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TCA9545A

ACTIVE

4-channel 1.65- to 5.5-V I2C/SMBus switch with interrupt, reset & voltage translation

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Data sheet

TCA9545A

ACTIVE
Data sheet Order now

Product details

Addresses 4 Supply voltage (max) (V) 5.5 Supply voltage (min) (V) 1.65 Features Interrupt pin, Reset pin Rating Catalog Frequency (max) (MHz) 0.4 Operating temperature range (°C) -40 to 85 Number of channels 4
Addresses 4 Supply voltage (max) (V) 5.5 Supply voltage (min) (V) 1.65 Features Interrupt pin, Reset pin Rating Catalog Frequency (max) (MHz) 0.4 Operating temperature range (°C) -40 to 85 Number of channels 4
TSSOP (PW) 20 41.6 mm² 6.5 x 6.4
  • 1-of-4 Bidirectional translating switches
  • I2C bus and SMBus compatible
  • Four active-low interrupt inputs
  • Active-low interrupt output
  • Active-low reset input
  • Two address terminals, allowing up to four devices on the I2C bus
  • Channel selection via I2C bus, in any combination
  • Power-up with all switch channels deselected
  • Low RON switches
  • Allows voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses
  • No glitch on power-up
  • Supports hot insertion
  • Low standby current
  • Operating power-supply voltage range of
    1.65 V to 5.5 V
  • 5.5 V Tolerant inputs
  • 0 to 400-kHz Clock frequency
  • Latch-Up performance exceeds 100 mA per JESD 78
  • ESD Protection exceeds JESD 22
    • 4000-V Human-body model (A114-A)
    • 1500-V Charged-device model (C101)
  • 1-of-4 Bidirectional translating switches
  • I2C bus and SMBus compatible
  • Four active-low interrupt inputs
  • Active-low interrupt output
  • Active-low reset input
  • Two address terminals, allowing up to four devices on the I2C bus
  • Channel selection via I2C bus, in any combination
  • Power-up with all switch channels deselected
  • Low RON switches
  • Allows voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses
  • No glitch on power-up
  • Supports hot insertion
  • Low standby current
  • Operating power-supply voltage range of
    1.65 V to 5.5 V
  • 5.5 V Tolerant inputs
  • 0 to 400-kHz Clock frequency
  • Latch-Up performance exceeds 100 mA per JESD 78
  • ESD Protection exceeds JESD 22
    • 4000-V Human-body model (A114-A)
    • 1500-V Charged-device model (C101)

The TCA9545A is a quad bidirectional translating switch controlled via the I2C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register. Four interrupt inputs (INT3–INT0), one for each of the downstream pairs, are provided. One interrupt (INT) output acts as an AND of the four interrupt inputs.

An active-low reset (RESET) input allows the TCA9545A to recover from a situation in which one of the downstream I2C buses is stuck in a low state. Pulling RESET low resets the I2C state machine and causes all the channels to be deselected, as does the internal power-on reset function.

The pass gates of the switches are constructed such that the VCC terminal can be used to limit the maximum high voltage, which will be passed by the TCA9545A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O terminals are 5.5 V tolerant.

The TCA9545A is a quad bidirectional translating switch controlled via the I2C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register. Four interrupt inputs (INT3–INT0), one for each of the downstream pairs, are provided. One interrupt (INT) output acts as an AND of the four interrupt inputs.

An active-low reset (RESET) input allows the TCA9545A to recover from a situation in which one of the downstream I2C buses is stuck in a low state. Pulling RESET low resets the I2C state machine and causes all the channels to be deselected, as does the internal power-on reset function.

The pass gates of the switches are constructed such that the VCC terminal can be used to limit the maximum high voltage, which will be passed by the TCA9545A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O terminals are 5.5 V tolerant.
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Technical documentation

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Type Title Date
* Data sheet TCA9545A Low Voltage 4-channel I2C and SMbus Switch With Interrupt Logic and Reset Functions datasheet (Rev. D) PDF | HTML 29 Oct 2019
Application note I2C Solutions for Hot Swap Applications (Rev. A) 31 Jan 2023
Application note I2C Dynamic Addressing 25 Apr 2019
Application note Choosing the Correct I2C Device for New Designs PDF | HTML 07 Sep 2016
Selection guide I2C Infographic Flyer 03 Dec 2015
Application note Understanding the I2C Bus PDF | HTML 30 Jun 2015
Application note Maximum Clock Frequency of I2C Bus Using Repeaters 15 May 2015
Application note I2C Bus Pull-Up Resistor Calculation PDF | HTML 13 Feb 2015

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