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Texas Instruments UC3854QTR
- Part No.:
- UC3854QTR
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-LCC (J-Lead)
- Datasheet:
-
UC3854QTR.pdf
- Description:
- IC PFC CTR AVERAGE 200KHZ 20PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,988
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Product details
Overview
UC3854QTR from Texas Instruments is a high-power-factor preregulator controller IC designed for average current-mode boost PFC stages in offline AC–DC power supplies. 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 - enabling compliance with EN61000-3-2 Class D for >75 W systems.
For engineers reviewing the UC3854QTR datasheet, UC3854QTR pinout, UC3854QTR application, or UC3854QTR equivalent, this page provides verified technical context, SOIC-16 package mapping, real-world PFC design values, functional alternatives, and supply-chain support for industrial, telecom, and medical power supply development.
Technical Context
The UC3854QTR implements average current-mode control using an analog multiplier/divider, voltage amplifier, and current amplifier - eliminating slope compensation while maintaining sinusoidal input current across 50–400 Hz line frequencies and 75–275 VAC inputs. Its feedforward line regulation (via VRMS) and RMS-scaled multiplier input (IAC) enable stable operation without switching adjustments during global voltage/frequency changes.
Internally, the device integrates a 7.5 V reference (±15 mV load/line regulation), soft-start circuitry (14 mA SS current source), peak current limit (PKLMT at 0 V threshold), and GTDRV output clamped to 15 V - allowing direct drive of power MOSFETs with VCC up to 35 V. The oscillator frequency is set by RSET and CT, with typical range 46–62 kHz at RSET = 15 kΩ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Power Factor | 0.99 - enables EN61000-3-2 Class D compliance for >75 W AC–DC supplies. |
| Line Current Distortion | <5% - achieved via average current-mode control without slope compensation. |
| Oscillator Frequency | 46–62 kHz (RSET = 15 kΩ) - sets fixed PWM timing for boost stage switching. |
| Voltage Reference | 7.5 V ±0.15 V over temperature - powers external circuitry and serves as soft-start reference. |
| Gate Driver Output | 1 A peak, 15 V clamped - directly drives power MOSFET gates without external buffers. |
| Operating Temperature | 0°C to +70°C - specified junction range for UC3854-grade commercial operation. |
| Supply Voltage Range | VCC = 10–20 V (recommended), up to 35 V absolute max - supports wide-input auxiliary supplies. |
Pinout & Package
UC3854QTR is housed in a 16-pin SOIC (DW package), 7.50 mm × 10.30 mm body size, with Gull-wing leads and standard JEDEC MS-012 outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Common return for all signals and timing capacitor discharge; requires direct 0.1 µF ceramic bypass. |
| PKLMT (Pin 2) | Peak current limit input | 0 V threshold comparator input; pulls GTDRV low when current-sense signal drops below ground. |
| CAOUT (Pin 3) | Current amplifier output | Drives PWM comparator; swings near GND to force zero duty cycle; remains active during disable. |
| ISENSE (Pin 4) | Current-sense inverting input | Accepts negative-going voltage from sense resistor; operates down to –0.3 V; protected by GND clamp diodes. |
| MULTOUT (Pin 5) | Multiplier output / current-sense non-inverting input | High-impedance node connecting multiplier output to current amplifier; used differentially with ISENSE for noise rejection. |
| IAC (Pin 6) | AC line current input | Current-mode input to analog multiplier; internally biased at 6 V; enables low-distortion RMS feedforward. |
| VAOUT (Pin 7) | Voltage amplifier output | Regulates boost output voltage; clamped to ~5.8 V; remains active during disable to retain feedback charge. |
| VRMS (Pin 8) | RMS line voltage input | Accepts 1.5–3.5 V proportional to input RMS voltage; compensates for line variations before multiplier stage. |
| VREF (Pin 9) | 7.5 V reference output | 10 mA capable; disabled when VCC low or ENA low; requires 0.1 µF ceramic bypass to GND. |
| ENA (Pin 10) | Enable logic input | Active-high (2.55 V threshold); releases SS clamp and enables oscillator/VREF; not intended for high-speed shutdown. |
| VSENSE (Pin 11) | Voltage amplifier inverting input | Connects to output divider network; bias current ±500 nA; offset voltage ±8 mV. |
| RSET (Pin 12) | Oscillator/multiplier set resistor | Resistor to GND programs oscillator charging current and maximum multiplier output (3.75 V/RSET). |
| SS (Pin 13) | Soft-start timing node | Charged by 14 mA internal current source; controls voltage amplifier reference ramp-up to prevent turn-on overshoot. |
| CT (Pin 14) | Oscillator timing capacitor | Capacitor to GND sets PWM frequency; CT ramp valley = 0.8–1.3 V, peak-to-valley = 4.9–5.9 V. |
| VCC (Pin 15) | Positive supply input | 10–20 V recommended; UVLO turn-on at 16 V typical; must supply ≥20 mA for gate drive. |
| GTDRV (Pin 16) | Gate driver output | Totem-pole MOSFET driver; 1 A peak; rise/fall time 35 ns (1 nF load); max duty cycle 95%. |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Enables stable, low-distortion sinusoidal line current without slope compensation across CCM/DCM transitions. |
| Feedforward line regulation | VRMS input scales multiplier gain in real time, minimizing output voltage deviation during line sags/swells. |
| Low-noise analog multiplier/divider | Uses IAC current input and VAOUT voltage input to generate precise instantaneous current command signal. |
| Integrated 7.5 V reference | Stable, low-drift reference with ±15 mV load regulation - powers external circuitry and soft-start timing. |
| 1 A totem-pole gate driver | Directly drives power MOSFET gates with 15 V clamp, eliminating need for external level-shifting or buffering. |
Applications
| Medical Power Supplies | Industrial AC–DC Converters |
|---|---|
Use Scenario: 250 W universal-input PFC front-end for MRI or diagnostic imaging equipment requiring low THD and high reliability. IC Role / Device Role / Timing Role: UC3854QTR acts as the average current-mode PFC controller, generating fixed-frequency PWM to regulate boost output at 400 VDC while shaping sinusoidal input current. Use Value: Achieves 0.999 PF and 3.81% THD (to 50th harmonic), meeting IEC 60601-1 EMI and efficiency requirements. |
Use Scenario: Factory automation PLC power module operating from 85–264 VAC with wide ambient temperature range. IC Role / Device Role / Timing Role: UC3854QTR manages continuous-conduction-mode boost stage, using VRMS feedforward to maintain regulation during brownouts. Use Value: Enables world-wide operation without hardware switches and maintains <5% line-current distortion across 50/60 Hz and 400 Hz line frequencies. |
| Telecom Rectifiers | Uninterruptible Power Supplies (UPS) |
Use Scenario: -48 V DC telecom rectifier with active PFC stage feeding downstream DC–DC converters. IC Role / Device Role / Timing Role: UC3854QTR controls the boost converter to deliver regulated 400 VDC bus, interfacing with VRMS and IAC for real-time line tracking. Use Value: Delivers 0.99 PF and stable output under dynamic load steps, reducing upstream transformer and filter sizing. |
Use Scenario: Line-interactive UPS with bidirectional PFC capability and battery backup staging. IC Role / Device Role / Timing Role: UC3854QTR serves as the PFC preregulator during AC mode, coordinating with VAOUT loop and PKLMT for overload protection. Use Value: Supports seamless transfer between AC and battery modes with minimal output droop due to fast voltage amplifier response (100 dB gain). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-power-factor preregulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC3854D | Same SOIC-16 pinout; improved 5 MHz current amplifier bandwidth vs UC3854QTR's 1 MHz; lower VCC UVLO hysteresis (0.5 V). | Supports higher-bandwidth current loops and faster transient response; optimized for designs targeting tighter THD specs. | Select UCC3854D when upgrading legacy UC3854QTR designs for enhanced stability margin or reduced current-sense noise sensitivity. |
| ICE3PCS01G | Fixed-frequency CCM PFC controller in PG-DSO-16; integrated zero-voltage-switching (ZVS) assist; no external RSET/CT required. | Reduces external component count; targets cost-sensitive consumer/IT power supplies rather than high-reliability industrial use. | Choose ICE3PCS01G for new designs prioritizing BOM reduction and ZVS efficiency gains, accepting different layout and control architecture. |
Compared with UC3854QTR, UCC3854D offers higher current-loop bandwidth for improved THD performance, while ICE3PCS01G eliminates timing components but lacks UC3854QTR's analog multiplier flexibility and wide-line-frequency support (50–400 Hz).
Availability
UC3854QTR is available at Aetrix Electronics and suitable for medical power supplies, industrial AC–DC converters, and telecom rectifiers requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for UC3854QTR 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 delivering analog, embedded processing, and power management solutions with focus on reliability, precision, and energy efficiency.
The UC3854QTR belongs to TI's high-power-factor preregulator IC family, engineered specifically for average current-mode boost PFC in universal-input offline power supplies from 75 W to >1 kW.
FAQ
What is the operating temperature range for the UC3854QTR?
The UC3854QTR is rated for 0°C to +70°C junction temperature, matching the UC3854 commercial-grade specification. This range supports deployment in enclosed industrial enclosures and telecom rectifier modules where ambient temperatures remain within commercial limits. Derating is required above 70°C, and thermal design must account for RθJA = 71.5°C/W in SOIC packaging.
Does the UC3854QTR support both 50 Hz and 400 Hz line frequencies?
Yes, the UC3854QTR supports line frequencies from 50 Hz to 400 Hz, as confirmed in the device description and recommended operating conditions. Its feedforward VRMS input and average current-mode architecture ensure stable power factor correction without configuration changes - making it suitable for aerospace (400 Hz) and global industrial (50/60 Hz) applications.
How does the UC3854QTR achieve <5% line-current distortion?
The UC3854QTR achieves <5% line-current distortion through average current-mode control, which directly regulates the average inductor current waveform to match the sinusoidal input voltage. Unlike peak current-mode, it avoids subharmonic oscillation and eliminates need for slope compensation - resulting in inherently low distortion even during CCM/DCM boundary transitions.
What is the function of the RSET pin on the UC3854QTR?
The RSET pin on the UC3854QTR programs both the oscillator charging current and the maximum multiplier output current. A resistor from RSET to GND sets the oscillator frequency (e.g., 46–62 kHz at 15 kΩ) and limits multiplier output to 3.75 V divided by the RSET resistance - preventing excessive current commands during overvoltage or overload events.
Can the UC3854QTR be used in discontinuous conduction mode (DCM)?
Yes, the UC3854QTR supports both continuous and discontinuous conduction modes without performance degradation. Its average current-mode control maintains accurate sinusoidal input current shape regardless of inductor operating mode - a key advantage over peak current-mode controllers that require slope compensation in DCM.
UC3854QTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 20-PLCC (9x9)
UC3854QTR FAQ
1.How can I place an order for UC3854QTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3854QTR 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 UC3854QTR reliable?
The price and inventory of UC3854QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3854QTR is usually 5 days.
3.What payment methods are accepted for UC3854QTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3854QTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3854QTR?
UC3854QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3854QTR 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 UC3854QTR?
For technical support, including UC3854QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3854QTR requirements.
6.How does Aetrix verify that UC3854QTR is sourced from the original manufacturer or authorized distributors?
All UC3854QTR 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 UC3854QTR meets industry standards.
7.What is the process for return or replacement of UC3854QTR?
All UC3854QTR units undergo pre-shipment inspection (PSI). If there is an issue with UC3854QTR, 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 UC3854QTR part is unused and in its original packaging.
Return procedure for UC3854QTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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