LTC4151CMS-1#PBF - Linear Technology Corporation

LTC4151

4151fd

Typical applicaTion

FeaTures

applicaTions

DescripTion

High Voltage I2C Current

and Voltage Monitor

The LT C

4151 is a high side power monitor that operates

over a wide voltage range of 7V to 80V. In default operation

mode, the onboard 12-bit ADC continuously measures

high side current, input voltage and an external voltage.

Data is reported through the I2C interface when polled

by a host. The LTC4151 can also perform on-demand

measurement in a snapshot mode. The LTC4151 features

a dedicated shutdown pin to reduce power consumption.

The LTC4151-1/LTC4151-2 feature split I2C data pins to

drive opto-isolators. The data out on the LTC4151-1 is

inverted while that on the LTC4151-2 is not.

High Side Power Sensing with Onboard ADC and I2C

n Wide Operating Voltage Range: 7V to 80V

n 12-Bit Resolution for Both Current and Voltages

n I2C Interface

n Additional ADC Input Monitors an External Voltage

n Continuous Scan and Snapshot Modes

n Shutdown Mode (LTC4151) Reduces Quiescent

Current to 120µA

n Split SDA for Opto-Isolation (LTC4151-1/LTC4151-2)

n Available in 10-Lead MSOP, 10-Lead 3mm × 3mm

DFN and 16-Lead SO Packages

n Telecom Infrastructure

n Automotive

n Industrial

n Consumer

12-Bit ADC DNL and INL

4151 TA01

3.3V

0.02Ω

µCONTROLLER

LTC4151

SHDN

VIN

7V to 80V VOUT

VIN

VDD

MEASURED

VOLTAGE

SCL

SDA

ADIN

ADR1

SCL

2k 2k

SDA

ADR0

GND

SENSE+SENSE–

CODE

ADC DNL (LSB)

0.5

4096

–0.5

–1.0 1024 2048 3072

1.0

4151 TA01b

CODE

ADC INL (LSB)

0.5

4096

–0.5

–1.0 1024 2048 3072

1.0

4151 TA01c

PART PACKAGE FEATURED PIN

LTC4151 DD10, MS10 SHDN

LTC4151-1 DD10, MS10 SDAO

LTC4151-2 S16 SDAO

L, LT , LT C , LT M , Linear Technology and the Linear logo are registered trademarks and

Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners.

LTC4151

4151fd

absoluTe MaxiMuM raTings

VIN Voltage .................................................–0.3V to 90V

SENSE+, SENSE– Voltages ...........................VIN – 10V or

–0.3V to VIN + 0.3V

ADR1, ADR0 Voltages .............................. –0.3V to 90V

ADIN, SHDN, SDAO, SDAO Voltages ........... –0.3V to 6V

SCL, SDA, SDAI Voltages (Note 2) ........... –0.3V to 5.5V

SCL, SDA, SDAI Clamp Current ............................... 5mA

(Notes 1, 3)

pin conFiguraTion

Operating Temperature Range

LTC4151C/LTC4151C-1/LTC4151C-2 ......... 0°C to 70°C

LTC4151I/LTC4151I-1/LTC4151I-2 .........–40°C to 85°C

LTC4151H ........................................... –40°C to 125°C

Storage Temperature Range

MSOP, SO .......................................... –65°C to 150°C

DFN .................................................... –65°C to 125°C

Lead Temperature (Soldering, 10 sec)

MSOP, SO ......................................................... 300°C

LTC4151 LTC4151

TOP VIEW

DD PACKAGE

10-LEAD (3mm × 3mm) PLASTIC DFN

1SENSE–

GND

SHDN

SDA

SCL

SENSE+

VIN

ADR1

ADR0

ADIN

TJMAX = 150°C, θJA = 45°C/W

EXPOSED PAD (PIN 11) PCB GND CONNECTION OPTIONAL

TOP VIEW

MS PACKAGE

10-LEAD PLASTIC MSOP

SENSE–

GND

SHDN

SDA

SCL

SENSE+

VIN

ADR1

ADR0

ADIN

TJMAX = 150°C, θJA = 85°C/W

LTC4151-1 LTC4151-1

TOP VIEW

DD PACKAGE

10-LEAD (3mm × 3mm) PLASTIC DFN

1SENSE–

GND

SDAO

SDAI

SCL

SENSE+

VIN

ADR1

ADR0

ADIN

TJMAX = 125°C, θJA = 45°C/W

EXPOSED PAD (PIN 11) PCB GND CONNECTION OPTIONAL

TOP VIEW

MS PACKAGE

10-LEAD PLASTIC MSOP

SENSE–

GND

SDAO

SDAI

SCL

SENSE+

VIN

ADR1

ADR0

ADIN

TJMAX = 125°C, θJA = 85°C/W

LTC4151-2

TOP VIEW

S PACKAGE

16-LEAD PLASTIC SO

SENSE+

VIN

ADR1

ADR0

SENSE–

GND

SDAO

SDAI

SCL

ADIN

TJMAX = 150°C, θJA = 100°C/W

LTC4151

4151fd

orDer inForMaTion

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC4151CDD#PBF LTC4151CDD#TRPBF LCWZ 10-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C

LTC4151IDD#PBF LTC4151IDD#TRPBF LCWZ 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C

LTC4151HDD#PBF LTC4151HDD#TRPBF LCWZ 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C

LTC4151CDD-1#PBF LTC4151CDD-1#TRPBF LCXC 10-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C

LTC4151IDD-1#PBF LTC4151IDD-1#TRPBF LCXC 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C

LTC4151CMS#PBF LTC4151CMS#TRPBF LTCWY 10-Lead Plastic MSOP 0°C to 70°C

LTC4151IMS#PBF LTC4151IMS#TRPBF LTCWY 10-Lead Plastic MSOP –40°C to 85°C

LTC4151HMS#PBF LTC4151HMS#TRPBF LTCWY 10-Lead Plastic MSOP –40°C to 125°C

LTC4151CMS-1#PBF LTC4151CMS-1#TRPBF LTCXB 10-Lead Plastic MSOP 0°C to 70°C

LTC4151IMS-1#PBF LTC4151IMS-1#TRPBF LTCXB 10-Lead Plastic MSOP –40°C to 85°C

LTC4151CS-2#PBF LTC4151CS-2#TRPBF LTC4151S-2 16-Lead Plastic SO 0°C to 70°C

LTC4151IS-2#PBF LTC4151IS-2#TRPBF LTC4151S-2 16-Lead Plastic SO –40°C to 85°C

Consult LT C Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.

Consult LT C Marketing for information on non-standard lead based finish parts.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/

elecTrical characTerisTics

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

General

VIN Supply Voltage l7 80 V

IIN Supply Current VIN = 48V, Normal Operation Mode

VIN = 12V, Shutdown Mode

1.2

120

1.7

300

µA

ISENSE+SENSE+ Input Current VIN, SENSE+, SENSE– = 48V l5 9 µA

ISENSE–SENSE– Input Current VIN, SENSE+, SENSE– = 48V l0.1 1 µA

VSHDN(TH) SHDN Input Threshold l1 1.5 2 V

ISHDN SHDN Input Current SHDN = 0V l–3 –5 –8 µA

ADC

RES Resolution (No Missing Codes) (Note 4) l12 Bits

VFS Full-Scale Voltage (SENSE+ – SENSE–)

VIN

ADIN

81.92

102.4

2.048

LSB LSB Step Size (SENSE+ – SENSE–)

VIN

ADIN

0.5

µV

TUE Total Unadjusted Error (SENSE+ – SENSE–)

VIN (Note 5)

ADIN, C-Grade

ADIN, I-, H-Grade

±1.25

±1

±0.75

±1

VOS Offset Error (SENSE+ – SENSE–)

VIN (Note 6)

ADIN

±5

±6

±8

LSB

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VIN is from 7V to 80V, unless noted. (Note 3)

LTC4151

4151fd

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

INL Integral Nonlinearity (SENSE+ – SENSE–)

VIN (Note 5)

ADIN

±1

±0.5

±3

±2

LSB

sTTransition Noise (SENSE+ – SENSE–)

VIN

ADIN

1.2

0.3

µVRMS

mVRMS

µVRMS

fCONV Conversion Rate (Continuous Mode) l6 7.5 9 Hz

tCONV Conversion Time (Snapshot Mode) (SENSE+ – SENSE–)

ADIN, VIN

RADIN ADIN Pin Input Resistance ADIN = 3V l2 10 MW

IADIN ADIN Pin Input Current ADIN = 3V l ±2 µA

I2C Interface

VADR(H) ADR0, ADR1 Input High Threshold l2.3 2.65 2.9 V

VADR(L) ADRO, ADRI Input Low Threshold l0.3 0.6 0.9 V

IADR(IN) ADRO, ADRI Input Current ADR0, ADR1 = 0V or 3V

ADR0, ADR1 = 0.8V or 2.2V

±8

±70 µA

µA

VSDA(OL) SDA, SDAO, SDAO Output Low Voltage ISDA, ISDAO, ISDAO = 8mA l0.15 0.4 V

ISDA,SCL(IN) SDA, SDAI, SDAO, SDAO, SCL Input

Current

SDA, SDAI, SDAO, SDAO, SCL = 5V l0 ±2 µA

VSDA,SCL(TH) SDA, SDAI, SCL Input Threshold l1.6 1.8 2 V

VSDA,SCL(CL) SDA, SDAI, SCL Clamp Voltage ISDA, ISDAI, ISCL = 3mA l5.5 6.1 6.6 V

I2C Interface Timing (Note 4)

fSCL(MAX) Maximum SCL Clock Frequency 400 kHz

tLOW Minimum SCL Low Period 0.65 1.3 µs

tHIGH Minimum SCL High Period 50 600 ns

tBUF(MIN) Minimum Bus Free Time Between Stop/

Start Condition

0.12 1.3 µs

tHD,STA(MIN) Minimum Hold Time After (Repeated) Start

Condition

140 600 ns

tSU,STA(MIN) Minimum Repeated Start Condition Set-Up

Time

30 600 ns

tSU,STO(MIN) Minimum Stop Condition Set-Up Time 30 600 ns

tHD,DATI(MIN) Minimum Data Hold Time Input –100 0 ns

tHD,DATO(MIN) Minimum Data Hold Time Output 300 600 900 ns

tSU,DAT(MIN) Minimum Data Set-Up Time Input 30 100 ns

tSP(MAX) Maximum Suppressed Spike

Pulse Width

50 110 250 ns

tRST Stuck-Bus Reset Time SCL or SDA/SDAI Held Low 20 33 ms

CXSCL, SDA Input Capacitance 5 10 pF

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: Internal clamps limit the SCL, SDA (LTC4151) and SDAI

(LTC4151-1/LTC4151-2) pins to a minimum of 5.5V. Driving these pins to

voltages beyond the clamp may damage the part. The pins can be safely

tied to higher voltages through a resistor that limits the current below

5mA.

elecTrical characTerisTics

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VIN is from 7V to 80V, unless noted. (Note 3)

Note 3: All currents into pins are positive. All voltages are referenced to

GND, unless otherwise noted.

Note 4: Guaranteed by design and not subject to test.

Note 5: Integral nonlinearity and total unadjusted error of VIN are tested

between 7V and 80V.

Note 6: Offset error of VIN is defined by extrapolating the straight line

measured between 7V and 80V.

LTC4151

4151fd

CODE

ADC DNL (LSB)

0.5

4096

–0.5

–1.0 1024 2048 3072

1.0

4151 G04

CODE

ADC INL (LSB)

0.5

4096

–0.5

–1.0 1024 2048 3072

1.0

4151 G05

Typical perForMance characTerisTics

Supply Current vs Supply Voltage

(Normal Mode)

Supply Current vs Supply Voltage

(Shutdown Mode)

ADC Total Unadjusted Error

vs Code (ADIN Voltage)

ADC INL vs Code (ADIN Voltage)

VIN = 12V, TA = 25°C, unless noted.

ADC DNL vs Code (ADIN Voltage)

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

1.00

1.15

0.85

0.70 20 40 60

1.30

4151 G01

– 40°C

85°C

25°C

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

200

300

100

020 40 60

400

4151 G02

– 40°C

85°C

25°C

CODE

ADC TOTAL UNADJUSTED ERROR (%)

0.05

4096

–0.05

–0.10 1024 2048 3072

0.10

4151 G03

ADC Total Unadjusted Error

vs Code (SENSE Voltage)

ADC DNL vs Code (SENSE Voltage)

ADC INL vs Code (SENSE Voltage)

CODE

ADC INL (LSB)

4096

–1

–2 1024 2048 3072

4151 G08

CODE

ADC TOTAL UNADJUSTED ERROR (%)

0.5

4096

–0.5

–1.0 1024 2048 3072

1.0

4151 G06

CODE

ADC DNL (LSB)

4096

–1

–2 1024 2048 3072

4151 G07

LTC4151

4151fd

pin FuncTions

ADIN: ADC Input. The onboard ADC measures voltage

range between 0V and 2.048V. Tie to GND if unused.

ADR1, ADR0: I2C Device Address Inputs. Connecting

ADR1 and ADR0 to VIN, GND or leaving the pins open

configures one of nine possible addresses. See Table 1

in the Applications Information section for details.

Exposed Pad (DD Package Only): Exposed pad may be

left open or connected to device ground (GND).

GND: Device Ground.

SCL: I2C Bus Clock Input. Data is shifted in and out at

the SDA pin on rising edges of SCL. This pin is driven

by an open-collector output from a master controller. An

external pull-up resistor or current source is required and

can be placed between SCL and VIN. The voltage at SCL

is internally clamped to 6V (5.5V minimum).

SDA (LTC4151 Only): I2C Bus Data Input/Output. Used

for shifting in address, command or data bits and sending

out data. An external pull-up resistor or current source

is required and can be placed between SDA and VIN.

The voltage at SDA is internally clamped to 6V (5.5V

minimum).

SDAI (LTC4151-1/LTC4151-2 Only): I2C Bus Data Input.

Used for shifting in address, command, data, and SDAO

acknowledge bits. This pin is driven by an open-collector

output from a master controller. An external pull-up resistor

or current source is required and can be placed between

SDAI and VIN. If the master separates SDAI and SDAO,

data read at SDAO needs to be echoed back to SDAI for

proper I2C communication. The voltage at SDAI is internally

clamped to 6V (5.5V minimum).

SDAO (LTC4151-2 Only): Serial Bus Data Output. Open-

drain output used for sending data back to the master

controller or acknowledging a write operation. Normally

tied to SDAI to form the SDA line. An external pull-up

resistor or current source is required.

SDAO (LTC4151-1 Only): Inverted Serial Bus Data Out-

put. Open-drain output used for sending data back to the

master controller or acknowledging a write operation. Data

is inverted for convenience of opto-isolation. An external

pull-up resistor or current source is required.

SENSE+: Kelvin Sense of the VIN Pin. See Figure 10 for

recommended Kelvin connection.

SENSE–: High Side Current Sense Input. Connect an

external sense resistor between SENSE+ and SENSE–.

The differential voltage between SENSE+ and SENSE– is

monitored by the onboard ADC with a full-scale sense

voltage of 81.92mV.

Typical perForMance characTerisTics

VIN = 12V, TA = 25°C, unless noted.

SDA, SDAO, SDAO Output Low vs

Pull-Up Current (VSDA(OL) vs ISDA)

SDA, SDAI, SCL Clamp Voltage

vs Load Current

ISDA (mA)

VSDA(OL) (V)

0.3

0.4

0.2

0.1

0510 15

0.5

4151 G09

– 40°C

25°C

85°C

ILOAD (mA)

0.01 0.1 1 10

6.2

6.1

6.0

5.9

6.3

4151 G10

VSDA,SCL(CL) (V)

– 40°C

85°C

25°C

LTC4151

4151fd

block DiagraM

operaTion

The LTC4151 accurately monitors high side current and

voltages. This device accepts a wide range of input volt-

ages from as low as 7V up to 80V and consumes less

than 1.7mA quiescent current in normal operation. A

shutdown mode is available with the LTC4151 to reduce

the quiescent current to less than 300µA by pulling the

SHDN pin below 1V.

In default continuous scan mode after power-up, the

onboard 12-bit analog-to-digital converter (ADC) continu-

ously and sequentially measures the high side differential

voltage between SENSE+ (Kelvin sense of VIN) and SENSE–

(full-scale 81.92mV) through an internal sense amplifier,

the input voltage VIN (full-scale 102.4V) through an internal

voltage divider, and the voltage applied to the ADIN pin

(full-scale 2.048V). The reference voltage of the ADC is

internally set to 2.048V. The digital data obtained by the

ADC is stored in the onboard registers.

In snapshot mode, the LTC4151 can perform on-demand

measurement of a selected voltage without the need of

continuous polling by a master controller. The snapshot

mode is enabled by programming the control register

through the I2C interface. A status bit in the data register

monitors the ADC’s conversion. When the conversion is

completed, the 12-bit digital code of the measured voltage

is held in the corresponding data registers.

The LTC4151 provides an I2C interface to read the ADC

data from the data registers and to program the control

used to decode nine device addresses (see Table 1). The

LTC4151 features a single SDA pin to handle both input

data and output data, while the LTC4151-1/LTC4151-2

provide separate data in (SDAI) and data out (SDAO on

the LTC4151-1 and SDAO on the LTC4151-2) pins to

facilitate opto-isolation.

SHUTDOWN

CONTROL

4151 BD

6.3V

I2C/

REGISTERS

DECODER

SHDN

(LTC4151)

VIN

5µA

VREF = 2.048V

SDA/SDAI

(LTC4151/

LTC4151-1)

ADR1

SCL

SDAO/SDAO

(LTC4151-1/

LTC4151-2)

ADR0

GND ADIN

15k

735k

INTERNAL

POWER

SENSE+SENSE–

–+

12-BIT ADC

MUX

25X

pin FuncTions

SHDN (LTC4151 Only): Shutdown Input. Internally pulled

up to 6.3V. Pull this pin below 1V to force the LTC4151

into shutdown mode. Leave this pin open if unused.

VIN: Supply Voltage Input. Accepts 7V to 80V. The voltage

at this pin is monitored by the onboard ADC with a full-

scale input range of 102.4V. SENSE+ must be connected

to VIN for proper ADC readout.

LTC4151

4151fd

applicaTions inForMaTion

The LTC4151 offers a compact complete solution for high

side power monitoring. With a wide operating voltage

range from 7V to 80V, this device is ideal for a variety of

applications including consumer, automotive, industrial

and telecom infrastructure. The simple application circuit as

shown in Figure 1 provides monitoring of high side current

with a 0.02W resistor (4.096A in full scale), input voltage

(102.4V in full scale) and an external voltage (2.048V in

full scale), all with an internal 12-bit resolution ADC.

Data Converter

The LTC4151 features an onboard, 12-bit ∆Σ A/D

converter (ADC) that continuously monitors three volt-

ages in the sequence of (VSENSE+ – VSENSE–) first, VIN

second and VADIN third. The ∆Σ architecture inherently

averages signal noise during the measurement period.

The differential voltage between SENSE+ and SENSE– is

monitored with an 81.92mV full scale and 20µV resolu-

tion that allows accurate measurement of the high side

input current. SENSE+ is a Kelvin sense pin for the VIN

pin and must be connected to VIN (see Figure 10) for

proper ADC readout. The supply voltage at VIN is directly

measured with a 102.4V full scale and 25mV resolution.

The voltage at the uncommitted ADIN pin is measured

with a 2.048V full scale and 0.5mV resolution that allows

monitoring of any external voltage. The 12-bit digital

Figure 1. Monitoring High Side Current and Voltages Using the LTC4151

code of each measured voltage is stored in two adjacent

registers out of the six total data registers A through F,

with the eight MSBs in the first register and the four LSBs

in the second (Table 2).

The data in registers A through F is refreshed at a frequency

of 7.5Hz in continuous scan mode. Setting control register

bit G4 (Table 6) invokes a test mode that halts updating

of these registers so that they can be written to and read

from for software testing.

The data converter features a snapshot mode allowing us-

ers to make one-time measurements of a selected voltage

(either the SENSE voltage, VIN voltage, or ADIN voltage).

To enable snapshot mode, set control register bit G7 and

write the 2-bit code of the desired ADC channel to G6

and G5 (Table 6) using a Write Byte command. When the

Write Byte command is completed, the ADC measures the

selected voltage and a Busy Bit in the LSB data register is

set to indicate that the data is not ready. After complet-

ing the conversion, the ADC is halted and the Busy Bit is

reset to indicate that the data is ready. To make another

measurement of the same voltage or to measure another

voltage, first disable the snapshot mode for the previous

measurement by clearing control bit G7, then re-enable the

snapshot mode and write the code of the desired voltage

according to the procedure described above. The Busy Bit

remains reset in the continuous scan mode.

4151 F01

0.02Ω

µ-CONTROLLER

LTC4151

SHDN

VIN

7V TO 80V

VIN

VDD

VADIN

SCL

SDA

ADIN

ADR1

SCL

SDA

ADR0

GND

SENSE+SENSE–

3.3V

VOUT

2k 2k

LTC4151

4151fd

SCL

SDA

START

CONDITION

STOP

CONDITION

ADDRESS R/W ACK DATA ACK DATA ACK

1 - 7 8 9

4151 F02

a6 - a0 b7 - b0 b7 - b0

1 - 7 8 9 1 - 7 8 9

Figure 2. General Data Transfer over I2C

I2C Interface

The LTC4151 features an I2C-compatible interface to

provide access to six ADC data registers and a control

shows a general data transfer format using the I2C. The

LTC4151is a read-write slave device and supports SMBus

Read Byte, Write Byte, Read Word and Write Word com-

mands. The device also supports Read Page and Write

Page commands that allow one to read or write more than

two bytes of data. When using the Read Page and Write

Page commands, the host need only to issue an initial

automatically increments by 1 after each byte of data is read

or written. After the register address reaches 06h, it will

be reset to 00h and continue the increment. Upon a Stop

condition, the register address is reset to 00h. If desired,

the Read Page and Write Page support can be disabled by

clearing control register bit G3. The data formats for the

above commands are shown in Figures 3 to 8.

applicaTions inForMaTion

Figure 3. LTC4151 Serial Bus SDA Write Byte Protocol

Figure 4. LTC4151 Serial Bus SDA Write Word Protocol

Figure 5. LTC4151 Serial Bus SDA Write Page Protocol

S ADDRESS

1 1 0 a3:a0

FROM MASTER TO SLAVE

FROM SLAVE TO MASTER

A: ACKNOWLEDGE (LOW)

A: NOT ACKNOWLEDGE (HIGH)

R: READ BIT (HIGH)

COMMAND DATA

X X X X X b2:b00

0 0 0b7:b0

A A A P

4151 F03

W: WRITE BIT (LOW)

S: START CONDITION

P: STOP CONDITION

S ADDRESS

1 1 0 a3:a0

COMMAND DATA DATA

X X X X X b2:b00

0 0 0 0

4151 F04

b7:b0b7:b0

AA A A P

S ADDRESS

1 1 0 a3:a0

COMMAND

0X X X X X b2:b00

0 0

4151 F05

A A A P

b7:b0

DATA

b7:b0

DATA

...

b7:b0

DATA

Figure 6. LTC4151 Serial Bus SDA Read Byte Protocol

S ADDRESS

1 1 0 a3:a0 1 1 0 a3:a0 1 0

COMMAND S ADDRESS R A

b7:b0 1

DATA

X X X X X b2:b00

0 0

4151 F06

A A AP

Figure 7. LTC4151 Serial Bus SDA Read Word Protocol

Figure 8. LTC4151 Serial Bus SDA Read Page Protocol

S ADDRESS

1 1 0 a3:a0 1 1 0 a3:a0 1 0

COMMAND S ADDRESS R A

b7:b0 1

DATA

X X X X X b2:b00

0 0

4151 F07

b7:b0

DATA

AAP

S ADDRESS

1 1 0 a3:a0 1 1 0 a3:a0 1 0

COMMAND S ADDRESS R A

b7:b0 1

DATA

X X X X X b2:b00

0 0

4151 F08

b7:b0

DATA

AAP

...

b7:b0

DATA

LTC4151

4151fd

Using Opto-Isolators with LTC4151-1 and LTC4151-2

The LTC4151-1/LTC4151-2 split the SDA line into SDAI

(input) and SDAO (LTC4151-1 inverted output) or SDAO

(LTC4151-2 output) for convenience of opto-coupling

with a host controller that sits at a different ground level.

When using opto-isolators with the LTC4151-1, connect

the SDAI to the output of the incoming opto-coupler and

connect the SDAO to the anode of the outgoing opto-

coupler (see Figure 9). With the outgoing opto-coupler

clamping SDAO and internal 6V (5.5V minimum) clamps

on SDAI and SCL, the pull-up resistors on these three pins

can be directly connected to VIN. In this way (with SDAO

rather than conventional SDAO), the need for a separate

low voltage supply for pull-ups is eliminated.

Figure 11 shows the LTC4151-2 with high speed opto-

couplers for faster bus speeds. The LTC4151-2 has a non-

inverter SDAO output. Powered from VIN, the high voltage

LT3010-5 low dropout regulator provides the supply for the

opto-couplers as well as the bus lines pull-up. If the SDAI

and SDAO on the master controller are not tied together,

the ACK bit of the SDAO must be returned back to SDAI.

Start and Stop Conditions

When the I2C bus is idle, both SCL and SDA must remain

in the high state. A bus master signals the beginning of a

transmission with a Start condition by transitioning SDA

from high to low while SCL stays high. When the master

has finished communicating with the slave, it issues a Stop

condition by transitioning SDA from low to high while SCL

stays high. The bus is then free for another transmission.

Stuck-Bus Reset

The LTC4151 I2C interface features a stuck-bus reset

timer. The low conditions of the SCL and the SDA/SDAI

pins are OR’ed to start the timer. The timer is reset when

both SCL and SDA/SDAI are pulled high. If the SCL pin or

the SDA/SDAI pin is held low for over 33ms, the stuck-bus

timer will expire and the internal I2C state machine will be

reset to allow normal communication after the stuck-bus

condition is cleared. The stuck-bus timer can be disabled

by clearing control register bit G2.

applicaTions inForMaTion

Figure 9. Opto-Isolation of the I2C Interface Between LTC4151-1 and a

Microcontroller (Data Rate of I2C is Limited by Slew Rate of Opto-Isolators)

4151 F09

3.3V

0.02Ω

µ-CONTROLLER

LTC4151-1

SCL

VIN

48V

VIN

VDD

VADIN

SDAI

ADIN

ADR1

0.51k

10k

0.51k

20k

5.1k

SDA

ADR0

GND

SENSE+SENSE–

SDA0

MOCD207M

LTC4151

4151fd

applicaTions inForMaTion

Table 1. LTC4151 Device Addressing*

DESCRIPTION

HEX DEVICE

ADDRESS BINARY DEVICE ADDRESS

LTC4151

ADDRESS PINS

h a6 a5 a4 a3 a2 a1 a0 R/WADR1 ADR0

Mass Write CC 1 1 0 0 1 1 0 0 X X

0 CE 1 1 0 0 1 1 1 X H L

1 D0 1 1 0 1 0 0 0 X NC H

2 D2 1 1 0 1 0 0 1 X H H

3 D4 1 1 0 1 0 1 0 X NC NC

4 D6 1 1 0 1 0 1 1 X NC L

5 D8 1 1 0 1 1 0 0 X L H

6 DA 1 1 0 1 1 0 1 X H NC

7 DC 1 1 0 1 1 1 0 X L NC

8 DE 1 1 0 1 1 1 1 X L L

*H = Tie High; L = Tie to GND; NC = Open; X = Don’t Care

I2C Device Addressing

Nine distinct I2C bus addresses are configurable using the

three-state pins ADR0 and ADR1, as shown in Table 1.

Address bits a6, a5 and a4 are configured to (110) and

the least significant bit is the R/W bit. In addition, the

LTC4151 will respond to a mass write address (1100 110)

b for writing to all LTC4151s, regardless of their individual

address settings.

Acknowledge

The acknowledge signal is used for handshaking between

the transmitter and the receiver to indicate that the last

byte of data was received. The transmitter always releases

the SDA line during the acknowledge clock pulse. The

LTC4151 pulls the SDA line low on the 9th clock cycle to

acknowledge receipt of the data. If the slave fails to ac-

knowledge by leaving SDA high, then the master can abort

the transmission by generating a Stop condition. When

the master is receiving data from the slave, the master

must pull down the SDA line during the clock pulse to

indicate receipt of a data byte, and that another byte is to

be read. After the last byte has been received the master

will leave the SDA line high (not acknowledge) and issue

a Stop condition to terminate the transmission.

Write Protocol

The master begins a write operation with a Start condition

followed by the seven bit slave address and the R/W bit

set to zero. After the addressed LTC4151 acknowledges

the address byte, the master then sends a command

byte which indicates which internal register the master

wishes to write. The LTC4151 acknowledges this and

then latches the lower three bits of the command byte

into its internal register address pointer. The master then

delivers the data byte and the LTC4151 acknowledges

once more and latches the data into its internal register.

If the master continues sending a second byte or more

data bytes, as in a Write Word or Write Page command,

the second byte or more data bytes will be acknowledged

by the LTC4151, the internal register address pointer

will increment automatically, and each byte of data will

be latched into an internal register corresponding to the

address pointer. The write operation terminates and the

sends a Stop condition.

Read Protocol

The master begins a read operation with a Start condition

followed by the seven bit slave address and the R/W bit

set to zero. After the addressed LTC4151 acknowledges

the address byte, the master then sends a command

byte that indicates which internal register the master

wishes to read. The LTC4151 acknowledges this and then

latches the lower three bits of the command byte into its

internal register address pointer. The master then sends

a repeated Start condition followed by the same seven bit

LTC4151

4151fd

Table 3. SENSE Registers A (00h) and B (O1h)—Read/Write

BIT NAME OPERATION

A7:0, B7:4 SENSE Voltage Data 12-Bit Data of Current Sense Voltage with 20µV LSB and 81.92mV Full-Scale

B3 ADC Busy in Snapshot Mode 1 = SENSE Being Converted; 0 = SENSE Conversion Completed. Not Writable

B2:0 Reserved Always Returns 0. Not Writable

Table 4. VIN Registers C (02h) and D (O3h)—Read/Write

BIT NAME OPERATION

C7:0, D7:4 VIN Voltage Data 12-Bit Data of VIN Voltage with 25mV LSB and 102.4V Full-Scale

D3 ADC Busy in Snapshot Mode 1 = VIN Being Converted; 0 = VIN Conversion Completed. Not Writable

D2:0 Reserved Always Returns 0, Not Writable

Table 5. ADIN Registers E (04h) and F (O5h)—Read/Write

BIT NAME OPERATION

E7:0, F7:4 ADIN Voltage Data 12-Bit Data of Current Sense Voltage with 500µV LSB and 2.048V Full-Scale

F3 ADC Busy in Snapshot Mode 1 = ADIN Being Converted; 0 = ADIN Conversion Completed. Not Writable

F2:0 Reserved Always Returns 0, Not Writable

applicaTions inForMaTion

Table 2. LTC4151 Register Address and Contents

00h SENSE (A) R/W** ADC Current Sense Voltage Data (8 MSBs)

01h SENSE (B) R/W** ADC Current Sense Voltage Data (4 LSBs)

02h VIN (C) R/W** ADC VIN Voltage Data (8 MSBs)

03h VIN (D) R/W** ADC VIN Voltage Data (4 LSBs)

04h ADIN (E) R/W** ADC ADIN Voltage Data (8 MSBs)

05h ADIN (F) R/W** ADC ADIN Voltage Data (4 LSBs)

06h CONTROL (G) R/W Controls ADC Operation Mode and Test Mode

07h Reserved

*Register address MSBs b7-b3 are ignored. **Writable if bit G4 is set.

Table 6. CONTROL Register G (06h)—Read/Write

BIT NAME OPERATION

G7 ADC Snapshot Mode

Enable

Enables ADC Snapshot Mode; 1 = Snapshot Mode Enabled. Only the channel selected by G6 and G5 is

measured by the ADC. After the conversion, the channel busy bit is reset and the ADC is halted.

0 = Snapshot Mode Disabled (ADC free running, Default).

G6 ADC Channel Label for

Snapshot Mode

ADC Channel Label for Snapshot Mode

G6 G5 ADC CHANNEL

0 0 SENSE (Default)

0 1 VIN

1 0 ADIN

G5 ADC Channel Label for

Snapshot Mode

G4 Test Mode Enable Test Mode Halts ADC Operation and Enables Writes to ADC Registers; 1 = Enable Test Mode,

0 = Disable Test Mode (Default)

G3 Page Read/Write Enable Enables Page Read/Write; 1 = Enable I2C Page Read/Write (Default), 0 = Disable I2C Page Read/Write

G2 Stuck-Bus Timer Enable Enables I2C Stuck-Bus Reset Timer; 1 = Enable Stuck-Bus Timer (Default), 0 = Disable Stuck-Bus Timer

G1:0 Reserved Always Returns 0, Not Writable

LTC4151

4151fd

address with the R/W bit now set to one. The LTC4151

acknowledges and sends the contents of the requested

sends a Stop condition. If the master acknowledges the

transmitted data byte, as in a Read Word command, the

LTC4151 will send the contents of the next register. If

the master acknowledges the second data byte and each

of the following (if more) data bytes, as in a Read Page

command, the LTC4151 will keep sending out each data

byte in the register that corresponds to the incrementing

sends a Stop condition.

Layout Considerations

A Kelvin connection between the sense resistor RS and

the LTC4151 is recommended to achieve accurate cur-

rent sensing (Figure 10). The minimum trace width for

1oz copper foil is 0.02" per amp to make sure the trace

applicaTions inForMaTion

4151 F10

SENSE–

GND

SENSE+

VIN

ADR1

ADR0

LTC4151

VIN

GND

RSILOAD

ILOAD

Figure 10. Recommended Layout for Kelvin Connection

stays at a reasonable temperature. Using 0.03" per amp

or wider is recommended. Note that 1oz copper exhibits

a sheet resistance of about 530µW per square.

ADINADIN

0.02Ω

LTC4151-2

VIN

7V to 80V VOUT

VCC

ISO_SDA

ISO_SCL

GND

1µF

100V

VIN

ADR1

ADR0

SDAO

LT3010-5

SHDN

OUT

SENSE

GND

SDAI

SCL

GND

SENSE+SENSE–

1µF

ISO1

PS9817-2

ISO2

PS9817-2

10k

R11

R13

10k

4151 F11

R12

R14

10k

1k C4

0.1µF

VCC

GND

Figure 11. LTC4151-2 I2C Opto-Isolation Interface with High Speed Opto-Couplers

LTC4151

4151fd

DD Package

10-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1699 Rev C)

Typical applicaTion

LTC4151

SCL

VIN

48V

VIN

SENSE+SENSE–

0.2Ω

I2C

SDA

ADR1

ADR0

ADIN

40.2k

100k AT 25°C

1.5k

VISHAY

2381 615 4.104

250mA

LOAD

GND

4151 TA02

Temperature Monitoring with an NTC Thermistor While

Measuring Load Current and LTC4151 Supply Current

T(°C) = 58.82 • (NADIN /NVIN – 0.1066), 20°C < T < 60°C.

NADIN AND NVIN ARE DIGITAL CODES MEASURED BY THE

ADC AT THE ADIN AND VIN PINS, RESPECTIVELY.

3.00 ±0.10

(4 SIDES)

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).

CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE

TOP AND BOTTOM OF PACKAGE

0.40 ± 0.10

BOTTOM VIEW—EXPOSED PAD

1.65 ± 0.10

(2 SIDES)

0.75 ±0.05

R = 0.125

TYP

2.38 ±0.10

(2 SIDES)

106

PIN 1

TOP MARK

(SEE NOTE 6)

0.200 REF

0.00 – 0.05

(DD) DFN REV C 0310

0.25 ± 0.05

2.38 ±0.05

(2 SIDES)

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

1.65 ±0.05

(2 SIDES)2.15 ±0.05

0.50

BSC

0.70 ±0.05

3.55 ±0.05

PACKAGE

OUTLINE

0.25 ± 0.05

0.50 BSC

PIN 1 NOTCH

R = 0.20 OR

0.35 × 45°

CHAMFER

package DescripTion

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

LTC4151

4151fd

MS Package

10-Lead Plastic MSOP

(Reference LTC DWG # 05-08-1661 Rev E)

MSOP (MS) 0307 REV E

0.53 0.152

(.021 .006)

SEATING

PLANE

0.18

(.007)

1.10

(.043)

MAX

0.17 –0.27

(.007 – .011)

TYP

0.86

(.034)

REF

0.50

(.0197)

BSC

1234 5

4.90 0.152

(.193 .006)

0.497 0.076

(.0196 .003)

REF

8910 76

3.00 0.102

(.118 .004)

(NOTE 3)

3.00 0.102

(.118 .004)

(NOTE 4)

NOTE:

1. DIMENSIONS IN MILLIMETER/(INCH)

2. DRAWING NOT TO SCALE

3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX

0.254

(.010) 0 – 6 TYP

DETAIL “A”

GAUGE PLANE

5.23

(.206)

MIN

3.20 – 3.45

(.126 – .136)

0.889 0.127

(.035 .005)

RECOMMENDED SOLDER PAD LAYOUT

0.305 0.038

(.0120 .0015)

TYP

0.50

(.0197)

BSC

0.1016 0.0508

(.004 .002)

package DescripTion

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

LTC4151

4151fd

package DescripTion

.016 – .050

(0.406 – 1.270)

.010 – .020

(0.254 – 0.508)× 45°

0° – 8° TYP

.008 – .010

(0.203 – 0.254)

2345678

N/2

.150 – .157

(3.810 – 3.988)

NOTE 3

16 15 14 13

.386 – .394

(9.804 – 10.008)

NOTE 3

.228 – .244

(5.791 – 6.197)

12 11 10 9

S16 REV G 0212

.053 – .069

(1.346 – 1.752)

.014 – .019

(0.355 – 0.483)

TYP

.004 – .010

(0.101 – 0.254)

.050

(1.270)

BSC

.245

MIN

1 2 3 N/2

.160 ±.005

RECOMMENDED SOLDER PAD LAYOUT

.045 ±.005

.050 BSC

.030 ±.005

TYP

INCHES

(MILLIMETERS)

NOTE:

1. DIMENSIONS IN

2. DRAWING NOT TO SCALE

3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)

4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE

S Package

16-Lead Plastic Small Outline (Narrow .150 Inch)

(Reference LTC DWG # 05-08-1610 Rev G)

package DescripTion

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

LTC4151

4151fd

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 representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

revision hisTory

REV DATE DESCRIPTION PAGE NUMBER

C 11/10 Added H-grade information

Revised order of Pin Functions section and added information to SDAI pin description

Added diode and 2k resistor to Block Diagram

Added information to Application Information section

2, 3

D 7/12 Changed part number in Pin Configuration section from LT4151 to LTC4151 2

(Revision history begins at Rev C)

LTC4151

4151fd

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

 LINEAR TECHNOLOGY CORPORATION 2008

LT 0712 REV D • PRINTED IN USA

4151 TA03

LOAD

0.02Ω

LTC4151

SCL

VIN2

48V

VIN

I2C

SDA

ADR1

ADR0

ADIN

301k

3.4k

150k

D2F2

GND

SENSE+SENSE–

V+

V–

VIN1

48V

D1F1

relaTeD parTs

Typical applicaTion

PART NUMBER DESCRIPTION COMMENTS

LTC2451 16-Bit I2C Ultra Tiny Delta Sigma ADC Single-Ended Input, 0 to VCC Input Range, 60Hz Output Rate, 3mm × 2mm

DFN-8 Package

LTC2453 16-Bit I2C Ultra Tiny Delta Sigma ADC Differential Input, ±VCC Input Range, 60Hz Output Rate, 3mm × 2mm

DFN-8 Package

LTC2970 Power Supply Monitor and Margining Controller 14-Bit ADC Monitoring Current and Voltages, Supplies from 8V to 15V

LTC4215 Positive Hot SwapTM Controller with ADC and I2C 8-Bit ADC Monitoring Current and Voltages, Supplies from 2.9V to 15V

LTC4260 Positive High Voltage Hot Swap Controller with

ADC and I2C

8-Bit ADC Monitoring Current and Voltages, Supplies from 8.5V to 80V

LTC4261/

LTC4261-2

Negative High Voltage Hot Swap Controller with

ADC and I2C

10-Bit ADC Monitoring Current and Voltages, Supplies from –12V

LTC6101/

LTC6101HV

High Voltage, High Side Current Sense Amplifier

in SOT-23 Package

Supplies from 4V to 60V (LTC6101) and 5V to 100V (LTC6101HV)

High Side Current, Input Voltage and Open Fuse Monitoring

with a Single LTC4151

CONDITION RESULT

NADIN ≥ 1.375 • NVIN Normal Operation

0.835 • NVIN ≤ NADIN < 1.375 • NVIN F2 is Open

0.285 • NVIN ≤ NADIN < 0.835 • NVIN F1 is Open

(Not Responding) Both F1 and F2 are Open

VIN1 AND VIN2 ARE WITHIN 20% APART. NADIN AND NVIN ARE DIGITAL CODES

MEASURED BY THE ADC AT THE ADIN AND VIN PINS, RESPECTIVELY.