PCAL9722HN/Q900MP

I/o Expanders Overview

The PCAL9722HN/Q900MP is a 22-bit general-purpose I/O expander featuring an SPI interface and Agile I/O capabilities. It supports bidirectional voltage translation between a 1.1 V to 5.5 V SPI bus side (VDD(SPI)) and a 1.8 V, 2.5 V, 3.3 V, or 5.5 V Port P side (VDD(P)). The device operates at up to 5 MHz SCLK speed with typical standby current of 2.0 μA at 3.3 V. It includes Schmitt trigger inputs, noise filters, and 5.5 V tolerant pins. The package is HVQFN32 (SOT617-3), measuring 5 mm x 5 mm x 0.85 mm. It is AEC-Q100 Grade 1 compliant for automotive applications.

I/o Expanders Feature Summary

• Agile I/O configuration allowing pin-selectable push-pull or open-drain outputs with four programmable drive strengths.
• Integrated hardware switch debounce and bit-wise interrupt masking with individual clear functionality.
• Input latch feature that holds input states until the register is read to minimize interrupt service response time.
• Programmable pull-up and pull-down resistors (100 kΩ) eliminating the need for discrete external components.

I/o Expanders Applications

• Battery-powered mobile applications interfacing with sensors, push buttons, and keypads.
• Industrial systems requiring remote I/O expansion across mixed power supply domains.
• IoT devices needing low-voltage microcontroller connectivity to higher voltage peripherals.
• Communication equipment utilizing SPI-based peripheral control.

I/o Expanders Procurement Notes

Verify the specific suffix Q900MP indicates the automotive-grade variant with an extended temperature range of -40 °C to +125 °C, distinct from the standard commercial grade (-40 °C to +85 °C). Confirm AEC-Q100 Grade 1 compliance requirements and PPAP submission needs directly with NXP support if deploying in automotive production lines. Ensure the HVQFN32 thermal pad grounding matches the PCB layout specifications.

I/o Expanders Selection Notes

Select this component when expanding GPIOs via SPI is required alongside significant voltage level differences between the host controller and target peripherals. The Agile I/O features are critical for designs needing configurable drive strength or internal pull-ups to reduce bill of materials. Consider the 22-bit capacity and single-chip addressability for space-constrained layouts where multiple smaller expanders would increase board complexity.

I/o Expanders Part Context

The PCAL9722HN/Q900MP belongs to NXP's ultra-low-voltage translating I/O expander family. It complements other SPI and I²C expanders like the PCAL9714 by offering higher channel density (22 bits vs 14 bits) and advanced interrupt handling. It serves as a bridge between modern low-voltage processors and legacy or high-voltage industrial/IoT sensors.

I/o Expanders Replacement Considerations

PCAL9722HN: Commercial grade version (-40 °C to +85 °C). PCAL9714HN/Q900MP: 14-bit variant with similar Agile I/O features but lower channel count. PCA9703PW/Q900MP: 16-bit SPI GPIO with 18V tolerance but different package and feature set.

I/o Expanders FAQ

How does the ADDR pin affect device addressing?

The ADDR pin allows selection between two fixed SPI target addresses (40h or 42h) by connecting it to VSS or VDD(SPI), enabling up to two devices to share the same SPI bus without additional logic.

What is the function of the Input Latch registers?

The Input Latch registers hold the state of an input pin that triggered an interrupt. This ensures the host controller reads the correct state even if the physical input signal changes before the interrupt is serviced.

Can the output drive strength be adjusted per pin?

Yes, each GPIO has independent output drive strength control via the Output Drive Strength registers, allowing selection of 0.25×, 0.5×, 0.75×, or 1× drive capability to optimize rise/fall times and power consumption.