LTC4151-1 View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LTC4151-1

High Voltage I2C Current and Voltage Monitor

Linear Technology 

1 2 3 4 5 6 7 8 9 10 Next

BLOCK DIAGRAM

RS

VIN

2

VIN

1

10

SENSE+ SENSE–

INTERNAL

POWER

25X

735k

15k

GND

9

MUX

ADIN

5

LTC4151/LTC4151-1

8

SHDN

6.3V

(LTC4151)

5μA

SHUTDOWN

CONTROL

VREF = 2.048V

12-BIT ADC

3

4

ADR1 ADR0

DECODER

I2C/

REGISTERS

8

SDAO

(LTC4151-1)

7

SDA/SDAI

6V (LTC4151/

LTC4151-1)

6

SCL

6V

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OPERATION

The LTC4151/LTC4151-1 accurately monitor high side cur-

rent and voltages. These devices accept a wide range of

input voltages from as low as 7V up to 80V and consume

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 differen-

tial 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/LTC4151-1 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 conver-

sion is completed, the 12-bit digital code of the measured

voltage is held in the corresponding data registers.

The LTC4151/LTC4151-1 provide an I2C interface to read

the ADC data from the data registers and to program the

control register. Two three-state pins, ADR0 and ADR1,

are 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 provides

separate SDAI (input) and SDAO (inverted output) pins to

facilitate optoisolation.

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