NXP Semiconductors PCA9535CD,118

Overview

PCA9535CD,118 from NXP Semiconductors is a 16-bit I²C-bus/SMBus GPIO expander in SO24 package, featuring 5 V-tolerant open-drain I/Os, active-low interrupt output, and individual I/O configuration registers. It operates from 2.3 V to 5.5 V supply, supports up to 400 kHz clock frequency, and is used for expanding digital control in ACPI power switches, LED drivers, push-button interfaces, and sensor subsystems.

For engineers reviewing the PCA9535CD,118 datasheet, PCA9535CD,118 pinout, PCA9535CD,118 application, or PCA9535CD,118 equivalent, key selection criteria include its open-drain I/O architecture (vs. totem-pole PCA9535), 24-pin SOIC thermal profile, interrupt-driven input change detection, and compatibility with multi-device I²C bus addressing via A0–A2 pins.

Technical Context

The PCA9535CD,118 implements two independent 8-bit I/O ports (Port 0 and Port 1), each with dedicated Configuration, Input, Output, and Polarity Inversion registers. Its open-drain I/O structure eliminates internal pull-up resistors-reducing standby current-and requires external pull-ups for logic HIGH assertion.

Interrupt generation is edge-sensitive and triggered only when an input-configured pin changes state relative to its Input Port register value; reading the corresponding Input Port register clears the INT signal. The device uses a fixed I²C address prefix (0x40–0x47) determined by A0–A2 pins and supports standard/fast-mode I²C timing up to 400 kHz.

Key Specifications

Pinout & Package

PCA9535CD,118 is housed in a plastic small outline package (SO24) with 24 leads and 7.5 mm body width (SOT137-1). The package supports surface-mount assembly and provides adequate thermal dissipation for typical I/O expansion applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar GPIO expander applications.

Compared with PCA9535D,118 and PCA9555D,118, the PCA9535CD,118 delivers lower static power consumption and true open-drain flexibility-critical for driving LEDs, interfacing with 5 V logic, or implementing wired-OR interrupt buses-without sacrificing register-level compatibility or I²C address scalability.

Availability

PCA9535CD,118 is available at Aetrix Electronics and suitable for industrial HMIs, ACPI-compliant power management systems, and sensor subsystem expansion requiring stable component supply across long production lifecycles.

Supply support for PCA9535CD,118 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 PCA9535 family was designed specifically to extend I²C-based microcontroller I/O capability in space-constrained, low-power systems-emphasizing interrupt efficiency, voltage flexibility, and multi-device bus scalability.

FAQ

What is the I²C address range supported by PCA9535CD,118?

The PCA9535CD,118 supports seven programmable slave addresses (0x40–0x46) plus one fixed address (0x47), determined by the logic states of A0, A1, and A2 pins. This allows up to eight PCA9535CD,118 devices-or mixed PCA9535/PCA9535C/PCA9555 variants-to coexist on the same I²C bus without address conflict.

Does PCA9535CD,118 require external pull-up resistors on its I/O pins?

Yes, PCA9535CD,118 requires external pull-up resistors on all I/O pins because it features open-drain outputs with no internal pull-ups. This design minimizes standby current and enables flexible voltage translation-e.g., connecting 3.3 V PCA9535CD,118 I/Os to 5 V peripherals using appropriate pull-up voltage and resistor values.

How does the interrupt function work on PCA9535CD,118?

The INT pin on PCA9535CD,118 is an active-low open-drain output that asserts when any I/O configured as an input changes state relative to its stored value in the Input Port register. Reading the corresponding Input Port register (Port 0 or Port 1) clears the interrupt condition-ensuring precise event capture without missed edges.

Can PCA9535CD,118 drive LEDs directly?

Yes, PCA9535CD,118 can drive LEDs directly in sink configuration (common-anode), as its open-drain I/Os support up to 25 mA per pin (per NXP characterization). No internal pull-up current path exists, eliminating unintended leakage-making it more efficient than PCA9535 or PCA9555 for LED applications.

What is the difference between PCA9535CD,118 and PCA9535D,118?

The PCA9535CD,118 uses open-drain I/Os only, whereas PCA9535D,118 uses totem-pole outputs with internal weak pull-ups. This makes PCA9535CD,118 ideal for wired-OR interrupt buses, 5 V level shifting, and ultra-low-power operation-while PCA9535D,118 suits push-pull signaling and legacy designs relying on internal pull-ups.