Overview
The PCA9555, produced by Texas Instruments, is a 16-bit I2C and SMBus I/O expander designed to provide general-purpose remote I/O expansion for most microcontroller families. This device operates within a voltage range of 2.3 V to 5.5 V and is compatible with the I2C interface, utilizing serial clock (SCL) and serial data (SDA) lines. At power-on, the I/Os are configured as inputs, but can be reconfigured as outputs by the system master through the I/O configuration bits. The PCA9555 includes features such as low standby-current consumption, open-drain active-low interrupt output, and high-current drive capability for directly driving LEDs.
Key Specifications
| Parameter | Description | Value |
|---|---|---|
| VCC Operating Range | Supply Voltage | 2.3 V to 5.5 V |
| I2C Bus Speed | Fast I2C Bus Speed | 400 kHz |
| Addressing | Number of Address Pins | Three hardware address pins (up to eight devices) |
| Interrupt Output | Type of Interrupt Output | Open-drain active-low |
| Standby Current | Maximum Standby Current | 1 μA |
| ESD Protection | Human-Body Model, Machine Model, Charged-Device Model | 2000 V, 200 V, 1000 V respectively |
| Output Drive Capability | High-Current Drive for LEDs | Up to 25 mA per pin |
| Packages Available | Package Types | SSOP (24), QSOP (24), TSSOP (24), TVSOP (24), SOIC (24), VQFN (24) |
Key Features
- Low standby-current consumption of 1 μA max
- 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
- Addressing by three hardware address pins for up to eight devices
- Polarity inversion register for active high or active low operation
- Latched outputs with high-current drive capability for directly driving LEDs
- ESD protection exceeding JESD 22 standards
Applications
- Servers
- Routers (Telecom Switching Equipment)
- Personal Computers
- Personal Electronics
- Industrial Automation Equipment
- Products with GPIO-limited processors
Q & A
- What is the operating voltage range of the PCA9555?
The PCA9555 operates within a voltage range of 2.3 V to 5.5 V.
- What is the speed of the I2C bus supported by the PCA9555?
The PCA9555 supports a 400 kHz fast I2C bus.
- How many devices can be addressed using the PCA9555?
The PCA9555 can address up to eight devices using three hardware address pins.
- What type of interrupt output does the PCA9555 have?
The PCA9555 has an open-drain active-low interrupt output.
- What is the maximum standby current consumption of the PCA9555?
The maximum standby current consumption is 1 μA.
- What level of ESD protection does the PCA9555 offer?
The PCA9555 offers ESD protection exceeding JESD 22 standards: 2000 V Human-Body Model, 200 V Machine Model, and 1000 V Charged-Device Model.
- Can the PCA9555 drive LEDs directly?
Yes, the PCA9555 has latched outputs with high-current drive capability for directly driving LEDs.
- What types of packages are available for the PCA9555?
The PCA9555 is available in SSOP, QSOP, TSSOP, TVSOP, SOIC, and VQFN packages.
- Is the PCA9555 compatible with most microcontrollers?
Yes, the PCA9555 is compatible with most microcontroller families.
- What is the purpose of the polarity inversion register in the PCA9555?
The polarity inversion register allows for active high or active low operation of the input port.
