MAX11068,pdf (battery-monitoring smart data acquisition)

The MAX11068 is a programmable, highly integrated,

high-voltage, 12-channel, battery-monitoring smart dataacquisiTIon

interface. It is opTImized for use with batteries

used in automoTIve systems, hybrid electric battery

packs, electric cars, and any system that stacks long

series strings of secondary metal batteries. This highly

integrated battery sensor incorporates a simple state

machine and a high-speed I2C bus for SMBusK-laddered

serial communicaTIon.

The MAX11068 analog front-end combines a 12-channel

voltage measurement data-acquisition system with a highvoltage

switch bank input. All measurements are done

differentially across each cell. The full-scale measurement

range is from 0 to 5.0V, with full stated accuracy guaranteed

from 0.5V to 4.7V. The input mux/switch bank allows

for differential measurement of each cell in a series stack.

A high-speed, 12-bit successive approximation (SAR) A/D

converter is used to digitize the cell voltages. All 12 cells

can be measured in less than 107Fs. The MAX11068 uses

a two-scan approach for collecting cell measurements

and correcting them for errors. The first phase of the scan

is the acquisition phase where the voltages of all 12 cells

are acquired. The second phase is the error-cancellation

phase where the ADC input is chopped to remove errors.

This two-phase approach yields excellent accuracy over

temperature and in the face of extreme noise in the system.

The MAX11068 incorporates an internal oscillator that

generates a 6.0MHz system clock with Q3.0% accuracy.

The MAX11068 consumes less than 2.0mA from the power

supply while in data-acquisition modes. This current is

reduced to 75FA in standby mode and less than 1FA in

shutdown mode. The device is packaged in a 38-pin,

9.7mm x 4.4mm x 1.0mm TSSOP package that is lead free

and RoHS compliant and is designed to operate over the

AEC-Q100 Grade 2, -40NC to +105NC temperature range.

Applications

High-Voltage, Multicell Series-Stacked-Battery

Systems

Electric and Hybrid Electric Vehicle (HEV)

Battery Packs

Electric Bikes

High-Power Battery Backup Systems

SuperCap Backup Systems

Power Tools