LTC4151/LTC4151-1

7

41511fa

BLOCK DIAGRAM

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-

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 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 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.

SHUTDOWN

CONTROL

41511 BD

6.3V

REGISTERS

DECODER

SHDN

(LTC4151)

5μA

SDA/SDAI

(LTC4151/

LTC4151-1)

ADR1

SCL

SDAO

(LTC4151-1)

ADR0

GND

ADIN

15k

735k

INTERNAL

POWER

–

+

1

2

10

8

3

4

8

7

9

5

6V

6

6V

12-BIT ADC

MUX

25X