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Texas Instruments UCC3818DTRG4
- Part No.:
- UCC3818DTRG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UCC3818DTRG4.pdf
- Description:
- IC PFC CTR AVERAGE 220KHZ 16SOIC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
UCC3818DTRG4 from Texas Instruments is a BiCMOS active power factor correction (PFC) controller for boost preregulators, implementing average current-mode control with leading-edge PWM modulation. It features a 7.5-V reference, 10.5 V/10 V UVLO threshold, 0.33 V zero-power detection, and integrated gate driver delivering up to 1.2 A peak sink current - enabling IEC 61000-3-2-compliant <300 W AC-DC supplies in PC and industrial power applications.
For engineers reviewing the UCC3818DTRG4 datasheet, UCC3818DTRG4 pinout, UCC3818DTRG4 application, or UCC3818DTRG4 equivalent, this device supports world-wide line operation (85–265 VAC), delivers accurate power limiting via PKLMT pin, integrates feed-forward line regulation via VFF, and enables stable soft-start via SS pin with 10 µA charge current - critical for low-distortion, high-efficiency PFC design.
Technical Context
The UCC3818DTRG4 implements average current-mode control using a wide-bandwidth current amplifier (CAI/MOUT inputs, CAOUT output) and a three-input analog multiplier (IAC, VFF, VAOUT) to shape input current waveform to match line voltage. Its oscillator uses RT/CT pins with f ≈ 0.6/(RT × CT), supporting 6–220 kHz switching frequencies.
It integrates a 7.5-V precision reference (±1.5% over temperature), voltage error amplifier (90 dB open-loop gain, 5.5 V clamp), overvoltage protection (OVP/EN window comparator with 1.9 V enable threshold and 500 mV hysteresis), and zero-power detection (0.33 V threshold on VAOUT) to disable gate drive under no-load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Turn-on / Turn-off | 10.5 V / 9.7 V - ensures reliable startup above brownout and graceful shutdown during undervoltage events |
| Voltage Reference (VREF) | 7.5 V ±1.5% - powers external circuitry and serves as precision bias for current-sense scaling |
| Oscillator Frequency Range | 6 kHz to 220 kHz - programmable via RT/CT; supports optimized EMI filtering and magnetics selection |
| Gate Driver Sink/Source | 1.2 A sink / 0.9 A source - drives MOSFET gates directly without external buffers in ≤300 W designs |
| Zero-Power Threshold | 0.33 V on VAOUT - disables DRVOUT when output regulation collapses, reducing no-load power loss |
| Current Amplifier Offset | ±2.5 mV - minimizes light-load current-sense error and preserves THD performance below 10% load |
| Soft-Start Charge Current | 10 µA - controls ramp rate of SS capacitor to limit inrush current during startup |
Pinout & Package
UCC3818DTRG4 is housed in a 16-pin SOIC (D) package measuring 3.91 mm × 9.9 mm, with standard JEDEC MS-012AC footprint and Gull-wing leads. Thermal resistance RθJA is 73.9°C/W on 5-inch² FR4 board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1) | Power and signal reference | Common return for VCC, VREF, and all analog inputs; requires direct 0.1 µF ceramic bypass |
| PKLMT (2) | Peak current limit input | Sets instantaneous current limit by level-shifting sense resistor voltage to 0 V threshold |
| CAOUT (3) | Current amplifier output | Drives PWM latch; compensation network placed between CAOUT and MOUT for stability |
| CAI (4) | Current amplifier non-inverting input | Connects to ground-side of current sense resistor; operates down to –0.5 V for bidirectional sensing |
| MOUT (5) | Multiplier output / CA inverting input | High-impedance node combining multiplier current and CA feedback; enables differential configuration for noise immunity |
| IAC (6) | Line voltage proportional current input | Accepts up to 500 µA current from rectified line; defines multiplier input scale for feed-forward accuracy |
| VAOUT (7) | Voltage error amplifier output | Regulates boost output; clamped at 5.5 V to prevent overshoot; feeds zero-power comparator |
| VFF (8) | Feed-forward RMS voltage | Generated by mirroring ½ IAC; sets 1.4 V at low line to maintain constant power across input range |
| VREF (9) | 7.5 V precision reference output | Supplies 20 mA; disabled below UVLO; used for biasing PKLMT divider and external circuits |
| OVP/EN (10) | Overvoltage/enable window comparator | Disables DRVOUT if boost voltage exceeds programmed threshold or pulls <1.9 V to reset soft-start |
| VSENSE (11) | Voltage amplifier inverting input | Connected to output divider; forms feedback loop with VAOUT for output voltage regulation |
| RT (12) | Oscillator timing current input | Programs charging current with 10–100 kΩ resistor; nominal 3 V bias enables frequency tuning |
| SS (13) | Soft-start control | Charged by 10 µA current source; used as error signal during startup to ramp duty cycle gradually |
| CT (14) | Oscillator timing capacitor | Defines switching frequency with RT; requires short, direct GND trace to minimize jitter |
| VCC (15) | Supply input | Operates from 10–17 V; requires ≥20 mA supply and local 0.1 µF ceramic bypass to GND |
| DRVOUT (16) | Integrated gate driver output | Totem-pole MOSFET driver; 5–12 Ω pull-up/pull-down resistances support fast rise/fall times into capacitive loads |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Enables stable, low-THD sinusoidal line current shaping without slope compensation |
| Leading-edge PWM modulation | Reduces bulk capacitor ripple current when synchronized with downstream DC-DC converter |
| Integrated 7.5 V reference | ±1.5% accuracy over –40°C to +85°C; delivers 20 mA for external biasing and sensing |
| Feed-forward line regulation (VFF) | Compensates for input voltage variation in real time, maintaining constant power across 85–265 VAC |
| Zero-power detection | Shuts down gate drive when VAOUT falls below 0.33 V, eliminating no-load standby losses |
| Low start-up current | 150 µA typical - reduces auxiliary supply burden and enables high-impedance VCC startup networks |
Applications
| PC Power Supply | Industrial AC-DC Module |
|---|---|
Use Scenario: 200–300 W ATX power supply meeting IEC 61000-3-2 Class D limits. IC Role / Device Role / Timing Role: Primary PFC controller regulating boost stage; sets switching frequency and shapes input current waveform. Use Value: Enables compliance with harmonic current limits using single-stage boost topology and internal average current sensing. |
Use Scenario: DIN-rail mounted 240 W industrial power module operating from universal AC input. IC Role / Device Role / Timing Role: Active PFC front-end controller; provides UVLO, OVP, and soft-start sequencing for robust field deployment. Use Value: Delivers >0.99 PF across full load range and maintains regulation during 100 ms AC dips due to tight UVLO hysteresis (0.5 V). |
| LED Driver Front-End | Consumer Audio Power Supply |
Use Scenario: High-efficiency 150 W LED driver for commercial lighting with dimmable output. IC Role / Device Role / Timing Role: PFC preregulator feeding isolated DC-DC stage; VFF pin enables consistent power delivery across input variations. Use Value: Maintains constant output power despite 10% line sag by dynamically adjusting current reference via feed-forward path. |
Use Scenario: Low-noise 120 W Class D audio amplifier power supply requiring low EMI and high efficiency. IC Role / Device Role / Timing Role: Average-current-mode PFC controller with leading-edge modulation synchronized to downstream converter. Use Value: Reduces bulk capacitor RMS current by 35%, extending capacitor lifetime and lowering audible transformer hum. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC2818D | Same pinout and function but rated for –40°C to +85°C; UVLO turn-on at 10.2 V (vs. 10.5 V for UCC3818) | Preferred for extended-temperature industrial deployments where ambient exceeds 70°C | Select UCC2818D when full industrial temp range is required; UCC3818DTRG4 is optimized for cost-sensitive commercial designs |
| L6562ADTR | Fixed-frequency CCM PFC controller; no VFF feed-forward; 1.5 V reference; lower gate drive (0.5 A sink) | Suitable for fixed-line applications (<230 VAC only); lacks universal input feed-forward and zero-power mode | Choose L6562ADTR for simpler, lower-cost designs where input range is narrow and standby loss is not critical |
Compared with UCC2818D and L6562ADTR, the UCC3818DTRG4 offers superior feed-forward line regulation, tighter reference accuracy (7.5 V vs. 1.5 V), and integrated zero-power shutdown - making it optimal for universal-input, low-standby-loss PFC stages in commercial power supplies.
Availability
UCC3818DTRG4 is available at Aetrix Electronics and suitable for PC power supplies, industrial AC-DC modules, LED driver front-ends, and consumer audio power supplies requiring stable component supply and long-term production continuity.
Supply support for UCC3818DTRG4 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 ICs, with decades of expertise in power conversion and energy-efficient design.
The UCC3818DTRG4 belongs to TI's BiCMOS PFC controller family, designed specifically for cost-effective, high-performance active power factor correction in sub-300 W AC-DC power supplies targeting IEC 61000-3-2 compliance.
FAQ
What is the operating temperature range for the UCC3818DTRG4?
The UCC3818DTRG4 is specified for operation from 0°C to +70°C ambient temperature. This commercial-grade rating distinguishes it from the UCC2818D (–40°C to +85°C), making the UCC3818DTRG4 ideal for indoor, temperature-controlled environments such as desktop PCs and consumer electronics power supplies where extended thermal range is unnecessary.
How does the UCC3818DTRG4 implement power factor correction?
The UCC3818DTRG4 achieves near-unity power factor using average current-mode control: it senses AC line current via CAI/MOUT, compares it to a voltage-derived reference shaped by the analog multiplier (IAC, VFF, VAOUT), and adjusts PWM duty cycle through CAOUT to force input current to track line voltage waveform. This eliminates harmonic distortion without requiring complex digital computation.
What is the purpose of the VFF pin on the UCC3818DTRG4?
The VFF pin on the UCC3818DTRG4 provides feed-forward line voltage information to the analog multiplier, enabling real-time adjustment of the current reference to maintain constant power across universal AC input ranges (85–265 VAC). At low line (e.g., 85 VAC), VFF is 1.4 V; at high line (265 VAC), it rises to ~4.7 V - ensuring stable PFC performance without output voltage droop or overcurrent at low input.
Can the UCC3818DTRG4 be used without an external soft-start capacitor?
No - the UCC3818DTRG4 requires an external capacitor on the SS pin to implement controlled startup. The internal 10 µA current source charges this capacitor, and its voltage serves as the initial error signal for the PWM latch. Grounding SS does not guarantee 0% duty cycle and may cause uncontrolled inrush; TI recommends 100 nF for typical 100 ms soft-start duration.
What protection features are integrated into the UCC3818DTRG4?
The UCC3818DTRG4 integrates multiple hardware-based protections: overvoltage protection (OVP/EN pin with 1.9 V enable threshold and 500 mV hysteresis), undervoltage lockout (10.5 V turn-on / 9.7 V turn-off), peak current limiting (via PKLMT pin referenced to 0 V), zero-power shutdown (0.33 V VAOUT threshold), and thermal shutdown (via junction temperature monitoring). These operate independently of external firmware or controllers.
UCC3818DTRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Mode:
- Average Current
- Frequency - Switching:
- 6kHz ~ 220kHz
- Current - Startup:
- 150 µA
- Voltage - Supply:
- 12V ~ 17V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
UCC3818DTRG4 FAQ
1.How can I place an order for UCC3818DTRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC3818DTRG4 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 UCC3818DTRG4 reliable?
The price and inventory of UCC3818DTRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC3818DTRG4 is usually 5 days.
3.What payment methods are accepted for UCC3818DTRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC3818DTRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC3818DTRG4?
UCC3818DTRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC3818DTRG4 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 UCC3818DTRG4?
For technical support, including UCC3818DTRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC3818DTRG4 requirements.
6.How does Aetrix verify that UCC3818DTRG4 is sourced from the original manufacturer or authorized distributors?
All UCC3818DTRG4 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 UCC3818DTRG4 meets industry standards.
7.What is the process for return or replacement of UCC3818DTRG4?
All UCC3818DTRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC3818DTRG4, 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 UCC3818DTRG4 part is unused and in its original packaging.
Return procedure for UCC3818DTRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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