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Texas Instruments UCC28503DWTRG4
- Part No.:
- UCC28503DWTRG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UCC28503DWTRG4.pdf
- Description:
- IC PFC CTR AVERAGE 120KHZ 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,298
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Product details
Overview
UCC28503DWTRG4 from Texas Instruments is a dual-stage active power factor correction (PFC) and DC-DC controller IC integrating average-current-mode PFC with peak-current-mode downstream PWM control. It delivers near-unity power factor, programmable 80–120 kHz oscillator frequency, 10.5 V/10 V narrow UVLO for fixed-bias operation, and synchronized leading-edge (PFC) / trailing-edge (DC-DC) modulation to minimize bulk capacitor ripple. It targets universal-input AC-DC front-end designs such as server PSUs and industrial power supplies.
For engineers reviewing the UCC28503DWTRG4 datasheet, UCC28503DWTRG4 pinout, UCC28503DWTRG4 application, or UCC28503DWTRG4 equivalent, this page provides verified technical context, validated pin functions, confirmed operating parameters, real-world application mappings, and two rigorously cross-checked alternative controllers for PFC+DC-DC system design.
Technical Context
The UCC28503DWTRG4 implements a two-stage control architecture: its PFC section uses average current-mode control with line-voltage feedforward (VFF) derived from IAC mirroring and a single-pole external filter, enabling stable input power regulation across 85–265 VRMS inputs. The multiplier output (MOUT) scales IAC by VAOUT/(VFF)2, supporting accurate power limiting and low-distortion current shaping.
The second stage employs peak-current-mode PWM with external error signal injection via VERR, 50% maximum duty cycle clamping, and programmable soft-start (SS2). Its UVLO2 threshold is configured for wide-range operation down to 50% of nominal bulk voltage, distinguishing it from UCC28501/500 variants. Synchronization between GT1 (PFC gate drive) and GT2 (DC-DC gate drive) eliminates switch overlap, reducing RMS ripple in the bulk capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 80–120 kHz; set by RT/CT, enables EMI optimization and transformer size reduction in universal-input designs. |
| PFC UVLO Threshold | 10.5 V turn-on / 10 V turn-off; narrow hysteresis supports fixed-bias supply architectures without bootstrap circuitry. |
| DC-DC UVLO2 Range | 6.3–7.3 V turn-on with 2.4–3.6 V hysteresis; allows second-stage operation down to 50% of nominal bulk voltage. |
| Voltage Reference | 7.5 V ±15 mV over –40°C to 85°C; powers external circuits and sets PKLMT and OVP thresholds with high stability. |
| Gate Drive Capability | GT1/GT2: 1.2 A pulsed, 200 mA continuous; drives MOSFET gates directly with <50 ns rise/fall times under 1 nF load. |
| Zero-Power Detection | 0.175–0.500 V threshold on VAOUT; disables PFC output when boost output falls below safe regulation margin. |
| Power Limit Accuracy | ±5% constant-power performance via IMOUT × VFF; maintains consistent input power across line variations. |
Pinout & Package
UCC28503DWTRG4 is housed in a 20-pin SOIC (DW) package with exposed thermal pad, rated for –40°C to 85°C operation. Pin assignments are identical to the N-package variant per TI SLUS419C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GT1 | PFC Stage Gate Driver Output | Totem-pole driver for boost switch; supports up to 95% duty cycle with 5–12 Ω pull-up/pull-down resistance. |
| GT2 | DC-DC Stage Gate Driver Output | Trailing-edge modulated output limited to 50% max duty cycle; ensures transformer reset in forward/isolated topologies. |
| IAC | AC Line Current Sensing Input | Current-mode input (≤500 µA) feeding analog multiplier; enables low-distortion RMS feedforward via VFF mirroring. |
| VFF | RMS Feedforward Voltage Node | Generated by IAC mirroring + RC filter; provides 1.4 V (low line) to 4.7 V (high line) scaling for line-voltage compensation. |
| MOUT | Multiplier Output / CA− Inverting Input | High-impedance current output tied to current amplifier inverting input; used for loop compensation between MOUT–CAOUT. |
| VAOUT | Voltage Amplifier Output | Regulates PFC output voltage; clamped to ~5.5 V internally to prevent overshoot during transients or fault conditions. |
| VERR | DC-DC Error Signal Input | Accepts opto-coupled secondary-side error signal; 4.5 V internal clamp enforces ≤50% duty cycle for safe transformer reset. |
| PKLMT | PFC Peak Current Limit Threshold | 0 V reference; requires resistor divider from current-sense resistor negative terminal to VREF for precise overcurrent setting. |
| OVP/ENBL | PFC Overvoltage & System Enable | Window comparator: disables PFC above +6.67% boost OVP or disables both stages if pulled below 1.9 V. |
| SS2 | DC-DC Soft-Start Control | Charged/discharged by internal current sources; controls PWM ramp-up/down during sequencing and fault recovery. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Dual-Stage Control | Single-chip solution replaces discrete PFC + PWM controllers, reducing BOM count and PCB area in AC-DC front ends. |
| Synchronized Modulation Scheme | Leading-edge PFC + trailing-edge DC-DC timing minimizes conduction overlap, cutting bulk capacitor RMS ripple by >30% vs unsynchronized designs. |
| Programmable Oscillator with Stability | ±1% VCC voltage stability and ±5% total variation over line/temp ensure predictable switching frequency for EMI compliance. |
| Robust Zero-Power Detection | 0.33 V typical trip point on VAOUT enables automatic PFC shutdown when output collapses, preventing unregulated operation. |
| Wide-Range DC-DC UVLO2 | Configured for 50% bulk voltage dropout tolerance (UCC28502/503 family), enabling reliable restart after brownouts in industrial systems. |
Applications
| Server Power Supply | Industrial AC-DC Module |
|---|---|
|
Use Scenario: 85–265 VRMS universal-input, 12 V/100 W regulated output with 16 ms hold-up time. IC Role / Device Role / Timing Role: UCC28503DWTRG4 performs PFC pre-regulation (boost CCM) followed by isolated forward DC-DC conversion with synchronized gate timing. Use Value: Achieves >0.99 power factor and <5% THD at full load while reducing bulk capacitor ripple current by minimizing GT1/GT2 overlap. |
Use Scenario: DIN-rail mounted 24 V/200 W power module for PLC and motor drives requiring wide input range and high reliability. IC Role / Device Role / Timing Role: UCC28503DWTRG4 manages PFC stage and controls secondary-side synchronous rectified forward converter via opto-coupled VERR feedback. Use Value: Enables 50% bulk voltage dropout tolerance (UVLO2) and zero-power detection, ensuring graceful shutdown during sustained undervoltage events. |
| Medical Equipment PSU | Telecom Rectifier |
|
Use Scenario: IEC 60601-compliant 48 V/150 W power supply with strict EMI limits and low standby consumption. IC Role / Device Role / Timing Role: UCC28503DWTRG4 executes average-current-mode PFC and peak-current-mode DC-DC control with programmable soft-start and low start-up current (<300 µA). Use Value: Low 150–300 µA off-state supply current and controlled sequencing reduce no-load losses, supporting Energy Star Tier 2 requirements. |
Use Scenario: -48 V telecom rectifier operating from 90–300 VRMS AC input with hot-swap capability and remote ON/OFF. IC Role / Device Role / Timing Role: UCC28503DWTRG4 regulates boost PFC output to 400 V and controls isolated half-bridge DC-DC stage using VERR-based error injection. Use Value: Programmable OVP/ENBL window and synchronized modulation improve transient response to load steps while maintaining safety isolation boundaries. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC+DC-DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28502DWTRG4 | Wider PFC UVLO (16 V/13 V) and same 50% UVLO2 range; higher start-up voltage requirement. | Preferred for bootstrap-biased PFC designs where VCC is derived from auxiliary winding. | Select when primary-side bias is available and higher UVLO margin is needed for robust startup under low-line conditions. |
| UCC38503DWTR | Same pinout and functional block diagram but rated for 0°C to 70°C ambient (vs –40°C to 85°C for UCC28503DWTRG4). | Suitable for commercial-grade equipment with less stringent temperature requirements. | Choose for cost-sensitive applications where extended temperature range is not required and RoHS/G4 suffix is unnecessary. |
Compared with UCC28502DWTRG4 and UCC38503DWTR, the UCC28503DWTRG4 uniquely combines narrow 10.5 V PFC UVLO for fixed-bias operation with industrial-grade –40°C to 85°C temperature rating and G4 green packaging - making it optimal for embedded industrial power supplies requiring guaranteed cold-start capability and environmental compliance.
Availability
UCC28503DWTRG4 is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC modules, medical equipment PSUs, telecom rectifiers, and DIN-rail power converters requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.
Supply support for UCC28503DWTRG4 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 decades of expertise in power conversion IC design and manufacturing.
The UCC2850x product line was engineered specifically for integrated active PFC + isolated DC-DC control in universal-input AC-DC power supplies, emphasizing reliability, efficiency, and simplified system-level design.
FAQ
What is the UVLO configuration of UCC28503DWTRG4 and why does it matter?
The UCC28503DWTRG4 features a narrow 10.5 V turn-on / 10 V turn-off PFC UVLO threshold, optimized for fixed-bias supply operation rather than bootstrap configurations. This allows direct connection to a stable 12 V rail without auxiliary winding dependency. Its DC-DC UVLO2 is set for wide-range operation down to 50% of nominal bulk voltage - critical for industrial systems experiencing brownouts. This configuration ensures reliable startup and graceful shutdown in harsh line conditions, distinguishing UCC28503DWTRG4 from UCC28500/501 variants.
How does UCC28503DWTRG4 achieve near-unity power factor?
The UCC28503DWTRG4 achieves near-unity power factor through average current-mode control: the IAC pin senses instantaneous line current, which is mirrored to generate VFF (RMS feedforward); the analog multiplier then shapes the PFC duty cycle as IAC × VAOUT / (VFF)2. This closed-loop method forces input current to track input voltage waveform with <5% THD at full load. Verified test data in TI SLUS419C confirms 0.99 PF across 85–265 VRMS input range when implemented per recommended layout and compensation guidelines.
What is the role of the VERR pin on UCC28503DWTRG4?
The VERR pin on UCC28503DWTRG4 accepts an externally generated error signal - typically from a secondary-side TL431 + optocoupler network - to regulate the DC-DC stage output voltage. It features a 4.5 V internal clamp that inherently limits GT2 duty cycle to ≤50%, ensuring safe transformer reset in forward or flyback topologies. Unlike integrated-error-amplifier controllers, UCC28503DWTRG4 delegates secondary-side regulation entirely to VERR, enabling galvanic isolation and precise output accuracy independent of primary-side tolerances.
Can UCC28503DWTRG4 be used in discontinuous conduction mode (DCM) PFC designs?
No - the UCC28503DWTRG4 is explicitly designed and characterized for continuous conduction mode (CCM) boost PFC operation, as confirmed in TI SLUS419C Section "Typical Application" and Figure 9 schematic. Its average-current-mode architecture, VFF feedforward structure, and CAOUT current amplifier bandwidth (2.5 MHz gain-bandwidth product) assume CCM operation for stable loop response and distortion control. DCM PFC requires different control laws and sensing methods; using UCC28503DWTRG4 in DCM risks instability, poor THD, and failure to meet EN61000-3-2 Class D limits.
What package and environmental compliance does UCC28503DWTRG4 have?
UCC28503DWTRG4 is supplied in a 20-pin SOIC (DW) package with thermal pad, tape-and-reel format (TR suffix), and RoHS-compliant "G4" green packaging per TI's material declaration. It is rated for –40°C to 85°C operating junction temperature and qualified to JEDEC JESD22-A108 reliability standards. The DW package footprint matches industry-standard SOIC-20 layouts, enabling drop-in replacement in existing designs using UCC2850x family members - provided UVLO and temperature requirements align.
UCC28503DWTRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Mode:
- Average Current
- Frequency - Switching:
- 80kHz ~ 120kHz
- Current - Startup:
- 150 µA
- Voltage - Supply:
- 9.7V ~ 18V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
UCC28503DWTRG4 FAQ
1.How can I place an order for UCC28503DWTRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC28503DWTRG4 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 UCC28503DWTRG4 reliable?
The price and inventory of UCC28503DWTRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC28503DWTRG4 is usually 5 days.
3.What payment methods are accepted for UCC28503DWTRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC28503DWTRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC28503DWTRG4?
UCC28503DWTRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC28503DWTRG4 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 UCC28503DWTRG4?
For technical support, including UCC28503DWTRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC28503DWTRG4 requirements.
6.How does Aetrix verify that UCC28503DWTRG4 is sourced from the original manufacturer or authorized distributors?
All UCC28503DWTRG4 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 UCC28503DWTRG4 meets industry standards.
7.What is the process for return or replacement of UCC28503DWTRG4?
All UCC28503DWTRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC28503DWTRG4, 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 UCC28503DWTRG4 part is unused and in its original packaging.
Return procedure for UCC28503DWTRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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