NXP Semiconductors PCA9665APW,118

Overview

PCA9665APW,118 from NXP Semiconductors is a Fast-mode Plus (Fm+) parallel-bus-to-I²C-bus controller IC that serves as a bidirectional protocol bridge between 8-bit parallel microcontrollers and the I²C-bus. It operates as master or slave, supports 1 Mbit/s data rates, delivers up to 25 mA drive on SCL/SDA, and integrates a 68-byte buffer and software reset-enabling robust I²C expansion in space-constrained industrial control modules.

For engineers reviewing the PCA9665APW,118 datasheet, PCA9665APW,118 pinout, PCA9665APW,118 application, or PCA9665APW,118 equivalent, this device is critical for adding high-speed, buffered I²C connectivity to legacy parallel-bus systems without external timing components, while supporting interrupt-driven or polled communication modes and glitch-free restarts for buffer-driver interfacing.

Technical Context

The PCA9665APW,118 implements full I²C-bus protocol handling-including arbitration, START/STOP generation, ACK/NACK management, and clock stretching-using an internal 32 MHz oscillator trimmed to ±15 % accuracy. Its register architecture separates four direct-access registers (I2CSTA, INDPTR, I2CDAT, I2CCON) from seven indirect-addressed registers (e.g., I2CSCLL, I2CADR, I2CPRESET), enabling precise control of bus timing, slave addressing, and timeout behavior.

It supports two operational modes: Byte mode for single-byte transfers and Buffered mode for up to 68-byte bursts, with status-driven interrupt signaling via the open-drain INT pin. The device maintains 5 V tolerant parallel I/Os while operating from 2.3 V to 3.6 V, and its "glitch-free" restart feature ensures reliable reinitialization when used with external buffer drivers in noise-sensitive environments.

Key Specifications

Pinout & Package

PCA9665APW,118 is housed in a 20-lead TSSOP package (SOT360-1), 4.4 mm body width, with exposed pad not electrically connected. All pins match the PCA9665PW footprint but implement PCA9665A-specific timing and restart behavior.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar parallel-to-I²C interface applications.

Compared with PCA9665PW,118 and PCA9564PW,118, the PCA9665APW,118 uniquely delivers 1 Mbit/s Fm+ operation, glitch-free restart for buffer-driver stability, and integrated 32 MHz oscillator-making it the only choice for new designs requiring high-speed, robust, and self-contained I²C expansion.

Availability

PCA9665APW,118 is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical infusion pump UIs, smart energy meter hubs, and industrial HMI systems requiring stable component supply across extended product lifecycles.

Supply support for PCA9665APW,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, with deep expertise in interface, power management, and secure MCU technologies.

The PCA9665A product line was designed specifically to extend I²C-bus capability into resource-constrained parallel-bus systems-emphasizing high-speed buffered transfer, robust bus recovery, and seamless integration with legacy microcontrollers.

FAQ

What is the maximum I²C-bus speed supported by the PCA9665APW,118?

The PCA9665APW,118 supports Fast-mode Plus (Fm+) operation at up to 1 Mbit/s. This is achieved using its internal 32 MHz oscillator and programmable SCL timing registers (I2CSCLL/I2CSCLH). Unlike standard Fast-mode (400 kbit/s), Fm+ allows higher data rates while maintaining backward compatibility with standard I²C slaves-provided pull-up strength and bus capacitance remain within specification limits. The PCA9665APW,118 achieves this without external timing components.

How does the "glitch-free restart" feature of the PCA9665APW,118 improve system reliability?

The "glitch-free restart" in the PCA9665APW,118 ensures deterministic reinitialization of the I²C state machine during software reset (via I2CPRESET register) or power-up, eliminating metastable states that could corrupt SCL/SDA lines when driving external buffer drivers. This prevents bus contention or spurious START/STOP conditions-critical in noise-prone industrial environments. The PCA9665APW,118 implements this behavior exclusively; the PCA9665PW,118 does not offer this guarantee.

Can the PCA9665APW,118 operate with a 5 V microcontroller parallel bus?

Yes-the parallel I/O pins (D0–D7, A0, A1, RD, WR, CE, RESET) of the PCA9665APW,118 are 5 V tolerant while the device itself operates from 2.3 V to 3.6 V on VDD. This eliminates the need for external level shifters when interfacing with legacy 5 V microcontrollers. However, the I²C-bus pins (SCL/SDA) remain 3.3 V compatible and require standard I²C pull-ups referenced to the I²C domain voltage-not the 5 V bus voltage.

What is the function of the INDPTR register in the PCA9665APW,118?

The INDPTR (Indirect Pointer) register in the PCA9665APW,118 is an 8-bit write-only register that selects which of the seven indirect-addressed registers (e.g., I2CSCLL, I2CADR, I2CPRESET) will be accessed next via the INDIRECT data field (A1=1, A0=0). Writing a value (00h–06h) to INDPTR configures subsequent reads/writes to the corresponding indirect register-enabling compact register access without dedicated address lines. This mechanism is essential for configuring clock timing, slave addressing, and timeout behavior in the PCA9665APW,118.

Does the PCA9665APW,118 support multi-master I²C-bus arbitration?

Yes-the PCA9665APW,118 fully implements I²C-bus arbitration logic per the Philips I²C specification. When operating as a master, it monitors SDA during START condition transmission and automatically relinquishes bus control if another master pulls SDA low simultaneously. Hardware handles arbitration loss detection, STOP generation, and state recovery-requiring no firmware intervention. This enables robust multi-master topologies in distributed control systems where the PCA9665APW,118 coexists with other I²C masters.