Low-Power, Bidirectional I2C Isolators  - ISO1541


Low-Power, Bidirectional I2C Isolators


The ISO1540 and ISO1541 are low-power, bidirectional isolators that are compatible with I2C interfaces. These devices have their logic input and output buffers separated by TI’s Capacitive Isolation technology using a silicon dioxide (SiO2) barrier. When used in conjunction 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 opto-couplers. The ISO1540 and ISO1541 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 ideally fit for multi-master applications.

Isolated bidirectional communications is accomplished within these devices by offsetting the Side 1 Low-Level Output Voltage to a value greater than the Side 1 High-Level Input Voltage thus preventing an internal logic latch that otherwise would occur with standard digital isolators.


  • Isolated Bidirectional, I2C Compatible,
  • 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

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Parametrics Compare all products in Isolated I2C

UL 1577 Isolation Voltage (Single) (Vrms)
DIN V VDE V 0884-10 Transient Overvoltage Rating (Vpk)
DIN V VDE V 0884-10 Surge Voltage Rating (Vpk)
DIN V VDE V 0884-10 Working Voltage (Vpk)
CSA Isolation Rating (Vrms)
CSA 60950-1 Basic Working (Vrms)
CSA 61010-1 Basic Working (Vrms)
CSA 61010-1 Reinforced Working (Vrms)
Datarate (Mbps)
Number of Channels (#)
Serial Clock
Serial Data
Operating Temperature Range (C)
Approx. Price (US$)
ISO1541 ISO1540
2.5     2.5    
4.3     4.2    
4     4    
0.0566     0.0566    
2.8     2.8    
390     390    
300     300    
150     150    
1     1    
2     2    
Uni-directional     Bi-directional    
Bi-directional     Bi-directional    
-40 to 125     -40 to 125    
8SOIC     8SOIC    
1.80 | 1ku     2.00 | 1ku    

Companion parts

Part # Name Product Family Comments
SN6501   Transformer Driver for Isolated Power Supplies   CONVERTER (INTEGRATED SWITCH) - ISOLATED DC/DC CONVERTER    Transfomer driver for generating isolated secondary power supply  
TPS76350   Single Output LDO, 150mA, Fixed(5.0V), Low Quiescent Current, Thermal Protection   LINEAR REGULATOR (LDO) - SINGLE CHANNEL LDO    Low-dropout (LDO) voltage regulator for isolated secondary power supply  
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