My Inquiry
My Account
Texas Instruments UC3903DWTR
- Part No.:
- UC3903DWTR
- Manufacturer:
- Texas Instruments
- Category:
- Supervisors
- Package:
- 18-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UC3903DWTR.pdf
- Description:
- IC SUPERVISOR 4 CHANNEL 18SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,553
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
UC3903DWTR from Texas Instruments is a quad supply and line monitor IC designed for power integrity supervision in industrial and telecom power systems. 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 redundant power supplies and distributed power architectures requiring early line-failure warning.
For engineers reviewing the UC3903DWTR datasheet, UC3903DWTR pinout, UC3903DWTR application, or UC3903DWTR equivalent, key selection considerations include its 0°C to +70°C operating temperature range, SOIC-18 package, proportional hysteresis scaling with window adjust voltage, dedicated line/switcher sense input with 2.0-V threshold, and integrated general-purpose op-amp capable of 20-mA sourcing.
Technical Context
The UC3903DWTR implements a fault-window architecture where OV and UV thresholds are generated as symmetric offsets around the 2.5-V reference, scaled linearly by the voltage applied to Pin 4 (WINDOW ADJUST). Threshold hysteresis is fixed at 8% of the window magnitude, ensuring glitch-free response during transient crossings.
It integrates three functional blocks: (1) four sense inputs (SENSE 1–4) with clamped ±20-V input range and ±1–6 µA bias current; (2) a dedicated inverting amplifier on SENSE 4 for negative-supply monitoring; and (3) a separate line/switcher sense comparator referenced to 2.0 V with 175-mV hysteresis and independent POWER OK output activation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temp Range | 0°C to +70°C - defines qualification for commercial-grade power system monitoring, not extended industrial or military use. |
| Supply Voltage Range | 8 V to 40 V - supports wide-input DC-DC converters and telecom rectified bus voltages without external regulation. |
| Reference Output | 2.5 V ±15 mV - stable, low-drift reference used to set fault windows and bias external dividers for rail-specific thresholds. |
| Fault Output Drive | >30 mA sink per output - enables direct driving of optocouplers, LEDs, or logic-level inputs without external buffers. |
| Window Adjust Sensitivity | ±0.25 V/V offset from VREF - allows precise, resistor-programmable fault windows from ±0.23 V to ±0.27 V per volt on Pin 4. |
| Line Sense Threshold | 2.0 V ±60 mV - triggers POWER OK deassertion for early detection of AC line sag or switcher failure before output collapse. |
| Standby Current | 7 mA typical - ensures low quiescent consumption in always-on supervisory applications. |
Pinout & Package
UC3903DWTR is housed in an 18-pin SOIC (DW) package, surface-mount compatible with standard reflow profiles and IPC-7351B footprint MS-012AC. The package provides thermal performance suitable for continuous operation at ambient temperatures up to +70°C with appropriate PCB copper pour.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +VIN | Main supply input | Power source for internal circuitry; must be ≥8 V for operation, with 40-V absolute max rating. |
| VREF (Pin 2) | Precision 2.5-V reference output | Stable, buffered reference used to bias external resistive dividers for sense input scaling. |
| GND (Pin 3) | Analog and power ground reference | Common return for all internal comparators, reference, and outputs; requires low-impedance connection. |
| WINDOW ADJUST (Pin 4) | Fault window magnitude control | Voltage input (0–10 V) that linearly scales OV/UV threshold offsets relative to VREF. |
| SENSE 4 INVERT INPUT (Pin 5) | Inverter non-inverting input | Enables negative-supply sensing when configured with external resistor network per Figure 6. |
| SENSE 4 (Pin 6) | Inverted sense input | Output of internal inverter; connects to emitter follower for high-impedance negative-rail monitoring. |
| SENSE 3 (Pin 7) | Third positive rail monitor input | Clamped ±20-V input with ±1–6 µA bias; used for +3.3 V, +5 V, or +12 V rail supervision. |
| SENSE 2 (Pin 8) | Second positive rail monitor input | Identical electrical characteristics to SENSE 3; supports multi-rail redundancy verification. |
| SENSE 1 (Pin 9) | First positive rail monitor input | Includes internal 2-kΩ series resistor and zener clamp for robustness against overvoltage transients. |
| LINE/SWITCHER SENSE (Pin 15) | Early failure warning input | 2.0-V comparator input with 175-mV hysteresis; asserts POWER OK fault before main outputs collapse. |
| POWER OK (Pin 16) | Active-low system status output | Open-collector output low during any fault condition (OV, UV, line, or supply under-voltage). |
| UV FAULT (Pin 17) | Active-low under-voltage indicator | Delayed open-collector output asserting only after user-defined UV delay capacitor charges to 1.8 V. |
| OV FAULT (Pin 18) | Active-low over-voltage indicator | Delayed open-collector output asserting only after user-defined OV delay capacitor charges to 1.8 V. |
Key Features
| Feature | Design Value |
|---|---|
| Four independent voltage monitors | Enables simultaneous supervision of primary, standby, auxiliary, and negative rails in single-chip solution. |
| Proportional hysteresis architecture | Hysteresis scales automatically with window width (8% of magnitude), eliminating need for discrete hysteresis resistors. |
| Dedicated SENSE 4 inverter | Allows direct monitoring of –5 V or –12 V rails without external op-amp, reducing BOM count and layout area. |
| General-purpose op-amp (20-mA source) | Supports feedback amplification, isolated error signal buffering, or logic-level translation without external components. |
| Programmable fault delays | Separate UV and OV delay capacitors enable independent timing for different fault severity levels. |
Applications
| Telecom Power Shelf Monitoring | Industrial PLC Power Supervision |
|---|---|
Use Scenario: Real-time monitoring of +48 V DC distribution, +3.3 V logic, +5 V I/O, and –5 V analog rails in carrier-grade power shelves. IC Role / Device Role / Timing Role: UC3903DWTR acts as centralized power-good arbiter, generating coordinated fault signals to shelf controller via POWER OK, OV FAULT, and UV FAULT outputs. Use Value: Enables early line-failure detection via LINE/SWITCHER SENSE input, preventing downstream brownouts before backup batteries engage. | Use Scenario: Supervising multiple isolated DC rails (+24 V, +5 V, +3.3 V, –12 V) powering CPU, I/O modules, and analog sensors in harsh factory environments. IC Role / Device Role / Timing Role: UC3903DWTR serves as fault coordinator, using its internal inverter on SENSE 4 to supervise negative analog supply while other inputs track positive rails. Use Value: Eliminates need for discrete inverting op-amp and reference buffer, reducing component count and improving long-term stability of rail thresholds. |
| Redundant Server PSU Control | Medical Imaging Power Sequencing |
Use Scenario: Coordinating dual hot-swap PSUs in data center servers, verifying both primary and backup supplies meet voltage tolerances before enabling load switches. IC Role / Device Role / Timing Role: UC3903DWTR functions as rail-comparison engine, using programmable WINDOW ADJUST to set tight ±1% windows on +12 V and +3.3 V outputs. Use Value: Proportional hysteresis prevents chatter during marginal conditions, ensuring clean POWER OK assertion only when all rails stabilize within spec. | Use Scenario: Managing power-up sequencing and fault containment across high-precision imaging subsystems (detector bias, FPGA core, ADC reference, analog front-end). IC Role / Device Role / Timing Role: UC3903DWTR provides independent, delayed fault reporting per rail-UV FAULT for detector bias, OV FAULT for FPGA core-to support safe shutdown prioritization. Use Value: Separate UV/OV delay pins allow critical rails (e.g., detector bias) to tolerate longer startup transients than less-sensitive rails (e.g., digital I/O). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad supply monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM393BQDR | Dual comparator only; no integrated reference, no hysteresis scaling, no line sense input, no open-collector outputs rated >30 mA. | Lacks quad monitoring, programmable windows, and POWER OK arbitration - requires full external design for same functionality. | Select only if cost sensitivity outweighs integration benefit and board space permits discrete implementation. |
| TPS3808G33DBVR | Single-channel supervisor with fixed 3.3-V threshold; no multi-rail capability, no negative rail support, no line sense, no adjustable hysteresis. | Designed for microprocessor reset only; cannot replace UC3903DWTR's rail coordination or fault window programming. | Use only for simple single-rail reset generation - not a functional alternative for quad monitoring tasks. |
Compared with LM393BQDR and TPS3808G33DBVR, UC3903DWTR delivers complete quad-rail supervision in one device-including negative rail handling, proportional hysteresis, and early line-failure warning-reducing design complexity, validation effort, and total BOM cost in multi-rail systems.
Availability
UC3903DWTR is available at Aetrix Electronics and suitable for telecom power shelves, industrial PLCs, redundant server PSUs, and medical imaging systems requiring stable component supply and long-term manufacturability assurance.
Supply support for UC3903DWTR 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, embedded processing, and power management solutions for industrial, automotive, and communications markets.
The UC3903DWTR belongs to TI's legacy power supervision product line, engineered specifically for high-reliability, multi-rail DC power system monitoring in commercial-grade applications where programmable fault windows and integrated negative-rail sensing are required.
FAQ
What is the operating temperature range of the UC3903DWTR?
The UC3903DWTR is specified for operation from 0°C to +70°C, qualifying it as a commercial-grade device. This range aligns with its SOIC-18 packaging and is documented in the Electrical Characteristics table for the UC3903 variant. It is not rated for extended industrial (–40°C to +85°C) or military (–55°C to +125°C) temperature ranges like the UC1903 or UC2903 family members.
Does the UC3903DWTR support monitoring of negative supply voltages?
Yes, the UC3903DWTR supports negative supply monitoring via its dedicated SENSE 4 inverter circuit. Pin 5 (SENSE 4 INVERT INPUT) and Pin 6 (SENSE 4) form an inverting amplifier stage that enables direct sensing of negative rails such as –5 V or –12 V, as detailed in Figure 6 of the datasheet. No external op-amp is required for this function.
How is hysteresis implemented in the UC3903DWTR fault detection?
The UC3903DWTR implements proportional hysteresis: the hysteresis voltage is fixed at 8% of the programmed fault window magnitude. For example, a ±0.5-V window yields 80-mV hysteresis. This scaling is achieved internally through current mirroring and transistor switching (Q4/Q5), eliminating the need for external hysteresis resistors and ensuring consistent noise immunity across all window settings.
Can the UC3903DWTR's general-purpose op-amp drive a 10-kΩ load?
Yes, the UC3903DWTR's general-purpose op-amp is specified to source up to 20 mA and sink up to 40 mA, meaning it can easily drive a 10-kΩ load at ±2.5 V output swing (requiring only 0.25 mA). Its output stage uses an NPN emitter follower for sourcing and a substrate PNP for sinking, providing robust performance for feedback buffering or level-shifting tasks.
What is the purpose of the LINE/SWITCHER SENSE input on the UC3903DWTR?
The LINE/SWITCHER SENSE input (Pin 15) provides early warning of AC line sags or switch-mode power supply failures before main output rails collapse. It features a 2.0-V comparator with 175-mV hysteresis; when the input falls below 2.0 V, the POWER OK output goes active-low, allowing system controllers to initiate graceful shutdown or backup activation well ahead of catastrophic failure.
UC3903DWTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 18-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 4
- Voltage - Threshold:
- Adjustable/Selectable
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 18-SOIC
UC3903DWTR FAQ
1.How can I place an order for UC3903DWTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3903DWTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for UC3903DWTR reliable?
The price and inventory of UC3903DWTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3903DWTR is usually 5 days.
3.What payment methods are accepted for UC3903DWTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3903DWTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3903DWTR?
UC3903DWTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3903DWTR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for UC3903DWTR?
For technical support, including UC3903DWTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3903DWTR requirements.
6.How does Aetrix verify that UC3903DWTR is sourced from the original manufacturer or authorized distributors?
All UC3903DWTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that UC3903DWTR meets industry standards.
7.What is the process for return or replacement of UC3903DWTR?
All UC3903DWTR units undergo pre-shipment inspection (PSI). If there is an issue with UC3903DWTR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The UC3903DWTR part is unused and in its original packaging.
Return procedure for UC3903DWTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
UC3903DWTR Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
