Texas Instruments UC2903DWG4

Overview

UC2903DWG4 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-V to 40-V supply operation. It is used in telecom power shelves and redundant DC-DC converter systems for early fault detection and power-OK signaling.

For engineers reviewing the UC2903DWG4 datasheet, UC2903DWG4 pinout, UC2903DWG4 application, or UC2903DWG4 equivalent, key selection considerations include its –40°C to +85°C operating temperature range, proportional hysteresis scaling with window adjust voltage, independent sense input scaling capability, and dedicated line/switcher sense input for pre-failure warning in high-reliability power supplies.

Technical Context

The UC2903DWG4 implements a fault window architecture where OV and UV thresholds are generated as symmetric offsets around the 2.5-V reference, with magnitude set by the voltage applied to Pin 4 (Window Adjust). Hysteresis is fixed at 8% of the window width and scales proportionally with the adjust voltage.

It integrates three functional blocks: four sense comparators (SENSE 1–4) with clamped inputs and zener protection, a dedicated inverting amplifier for SENSE 4 enabling negative supply monitoring, and a general-purpose op-amp capable of sourcing 20 mA-used for auxiliary functions like feedback signal conditioning or tighter fault window generation.

Key Specifications

Pinout & Package

UC2903DWG4 is packaged in an 18-pin SOIC (DW) with exposed pad, compatible with JEDEC MS-013AC. The package supports surface-mount reflow and provides thermal performance suitable for continuous operation at full supply voltage.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UC3903DW and TPS3808G33, UC2903DWG4 uniquely delivers quad-rail supervision with negative supply capability, programmable hysteresis scaling, and integrated op-amp-all in one SOIC-18 package-making it irreplaceable for compact, thermally demanding industrial power management.

Availability

UC2903DWG4 is available at Aetrix Electronics and suitable for telecom power shelf supervision, redundant DC-DC converter monitoring, and industrial PLC power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for UC2903DWG4 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 communications markets since 1930.

The UC2903DWG4 belongs to TI's legacy power management supervisor family, specifically engineered for high-reliability, multi-rail power system monitoring in harsh environments where precise fault detection and predictable sequencing are critical.

FAQ

What is the operating temperature range of the UC2903DWG4?

The UC2903DWG4 is specified for operation from –40°C to +85°C, distinguishing it from the UC1903 (–55°C to +125°C) and UC3903 (0°C to +70°C). This range makes UC2903DWG4 suitable for industrial control cabinets and telecom outdoor enclosures where ambient extremes exceed commercial limits but do not reach military-grade requirements. All electrical parameters in the datasheet are guaranteed across this full range.

How does the WINDOW ADJUST pin (Pin 4) affect UC2903DWG4 fault thresholds?

The WINDOW ADJUST pin (Pin 4) sets both the magnitude of the OV/UV fault window and its proportional hysteresis. A voltage between 0.5 V and 2.5 V applied here generates symmetric offsets from the 2.5-V reference: OV threshold = V_REF + (0.25 × V_ADJ), UV threshold = V_REF – (0.25 × V_ADJ). Hysteresis scales at 8% of that window width. For example, 1.0 V on Pin 4 yields ±250 mV thresholds with 20 mV hysteresis.

Can UC2903DWG4 monitor a negative supply voltage?

Yes, UC2903DWG4 can monitor a negative supply using the dedicated inverter on SENSE 4. By grounding Pin 5 (INVERT INPUT), the internal emitter-follower inverter activates, allowing SENSE 4 (Pin 6) to accept an inverted signal from a resistive divider across the negative rail. The inverter's output feeds the comparator directly, enabling accurate –V_S detection without external components-confirmed in Figure 6 of the UC2903DWG4 datasheet.

What is the function of the LINE/SWITCHER SENSE input on UC2903DWG4?

The LINE/SWITCHER SENSE input (Pin 15) provides early warning of AC line loss or switch-mode power supply failure before output voltages deviate. Internally referenced to 2.0 V with 175-mV hysteresis, it asserts the POWER OK output low when the sensed signal drops below 2.0 V. This enables proactive system response-such as initiating backup battery switchover-well before main rail collapse, improving system resilience in mission-critical applications.

Does UC2903DWG4 include an internal voltage reference?

Yes, UC2903DWG4 integrates a precision 2.5-V bandgap reference (V_REF, Pin 2) with ±15 mV initial accuracy and ±0.01%/V line regulation. This reference serves as the centerpoint for all OV/UV thresholds and is also available as a buffered output to bias external resistor networks for sense input scaling. Its stability over temperature (±0.02%/°C typical) ensures consistent fault detection across the –40°C to +85°C operating range.