The TCA9535 is a 24-pin device that provides 16 bits of general purpose parallel input and output (I/O) expansion for the two-line bidirectional I2C bus or (SMBus) protocol. The device can operate with a power supply voltage ranging from 1.65V to 5.5V.
The TCA9535 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 controller can enable the I/Os as either inputs or outputs by writing to the I/O configuration bits.
The TCA9535 is identical to the TCA9555, except that the TCA9535 does not include the internal I/O pullup resistor, which requires pull ups and pull downs on unused I/O pins when configured as an input and undriven.
| Top documentation | Type | Title | Format options | Date |
|---|---|---|---|---|
| * | Data sheet | TCA9535 Low Voltage 16-Bit I2C and SMBus Low-Power I/O Expander | PDF | HTML | Sep 16, 2026 |
| Application note | I2C: What is the Auto Increment Feature? | PDF | HTML | Jul 5, 2024 | |
| Application note | Understanding Transient Drive Strength vs. DC Drive Strength in Level-Shifters (Rev. A) | PDF | HTML | Jul 3, 2024 | |
| Application note | I2C Dynamic Addressing | Apr 25, 2019 | ||
| Application note | Choosing the Correct I2C Device for New Designs | PDF | HTML | Sep 7, 2016 | |
| Application note | Understanding the I2C Bus | PDF | HTML | Jun 30, 2015 | |
| Application note | Maximum Clock Frequency of I2C Bus Using Repeaters | May 15, 2015 | ||
| Application note | I2C Bus Pull-Up Resistor Calculation | PDF | HTML | Feb 13, 2015 |
For additional terms or required resources, click any title below to view the detail page where available.
The IO expander evaluation module (EVM) lets you evaluate TI's portfolio of SMBus and I2C IO expander line devices. The TCA6424A and TCA9539 come installed on the board. The 24-pin TSSOP footprint also supports TCA6408A, TCA6416A, TCA9534, TCA9534A, TCA9535, TCA9538, TCA9554, TCA9554A and TCA9555.
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| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| WQFN (RTW) | 24 | Ultra Librarian |
| TSSOP (PW) | 24 | Ultra Librarian |
| VQFN (RGE) | 24 | Ultra Librarian |
| SSOP (DB) | 24 | Ultra Librarian |
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