TCAL9539PWR

Overview

The TCAL9539PWR is a low-voltage 16-bit I2C and SMBus I/O expander designed for operation within a 1.08 V to 3.6 V supply range. It provides 16 general-purpose parallel input/output ports accessible via the two-line bidirectional I2C bus, supporting clock frequencies of 100 kHz, 400 kHz, and 1 MHz. The device features an active-low hardware reset input and an open-drain active-low interrupt output. Key electrical characteristics include a typical standby current of 1 µA at 1.8 V and ESD protection ratings exceeding 2000 V (HBM) and 1000 V (CDM). It is housed in a 24-pin TSSOP package.

Feature Summary

• Agile I/O functionality with programmable output drive strength, configurable pull-up/pull-down resistors, and selectable push-pull or open-drain output structures.
• Hardware address pins allow multiple devices to share the same I2C or SMBus bus without software conflict.
• Interrupt output activates on input state changes, enabling processor notification without continuous bus polling.
• Integrated noise filters on SCL and SDA inputs enhance signal integrity in electrically noisy environments.

Applications

• Servers
• Routers and telecom switching equipment
• Personal computers
• Industrial automation systems

Procurement Notes

Verify the specific package variant during procurement, as the base part number may correspond to different physical packages such as TSSOP or WQFN. Confirm that the ordering suffix matches the required mechanical footprint and thermal performance specifications for the target design.

Selection Notes

Select this component when system architecture requires expanding GPIO capabilities beyond the main processor limits while operating under strict low-voltage constraints. Ensure the host controller supports the desired I2C clock speed and can manage the interrupt logic if real-time response is required.

Part Context

This device belongs to the TCAL9539 family of low-voltage I/O expanders. It shares functional similarities with the TCA9539 but operates at lower voltage levels and supports higher data rates up to 1 MHz. The PWR suffix typically denotes the TSSOP-24 package variant.

Replacement Considerations

TCAL9539RTWR

FAQ

How does the device handle simultaneous switching noise?

The TCAL9539 allows users to program the output drive strength for each GPIO independently. Reducing the drive strength mitigates Simultaneous Switching Noise (SSN) by lowering peak currents during output transitions.

What is the default state of the I/O ports upon power-up?

At power-on or after a reset, all I/O ports are configured as inputs by default. The system controller must write to the Configuration registers to change them to outputs.

Can the interrupt pin be used without an external resistor?

No, the INT output has an open-drain structure and requires an external pull-up resistor connected to VCC to function correctly.