, Figure 1

l

200

mA

VLO

VLO Regulated Output Voltage

IVLO = 0mA to 10mA, Figure 1

l

3.15

3.3

3.45

V

VLO Output Voltage Maximum Current

Figure 1

l

10

mA

VLO2

VLO2 Regulated Output Voltage

IVLO2 = 0mA to 10mA, Figure 1

l

3.15

3.3

3.45

V

VLO2 Output Voltage Maximum Current

Figure 1

l

10

mA

USB Input Levels (D1+, D1–, D2+, D2–)
VIH

Single-Ended Input High Voltagel

VIL

Single-Ended Input Low Voltage

l

VHYS

Single-Ended Input Hysteresis

VDIFF

Differential Input Sensitivity|(D1+ – D1–)| or |(D2+ – D2–)|l

0.2

Common Mode Voltage Range|(D1+ + D1–)|/2 or |(D2+ + D2–)|/2

l

0.8
2.0

VCM

2.0

V
0.8
200

V
mV
V

2.5

V

Logic Input Levels (ON, SPNDPWR)
VIHL

Logic Input High Voltage

l

VILL

Logic Input Low Voltage

l

0.8

V
V

IINL

Logic Input Current

l

±1

µA

VHYSL

Logic Input Hysteresis

200

mV

USB Output Levels (D1+, D1–, D2+, D2–)
VOL

Output Low Voltage

RPU = 1.5k to 3.6V, Figure 4

l

0

0.3

V

VOH

Output High Voltage

RPD = 15k to 0V, Figure 4

l

2.8

3.6

V

VCRS

Differential Output Signal Cross-Point Voltage

l

1.3

2.0

V

1.425

1.575

kΩ

14.25

15.75

kΩ

Terminations
Bus Pull-Up Resistance on Upstream Facing PortD2+ or D2– Pull-Up to 3.3V

RPD

Bus Pull-Down Resistance on Downstream Facing PortD2+ and D2– Pull-Down to GND2ZDRVUSB Driver Output Resistance

CINUSBUSB Transceiver Pad Capacitance to GND

RPUl(Note 2)

28

44
10

Ω
pF

2884f

For more information www.linear.com/LTM2884

3

LTM2884
SWITCHING Characteristics The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VBUS = 5V, GND = GND2 = 0V, ON = VLO, unless otherwise noted.
SYMBOLPARAMETERCONDITIONS

MIN

TYP

MAX

UNITS

Low Speed USB
t LDR

Low Speed Data Rate

CL = 50pF to 450pF (Note 4)t LR

Rise Time

Figure 2, CL = 50pF to 600pF

l

75

1.5
300

ns

t LF

Fall Time

Figure 2, CL = 50pF to 600pF

l

75

300

ns

t LPRR, t LPFF

Propagation Delay

Figure 2, CL = 50pF to 600pF

l

300

ns

t LDJ1

Differential Jitter

To Next Transition (Note 2)

±45

ns

t LDJ2Differential Jitter

To Paired Transitions (Note 2)

± 15

ns

t FDR

Full Speed Data Rate

CL = 50pF (Note 4)

200

Mbps

Full Speed USB
12

Mbps

t FR

Rise Time

Figure 3, CL = 50pF

l

4

20

ns

t FF

Fall Time

Figure 3, CL = 50pF

l

4

20

ns

t FPRR, t FPFF

Propagation Delay

Figure 3, CL = 50pF

l

60

115

ns

t FDJ1

Differential Jitter

To Next Transition (Note 2)2ns

t FDJ2Differential Jitter

To Paired Transitions (Note 2)

1

ns

80

Power Supply Generatort WUSPND

VCC2 – GND2 Supply Start-Up Time(ON VLO, VCC2 to 4.5V)

RLOAD = 50Ω, CLOAD = 100µF
RLOAD = 10Ω, CLOAD = 100µF, VCC = 12V

l
l

2
3

5
10

ms
ms

Wake Up from Suspend Mode

Resume Signal, SPNDPWR = 0

l

0.25

10

µs

ESD (HBM) (Note 2) Isolation Barrier
D1+, D1–, D2+, D2–

GND to GND2

±15

kV

D1+/D1– to GND, VCC, VBUS, or VLO andD2+/D2– to GND2, VCC2, or VLO2

±15

kV

±3

kV

ON, SPNDPWR

Isolation Characteristics
SYMBOLPARAMETER

TA = 25°C.
CONDITIONS

MIN

TYP

MAX

UNITS

Rated Dielectric Insulation Voltage(Notes 6, 7)

1 Minute (Derived from 1 Second Test)

2500

1 Second (Note 5)

3000

VRMS

Common Mode Transient Immunity

VBUS = VCC = 5V, ON = 3.3V, 1000V in 33ns
Transient Between GND and GND2 (Note 2)

±30

kV/µs

Maximum Working Insulation Voltage(Notes 2, 5)

560
400

VPEAK
VRMS

Partial Discharge

VPR = 750VRMS (Note 5)

Comparative Tracking Index

IEC 60112 (Note 2)

Depth of Erosion

IEC 60112 (Note 2)

0.017

mm

Distance Through Insulation(Note 2)0.1

mm

Isolation Barrier: GND to GND2
VISO

VIORM

CTI
DTI

4

VRMS

<5
600

pC
VRMS

1012

Ω

Input to Output Resistance(Notes 2, 5)

Input to Output Capacitance(Notes 2, 5)

13

pF

Creepage Distance(Notes 2, 5)

9.48

mm

2884f

For more information www.linear.com/LTM2884

LTM2884
Electrical Characteristics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Guaranteed by design and not production tested.
Note 3: This µModule transceiver includes over temperature protectionthat is intended to protect the device during momentary overload
conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above specified
maximum operating junction temperature may result in device degradation
or failure.

Note 4: Maximum data rate is guaranteed by other measured parameters
and is not directly tested.
Note 5: Device considered a 2-terminal device. Measurement between
groups of pins A1 through B11 shorted together and pins K1 through L11
shorted together.
Note 6: The rated dielectric insulation voltage should not be interpreted asa continuous voltage rating.
Note 7: In accordance with UL1577, each device is proof tested for the
2500VRMS rating by applying the equivalent positive and negative peakvoltage multiplied by an acceleration factor of 1.2 for one second.

2884f

For more information www.linear.com/LTM2884

5

LTM2884
Typical Performance Characteristics TA = 25°C, VCC = 5V, VBUS = 5V, GND = GND2 = 0V,

ON = 3.3V, unless otherwise noted.

Full Speed Propagation Delayvs Temperature
100

Low Speed Propagation Delayvs Temperature
250

CLOAD = 120pF
PROPAGATION DELAY (ns)PROPAGATION DELAY (ns)

95
90
85
80
75

Full Speed Differential Jitter

CLOAD = 120pF
D1–

240

D1+

230

1V/DIV
D2–

220

210

–25

0
50
25
75
TEMPERATURE (°C)

100

200
–50

125

–25

25
75
0
50
TEMPERATURE (°C)

100

VCC2 Output Current
vs Temperature

Low Speed Differential Jitter
800
D1+

JITTER 7.5nsP-P

2884 G04

50ns/DIVVCC = 5V
60

VCC = 12V

600

EFFICIENCY (%)

D2+

OUTPUT CURRENT (mA)

1V/DIV70500
400
VCC = 5V

300
200
–50

–25

1.0

50

0.8
40

VCC = 5V

30

0
50
25
75
TEMPERATURE (°C)

100

125

0

0.2
0.2

0

200

4.75
VCC = 5V
4.50
VCC = 4.4V
4.25

0.35
0.30
0.25
0.20
0.15
0.05

0

0.4
0.2
0.6
OUTPUT CURRENT (A)

0.8
2884 G07

2884 G06

0.40

0.10

50
4.00

0
0.8

0.45

VCC = 12V

150
100

0.6

0.50

VCC = 8.1V

300
250

0.4
IOUT (A)

0.55

5.00

VCC2 (V)INPUT CURRENT (mA)

350

VCC = 12V

0.4

Derating for 125°C MaximumInternal Operating Temperature

LOAD CURRENT (A)VCC = 5V

0.6

20

5.25

400

VCC = 12V

POWER LOSSVCC2 Output Voltage
vs Load Current

450

1.2

VCC = 12V

2884 G05

VCC Input Current
vs VCC2 Output Current

1.4

EFFICIENCY

POWER LOSS (W)

D1–

VCC to VCC2 Efficiency and PowerLoss
VCC2 = 4.75V

700

D2–

125

2884 G02

2884 G01

62884 G03

10ns/DIV

70
–50

0

JITTER 1.4nsP-P

D2+

0

0.2

0.6
0.4
LOAD CURRENT (A)

0.8

1.0
2884 G08

0

VBUS – VCC = 5V
VBUS – VCC = 8.6V
VBUS – VCC = 12V
VBUS – VCC = 16.5V
25 35 45 55 65 75 85 95 105 115 125
TEMPERATURE (°C)
2884 G09

2884f

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LTM2884
Typical Performance Characteristics TA = 25°C, VCC = 5V, VBUS = 5V, GND = GND2 = 0V,
ON = 3.3V, unless otherwise noted.
VCC2 Ripple, VCC = 5V,
ICC2 = 200mA

VCC2 Ripple, VCC = 12V,
ICC2 = 500mA

VCC2 Start-Up Ramp

VCC2
100mV/DIV

100mV/DIV

2µs/DIV

2884 G102884 G112µs/DIV

VCC2 = Load Step Response,
0mA to 500mA (VCC = 12V)

VCC2 = Load Step Response,
0mA to 200mA (VCC = 5V)

ICC vs Temperature

ICC2

500mV/DIV

VCC2

100µs/DIV2884 G13

ICC2 = 0mA

VCC = 4.4V

60

ICC2
SUPPLY CURRENT (mA)

500mV/DIV

200mA/DIV

VCC2

100µs/DIV2884 G12500µs/DIV

70200mA/DIVON

1V/DIV2884 G14

VCC = 5V

50
40

VCC = 8.1V

30

VCC = 12.5V

20

VCC = 16.5V

10
0
–50

–25

25
50
75
0
TEMPERATURE (°C)

100

125

2884 G15

Upstream VBUS Droop During
Plug-In with CLOAD = 100µF

VCC2 Droop/Plug-In Response

Full Speed Data Start of Packet

VCC

D2+

HOST VBUS
VCC2
1V/DIV

1V/DIVPLUG IN TO HOST

500mV/DIVISOLATED VCC2
D2–

200µs/DIV2884 G16

500µs/DIV2884 G16

100ns/DIV2884 G17

2884f

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7

LTM2884
Pin Functions
Upstream Side (VCC, VBUS, VLO, GND)

Isolated Downstream Side (VCC2, VLO2, GND2)

D1– (A1): USB Data Bus Upstream Facing Negative
Transceiver Pin. A 1.5k pull-up resistor is automaticallyconfigured to indicate the idle condition of the D2– pin.

GND2 (K1-K11, L3, L4, L6, L7): Downstream Circuit
Ground.

D1+ (A2): USB Data Bus Upstream Facing Positive
Transceiver Pin. A 1.5k pull-up resistor is automaticallyconfigured to indicate the idle condition of the D2+ pin.
SPNDPWR (A3): Suspend Power Control. A high input
enables the DC/DC converter shutdown control if the USB
bus is suspended. A low input (GND) disables the shutdown control to the DC/DC converter maintaining power
to the isolated downstream side during suspend mode.
The recovery time from suspend mode may be equivalent
to the power supply start-up time if the DC/DC converter
was shut down. The SPNDPWR pin is referenced to VLO
and GND.
ON (A4): Enable for Power and Data Communication
Through the Isolation Barrier. If ON is high, the part isenabled. If ON is low, the upstream side is held in reset
and the isolated side is unpowered by the DC/DC converter.
The ON pin is referenced between VLO and GND.

D2 – (L1): USB Data Bus Downstream Facing Negative
Transceiver Pin. The pin has a 15k pull-down resistor to
GND2.
D2+ (L2): USB Data Bus Downstream Facing Positive Transceiver Pin. The pin has a 15k pull-down resistor to GND2.
VLO2 (L5): Internally Regulated 3.3V Logic Voltage Output.
The VLO2 pin can source up to 10mA of surplus current.
Internally bypassed to GND2 with 2.2µF. Output supply,
no external connection necessary.
VCC2 (L8-L11): Isolated Voltage Supply Output from DC/
DC Converter. Output voltage is 5V and can support up to
500mA of peripheral device current referenced to GND2.
Output current is dependant on input supply voltage andcurrent limit. Internally bypassed to GND2 with 22µF.
Output supply, no external connection necessary.

VLO (A5): Internally Regulated 3.3V Logic Voltage Output.
The VLO pin is used as a positive reference for the ON and
SPNDPWR pins and can source up to 10mA of surplus
current. Internally bypassed to GND with 2.2µF. Output
supply, no external connection necessary.
GND (A6, B1-B11): Upstream Circuit Ground.
VBUS (A7): Voltage Supply Input to USB Transceiver. The
operating range is 4.4V to 16.5V. Connect to the USB
VBUS supply or an external source. Internally bypassed
to GND with 2.2µF.
VCC (A8-A11): Voltage Supply Input to DC/DC Converter.
The operating range is 4.4V to 16.5V. Connect to an external
supply greater than 8.6V for 500mA on VCC2. Connect tothe USB VBUS for up to 200mA on VCC2. Connect VCC to
VBUS when the peripheral device has an external powersource. Internally bypassed to GND with 4.7µF.

8

2884f

For more information www.linear.com/LTM2884

LTM2884
Block Diagram
VBUS

VCC

2.2µF

4.7µF

VCC2
22µF
DC/DC
VLO2

3.3V
REG

3.3V
REG

2.2µF

VLO
2.2µF
ISOLATED COMMUNICATIONINTERFACEON

D1+
UPSTREAM
PORT

1.5k

ISOLATED COMMUNICATIONINTERFACE

1.5k

D2+
D2–

D1–
15k

SPNDPWRGND

DOWNSTREAM
PORT

15k

GND2
2884 BD= UPSTREAM SIDE COMMON= DOWNSTREAM SIDE COMMON

2884f

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9

LTM2884
Test Circuits
ICC

LTM2884

VCC2

VCC

IBUS

ISOLATION BARRIER

VBUS
VLO

+ VCC
–

+ VBUS
–

IVLO

VLO2

IVLO2

ICC2

GND2

GND

2884 F01

Figure 1. Power Supply Loads

D1+ OR D2+

D2+ OR D1+

3.3V

CL
0V
3.6V

D1– OR D2–

3.3V

1.5k

D2– OR D1–0V

D1– OR D2–
D1+ OR D2+

tLPRR

tLPFF

D2– OR D1–
D2+ OR D1+

90%
10%

90%
10%
2884 F02

CL

tLR

tLF

Figure 2. Low Speed Timing Measurements

D1+ OR D2+

D2+ OR D1+

3.3V

CL
0V
3.3V

D1– OR D2–

D2– OR D1–0V

D1+ OR D2+
D1– OR D2–

tFPFF

tFPRR

D2+ OR D1+
D2– OR D1–

90%
10%

CL

90%
10%
2884 F03

tFF

tFR

Figure 3. Full Speed Timing Measurements

10

2884f

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LTM2884
Functional Table
USB Transceiver Functional Table
D1+

MODE

D1–

AUTOMATIC PULL-UP
CONNECTION

D2+

Full Speed (Idle)

1.5k Pull-Up

Host Pull-Down

D1+

Low Speed (Idle)

Host Pull-Down

1.5k Pull-Up

D1–

D2–

SPNDPWR

Peripheral Pull-Up

15k Pull-Down

X

15k Pull-Down

Peripheral Pull-Up

X

Disconnected (Idle)

Host Pull-Down

Host Pull-Down

None

15k Pull-Down

15k Pull-Down

X

Suspend (Idle >3ms)

Set at Device Connect

Set at Device Connect

Set at Device Connect

Peripheral or 15k

Peripheral or 15k

0

Suspend No Power(Idle >3ms)

Set at Device Connect

Set at Device Connect

Set at Device Connect

15k Pull-Down

15k Pull-Down

3.3V

D1 to D2 Data

IN+

IN–

Set at Device Connect

OUT+

OUT–

X

D2 to D1 Data

OUT+

OUT–

Set at Device Connect

IN+

IN–

X

ON

SPNDPWR

Power Functional Table
MODE

VCC

VBUS

DC/DC CONVERTER

Off

0

X

X

X

OFF

On

3.3V

X

>4.4V

>4.4V

ON

On, Suspend (Idle >3ms)

3.3V

0

>4.4V

>4.4V

ON

On, Suspend (Idle >3ms), Power Off

3.3V

3.3V

>4.4V

>4.4V

OFF

On, USB Transceiver Only Power Off

3.3V

X

0

>4.4V

OFF

2884f

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11

LTM2884
Operation
The LTM2884 µModule transceiver provides a galvanicallyisolated robust USB interface, powered by an integrated,
regulated DC/DC converter, complete with decoupling
capacitors. This flexible device can support a variety ofUSB configurations, either bus powered or externally
powered. Applications include isolation in hosts, hubs,
peripherals, or standalone inline bus splitters. Automatically configured pull-up resistors are included to represent
the condition of the isolated downstream USB bus to the
upstream USB bus. The LTM2884 is ideal for use in USB
connections where grounds between upstream hub/hostand downstream devices can take on different voltages.
Isolation in the LTM2884 blocks high voltage differencesand eliminates ground loops and is extremely tolerant ofcommon mode transients between ground potentials. Error
free operation is maintained through common mode events
exceeding 30kV/µs providing excellent noise isolation.
The LTM2884 contains a fully integrated DC/DC converter
including the transformer, so that no external components
are necessary in many configurations. The upstream side
contains a flyback converter that regulates the downstream
output voltage through primary sensing techniques. Theinternal power solution is sufficient to support the transceiver interface and supply up to 500mA at 5V through
VCC2 to an attached device dependent on the supply voltage
and available current on VCC.
The integrated USB transceivers on both sides of the isolation barrier support full and low speed modes defined in
the USB 2.0 specification. The communication through theisolation barrier for USB is bidirectional and as such the
LTM2884 determines data flow direction based on whichside a start of packet (SOP) begins first. The direction ofdata is maintained until an end of packet (EOP) patternis observed or a timeout occurs due to a lack of activity.
The USB interface maintains a consistent propagation
delay representative of a hub delay and transfers all data.

12

Pull-up resistors integrated in the upstream interface
automatically indicate device connections and disconnections. A downstream device connection automaticallyselects the proper pull-up resistor at the upstream facing
port after sensing the idle state of the downstream device
at connection time. Disconnection of a downstream device
automatically releases the pull-up resistor on the upstream
facing port allowing the upstream 15k pull-down resistors
to pull the bus signals to a disconnect condition. This function makes the LTM2884 ideal for host, hub, bus splitter,or peripheral device integration.
Isolator µModule Technology
The LTM2884 utilizes isolator µModule technology totranslate signals and power across an isolation barrier.
Signals on either side of the barrier are encoded into
pulses and translated across the isolation boundary using differential signaling through coreless transformers
formed in the µModule substrate. This system, completewith data refresh, error checking, safe shutdown on fail,and extremely high common mode immunity, provides
a robust solution for bidirectional signal isolation. TheµModule technology provides the means to combine theisolated signaling with a USB transceiver and powerful
isolated DC/DC converter in one small package.
USB Transceiver Pin Protection
The LTM2884 USB transceiver pins D1+, D1–, D2+, andD2– have protection from ESD and short-circuit faults.
The transceiver pins withstand ±15KV HBM ESD events.
Overcurrent circuitry on the transceiver pins monitor fault
conditions from D1+ and D1– to GND, VLO, or VBUS and from
D2+ and D2– to GND2, VLO2, or VCC2. A current detection
circuit disables the transceiver pin if the pin sinks about
40mA for greater than 600ns. The VLO and VLO2 output
supplies protect the USB transceiver pins from shorts
to GND or GND2 respectively with a 40mA current limit.

2884f

For more information www.linear.com/LTM2884

LTM2884
Applications Information
Idle State Communication and Automatic Speed
Selection

USB Connectivity
The LTM2884 µModule transceiver connects directly to
USB ports on the upstream side and the downstream side
without the addition of external components. The transceiver passes through all data and does not act as a hub
or intelligent device. The bus lines are monitored for idle
conditions, start of packet, and end of packet conditions
to properly maintain bus speed and data direction. The
series resistance, pull-up, and pull-down resistors arebuilt into the LTM2884. The upstream facing USB port
contains automatically configured 1.5k pull-up resistors
which are switched in or out based on the downstreamside peripheral device configuration. This implementation
allows upstream reporting of the downstream bus speed
and connection/disconnection conditions. Built-in 15k pulldown resistors are included from the D2+ and D2– signals
to GND2 supporting the downstream bus configuration.

The LTM2884 µModule transceiver maintains the conditions of the USB bus idle state by monitoring the downstream side bus idle condition and refreshing the stateacross the isolation barrier at a consistent rate. Furthermore, the LTM2884 monitors the speed of the downstream
peripheral once connected and sets its own operation tomatch. Figure 4 shows the abbreviated circuitry of theautomatic monitoring and reporting of the bus speeds.
The D2+ or D2– signals are monitored for a connection topull-ups on D2+ or D2– and the result is processed as fullspeed or low speed, otherwise disconnect. The idle stateis communicated to the upstream side through a refreshtransmission. The switches SW1 or SW2 are controlled
based on the received information. SW1 is closed if D2+
is detected to have a pull-up and D2– was open. SW2 isclosed if D2– is detected to have a pull-up and D2+ was
open. Both SW1 and SW2 are opened if the downstream
USB bus is disconnected. During a USB suspend, the pullup resistor will maintain the condition prior to detecting
the suspend command.

Monitoring the USB data pins, the LTM2884 detects a
K-state to begin a data packet and set the data direction.
The data is monitored for an end of packet signature and afinishing J-state before the bus is released. The data payload between the K-state and J-state is transferred throughthe LTM2884 isolator with a delay of approximately 80ns.

UPSTREAM CONNECTIONDOWNSTREAM CONNECTION
LTM2884

3.3V

D1+
D1–
15k

15k

SW1

SW2

RPU
1.5k

RPU
1.5k

ISOLATION BARRIERVLOREFRESH

3.3V

FULL
SPEED

LOW
SPEED

1.5k

1.5k

D2+
D2–
RPD
15k

RPD
15k

OR
OR DISCONNECTED

2884 F04

Figure 4. Idle State Automatic Resistor Setting

2884f

For more information www.linear.com/LTM2884

13

LTM2884
Applications Information
Suspend Mode

DC/DC Power Supply

When the upstream USB bus is idle for greater than 3ms,
the LTM2884 enters suspend mode. The power savingsand behavior in suspend mode depend on the state of the
SPNDPWR pin, as summarized in Table 1.

The internal DC/DC converter converts the input powerfrom the VCC pin to the VCC2 output. The power delivered
to the VCC2 pin is regulated and current limited to protect
against overcurrent conditions. The voltage supply, VCC ,is sensed to limit the maximum current that can be delivered
before USB specifications are exceeded. Connecting the VCC
and VBUS supply pins to the USB VBUS pin (4.4V to 5.5V) limits the maximum downstream side supply current to 200mA
before VCC2 supply degradation. When VCC is connected toa high voltage external DC source (8.6V to 16.5V) the current limit is increased so that 500mA is sourced from VCC2.
If a downstream device sinking current from VCC2 draws
more than 25mA, the input current on VCC may exceed
100mA, the USB single unit load specification for low
power devices. The LTM2884 does not enforce a 100mA
current limit for low power peripherals.

Table 1. Suspend Mode Operation
WAKE-UP

WAKE-UPTIME

SPNDPWR

VCC2

IBUS

ICC

High

Off

< 500µA

VCC/45k

Resume

3ms

Low

On

1.5mA

50mA

Resume or
Remote Wake-Up

10µs

The biggest power savings in suspend mode comes when
SPNDPWR is high. In this case, the DC/DC converter isdisabled, shutting down power to the isolated side, while
the current draw on VCC and VBUS are minimized. However, in this mode, if a downstream device is connected or
disconnected from the bus or remote wake-up functionality
is configured, it will not be recognized by the LTM2884
and will not be relayed to the host. A resume commandat the upstream side will wake up the LTM2884 and a renumeration by the host will be required. Recovery time
is about 3ms from the start of the resume command on
the upstream side.
If SPNDPWR is low in suspend mode, the LTM2884 operates in a low power mode but maintains a higher functional
state with the DC/DC converter on and the downstream
transceiver powered. The VBUS current is reduced to
1.5mA and VCC current is about 50mA when there is no
external draw on VCC2. Wake-up is initiated with disconnects, reconnects, or a remote wake-up command from adownstream device or a resume command from the host.
Recovery time from suspend mode is about 10µs fromwhen the first state change is detected.
During suspend mode DC current drawn from VLO into
external circuits will be supplied from VBUS and may exceed
the limits set in the USB specification.

14

VCC2 is internally decoupled to GND2 with a 22µF capacitor. Add an additional low ESR 100µF capacitor to VCC2 tomeet the VBUS downstream supply decoupling minimum
specification of 120µF when supporting device plug in.
Locate the additional 100µF capacitor adjacent to thedownstream USB connector. Additional capacitance may
not be necessary when the LTM2884 is used in a peripheraldevice, or upstream hub application.
VLO and VLO2 Supplies
The VLO and VLO2 output supply pins are available for use
as low current 3.3V supplies on both sides of the isolation
barrier. They also serve as supplies for the USB interface
circuitry. An internal linear regulator maintains 3.3V on
VLO from the VBUS input supply. A separate linear regulator
maintains 3.3V on VLO2 from VCC2. The current is limited
to 10mA for external applications. Exceeding this limit
may cause degradation in the VLO or VLO2 supplies andundesirable operation from the USB isolator. Connection of
signals ON or SPNDPWR to VLO will not cause a significant
change in the available VLO current. These supplies areavailable to support interface logic to the isolated USB port.
In order to meet the suspend mode current limit, minimize
the DC current of external applications on the VLO output
supply. VLO and VLO2 are protected from overcurrent andovertemperature conditions.
2884f

For more information www.linear.com/LTM2884

LTM2884
Applications Information
Supply Current
Loading the multiple output supply pins of the LTM2884
affects the supply current on VBUS and VCC. The VBUS input
supplies current to the the upstream side of the transceiver and to the VLO pin. The VCC input supplies power
to VCC2 and VLO2 through an isolated DC/DC converter.
The efficiency (η) of the DC/DC converter is shown in the
Typical Performance Characteristics section for 5V and
12V inputs from VCC to VCC2.
Supply Current Equations
IBUS = 6mA + IVLO(VCC2 • 6mA + ICC2 + IVLO2
η • VCC)

Suspend: SPNDPWR = 0
IBUS = 1.5mA + IVLO
ICC =

(

VCC2 • 6mA + ICC2 + IVLO2
η • VCC)

Suspend: SPNDPWR = VLO
IBUS = 0.45mA + IVLO
ICC =

VCC
45k

Off:
IBUS = 10µA
ICC =First, the propagation delay for full speed data of 80ns
exceeds the specification for a single hub of 44ns plus
the attached cable delay of 26ns. This is due to driving
the signal to the 3.3V rail prior to a K-state transition tomaintain balanced crossover voltages equivalent to thecross over voltages of the successive data transitions.
USB ports commonly drive the idle state bus to the 3.3V
rail prior to the k-state start of packet transition.
Second, setting SPNDPWR = VLO will cause the DC/DC
power converter to turn off during a bus suspend. VCC2
will lose power causing the downstream device to lose
enumeration. Remote wake-up, disconnect, and reconnect events are ignored. A resume command from thehost or upstream hub will start the DC/DC converter andwake up the downstream device. The downstream device
will require re-enumeration, which causes a failure in USB
compliance testing. After a resume command initiates,
a delay of 3ms will elapse before the isolated device isfully powered. When SPNDPWR = 0V, the DC/DC power
converter remains on during suspend, therefore powerand enumeration information is retained. The VCC supply
consumes 50mA to support the isolated power duringsuspend. Separate the VBUS and VCC supplies to comply
with the 2.5mA USB 2.0 VBUS suspend current specification.

Operating:

ICC =cases exist within the LTM2884 µModule transceiver andthe integrated DC/DC power converter.

VCC
45k

USB 2.0 Compatibility
The LTM2884 µModule transceiver is compatible with theUSB 2.0 specification of full and low speed operation. Somecharacteristics and implementations may not support fullcompliance with the USB 2.0 specification. Three specificThird, when connecting a low power device to thedownstream side of the LTM2884 and VBUS and VCC
are connected together, the input current is higher due
to the operating current and the efficiency of the DC/DC
converter. The operating current of the DC/DC converter
and the USB transceiver function is 46mA. The efficiencyof the converter is approximately 55%, resulting in a 1/0.55
increase in the input current due to the load current on
VCC2. A 100mA load on VCC2 appears as a 181mA load
+ operating current at VBUS and VCC. In order to meet a
100mA input current, the VCC2 load current must be lessthan 25mA. This characteristic of an isolated supply may
limit the use of the LTM2884 in bus powered hub applications or downstream connection to a bus powered hub.
Connect VCC to an external supply to mitigate this concern.

2884f

For more information www.linear.com/LTM2884

15

LTM2884
Applications Information
Hot Plug Protection

RF, Magnetic Field Immunity

The VCC and VBUS inputs are bypassed with low ESR
ceramic capacitors. During a hot plug event, the supply
inputs can overshoot the supplied voltage due to cableinductance. When using external power supply sources
greater than 10V that can be hot plugged, add an additional 2.2µF tantalum capacitor with greater than 1Ω
of ESR, or a ceramic capacitor with a series 1Ω resistor
to the VCC input to reduce the possibility of exceeding
absolute maximum ratings. Refer to Application Note 88,“Ceramic Capacitors Can Cause Overvoltage Transients,”
for a detailed discussion of this problem.

The isolator µModule technology used within the LTM2884
has been independently evaluated, and successfully passed
the RF and magnetic field immunity testing requirements
per European Standard EN 55024, in accordance with thefollowing test standards:

PC Board Layout

Tests were performed using an unshielded test card designed per the data sheet PCB layout recommendations.
Specific limits per test are detailed in Table 2.

The high integration of the LTM2884 makes PCB layout
simple. However, to optimize its electrical isolation characteristics, EMI, and thermal performance, some layout
considerations are necessary. The PCB layout in Figure 5
is a recommended configuration for a low EMI USB
application. The following considerations optimize theperformance of the LTM2884:• Under loaded conditions, VCC and GND current exceed
700mA, VCC2 and GND2 current is up to 500mA. Usesufficient copper on the PCB to ensure resistive losses
do not cause the supply voltage to drop below theminimum allowed level. The heavy copper traces will
also help to reduce thermal stress and improve thermal
conductivity.
• Input and output decoupling is not required on peripheralor hub inputs. Add additional low ESR capacitance toreduce noise induction on the power supply connections. Hub/bus splitter outputs require an additional
100µF of low ESR capacitance.

EN 61000-4-3

Radiated, Radio-Frequency,
Electromagnetic Field Immunity

EN 61000-4-8

Power Frequency Magnetic
Field Immunity

EN 61000-4-9

Pulsed Magnetic Field Immunity

Table 2. Test Frequency Field Strength
EN 61000-4-3, Annex D, 80MHz to 1GHz
1.4MHz to 2GHz
2GHz to 2.7GHz

10V/m
3V/m
1V/m

EN61000-4-8, Level 4 50Hz and 60Hz

30A/m

EN61000-4-8, Level 5 60Hz

100A/m*

EN61000-4-9, Level 5 Pulse

1000A/m*Non IEC Method

EMI
Radiated emissions have been measured for the LTM2884
using a gigahertz transverse electromagnetic (GTEM) cellwith and without a USB cable attached. The performance
shown in Figure 6 was achieved with the layout structurein Figure 5. Results are corrected per IEC 61000-4-20.

• Do not place copper between the inner columns ofpads on the top or bottom of the PCB. This area mustremain open to withstand the rated isolation voltage
and maintain the creepage distance.

16

2884f

For more information www.linear.com/LTM2884

LTM2884
Applications Information

TECHNOLOGY

DC1789a Demo Board

DC1789a Top

DC1789a Bottom

2884 F04

Figure 5. PC Board Layout

60
50

CISPR 22 CLASS B LIMIT

40

dBµV/m

30
20
10
0
–10
–20
–30

DETECTOR = PEAK-HOLD
RBW = 120kHz
VBW= 300kHzSWEEP TIME = 680ms# OF POINTS = 501
0 100 200 300 400 500 600 700 800 900 1000
FREQUENCY (MHz)2884 F06

Figure 6. EMI Plot

2884f

For more information www.linear.com/LTM2884

17

LTM2884
Typical Applications
100mA
OR 500mA

5V
25mA
OR
200mA

VBUS
VBUS

VCC

LTM2884

ISOLATION BARRIERON
SPNDPWR

UPSTREAM
USB PORT
D+
D–

VBUS2

VCC2

VLO

D1+

PWR

100µF

VLO2

ISOLATEDDOWNSTREAM
USB PORT

D2+

D1–

D+

D2–

GND

D–
GND2

GND2

GND

2884 F07

Figure 7. Bus Powered Inline Bus Splitter

5V

VBUS
VBUS

VCC

LTM2884
VCC2

VLO

SPNDPWR

UPSTREAM TO
USB HOST
D+
D–

D1+

ISOLATION BARRIER

ON

PWR

DA+
DA–
USB HUBCONTROLLER

DB+
DB–

VLO2

4 USB
DOWNSTREAM
DC+ PORTS
DC–

D2+

D1–

D2–
DD+
DD–
GND

GND2

GND

2884 F08

GND2

Figure 8. USB Hub Upstream Isolator

18

2884f

For more information www.linear.com/LTM2884

LTM2884
Typical Applications
4.4V TO 16.5V

VBUS

VCC

5V UP TO
200mA FOR VCC 4.4V TO 5.5V
500mA FOR VCC 8.6V TO 16.5V

LTM2884

ON

PWR

ISOLATION BARRIER

SPNDPWRUSB HOSTCONTROLLER

D1+

100µF

VLO2
DOWNSTREAM
USB PORT

D2+

D1–
15k

VBUS2

VCC2

VLO

D+

D2–

D–

15k
GND

GND2

GND2
2884 F09

Figure 9. USB Host Integration

5V

VBUS
VBUS

VCC

LTM2884
VCC2

VLO

SPNDPWR

UPSTREAM
USB PORT
D+
D–

D1+

ISOLATION BARRIERONPWRPERIPHERAL
VLO2

D2+

D1–

D2–

GND

GND2
2884 F10

GND

Figure 10. Powered Peripheral Device with USB Isolation and Low Current Suspend

2884f

For more information www.linear.com/LTM2884

19

LTM2884
Typical Applications
SiA921EDJ

VIN
GND
CTL

200mA FOR VCC 4.4V TO 5.5V
500mA FOR VCC 8.6V TO 16.5V
VBUS

LTC4412
SENSE
GATE
STAT

VCC

VCC2

ON
SPNDPWR

9V TO 16V (500mA)

Si4230DY-TI-GE3

VPLUG

UPSTREAM
USB PORT

150k

4.99k

D1+

D+

LTC4365
VIN
SHDN
UV
OV

LTM2884

VLO

PERIPHERAL
VLO2

D2+

D1–

D–

GATE
VOUT
FAULT
GND

PWR

ISOLATION BARRIER

VBUS

D2–

GND

GND2
2884 F11

GND

4.75k
OVERVOLTAGE = 16.7V
UNDERVOLTAGE = 8.1V

Figure 11. Bus or Self Powered USB Isolation with Low Current Suspend and Power Plug Detection

4.4V TO 16.5V (500mA)
VPLUG

200mA FOR VCC 4.4V TO 5.5V
500mA FOR VCC 8.6V TO 16.5V
VBUS

VCC

LTM2884
VCC2

VLO
ON
SPNDPWR

D1+

ISOLATION BARRIER

ON OFF

PWR

VLO2

D2+

D1–

D2–

GND
GND

5V

GND2
2884 F12

Figure 12. Isolated 1W or 2.5W Power Supply

20

2884f

For more information www.linear.com/LTM2884

aaa Z

0.630 ±0.025 Ø 44x

2.540

E

SUGGESTED PCB LAYOUTTOP VIEW

1.270

PACKAGE TOP VIEW

0.31750.000

0.3175

4

2.540

PIN “A1”CORNER

1.270

Y

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnectionof its circuits
as describedherein will not infringe on existing patent rights.
For more
informationwww.linear.com/LTM2884
6.350

5.080

0.000

5.080

6.350

X

D

aaa Z

3.95 – 4.05

6.350

5.080

3.810

3.810

5.080

6.350

SYMBOL
A
A1
A2
b
b1
D
E
e
F
G
aaa
bbb
ccc
ddd
eee

NOM
5.02
0.60
4.42
0.78
0.63
15.0
15.0
1.27
12.70
12.70

DIMENSIONS

0.15
0.10
0.20
0.30
0.15

MAX
5.22
0.70
4.52
0.85
0.66

NOTES

DETAIL B
PACKAGE SIDE VIEWTOTAL NUMBER OF BALLS: 44

MIN
4.82
0.50
4.32
0.71
0.60

DETAIL A

b1

0.37 – 0.47

SUBSTRATE

ddd M Z X Y
eee M ZDETAIL B

MOLD
CAP

ccc Z

A1

A2

A

Z

F

b

10

9

7

G

6

5

4

PACKAGE BOTTOM VIEW

8

e

3

2

1

DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL,
BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.
THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE

47

TRAY PIN 1
BEVEL

!

PACKAGE IN TRAY LOADING ORIENTATIONµModuleLTMXXXXXX

3

SEE NOTES

L

K

J

H

G

F

E

D

C

B

A

7

SEE NOTESPIN 1

BGA 44 1212 REV A

PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGELAYOUT CAREFULLY

6. SOLDER BALL COMPOSITION CAN BE 96.5% Sn/3.0% Ag/0.5% Cu
OR Sn Pb EUTECTIC

5. PRIMARY DATUM -Z- IS SEATING PLANE

BALL DESIGNATION PER JESD MS-028 AND JEP95

3

2. ALL DIMENSIONS ARE IN MILLIMETERSNOTES:
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994

11

DETAIL A

COMPONENTPIN “A1”eb(Reference LTC DWG # 05-08-1881 Rev A)

Øb (44 PLACES)// bbb Z

BGA Package
44-Lead (15mm × 15mm × 5.02mm)

LTM2884

Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.

21

2884f

LTM2884

91k

3.3V

MAX4594 SPSTINNOGND COM

DP0
DM0

LTC1154
STATUS VS
EN
DS
SD
GATE
IN
GND

OVRCUR4

SN74LVC04

27Ω

DP0

DM4

DM0

DP4

3.3V LDO
LT1762-3.3

12V

27Ω

D4D+

D1+

VCC

OVRCUR3GND

PWRON_CPWRON3
DM3
XTAL1

DP3

XTAL2

VCC
12V

ON

D2B+

D1+

EEDATA/GANGED

DP1

DC–

VCC2

VCC

VBUSB
100µF

PWR

GNDB

GND2
VLO2

USB PORT B

D2+

LTM2884

DB+
DB–

VCC2

VLO
VBUS
ON

D1A–

D1–

27Ω

D1A+

D1+

15k

DC+

SPNDPWR
GND

27Ω

GND

USB PORT C

D2+

0.2Ω

12V

DM1

GNDC

VLO2

D2–

PWRON_APWRON1

100µF
GND2

15k

12V

OVRCUR1

BUSPWR

VBUS

27Ω

LTC1154
STATUS VS
EN
DS
SD
GATE
IN
GND

VBUSC

PWR

LTM2884

VLO

D1–

51k

VCC2

0.2Ω

D2B–

3.3V

DD–

SPNDPWR
GND

27Ω

15k

DD+

D2–

12V

PWRON_B

USB PORT D

D2+

15k

LTC1154
STATUS VS
DS
EN
GATE
SD
GND
IN

PWRON2

DP2

ON

D1+

RESET

VLO2

LTM2884

VBUS

D3C+

OVRCUR2

DM2

12V

27Ω

51k
SYSTEM
POWER-ON
RESET

VCC
VLO

D1–

3.3V

GNDD

GND2

0.2Ω

D3C–

15k

100µF

PWR

SPNDPWR
GND

27Ω

6MHz CLOCK
SIGNAL

VBUSD

D2–

12V
LTC1154
STATUS VS
DS
EN
GATE
SD
IN
GND

4.7µF

4.7µF

VCC2

15k

3.3V
51k

3.3V

ON
D1–

15k

LTM2884

VBUS

D4D–

C
D
EXTMEM

12V

27Ω

SN75240
A
B

VCC
VLO

PWRON_DPWRON4

1.5k

27Ω

0.2Ω

ISOLATION BARRIER

47k

12V

51k

ISOLATION BARRIER

VBUS

3.3V

TUSB2046B

ISOLATION BARRIER

3.3V
V+

15k

ISOLATION BARRIER

Typical Application

VBUSA
100µF

PWR

GNDA

GND2
VLO2

USB PORT A
D2+

DA+

D2–

DA–

SPNDPWR
GND
2884 F13

Figure 13. Self Powered 4-Port Hub with Independent Isolation

Related Parts
PART NUMBER
LTM2881
LTM2882
LTM2883
LTM2892

DESCRIPTION
Complete Isolated RS485/RS422 µModule Transceiver + Power
Dual Isolated RS232 µModule Transceiver with Integrated DC/DC Converter
SPI or I2C µModule Isolator with Adjustable ±12.5V and 5V Regulated PowerSPI/Digital or I2C Isolated µModule

22 Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTM2884(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTM2884

COMMENTS
2500VRMS Isolation in Surface Mount BGA or LGA
2500VRMS Isolation in Surface Mount BGA or LGA
2500VRMS Isolation in Surface Mount BGA
3500VRMS Isolation, 6 Channels
2884f
LT 0414 • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 2014