NXP Semiconductors PCA9665N,112

Overview

PCA9665N,112 from NXP Semiconductors is a Fast-mode Plus (Fm+) parallel-bus-to-I²C-bus controller IC that bridges standard 8-bit parallel microcontrollers to the I²C-bus as either master or slave. It operates from 2.3 V to 3.6 V, delivers 1 Mbit/s I²C throughput with 25 mA SCL/SDA drive strength, and integrates a 68-byte buffer for efficient data transfer in industrial control and embedded systems.

For engineers reviewing the PCA9665N,112 datasheet, PCA9665N,112 pinout, PCA9665N,112 application, or PCA9665N,112 equivalent, key selection criteria include its DIP20 package compatibility, 5 V tolerant parallel I/Os, software reset capability, General Call support, and Fm+ timing compliance - all critical for legacy parallel bus integration and multi-master I²C expansion.

Technical Context

The PCA9665N,112 implements a fully autonomous I²C protocol engine with internal 28.5 MHz oscillator (±15% accuracy), eliminating external timing components. It handles arbitration, START/STOP generation, ACK/NACK, clock stretching, and timeout recovery without CPU intervention during transfers.

Its dual-mode operation supports Byte mode (single-byte transactions) and Buffered mode (up to 68 bytes per transaction), controlled via the MODE bit in I2CCON. Register access uses direct addressing (A0/A1) for four core registers and indirect addressing (via INDPTR) for seven configuration and status registers including I2CSCLL/I2CSCLH for precise SCL timing control.

Key Specifications

Pinout & Package

PCA9665N,112 is supplied in a 20-pin plastic dual in-line package (DIP20), 300 mil width, with through-hole mounting and 2.54 mm pitch. Pin 1 is index-marked; pin 9 (i.c.) is internally connected and must be left floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9564D,118, PCA9665N,112 delivers 2.5× higher I²C speed, 17× larger buffer, and Fm+-grade drive strength; versus PCA9665PW,118, it offers identical performance in through-hole DIP20 form factor for prototyping and legacy board upgrades.

Availability

PCA9665N,112 is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and test equipment requiring stable component supply across long product lifecycles and mixed-technology PCB assemblies.

Supply support for PCA9665N,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, with deep expertise in interface and mixed-signal IC design.

The PCA9665N,112 belongs to NXP's I²C protocol controller product line, engineered specifically to simplify migration from parallel-bus architectures to standardized serial interconnects in resource-constrained embedded systems.

FAQ

What is the maximum I²C bus speed supported by the PCA9665N,112?

The PCA9665N,112 supports Fast-mode Plus (Fm+) operation up to 1 Mbit/s. This is achieved using its internal 28.5 MHz oscillator and 25 mA SCL/SDA drive capability, which ensures robust signal integrity on loaded or noisy buses. The actual speed depends on programmed I2CSCLL/I2CSCLH register values and external pull-up strength, but the PCA9665N,112 is fully compliant with Fm+ timing specifications.

Does the PCA9665N,112 require external crystals or timing components?

No, the PCA9665N,112 contains a trimmed internal 28.5 MHz oscillator with ±15% accuracy, eliminating the need for external crystals, capacitors, or RC networks. This oscillator powers all I²C timing functions including SCL generation, arbitration, and timeout detection - significantly reducing bill-of-materials and PCB area compared to discrete timing solutions.

How does the 68-byte buffer in the PCA9665N,112 improve system performance?

The 68-byte buffer in the PCA9665N,112 enables Buffered mode operation, allowing the host microcontroller to issue single read/write commands for up to 68 bytes instead of managing individual byte transfers. This reduces interrupt frequency, minimizes CPU overhead, and improves throughput - especially valuable in applications like sensor data logging or display memory updates where large sequential transfers occur.

Can the PCA9665N,112 operate with a 5 V parallel bus while powered at 3.3 V?

Yes, the PCA9665N,112 features 5 V tolerant parallel I/O pins (D0–D7, RD, WR, CE, A0, A1, RESET, INT), allowing direct connection to 5 V microcontrollers even when VDD is supplied at 2.3 V to 3.6 V. This eliminates level-shifter components and simplifies interfacing with legacy 5 V logic families while maintaining low-power operation.

What is the purpose of the i.c. pin on the PCA9665N,112 DIP20 package?

The i.c. pin (pin 9) on the PCA9665N,112 is internally connected and pulled LOW - it serves no external function and must be left unconnected (floating). Connecting it to any voltage or ground may cause undefined behavior or damage. This pin exists for package symmetry and die bonding purposes only; the PCA9665N,112 operates correctly with i.c. unconnected.