Texas Instruments PCA8550DBR

Overview

PCA8550DBR from Texas Instruments is a nonvolatile 5-bit register with I²C interface, designed as a 4-bit 1-of-2 multiplexer for jumperless PC motherboard configuration. It operates from 3 V to 3.6 V, features 400 kbit/s fast-mode I²C, 10-year data retention, and 1000 write cycles. Its MUX OUT outputs deliver 2.5 V logic levels while NON-MUXED OUT provides 3.3 V.

For engineers reviewing the PCA8550DBR datasheet, PCA8550DBR pinout, PCA8550DBR application, or PCA8550DBR equivalent, key selection considerations include I²C slave address (1001110), write-protect control, OVERRIDE forcing capability, and dual-output voltage domains (2.5 V MUX OUT / 3.3 V NON-MUXED OUT) in a 16-pin DB package.

Technical Context

The PCA8550DBR implements a fixed I²C slave interface with hardwired 7-bit address 1001110 and supports standard (100 kbit/s) and fast (400 kbit/s) modes. Its internal 5-bit nonvolatile register stores configuration data readable/writable via I²C, with write enable gated by WP input and output override controlled by OVERRIDE pin.

It integrates Schmitt-trigger SCL/SDA inputs with 5-V tolerance and internal pullups, accepts input voltages up to 5.5 V, and delivers MUX OUT signals at 2.5 V and NON-MUXED OUT at 3.3 V - both with ±2 mA drive capability and specified propagation delays (e.g., 20 ns mux-in-to-out, 22 ns MUX SELECT to output valid).

Key Specifications

Pinout & Package

PCA8550DBR is housed in a 16-pin Shrink Small-Outline (DB) package, 3.9 mm × 4.9 mm body, 1.0 mm max height, with 0.65 mm lead pitch and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile I²C register applications.

Compared with PCA9554APW and AT24C02C-SSHM-T, the PCA8550DBR uniquely integrates nonvolatile storage, multiplexing, and dual-voltage outputs in one 16-pin package - eliminating external components and guaranteeing deterministic power-on behavior without firmware dependency.

Availability

PCA8550DBR is available at Aetrix Electronics and suitable for PC motherboard design, industrial control I/O mapping, embedded boot mode selection, and automated test fixture signal routing requiring stable component supply and long-term obsolescence management.

Supply support for PCA8550DBR 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The PCA8550DBR belongs to TI's legacy interface and configuration IC product line, designed specifically for eliminating mechanical jumpers in 3.3-V computing and control platforms while maintaining I²C compatibility and nonvolatile state retention.

FAQ

What is the I²C slave address of the PCA8550DBR?

The PCA8550DBR has a fixed 7-bit I²C slave address of 1001110 (0x4E in hexadecimal). This address is hardwired internally with no address pins, so multiple PCA8550DBR devices cannot share the same I²C bus without external arbitration. The address is used during both read and write operations to target the PCA8550DBR specifically.

Does the PCA8550DBR support 5-V I²C masters?

Yes, the PCA8550DBR supports 5-V I²C masters: its SCL and SDA inputs are 5-V tolerant with Schmitt-trigger inputs and integrated pullup resistors. They accept input voltages up to 5.5 V while operating from a 3.3-V VCC supply, enabling direct connection to legacy 5-V microcontrollers without external level shifters - a key feature confirmed in the absolute maximum ratings and recommended operating conditions tables for the PCA8550DBR.

How does the OVERRIDE pin function on the PCA8550DBR?

The OVERRIDE pin on the PCA8550DBR is an active-high control that forces all MUX OUT A–D and NON-MUXED OUT signals to logic low, overriding both register contents and parallel inputs. This occurs independently of MUX SELECT state or I²C activity. It provides a hardware-level safety mechanism for system reset or fail-safe shutdown - a documented function verified in the device's function table and logic diagram for the PCA8550DBR.

What is the voltage level of the MUX OUT pins on the PCA8550DBR?

The MUX OUT pins (A–D) on the PCA8550DBR deliver 2.5-V logic-level outputs, as explicitly stated in the datasheet's "description" section and confirmed in electrical characteristics (VOH = 2.0–2.625 V at IOH = –100 µA). This 2.5-V domain is distinct from the 3.3-V NON-MUXED OUT, allowing the PCA8550DBR to interface directly with mixed-voltage subsystems without external level translation.

Can the PCA8550DBR retain configuration after power loss?

Yes, the PCA8550DBR retains configuration after power loss using its on-chip nonvolatile register: it guarantees minimum 10 years of data retention and 1000 write cycles. The register contents - including all 5 bits controlling MUX OUT and NON-MUXED OUT states - persist without battery backup or external memory. This behavior is intrinsic to the PCA8550DBR's EPIC process and is validated in the nonvolatile storage specifications section of its datasheet.