Texas Instruments UC2903DW

Overview

UC2903DW from Texas Instruments is a quad supply and line monitor IC designed for industrial power system supervision. It monitors up to four independent voltage rails-including one negative rail via internal inverter-with programmable under- and over-voltage thresholds centered on a 2.5-V precision reference, 30-mA open-collector fault outputs, and 8–40-V supply operation. It is used in telecom power shelves, server PSUs, and industrial PLC power modules.

For engineers reviewing the UC2903DW datasheet, UC2903DW pinout, UC2903DW application, or UC2903DW equivalent, key selection considerations include its –40°C to +85°C operating range, proportional hysteresis scaling with window adjust voltage, independent fault delay timing per channel, integrated general-purpose op-amp (20-mA source), and dedicated Sense 4 inverter for negative supply sensing.

Technical Context

The UC2903DW implements a fault window architecture where OV/UV thresholds are generated as symmetric offsets around the 2.5-V reference, scaled linearly by the voltage applied to Pin 4 (Window Adjust). Hysteresis is fixed at 8% of the window magnitude and scales proportionally with adjust voltage-e.g., 20 mV/V hysteresis sensitivity yields 200 mV hysteresis for a 10-V window.

It integrates three open-collector outputs: UV FAULT, OV FAULT, and POWER OK (active-low), each with user-programmable RC delay timing (20–50 ms/µF); a fourth Line/Switcher Sense input triggers POWER OK deassertion at 2.0 V ±175 mV; and a standalone op-amp (input offset <5 mV, gain >65 dB) supports auxiliary feedback or signal conditioning.

Key Specifications

Pinout & Package

UC2903DW is housed in an 18-pin SOIC (DW) package with 0.300-inch body width and standard JEDEC MS-013 outline. Pin numbering follows top-view orientation with Pin 1 in bottom-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad voltage monitoring applications.

Compared with UC3903DW and TPS3808G33, the UC2903DW delivers integrated quad monitoring, negative rail support, and auxiliary op-amp functionality in a single SOIC-18 package-reducing component count, layout complexity, and total solution cost for multi-rail industrial power systems.

Availability

UC2903DW is available at Aetrix Electronics and suitable for telecom power shelves, industrial PLC power modules, and server PSU redundancy control requiring stable component supply and long-term industrial lifecycle support.

Supply support for UC2903DW 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 leader specializing in analog, embedded processing, and power management technologies with over 50 years of industrial reliability heritage.

The UC2903DW belongs to TI's UCx903 family of precision voltage supervisors, engineered specifically for high-reliability power system monitoring in industrial, telecom, and computing infrastructure where multi-rail integrity and early fault detection are critical.

FAQ

What is the operating temperature range for the UC2903DW?

The UC2903DW is specified for operation from –40°C to +85°C. This industrial-grade temperature range makes it suitable for deployment in demanding environments such as factory automation controllers, outdoor telecom cabinets, and power conversion systems where ambient temperatures exceed commercial limits. The UC2903DW datasheet confirms this range applies across all electrical parameters unless otherwise noted.

How does the UC2903DW support negative voltage monitoring?

The UC2903DW supports negative voltage monitoring through its dedicated SENSE 4 INVERT INPUT (Pin 5) and SENSE 4 (Pin 6) pair. When Pin 5 is held high, the internal emitter-follower inverter activates, allowing SENSE 4 to accept –20 V to 0 V inputs. The inverter output is referenced to GND, enabling direct comparison against the 2.5-V reference. This eliminates the need for external level-shifting circuitry when monitoring rails like –12 V or –5 V.

Can the UC2903DW monitor more than four voltage rails?

No, the UC2903DW natively monitors exactly four voltage rails: SENSE 1 through SENSE 4. However, its integrated general-purpose op-amp (Pins 10–12) can be configured as a fifth comparator or amplifier to condition and scale additional rail signals for input to one of the existing sense channels-e.g., using the op-amp to invert and level-shift a fifth rail into the SENSE 4 path. This extends monitoring capability without adding discrete comparators.

What is the purpose of the WINDOW ADJUST pin on the UC2903DW?

The WINDOW ADJUST pin (Pin 4) sets the magnitude of the programmable fault window around the 2.5-V reference. Applying 0.5–2.5 V to this pin generates symmetric ±(0.25 × V_ADJ) V offsets for OV and UV thresholds. For example, 1.0 V on Pin 4 yields ±250 mV windows, enabling precise tolerance settings from ±1% to ±10% depending on nominal rail voltage-critical for accommodating manufacturing tolerances and aging drift in multi-rail systems.

Does the UC2903DW require external components to function?

Yes, the UC2903DW requires external passive components for full operation: RC networks on OV DELAY (Pin 2) and UV DELAY (Pin 17) to set fault response timing; resistive dividers on each SENSE input to scale higher voltages to the 0–20 V input range; and a pull-up resistor on each open-collector output (e.g., POWER OK, UV FAULT) to define logic-high voltage. The internal 2.5-V reference and op-amp eliminate need for external references or signal-conditioning ICs.