1 Features

• Qualified for automotive applications

• AEC-Q100 qualified with the following results:

– Device temperature grade 1: –40°C to +125°C

ambient operating temperature

– Device HBM ESD classification level 3A

– Device CDM ESD classification level C6

• Functional Safety-Capable

– Documentation available to aid functional safety

system design: ISO1540-Q1, ISO1541-Q1

• Isolated bidirectional, I2C compatible,

communication

• Supports up to 1-MHz operation

• 3-V to 5.5-V supply range

• Open-drain outputs With 3.5-mA Side 1 and 35-

mA Side 2 sink current capability

• ±50-kV/μs transient immunity (Typical)

• Safety-related certifications:

– 4242-VPK isolation per DIN EN IEC 60747-17

(VDE 0884-17)

– 2500-VRMS isolation for 1 minute per UL 1577

– CSA approval per IEC 62368-1 end equipment

standard

– CQC basic insulation per GB4943.1-2011

2 Applications

• Electric and hybrid-electric vehicles

• Isolated I2C buses

• SMBus and PMBus interfaces

• Open-drain networks

• Motor control systems

• Battery management

• I2C level shifting

3 Description

The ISO1540-Q1 and ISO1541-Q1 devices are lowpower,

bidirectional isolators that are compatible

with I2C interfaces. These devices have logic input

and output buffers that are separated by Texas

Instruments Capacitive Isolation technology using a

silicon dioxide (SiO2) barrier. When used with isolated

power supplies, these devices block high voltages,

isolate grounds, and prevent noise currents from

entering the local ground and interfering with or

damaging sensitive circuitry.

This isolation technology provides for function,

performance, size, and power consumption

advantages when compared to optocouplers. The

ISO1540-Q1 and ISO1541-Q1 devices enable a

complete isolated I2C interface to be implemented

within a small form factor.

The ISO1540-Q1 has two isolated bidirectional

channels for clock and data lines while the ISO1541-

Q1 has a bidirectional data and a unidirectional clock

channel. The ISO1541-Q1 is useful in applications

that have a single controller while the ISO1540-

Q1 is suitable for multi-controller applications. For

applications where clock stretching by the target is

possible, the ISO1540-Q1 device should be used.

Isolated bidirectional communication is accomplished

within these devices by offsetting the low-level output

voltage on side 1 to a value greater than the highlevel

input voltage on side 1, thus preventing an

internal logic latch that otherwise would occur with

standard digital isolators.