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1.65 to 5.5V 16-Bit I2C and SMBus I/O Expander With Interrupt Output and Configuration Registers


Package | PIN: TSSOP (PW) | 24
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $1.26
10-24 $1.13
25-99 $1.05
100-249 $0.91
250-499 $0.84
500-749 $0.71
750-999 $0.58
1000+ $0.53


  • Low Standby-Current Consumption of 3.5 µA Maximum
  • I2C to Parallel Port Expander
  • Open-Drain Active-Low Interrupt Output
  • 5-V Tolerant I/O Ports
  • Compatible With Most Microcontrollers
  • 400-kHz Fast I2C Bus
  • Configurable Slave Address with 3 Address Pins
  • Polarity Inversion Register
  • Latched Outputs With High-Current Drive Capability for Directly Driving LEDs
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 1000-V Charged-Device Model (C101)

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Texas Instruments  TCA9555PWR

This 16-bit I/O expander for the two-line bidirectional bus(I2C) is designed for 1.65-V to 5.5-V VCCoperation. It provides general-purpose remote I/O expansion for most microcontroller families viathe I2C interface.

The TCA9555 consists of two 8-bit Configuration (input or output selection), Input Port,Output Port, and Polarity Inversion (active high or active low operation) registers. At power on,the I/Os are configured as inputs. The system master can enable the I/Os as either inputs oroutputs by writing to the I/O configuration bits. The data for each input or output is kept in thecorresponding Input or Output register. The polarity of the Input Port register can be invertedwith the Polarity Inversion register.

The TCA9555 is identical to the TCA9535, except for the inclusion of the internalI/O pull-up resistor, which pulls the I/O to a default high when configured as an input andundriven.

Three hardware pins (A0, A1, and A2) are used to program theI2C address, which allows up to eight TCA9555 devices to share the sameI2C bus or SMBus. The fixed I2C address ofthe TCA9555 is the same as the PCF8575,PCF8575C, andPCF8574, allowing up to eight of thesedevices in any combination to share the same I2C bus or SMBus.