Data Sheet

ADBMS6821/ADBMS6822

Single/Dual isoSPI Transceiver

Rev. B

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FEATURES

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Up to 2 Mbps isolated bidirectional serial data communications

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Drop in compatible: single (ADBMS6821) and dual

(ADBMS6822)

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Fully independent dual transceivers (ADBMS6822)

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Simple galvanic isolation using capacitors or transformers

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Bidirectional interface over a single twisted pair

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Supports cable lengths up to 100 meters

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Very low EMI susceptibility and emissions

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LPCM support for ADBMS battery monitors

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Interrupt output for LPCM system wake-up

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4 Mbps unidirectional mode

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Requires no software changes in most SPI systems

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Ultra-low idle current

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Automatic interface wake-up detection

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Operating temperature range: −40°C to +125°C

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3.0 V to 5.5 V isoSPI driver power supply

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1.7 V to 5.5 V interface to microcontrollers

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3.0 V to 30 V input for powering wake-up and monitoring func-

tions (12 V battery compatible)

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Available in 32-lead, side solderable LFCSP package

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AEC-Q100 qualified for automotive applications

APPLICATIONS

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Electric and hybrid electric vehicles

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Backup battery systems

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Industrial networking

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Remote sensors

TYPICAL APPLICATION CIRCUIT

A typical application of the ADBMS6822 in a system with the

ADBMS6815 battery monitor is shown in Figure 1.

Figure 1. Typical Application Circuit

GENERAL DESCRIPTION

The ADBMS68211 (single) and ADBMS68221 (dual) provide bidir-

ectional isolated serial-port interface (isoSPI™) communications

between two isolated devices through a single twisted pair connec-

tion for each data link. Each transceiver encodes logic states into

signals that are transmitted across an isolation barrier to another

transceiver. The receiving device decodes the transmission and

drives the peripheral bus to the appropriate logic states. The isola-

tion barrier can be bridged by capacitors or by a pulse transformer

to achieve hundreds of volts of isolation.

The ADBMS6821/ADBMS6822 transceivers drive differential sig-

nals using matched source and sink currents, which eliminate

the requirement for a transformer center tap and reducing electro-

magnetic interference (EMI). Precision window comparators in the

receiver detect the differential signals.

The transceivers can be paired with advanced ADBMS stack moni-

tors to enable cell voltage and sensor monitoring even while the

system controller is powered down (low-power cell monitoring, or

LPCM). The transceivers provide a timeout function that wakes up

or alerts the system when a pass heartbeat message has not been

received in the programmed time period.

Throughout this data sheet, all pin names refer to both transceivers

on the ADBMS6822. For example, VDD refers to both VDD and

VDD2.

1 Protected by U.S. patents, including 8,908,779.