ISO1541

• 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
• –40°C to +125°C operating temperature
• ±50-kV/µs transient immunity (Typical)
• HBM ESD protection of 4 kV on all pins;
  8 kV on bus pins
• Safety-related certifications:
  • 4242-V_PK isolation per DIN VDE V 0884-11:2017-01
  • 2500-V_RMS isolation for 1 minute per UL 1577
  • CSA approval per IEC 60950-1 and IEC 62368-1 end equipment standards
  • CQC basic insulation per GB4943.1-2011

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The ISO1540 and ISO1541 devices are low-power, 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 and ISO1541 devices enable a complete isolated I²C interface to be implemented within a small form factor.

The ISO1540 has two isolated bidirectional channels for clock and data lines while the ISO1541 has a bidirectional data and a unidirectional clock channel. The ISO1541 is useful in applications that have a single master while the ISO1540 is suitable for multi-master applications. For applications where clock stretching by the slave is possible, the ISO1540 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 high-level input voltage on side 1, thus preventing an internal logic latch that otherwise would occur with standard digital isolators.