NXP Semiconductors PCA9559PW,118

Overview

PCA9559PW,118 from NXP Semiconductors is a 20-pin TSSOP I²C-bus EEPROM DIP switch IC with 6-bit non-volatile register storage, 5-bit multiplexed open-drain outputs, and 1-bit latched open-drain output. It operates from 3.0 V to 3.6 V, supports up to 400 kHz I²C clock frequency, and retains configuration for CPU VID voltage selection in performance/deep-sleep modes. Used between CPU and VRM for dynamic voltage override.

For engineers reviewing the PCA9559PW,118 datasheet, PCA9559PW,118 pinout, PCA9559PW,118 application, or PCA9559PW,118 equivalent, this page delivers verified functional architecture, I²C address mapping (0x48–0x4B), MUX_SELECT logic behavior, OVERRIDE_N override timing, and non-volatile write-cycle endurance (100,000 cycles).

Technical Context

The PCA9559PW,118 integrates a 6-bit EEPROM register with dual-path output control: five multiplexed outputs (MUX_OUT A–E) select either external MUX_IN pins or internal register bits based on the MUX_SELECT signal, while NON_MUXED_OUT latches register data only when MUX_SELECT transitions high. The device uses Schmitt-trigger inputs on OVERRIDE_N, WP, and MUX_SELECT with internal pull-ups.

I²C communication follows standard 7-bit addressing with two hardware-selectable address bits (A1/A0), enabling four devices per bus. Write protection is controlled by the WP pin: low enables register writes; high disables them. Power-on reset initializes volatile state but preserves EEPROM contents across power cycles.

Key Specifications

Pinout & Package

TSSOP20 package (SOT360-1), 4.4 mm body width, 0.65 mm lead pitch, 1.1 mm max height - optimized for high-density motherboard layouts with automated reflow soldering compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DIP-switch replacement applications.

Compared with PCA9557PW,118 and PCA9555PW,118, the PCA9559PW,118 uniquely combines EEPROM persistence, hardware/firmware multiplexing, and dedicated override functionality - making it the only option for systems requiring both fallback jumperless configuration and field-updatable VID profiles.

Availability

PCA9559PW,118 is available at Aetrix Electronics and suitable for desktop motherboard design, server platform voltage tuning, and telecom baseband processor setup requiring stable component supply and long-term lifecycle support.

Supply support for PCA9559PW,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 company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and communications markets.

The PCA9559PW,118 belongs to NXP's I²C interface and system configuration IC product line, designed specifically to replace mechanical DIP switches and jumpers in high-reliability computing platforms where firmware-controlled voltage identification is critical.

FAQ

What is the I²C address range supported by the PCA9559PW,118?

The PCA9559PW,118 supports four I²C addresses: 0x48, 0x49, 0x4A, and 0x4B. These are determined by the logic levels on A0 and A1 pins, with internal pull-up resistors defaulting both to high for address 0x4B unless externally pulled low. This allows up to four PCA9559PW,118 devices on a single I²C bus without address conflict.

How does the MUX_SELECT pin control output behavior in the PCA9559PW,118?

The MUX_SELECT pin determines source selection for the five multiplexed outputs (MUX_OUT A–E): logic 0 routes EEPROM register bits to outputs; logic 1 routes external MUX_IN signals. Simultaneously, a rising edge on MUX_SELECT latches the current EEPROM bit 5 value onto NON_MUXED_OUT. This dual function enables synchronized hardware/firmware configuration switching in the PCA9559PW,118.

Can the PCA9559PW,118 retain its configuration after power loss?

Yes, the PCA9559PW,118 retains its 6-bit non-volatile EEPROM register contents for a minimum of 10 years after power loss. The stored VID values persist through complete power cycles and remain intact even when VCC drops below operating range, provided write operations are completed before power interruption - a key reliability feature of the PCA9559PW,118.

What is the purpose of the OVERRIDE_N pin on the PCA9559PW,118?

The OVERRIDE_N pin is an active-low signal that forces all MUX_OUT A–E and NON_MUXED_OUT outputs to logic 0 regardless of EEPROM content or MUX_SELECT state. This provides a hardware-level safety mechanism to guarantee minimum CPU voltage during fault conditions or system initialization, ensuring predictable behavior in the PCA9559PW,118.

Does the PCA9559PW,118 require external pull-up resistors on its I²C lines?

Yes, the PCA9559PW,118 requires external pull-up resistors on both SCL and SDA lines to ensure proper I²C bus operation. While inputs like OVERRIDE_N, WP, and MUX_SELECT have internal pull-ups, the open-drain SCL and SDA pins rely on external resistors (typically 2.2 kΩ to 4.7 kΩ) referenced to VCC to establish valid logic-high levels - a mandatory design requirement for reliable communication with the PCA9559PW,118.