Part Number: TCA9555PWR

Manufacturer: Texas Instruments

Description: Interface – I/O Expanders Remote 16B I2C & SMBus I/O Expander

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Technical Specifications of TCA9555PWR

Datasheet  TCA9555PWR datasheet
Category Integrated Circuits (ICs)
Family Interface – I/O Expanders
Manufacturer Texas Instruments
Packaging Cut Tape (CT)
Part Status Active
Number of I/O 16
Interface I2C, SMBus
Interrupt Output Yes
Features POR
Output Type Push-Pull
Current – Output Source/Sink 10mA, 25mA
Frequency – Clock 400kHz
Voltage – Supply 1.65 V ~ 5.5 V
Operating Temperature -40°C ~ 85°C
Mounting Type Surface Mount
Package / Case 24-TSSOP (0.173″, 4.40mm Width)
Supplier Device Package 24-TSSOP

TCA9555PWR Description

This 16-bit I/O expander for the I2C bus has a VCC range of 1.65 V to 5.5 V, making it appropriate for various applications. It can be used with various microcontroller families to add remote I/O for several uses because of its I 2C interface. The TCA9555 contains four registers: Polarity Inversion (active high/active low operation, respectively, in either way), Input Port, Output Port, and Configuration (input/output selection).

All input/output (I/O) ports are in input mode when power is first provided. By writing to the correct bits in the corresponding registers, the system master can configure the I/Os as inputs or outputs. The data is kept in a separate register for each input and output. Use the Polarity Inversion register to alter the polarity of the Input Port register.

TCA9555PWR Features

  • Low maximum standby current consumption of 3.5 A.
  • Expander for 2C to Parallel Port.
  • Output with Open-Drain Active-Low Interrupts
  • I/O Ports That Tolerate 5 V.
  • suitable with the majority of microcontrollers.
  • Fast I 2C Bus 400 kHz.
  • Slave Address Configurable with 3 Address Pins
  • Register for Polarity Inversion.
  • Latched Outputs for Direct LED Driving with High Current Drive Capability
  • The performance of the latch exceeds 100 mA per.

Detailed Description


For supply voltages ranging from 1.65 V to 5.5 V, the TCA9555 is a 16-bit I/O expander for the I2C bus. For most families of microcontrollers, it adds remote I/O via the I 2C interface, which is useful for various tasks. The INT output of the TCA9555 can be wired to the interrupt input of a microcontroller. Without using the I 2C bus, the remote I/O can signal the microcontroller with an interrupt if data has arrived at one of its ports. That’s why the TCA9555 doesn’t have to become anything more than a slave component.

Feature Description

● Hardware Address Pins

The I 2C address of the TCA9555 can be set by connecting the three hardware address pins (labeled A0, A1, and A2) to VCC and GND, respectively, to represent individual bits of the address. This allows for up to eight TCA9555 to share a bus without causing any address collisions.

● Interrupt (INT) Output

When the port inputs’ rising and falling edges change in the input mode, an interrupt will be fired. The INT signal is operational as of tiv. The interrupt circuit is reset when the data on the port is changed back to what it was before the interrupt or when data is read from the port that caused the interrupt. When read mode, the reset occurs on the ACK bit after the SCL signal’s rising edge. Remember that the INT is cleared at the ACK just before transmitting the changed data byte. When the next clock cycle begins, an interrupt that happened during the ACK clock pulse will be reset, possibly rendering it useless (or at least very brief).

Any further modifications to the I/Os are recorded and delivered as INT once the device is reset. Reading or writing to another device does not impact the interrupt circuit, and an output pin cannot start an interrupt. After converting an I/O from output to input, a false interrupt could be produced if the state of the pin does not match the values of the Input Port register. Both readings from port 0 and reading from port 1 do not end the interruption caused by the reading from port 0, respectively. A pull-up resistor to VCC is necessary due to the open-drain design of the INT (usually 10 k in value).

Device Functional Modes

● Power-On Reset (POR)

The TCA9555 features an internal power-on reset circuit that keeps it reset until VCC reaches VPOR when power is introduced (from 0 V). After removing the reset condition, the TCA9555 registers and the I 2C-SMBus state machine initialize to their default states. After that, a power-reset cycle is performed by bringing VCC below VPORF and back up to the operating voltage.

● Powered-Up

The POR occurs when power is provided to VCC more than VPOR, and the device is operational at this point. The gadget is ready to receive. I 2C requests and actively watches the inputs for any changes.


● I/O Port

A high-impedance input is created by turning off FETs Q1 and Q2 in an I/configuration O’s as an input. Up to 5.5 V above VCC, the input voltage can be increased. Depending on the value stored in the Output Port register, Q1 or Q2 will be active if the I/O is set up as an output. In this scenario, connections between the I/O pin and VCC or GND have low impedance. This I/O pin must not have more than the specified amount of external voltage supplied to it.

● I 2C Interface

The TCA9555 can be set up or checked for errors through the standard bidirectional I 2C interface, which requires a master device for control. A unique device address is used by each slave device on the I 2C bus to tell it apart from all the other slaves sharing the same bus. When first powered up, many slave devices must have their behaviors predetermined through configuration. This is done whenever the master uses the slave’s unique register addresses to access the slave’s internal register mappings. There may be a single register or several registers in a given device.


If the TCA9555 experiences a problem (with the data output, input, or even power) or data corruption, you can restore factory settings by pressing the reset button while the device is turned on. When using a power-on reset, a full reset requires a power cycle. When a device is powered on for the first time in a certain application, it also does a reset.

If you need additional information or wish to order TCA9555, you’ve come to the correct place. Give us a call at ICRFQ, your leading electronic distributor in China, and we will ensure you receive the best goods at a reasonable price.

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