1 Features

• 26 Channels

– 26S – 0 to 5.5V range for cell, -2V to 2V range

for busbar

– 143V Abs Max Rating, 9V minimum

– Busbar support on every channel, except first

channel.

– Stackable up to 128 devices

• Voltage Accuracy

– <1.7 mV accuracy, -40 to 125C, Cell: 0V to

5.5V

– Dedicated ADC per channel. Synchronized

redundant measurement.

• Passive Cell Balancing with integrated FETs up

to 300mA odd/even balancing with programmable

PWM control

• Smart EIS Engine

– Integrated Electrochemical Impedance

Spectroscopy measurement engine

– Impedance Accuracy: 1% (with 1A excitation

and 200uΩ impedance)

– Measurement frequency: 0.01Hz to 3.5kHz

– < 5us I/V synchronization from device to device

– Support for global and local excitation

• Sensor & GPIOs

– 20 GPIO: Temp Sensor (NTC/PTC), voltage

measurement, Interrupt

– SPI / I2C Interface

– Temperature Threshold (Active / Sleep)

– Pressure Threshold / Peak Detector (Active /

Sleep)

– On-chip memory for one-time custom

programming

• Diagnostics & Protection

– Monitoring

• Low Power Monitoring Mode (<20uA power

consumption)

• Cell Over-voltage, Under-voltage (OVUV)

• Cell Over-temperature, Under-temperature

(OTUT)

• 2x die temperature monitors

• Supply (BAT)

• Open Wire Detection

– Reverse Wake Up based on selectable faults

– Redundancy Paths

• Cell Voltage

• GPIO/NTC Voltage

• Limp Home Mode

– Diagnostics

• Automatic diagnostics during cell balancing

in active mode

– Functional Safety Compliant

• Developed under ISO26262

• System and hardware capability up to ASILD

• Upgraded Daisy Chain Interface

– 2Mbps bus speed, Up to 4Mbps with dual SPI

– <+/-5us device to device synchronization

– Closed Loop BCI: 200mA, Open Loop BCI:

300mA

– Isolation: Transformer or capacitor-only

– FDTI Time: <100ms for 800V packs or 250 cells

– Support for stack, ring, multidrop, and split-ring

– Device-to-device automatic communications

balancing

• Power

– Integrated DC-DC Converter

– Shutdown: <10uA

– Sleep Mode with monitoring: As low as 20uA

– Active Mode: <5mA

• Package

– 100-pin QFP, 4mm pitch

– PowerPad on bottom

2 Applications

• EV - Electric Vehicles

• ESS - Energy Storage Systems

3 Description

The BQ79826Z-Q1 is a new high-cell count 26S

stackable battery monitor that includes integrated

electrochemical impedance spectroscopy (EIS)

engine. The EIS engine provides a new way

to detect impedance changes in the cell that

allows for monitoring of aging, temperature, SoC,

thermal runaway and many other cell parameters. In

addition, the device incorporates an intelligent sensor

controller to enable easier and more reliable sensor

measurements.