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Texas Instruments UCC3818PWTR
- Part No.:
- UCC3818PWTR
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
UCC3818PWTR.pdf
- Description:
- IC PFC CTRLR AVER 220KHZ 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,856
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Product details
Overview
UCC3818PWTR from Texas Instruments is a BiCMOS active power factor correction (PFC) controller for boost preregulators, implementing average current-mode control to achieve near-unity power factor and low line-current distortion. It features 7.5-V reference output, 10.5 V/10 V UVLO thresholds, leading-edge PWM modulation, and integrated gate driver with 0.2-A continuous sink/source capability - deployed in sub-300 W IEC61000-3-2-compliant PC and industrial power supplies.
For engineers reviewing the UCC3818PWTR datasheet, UCC3818PWTR pinout, UCC3818PWTR application, or UCC3818PWTR equivalent, key selection criteria include its 10.5 V turn-on UVLO threshold, 7.5-V precision reference, soft-start (SS) pin programmability, OVP/EN window comparator functionality, and compatibility with 16-pin TSSOP (PW) packaging for high-density PFC stage integration.
Technical Context
The UCC3818PWTR integrates a voltage error amplifier (90 dB open-loop gain, ±2-mV offset), a wide-bandwidth current amplifier (CAOUT/CAI/MOUT differential sensing), and an analog multiplier (K = 1/V) that computes IMOUT = IAC × (VAOUT − 1) / (K × VFF²) to shape input current waveform. Its oscillator uses RT/CT programming (f ≈ 0.6/(RT × CT)) and supports 6–220 kHz operation with ramp amplitude of 4.0 Vpp.
It implements zero-power detection (0.33 V threshold on VAOUT), overvoltage protection via OVP/EN pin (VREF + 0.50 V trip, 500 mV hysteresis), and peak current limiting through PKLMT (−15 to +15 mV reference). The DRVOUT totem-pole gate driver delivers 900 mA source / 1.2 A sink with 25 ns rise time (CL = 1 nF).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Turn-On Threshold | 10.5 V - enables operation only after stable 10.5 V VCC rail is established, preventing erratic startup |
| Voltage Reference (VREF) | 7.5 V ±1.5% - powers external circuitry and serves as precision bias for PKLMT and VSENSE scaling |
| Oscillator Frequency Range | 6–220 kHz - set by RT/CT values; supports optimized EMI filtering and magnetics sizing |
| Gate Driver Sink/Source | 1.2 A sink / 0.9 A source - directly drives MOSFET gates without external buffers in ≤300 W designs |
| Current Amplifier Offset | ±2 mV - minimizes light-load current-sense error, critical for maintaining THD < 5% at 10% load |
| OVP Trip Voltage | VREF + 0.50 V (≈8.0 V) - protects bulk capacitor from overvoltage during transient or regulation fault |
| Soft-Start Charge Current | −10 µA - linearly ramps SS voltage to limit inrush current and prevent output overshoot at startup |
Pinout & Package
TSSOP-16 (PW) package: 5.0 mm × 4.4 mm body, 0.65 mm pitch, thermally enhanced pad, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1) | Power and signal reference ground | Common return for VCC, VREF, CAI, MOUT; requires direct 0.1-µF ceramic bypass to minimize noise coupling |
| PKLMT (2) | Peak current limit sense input | Accepts level-shifted current-sense signal; triggers shutdown when voltage falls below 0 V |
| CAOUT (3) | Current amplifier output | Drives PWM latch; compensation network placed between CAOUT and MOUT sets loop stability |
| CAI (4) | Current amplifier non-inverting input | Connects to GND-side of current-sense resistor; operates down to −0.5 V for bidirectional sensing |
| MOUT (5) | Multiplier output / current amp inverting input | High-impedance node combining multiplier current and CA amp feedback; enables leading-edge modulation |
| IAC (6) | Line-voltage proportional current input | Accepts up to 500 µA from rectified AC feedforward network; primary input for RMS-based current shaping |
| VAOUT (7) | Voltage error amplifier output | Regulates boost output; clamped at 5.5 V to prevent overdrive; feeds zero-power comparator at 0.33 V |
| VFF (8) | Feed-forward voltage input | Represents RMS line voltage (1.4 V at low line); scales multiplier gain to maintain constant power across 85–265 VAC |
| VREF (9) | 7.5-V precision reference output | Supplies 20 mA max; used for biasing PKLMT divider and VSENSE scaling; disabled below UVLO |
| OVP/EN (10) | Overvoltage protection / enable input | Window comparator: disables DRVOUT if >VREF+0.50 V or <1.9 V; resets soft-start on under-voltage |
| VSENSE (11) | Voltage error amplifier inverting input | Connected to output divider; sets regulated boost voltage (e.g., 385 VDC via 1000:1 divider) |
| RT (12) | Oscillator timing resistor connection | 10–100 kΩ to GND sets charging current; nominal 3 V bias enables frequency tuning without trimming |
| SS (13) | Soft-start control | Charged by −10 µA current; voltage ramps to set initial duty cycle; discharges rapidly on VCC dropout |
| CT (14) | Oscillator timing capacitor connection | Capacitor to GND sets frequency per f ≈ 0.6/(RT × CT); short GND trace required for jitter reduction |
| VCC (15) | Positive supply input | Operates 10–17 V; requires ≥20 mA supply; bypassed directly to GND to support gate-drive current spikes |
| DRVOUT (16) | Integrated MOSFET gate driver output | Totem-pole output driving boost switch; series gate resistor (≥11 Ω @ 18 V) prevents ringing and overshoot |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Enables stable, low-distortion sinusoidal line current without slope compensation, reducing THD to <5% across full load range |
| Leading-edge PWM modulation | Synchronizes with downstream DC-DC converter to reduce bulk capacitor ripple current, extending capacitor lifetime by >30% |
| 7.5-V ±1.5% reference with 20 mA drive | Eliminates need for external reference; powers PKLMT scaling network and VSENSE divider while maintaining accuracy over temperature |
| Integrated zero-power detection (0.33 V threshold) | Disables gate drive when VAOUT drops below 0.33 V, preventing reverse conduction and efficiency loss at light/no load |
| Programmable overvoltage protection (OVP/EN) | Configurable trip point at VREF + 0.50 V with 500 mV hysteresis ensures robust bulk-capacitor protection without external components |
Applications
| PC Power Supply | Industrial AC-DC Converter |
|---|---|
|
Use Scenario: 250 W ATX power supply operating from 85–265 VAC input with IEC61000-3-2 Class D compliance requirement. IC Role / Device Role / Timing Role: Primary PFC controller regulating boost stage; sets switching frequency and shapes input current using average current-mode control. Use Value: Achieves >0.99 power factor and <8% THD at full load, meeting regulatory limits without additional filtering components. |
Use Scenario: 300 W DIN-rail mounted industrial power supply requiring high reliability and wide input voltage range. IC Role / Device Role / Timing Role: Active PFC front-end controller; provides OVP/EN fault signaling and soft-start sequencing for system-level safety. Use Value: Enables single-stage PFC design with 10.5 V UVLO ensuring clean startup even under brownout conditions. |
| LED Driver Front-End | Consumer Audio Power Supply |
|
Use Scenario: Constant-power LED driver for commercial lighting, accepting universal AC input and delivering regulated DC bus. IC Role / Device Role / Timing Role: Boost PFC controller maintaining constant power delivery via VFF feed-forward and multiplier-based current shaping. Use Value: Delivers stable 385 VDC bus with <3% output variation across 90–264 VAC, enabling consistent LED current regulation. |
Use Scenario: High-fidelity audio amplifier power supply requiring ultra-low noise and minimal mains disturbance. IC Role / Device Role / Timing Role: Low-noise PFC controller using differential CAI/MOUT sensing and leading-edge modulation to suppress audible switching artifacts. Use Value: Reduces conducted EMI by 12 dB compared to voltage-mode alternatives, easing EMC filter design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar active PFC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC2818PWTR | Same pinout, identical functional block diagram, but rated for −40°C to +85°C industrial temperature range vs. UCC3818PWTR's 0°C to +70°C | Preferred for extended-temperature industrial or outdoor deployments where ambient exceeds 70°C | Select UCC2818PWTR when operating temperature must exceed 70°C; otherwise UCC3818PWTR offers cost-optimized commercial-grade performance |
| L6562ATDTR | SO-8 package (vs. TSSOP-16), no integrated 7.5-V reference, requires external Vref; lower gate drive (0.5 A sink) | Used in cost-sensitive, space-constrained <150 W designs where external reference and reduced drive are acceptable | Choose L6562ATDTR only for compact, low-power applications; UCC3818PWTR provides superior integration and drive strength for ≥200 W systems |
Compared with UCC2818PWTR and L6562ATDTR, the UCC3818PWTR delivers optimal balance of integration (on-chip VREF, OVP, SS), thermal margin (0°C to +70°C), and gate drive capability (1.2 A sink) for mainstream 200–300 W PFC stages - making it the preferred choice where board space, BOM count, and design simplicity are prioritized over extended temperature rating or ultra-compact footprint.
Availability
UCC3818PWTR is available at Aetrix Electronics and suitable for PC power supplies, industrial AC-DC converters, LED driver front-ends, and consumer audio power supplies requiring stable component supply and long-term manufacturability.
Supply support for UCC3818PWTR 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 specializing in analog and embedded processing technologies, with leadership in power management ICs and industrial-grade controllers.
The UCC3818PWTR belongs to TI's UCCx81x family of BiCMOS PFC controllers, designed specifically for high-efficiency, low-THD boost preregulators in sub-300 W IEC61000-3-2-compliant power supplies.
FAQ
What is the UVLO threshold for UCC3818PWTR?
The UCC3818PWTR has a VCC undervoltage lockout (UVLO) turn-on threshold of 10.5 V and turn-off threshold of 9.7 V, providing 0.8 V hysteresis. This ensures reliable startup only after sufficient VCC rail stability is achieved, preventing erratic operation during brownouts. The UCC3818PWTR remains disabled until VCC exceeds 10.5 V, and latches off if VCC drops below 9.7 V.
Does UCC3818PWTR include an integrated voltage reference?
Yes, the UCC3818PWTR integrates a precision 7.5-V voltage reference (VREF) with ±1.5% accuracy over temperature and load. It can source up to 20 mA and is internally short-circuit protected. VREF is disabled when VCC falls below the UVLO threshold and must be bypassed to GND with ≥0.1-µF ceramic capacitor for stability - a key feature distinguishing UCC3818PWTR from reference-less alternatives like L6562ATDTR.
How is the switching frequency set on UCC3818PWTR?
The UCC3818PWTR oscillator frequency is set externally using resistor RT (pin 12) and capacitor CT (pin 14), per the formula f ≈ 0.6/(RT × CT). With typical values RT = 22 kΩ and CT = 270 pF, the nominal frequency is ~100 kHz. The UCC3818PWTR supports 6–220 kHz tuning, and CT must connect directly to GND with minimal trace length to minimize jitter and ensure stable operation.
What protection features does UCC3818PWTR provide?
The UCC3818PWTR provides overvoltage protection (OVP) via the OVP/EN pin (trip at VREF + 0.50 V, 500 mV hysteresis), peak current limiting (PKLMT pin with 0 V threshold), zero-power detection (0.33 V on VAOUT), and undervoltage lockout (10.5 V/9.7 V). These features enable fully self-protected PFC operation without external comparators or supervisors - a core advantage of the UCC3818PWTR architecture.
Is UCC3818PWTR pin-compatible with other members of the UCCx81x family?
Yes, the UCC3818PWTR is pin-compatible with UCC2818PWTR, UCC3817PWTR, and UCC2817PWTR in the same TSSOP-16 (PW) package. All share identical pin functions and electrical characteristics except UVLO thresholds (UCC281x: 16 V/9.7 V; UCC381x: 10.5 V/9.7 V) and temperature grade (UCC281x: −40°C to +85°C; UCC3818PWTR: 0°C to +70°C). This allows drop-in replacement within the same package footprint.
UCC3818PWTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-TSSOP
UCC3818PWTR FAQ
1.How can I place an order for UCC3818PWTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC3818PWTR 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 UCC3818PWTR reliable?
The price and inventory of UCC3818PWTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC3818PWTR is usually 5 days.
3.What payment methods are accepted for UCC3818PWTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC3818PWTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC3818PWTR?
UCC3818PWTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC3818PWTR 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 UCC3818PWTR?
For technical support, including UCC3818PWTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC3818PWTR requirements.
6.How does Aetrix verify that UCC3818PWTR is sourced from the original manufacturer or authorized distributors?
All UCC3818PWTR 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 UCC3818PWTR meets industry standards.
7.What is the process for return or replacement of UCC3818PWTR?
All UCC3818PWTR units undergo pre-shipment inspection (PSI). If there is an issue with UCC3818PWTR, 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 UCC3818PWTR part is unused and in its original packaging.
Return procedure for UCC3818PWTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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