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Texas Instruments UC3854DWTR-FG4
- Part No.:
- UC3854DWTR-FG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UC3854DWTR-FG4.pdf
- Description:
- IC PFC CTR AVERAGE 200KHZ 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,720
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Product details
Overview
UC3854DWTR-FG4 from Texas Instruments is a high-power-factor preregulator controller IC implementing average current-mode control for boost-type active PFC stages. It delivers 0.99 power factor, <5% line-current distortion, fixed 46–62 kHz PWM frequency (RSET-programmable), 7.5 V precision reference, and 1 A totem-pole gate driver - used in offline AC-DC converters delivering up to 400 VDC output.
For engineers reviewing the UC3854DWTR-FG4 datasheet, UC3854DWTR-FG4 pinout, UC3854DWTR-FG4 application, or UC3854DWTR-FG4 equivalent, key selection considerations include RMS line feedforward (VRMS), analog multiplier input linearity (IAC/MULTOUT), soft-start timing (SS/CT), peak current limit threshold (PKLMT), and gate driver voltage clamping (GTDRV).
Technical Context
The UC3854DWTR-FG4 integrates a voltage error amplifier (70–100 dB gain, 0.5–5.8 V output swing), analog multiplier/divider with IAC current input and VRMS feedforward, and a wideband current amplifier (1 MHz typical bandwidth, –4 to +4 mV offset) to enforce sinusoidal line current without slope compensation. Its fixed-frequency oscillator uses CT and RSET to set 46–62 kHz operation, with internal 14 mA SS charge current enabling controlled ramp-up of duty cycle.
It employs average current-mode control - not peak mode - ensuring stable transition between continuous and discontinuous conduction modes while rejecting noise transients. The 7.5 V VREF output powers external circuitry (≤10 mA), and GTDRV provides internally clamped 13–14.5 V drive with ≤35 ns rise/fall time into 1 nF load, supporting MOSFET gate switching up to 200 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 10–20 V operating; 35 V absolute max - supports direct rectified line-derived bias with robust overvoltage tolerance. |
| Oscillator Frequency | 46–62 kHz (RSET = 15 kΩ) - sets fixed PWM timing for EMI-controlled boost switching. |
| VREF Output | 7.5 V ±0.15 V over temperature - supplies stable reference for feedback dividers and external circuitry. |
| Gate Driver Output | 1 A peak, 13–14.5 V clamped, ≤35 ns edge speed - directly drives medium-power MOSFET gates without external buffers. |
| Current Amplifier BW | 400–800 kHz - enables accurate average current sensing across full AC line cycle without phase lag-induced distortion. |
| Power Factor | 0.99 typical - achieved via feedforward VRMS input and analog multiplier architecture minimizing harmonic injection. |
| THD | <5% line-current distortion - meets EN61000-3-2 Class D requirements for >75 W equipment. |
Pinout & Package
UC3854DWTR-FG4 is housed in a 16-pin SOIC (DW) package measuring 7.50 mm × 10.30 mm, with gull-wing leads and standard JEDEC MS-012AC footprint. Thermal resistance RθJA = 71.5°C/W enables operation up to +70°C ambient without forced airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Common return for all signals and timing capacitor discharge - requires short, low-inductance 0.1 µF ceramic bypass to VCC/VREF. |
| PKLMT (Pin 2) | Peak current limit input | Threshold at 0 V; connects to negative side of sense resistor - triggers immediate PWM shutdown on overcurrent events. |
| CAOUT (Pin 3) | Current amplifier output | Drives PWM comparator; swings near GND to force zero duty cycle - remains active even during disable for fast recovery. |
| ISENSE (Pin 4) | Current-sense inverting input | Accepts differential current-sense signal down to –0.3 V - used with MULTOUT to reject ground noise in high-noise boost environments. |
| MULTOUT (Pin 5) | Multiplier output / current-sense non-inverting input | High-impedance current source (–27 µA typ) feeding CAOUT - forms core of analog multiplier loop with IAC and VRMS inputs. |
| IAC (Pin 6) | AC line current input | Current-mode input (nominal 6 V bias) for instantaneous line voltage waveform - critical for low-cross-over distortion in universal-input designs. |
| VAOUT (Pin 7) | Voltage amplifier output | Regulates boost output voltage; clamped to ~5.8 V - provides feedforward signal to multiplier and controls soft-start via SS pin. |
| VRMS (Pin 8) | RMS line voltage feedforward | Accepts 1.5–3.5 V proportional to input RMS - compensates for line-voltage variations to maintain constant output power and reduce THD. |
| VREF (Pin 9) | 7.5 V reference output | Stable, short-circuit protected reference (±0.15 V over temp); powers external dividers and bias networks - disabled when VCC < 10 V or ENA low. |
| ENA (Pin 10) | Enable logic input | Active-high TTL/CMOS-compatible enable (2.55 V threshold); releases SS clamp and activates oscillator/VREF - not intended for high-speed PWM shutdown. |
| VSENSE (Pin 11) | Voltage amplifier inverting input | Connects to output voltage divider - sets regulated output level (e.g., 400 VDC) via feedback ratio; bias current < 500 nA minimizes divider error. |
| RSET (Pin 12) | Oscillator charging current / multiplier limit | Resistor to GND programs both oscillator frequency and maximum multiplier output current - defines system switching point and current limit ceiling. |
| SS (Pin 13) | Soft-start timing node | Internally charged at 14 mA; ramps VAOUT reference slowly - prevents inrush current and output overshoot during startup. |
| CT (Pin 14) | Oscillator timing capacitor | Capacitor to GND sets PWM ramp frequency - valley at 0.8–1.3 V, peak at 4.9–5.9 V - determines switching period and EMI profile. |
| VCC (Pin 15) | Positive supply input | Requires ≥20 mA at ≥17 V; bypassed directly to GND - UVLO turn-on at 16 V (±1.5 V), hysteresis 6 V ensures clean power sequencing. |
| GTDRV (Pin 16) | Gate driver output | Totem-pole MOSFET driver, internally clamped to 15 V - drives gate capacitance directly; series resistor ≥5 Ω required to suppress ringing. |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Eliminates need for slope compensation and maintains sinusoidal line current across CCM/DCM transitions - reduces design complexity and improves stability margin. |
| Feedforward line regulation (VRMS) | Compensates for input voltage variation before it affects output - enables tight output regulation and <5% THD across 75–275 VAC universal input range. |
| Low-noise analog multiplier | Uses IAC current input and VRMS-squared feedforward to generate precise current command - achieves 0.99 PF without digital computation or calibration. |
| Integrated 1 A gate driver | Drives MOSFET gates directly with <35 ns edges and 15 V clamp - avoids external driver ICs and reduces BOM count in high-efficiency PFC stages. |
| 7.5 V precision reference | Stable ±0.15 V over temperature and line - powers feedback networks and external comparators without requiring auxiliary LDOs. |
| Soft-start with SS pin | 14 mA internal current source charges external capacitor - enables controlled ramp of output voltage and prevents inrush-induced stress on boost diode and bulk capacitor. |
Applications
| Medical Power Supplies | Industrial AC-DC Converters |
|---|---|
|
Use Scenario: 250 W universal-input PFC front-end for MRI imaging power systems requiring EN61000-3-2 compliance and low EMI. IC Role / Device Role / Timing Role: UC3854DWTR-FG4 acts as the average current-mode PFC controller, regulating boost output to 400 VDC while enforcing sinusoidal line current synchronized to 50/60 Hz input. Use Value: Achieves 0.999 PF and 3.81% THD measured to 50th harmonic - exceeds medical safety standards and reduces upstream transformer heating. |
Use Scenario: Factory automation PLC power module with 3-phase input rectification and single-phase PFC stage using UC3854DWTR-FG4. IC Role / Device Role / Timing Role: UC3854DWTR-FG4 implements fixed-frequency (55 kHz) average current control to stabilize DC bus under variable motor load transients. Use Value: Maintains <5% line-current distortion despite 400 Hz line frequency and rapid load steps - ensures compatibility with sensitive motion control circuits. |
| Telecom Rectifiers | Uninterruptible Power Supplies (UPS) |
|
Use Scenario: 1 kW telecom rectifier operating from 90–264 VAC with active PFC stage based on UC3854DWTR-FG4 and SiC MOSFETs. IC Role / Device Role / Timing Role: UC3854DWTR-FG4 provides VRMS feedforward and analog multiplier-based current shaping - synchronizing boost current to line voltage waveform. Use Value: Enables >95% system efficiency at full load while meeting IEC 61000-3-2 Class A limits - reduces cooling requirements in dense rack-mounted systems. |
Use Scenario: Online double-conversion UPS with PFC front-end and battery backup, using UC3854DWTR-FG4 to regulate 400 VDC intermediate bus. IC Role / Device Role / Timing Role: UC3854DWTR-FG4 serves as the primary PFC controller during AC operation and maintains bus regulation during transfer to battery mode via hold-up capacitors. Use Value: Soft-start (SS pin) prevents inrush during AC restoration - extends electrolytic capacitor life and avoids breaker tripping during grid recovery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar active power factor correction applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC3854D | Pin-compatible SOIC-16 variant with identical functional block diagram; differs in UVLO thresholds (10.5 V turn-on vs 16 V) and VCC max (22 V vs 35 V). | Optimized for lower-voltage auxiliary supplies; unsuitable for direct rectified-line bias above 22 V. | Select UCC3854D only when VCC is derived from regulated 15 V rail - UC3854DWTR-FG4 remains preferred for direct rectified-line biasing. |
| ICE3PCS01G | Fixed-frequency CCM PFC controller with integrated 650 V MOSFET; no analog multiplier - uses digital current sensing and internal feedforward. | Reduces component count but lacks VRMS/IAC flexibility; limited to 230 VAC nominal input with no universal 75–275 VAC support. | Choose ICE3PCS01G for cost-sensitive, single-input designs; UC3854DWTR-FG4 offers superior THD performance and universal input adaptability. |
Compared with UCC3854D and ICE3PCS01G, UC3854DWTR-FG4 provides higher VCC tolerance (35 V), analog multiplier precision for ultra-low THD, and proven 0.99 PF across 50–400 Hz line frequencies - making it the optimal choice for high-reliability universal-input PFC stages.
Availability
UC3854DWTR-FG4 is available at Aetrix Electronics and suitable for medical power supplies, industrial AC-DC converters, and telecom rectifiers requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for UC3854DWTR-FG4 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, embedded processing, and power management technologies, with decades of leadership in power conversion ICs.
The UC3854DWTR-FG4 belongs to TI's UCx854 family of high-power-factor preregulators, designed specifically for continuous-conduction-mode boost PFC stages in universal-input offline power supplies.
FAQ
What is the recommended VCC supply configuration for UC3854DWTR-FG4?
The UC3854DWTR-FG4 requires a stable 10–20 V supply capable of delivering ≥20 mA. It is commonly biased from a resistive dropper + zener or auxiliary winding rectifier. VCC must exceed 16 V (typical) to exit UVLO, and the 0.1 µF ceramic bypass capacitor must connect directly between Pin 15 (VCC) and Pin 1 (GND) to suppress gate-drive current spikes that could destabilize regulation.
How does the VRMS pin improve power factor performance in UC3854DWTR-FG4?
The VRMS pin (Pin 8) accepts a DC voltage proportional to RMS input line voltage (1.5–3.5 V). Internally squared and fed into the analog multiplier's denominator, it dynamically scales the current command to maintain constant output power across varying line conditions - reducing THD by up to 2% and enabling 0.99 PF across 75–275 VAC universal input.
Can UC3854DWTR-FG4 operate with discontinuous conduction mode (DCM) boost topologies?
Yes - UC3854DWTR-FG4's average current-mode control inherently supports both CCM and DCM operation without instability or performance degradation. Unlike peak current-mode controllers, it does not require slope compensation in DCM and maintains low THD (<5%) and 0.99 PF regardless of inductor size or load level, verified in 250 W test setups.
What is the function of the PKLMT pin on UC3854DWTR-FG4, and how should it be connected?
PKLMT (Pin 2) is the peak current limit input with a 0 V threshold. It connects to the negative terminal of the current-sense resistor placed in series with the boost switch. A resistor from PKLMT to VREF offsets the negative sense voltage to GND, allowing accurate detection of overcurrent events and immediate PWM shutdown - protecting the MOSFET during short-circuit or overload conditions.
Does UC3854DWTR-FG4 support soft-start, and how is it implemented?
Yes - UC3854DWTR-FG4 implements soft-start via the SS pin (Pin 13). An internal 14 mA current source charges an external capacitor from GND, causing VAOUT's reference to rise gradually. This linearly increases PWM duty cycle, limiting inrush current into the output capacitor and preventing output overshoot - critical for reliability in high-voltage 400 VDC PFC designs.
UC3854DWTR-FG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Mode:
- Average Current
- Frequency - Switching:
- 200kHz
- Current - Startup:
- 1.5 mA
- Voltage - Supply:
- 14.5V ~ 30V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
UC3854DWTR-FG4 FAQ
1.How can I place an order for UC3854DWTR-FG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3854DWTR-FG4 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 UC3854DWTR-FG4 reliable?
The price and inventory of UC3854DWTR-FG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3854DWTR-FG4 is usually 5 days.
3.What payment methods are accepted for UC3854DWTR-FG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3854DWTR-FG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3854DWTR-FG4?
UC3854DWTR-FG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3854DWTR-FG4 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 UC3854DWTR-FG4?
For technical support, including UC3854DWTR-FG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3854DWTR-FG4 requirements.
6.How does Aetrix verify that UC3854DWTR-FG4 is sourced from the original manufacturer or authorized distributors?
All UC3854DWTR-FG4 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 UC3854DWTR-FG4 meets industry standards.
7.What is the process for return or replacement of UC3854DWTR-FG4?
All UC3854DWTR-FG4 units undergo pre-shipment inspection (PSI). If there is an issue with UC3854DWTR-FG4, 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 UC3854DWTR-FG4 part is unused and in its original packaging.
Return procedure for UC3854DWTR-FG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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