NXP Semiconductors PCA8575PW,112

Overview

PCA8575PW,112 from NXP Semiconductors is a 16-bit remote I/O expander IC for I²C-bus systems, providing quasi-bidirectional GPIO with interrupt signaling. It operates from 2.3 V to 5.5 V, supports 400 kHz Fast-mode I²C, features 25 mA per-pin sink capability, and initializes all I/Os as inputs at power-up via internal POR. It is used in industrial control panels to extend microcontroller GPIO for LED status indicators and sensor interface logic.

For engineers reviewing the PCA8575PW,112 datasheet, PCA8575PW,112 pinout, PCA8575PW,112 application, or PCA8575PW,112 equivalent, key selection criteria include its active-low open-drain INT output timing behavior during byte-wise read operations, 8 programmable slave addresses via AD0–AD2, latched output architecture enabling direct LED drive, and 400 mA total package sink current limit.

Technical Context

The PCA8575PW,112 implements a two-byte register map where P00–P07 are controlled by the first data byte and P10–P17 by the second, with automatic wraparound on successive writes. Its quasi-bidirectional I/O architecture uses internal current sources (IOH) and strong transient pull-ups (Itrt(pu)) to ensure fast rising edges without external components.

Interrupt generation occurs on any port input edge (rising or falling), and INT is cleared byte-wise: reading the first byte clears P0n-associated interrupts only; reading the second byte clears P1n-associated interrupts. This differs from PCF8575, which clears INT only after both bytes are read.

Key Specifications

Pinout & Package

TSSOP24 package (SOT355-1): plastic thin shrink small outline, 24 leads, body width 4.4 mm, lead pitch 0.65 mm, exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I/O expander applications.

Compared with PCF8575T/3,118 and PCA9555D,112, the PCA8575PW,112 delivers superior interrupt precision for input monitoring while maintaining lowest standby current and highest per-pin sink strength - making it ideal for industrial LED control where deterministic response and minimal BOM count are critical.

Availability

PCA8575PW,112 is available at Aetrix Electronics and suitable for industrial control panels, medical equipment interfaces, and LED signage systems requiring stable component supply and long-term production continuity.

Supply support for PCA8575PW,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications.

The PCA8575 product line was designed specifically for robust, low-power I²C-based GPIO expansion in harsh industrial environments - emphasizing interrupt reliability, wide voltage operation, and direct LED drive capability.

FAQ

What is the maximum sink current per I/O pin on the PCA8575PW,112?

The PCA8575PW,112 supports up to 25 mA sink current per I/O pin when VOL = 0.5 V and VDD = 4.5 V. This value is confirmed in Table 5 of the NXP datasheet under "IOL LOW-level output current". Exceeding this limit risks violating absolute maximum ratings and may cause thermal stress or output voltage degradation. The PCA8575PW,112 must not be operated beyond its specified 25 mA per-pin limit to ensure long-term reliability.

How does the interrupt behavior of PCA8575PW,112 differ from PCF8575?

The PCA8575PW,112 clears its INT output byte-wise: reading the first data byte clears interrupts associated with P00–P07, while reading the second byte clears those for P10–P17. In contrast, the PCF8575 clears INT only after both bytes are read. This difference is documented in Section 10.3 of the PCA8575 datasheet. For systems relying on precise interrupt source identification, the PCA8575PW,112 provides finer-grained control than the PCF8575.

Which package type corresponds to the PCA8575PW,112 orderable part number?

The PCA8575PW,112 uses the TSSOP24 package (SOT355-1), defined as a plastic thin shrink small outline package with 24 leads, 4.4 mm body width, and 0.65 mm lead pitch. This is explicitly stated in the Ordering Information table (Table 1) of the NXP datasheet. The "PW" suffix in the part number directly denotes the TSSOP24 variant, distinguishing it from SO24 (PCA8575D), SSOP24 (PCA8575DB), or QFN variants.

Can PCA8575PW,112 operate with a 3.3 V microcontroller I²C bus?

Yes, the PCA8575PW,112 is fully compatible with 3.3 V I²C buses. Its I²C interface operates from 2.3 V to 5.5 V, and its I/O pins are 5.5 V tolerant - meaning SDA and SCL signals at 3.3 V levels meet VIH (≥0.7×VDD) and VIL (≤0.3×VDD) thresholds. Pull-up resistors should be referenced to the 3.3 V rail. The PCA8575PW,112 functions correctly in mixed-voltage systems without level shifters.

Does PCA8575PW,112 require external pull-up resistors on SDA and SCL lines?

Yes, the PCA8575PW,112 requires external pull-up resistors on both SDA and SCL lines. Its I²C interface uses open-drain outputs, and no internal pull-ups are integrated. Typical values range from 1.8 kΩ to 10 kΩ depending on bus capacitance and speed; for 400 kHz Fast-mode operation with ≤400 pF total bus capacitance, 2.2 kΩ is commonly used. This requirement is specified in Section 9 of the NXP datasheet and applies to all I²C implementations using the PCA8575PW,112.