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Texas Instruments UC3854ADWTRG4
- Part No.:
- UC3854ADWTRG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UC3854ADWTRG4.pdf
- Description:
- IC PFC CTR AVERAGE 200KHZ 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,171
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Product details
Overview
UC3854ADWTRG4 from Texas Instruments is a fixed-frequency average current-mode active power factor correction (PFC) controller IC designed for boost preregulator topologies. It delivers near-unity power factor, limits line current distortion to <3%, features a 7.5-V reference, 5-MHz current amplifier bandwidth, and operates across 0°C to 70°C with 10.5 V/10 V UVLO thresholds. It is used in offline AC-DC front-end stages of industrial power supplies and server PSUs.
For engineers reviewing the UC3854ADWTRG4 datasheet, UC3854ADWTRG4 pinout, UC3854ADWTRG4 application, or UC3854ADWTRG4 equivalent, key selection considerations include its average current-mode control architecture, integrated multiplier with 0 V–5 V VRMS input range, 1.5-A peak gate driver output, soft-start via SS pin, and SOIC-16 package compatibility with standard PFC layout practices.
Technical Context
The UC3854ADWTRG4 implements average current-mode control using a high-bandwidth (5 MHz) current amplifier and a precision analog multiplier that accepts IAC (line voltage proportional current), VRMS (RMS-scaled voltage), and VAO (voltage error amplifier output) to generate the MOUT current command. Its multiplier gain constant is –1.0 A/A (typ) with improved linearity and 500 mV VAC offset eliminating external zero-crossing compensation resistors.
It integrates a 7.5-V reference with ±15 mV tolerance, oscillator with 80–120 kHz frequency range (set by RSET/CT), enable comparator with 2.55 V threshold and 600 mV hysteresis, and a 1.5-A totem-pole GTDRV output capable of driving MOSFET gates directly. The device supports world-wide operation without manual switching via line-voltage feedforward and accurate power limiting through PKLMT and RSET-controlled foldback during brownout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC UVLO Turn-on/Off | 10.5 V / 10 V - Enables startup from auxiliary 12-V rail; ensures reliable disable below valid supply level. |
| Oscillator Frequency | 80–120 kHz - Fixed-frequency operation set by RSET and CT; stable across line/temperature variation. |
| Current Amplifier GBW | 5 MHz - Enables low-distortion sinusoidal line current shaping even at 400 Hz avionics inputs. |
| Multiplier Gain Constant | –1.0 A/A - Precise current command generation from VRMS² × VAO/IAC; eliminates external scaling networks. |
| GTDRV Peak Output | 1.5 A - Directly drives boost MOSFET gates without external buffer; reduces BOM count and layout complexity. |
| Reference Voltage | 7.5 V ±15 mV - High-accuracy internal reference for voltage loop stability and consistent regulation across temperature. |
| Soft-Start Charge Current | 14 µA - Controls ramp rate of SS pin voltage to limit inrush current during power-up. |
Pinout & Package
UC3854ADWTRG4 is housed in a 16-pin SOIC (DW) package with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and MSL Level-2 moisture sensitivity rating. Thermal resistance θJA is 50–130°C/W on FR4 PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Power and signal reference ground | Common return for all analog/digital circuits; requires short, low-inductance connection to PCB ground plane. |
| PKLMT (Pin 2) | Peak current limit threshold input | Accepts negative voltage from current-sense resistor; sets instantaneous MOSFET conduction limit to prevent overcurrent. |
| CAO (Pin 3) | Current amplifier output | Drives PWM comparator; swings 0.1–7.5 V to command duty cycle based on sensed inductor current. |
| ISENSE (Pin 4) | Inverting current sense input | Connects to low-side current-sense resistor; works down to –0.5 V to support bidirectional sensing in continuous conduction mode. |
| MOUT (Pin 5) | Multiplier output / current amp non-inverting input | High-impedance node combining multiplier result and current feedback path; common-mode range –0.3 V to 5.0 V. |
| IAC (Pin 6) | Line voltage proportional current input | Accepts 100 µA nominal current from resistive divider; regulated to 500 mV offset eliminates external zero-crossing compensation. |
| VAO (Pin 7) | Voltage amplifier output | Clamped to 6.0 V internally; forms third multiplier input and provides voltage loop error signal. |
| VRMS (Pin 8) | RMS-scaled line voltage input | 0–5.5 V linear input range enables accurate squaring; 1.5 V at 85 VAC ensures full dynamic range up to 270 VAC. |
| VREF (Pin 9) | 7.5-V reference output | Stable reference for external circuitry and internal comparators; short-circuit protected to 60 mA. |
| ENA (Pin 10) | Enable/disable control input | 2.55 V threshold with 600 mV hysteresis; internal clamp to ~10 V allows direct MCU GPIO interfacing. |
| VSENSE (Pin 11) | Voltage feedback input | Connects to output voltage divider; feeds into voltage error amplifier to regulate DC bus voltage. |
| RSET (Pin 12) | Oscillator charging current set | Resistor to GND programs oscillator frequency only; no longer affects multiplier current clamping (simplifies design). |
| SS (Pin 13) | Soft-start timing capacitor node | Internally sourced 14 µA current charges external capacitor; controls PWM ramp-up to limit inrush current. |
| CT (Pin 14) | Oscillator timing capacitor node | Capacitor to GND sets oscillator frequency with RSET; ramp valley at 0.8–1.3 V, peak-to-peak amplitude 4.9–5.9 V. |
| VCC (Pin 15) | Positive supply input | Operates from 10–20 V; clamped to 22 V max; 18 mA typical operating current supports self-biasing from boost output. |
| GTDRV (Pin 16) | Gate driver output | 1.5-A peak totem-pole output; rise/fall times ≤35 ns into 1 nF; requires ≥5 Ω series gate resistor to prevent overshoot. |
Key Features
| Feature | Design Value |
|---|---|
| Average current-mode control | Eliminates slope compensation requirement and enables stable, low-distortion sinusoidal line current without instability at high duty cycles. |
| Integrated 5-MHz current amplifier | Reduces line current THD to <3% even under 400 Hz input conditions; improves transient response during line dropouts. |
| 0 V–5.5 V VRMS input range | Supports universal input (85–270 VAC) with single resistor divider; avoids clipping at high line and preserves accuracy at low line. |
| Internal 6.0-V VAO clamp | Removes need for external Zener diode; prevents voltage amplifier saturation and maintains multiplier linearity across load transients. |
| VREF GOOD comparator | Ensures GTDRV remains low until 7.5-V reference is fully stabilized; eliminates need for external Schottky diodes on PKLMT/MOUT. |
| 10.5 V/10 V UVLO option | Enables direct operation from 12-V auxiliary supply in multi-rail systems; simplifies startup sequencing in complex power architectures. |
Applications
| Industrial AC-DC Power Supplies | Server and Telecom Rectifiers |
|---|---|
Use Scenario: 3 kW front-end rectifier in programmable AC source with strict EN 61000-3-2 Class A harmonic limits. IC Role / Device Role / Timing Role: Primary PFC controller generating precise average inductor current command synchronized to line voltage zero crossings. Use Value: Achieves <3% line current distortion and >0.99 power factor across 10–100% load, reducing upstream transformer and filter sizing. |
Use Scenario: Dual-stage 12 V/48 V telecom rectifier requiring high efficiency and fast load transient response. IC Role / Device Role / Timing Role: Boost PFC stage controller regulating 380 VDC bus with adaptive soft-start and brownout foldback. Use Value: Integrated 1.5-A GTDRV drives 60-mΩ MOSFETs directly; 5-MHz current amplifier enables <50 µs current-loop recovery during 50% load steps. |
| Medical Imaging Power Systems | LED Driver Front-Ends |
Use Scenario: CT scanner power module requiring ultra-low EMI and zero audible noise during imaging sequences. IC Role / Device Role / Timing Role: Fixed-frequency average current-mode PFC controller minimizing subharmonic content in conducted emissions. Use Value: 80–120 kHz oscillator avoids AM radio band; multiplier linearity and 5-MHz amplifier suppress 3rd/5th harmonic generation. |
Use Scenario: Outdoor LED streetlight with universal AC input and surge immunity requirements per IEC 61000-4-5. IC Role / Device Role / Timing Role: PFC pre-regulator feeding downstream LLC resonant converter with tightly regulated 400 VDC bus. Use Value: 10.5 V/10 V UVLO enables robust start-up from auxiliary 12-V rail during cold cranking; PKLMT foldback protects against lightning-induced surges. |
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 |
|---|---|---|---|
| UC3854BDWTRG4 | 10.5 V/10 V UVLO only; identical pinout, specs, and SOIC-16 packaging. | Designed for auxiliary-supply-powered systems; lacks 16 V/10 V UVLO option for direct offline start-up. | Select UC3854BDWTRG4 when primary bias is derived from 12-V auxiliary rail rather than bulk DC. |
| L6562ATDTR | Fixed-frequency average current-mode PFC controller with 12.5 V/7.5 V UVLO, 500 kHz max frequency, and integrated 1.2-A driver. | Optimized for higher-frequency designs (≥200 kHz); lower VCC operating range (10.5–22 V); different multiplier architecture (no IAC input). | Choose L6562ATDTR for compact, high-frequency PFC stages where board space is constrained and 85–265 VAC input suffices. |
Compared with UC3854BDWTRG4, the UC3854ADWTRG4 offers identical functionality but targets broader input voltage ranges including offline start-up; versus L6562ATDTR, it provides superior low-line performance and legacy design compatibility while trading off maximum switching frequency for proven 50/60 Hz harmonic suppression.
Availability
UC3854ADWTRG4 is available at Aetrix Electronics and suitable for industrial AC-DC power supplies, server rectifiers, and medical imaging systems requiring stable component supply with long-term lifecycle support and traceable sourcing.
Supply support for UC3854ADWTRG4 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 connectivity solutions with emphasis on reliability, precision, and energy efficiency.
The UC3854A/B product line was engineered specifically for high-performance active power factor correction in offline AC-DC conversion, targeting >0.99 PF, <3% THD, and robust operation across universal input ranges and temperature extremes.
FAQ
What is the operating temperature range for the UC3854ADWTRG4?
The UC3854ADWTRG4 is rated for operation from 0°C to 70°C ambient temperature. This commercial-grade specification aligns with its SOIC-16 DW package and makes it suitable for enclosed power supply environments where thermal management is controlled. The device's internal thermal protection and UVLO thresholds remain stable across this full range, ensuring consistent PFC performance in server and industrial applications.
Does the UC3854ADWTRG4 require external slope compensation?
No, the UC3854ADWTRG4 does not require external slope compensation because it uses average current-mode control instead of peak current-mode control. Its high-bandwidth (5 MHz) current amplifier continuously compares sensed inductor current to the MOUT command signal, inherently stabilizing the control loop across all duty cycles and line conditions - a key advantage over older PFC controllers like the UC3854.
How does the UC3854ADWTRG4 achieve near-unity power factor?
The UC3854ADWTRG4 achieves near-unity power factor by multiplying three signals - IAC (proportional to instantaneous line voltage), VRMS (squared line voltage), and VAO (voltage error amplifier output) - to generate a sinusoidal current command (MOUT). This forces the average inductor current to track the line voltage waveform, resulting in <3% line current distortion and power factors exceeding 0.99 across 10–100% load in properly designed boost PFC stages.
Can the UC3854ADWTRG4 be used with a 12-V auxiliary supply?
Yes, the UC3854ADWTRG4 supports startup from a 12-V auxiliary supply due to its 10.5 V/10 V UVLO configuration. When VCC rises above 10.5 V, the device enables; it remains active until VCC drops below 10 V. This eliminates the need for high-voltage startup resistors and simplifies biasing in multi-rail systems where an auxiliary rail is already present - a capability confirmed in the UC3854A/B datasheet SLUS329E.
What is the purpose of the RSET pin on the UC3854ADWTRG4?
The RSET pin on the UC3854ADWTRG4 programs only the oscillator charging current - and thus the switching frequency - via an external resistor to ground. Unlike earlier UC3854 variants, RSET no longer affects multiplier output current clamping, which is now fixed at 2×IAC. This decoupling simplifies design, improves consistency, and removes a critical interaction between frequency setting and power limiting behavior in the UC3854ADWTRG4.
UC3854ADWTRG4 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:
- 250 µA
- Voltage - Supply:
- 10V ~ 20V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
UC3854ADWTRG4 FAQ
1.How can I place an order for UC3854ADWTRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3854ADWTRG4 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 UC3854ADWTRG4 reliable?
The price and inventory of UC3854ADWTRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3854ADWTRG4 is usually 5 days.
3.What payment methods are accepted for UC3854ADWTRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3854ADWTRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3854ADWTRG4?
UC3854ADWTRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3854ADWTRG4 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 UC3854ADWTRG4?
For technical support, including UC3854ADWTRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3854ADWTRG4 requirements.
6.How does Aetrix verify that UC3854ADWTRG4 is sourced from the original manufacturer or authorized distributors?
All UC3854ADWTRG4 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 UC3854ADWTRG4 meets industry standards.
7.What is the process for return or replacement of UC3854ADWTRG4?
All UC3854ADWTRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UC3854ADWTRG4, 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 UC3854ADWTRG4 part is unused and in its original packaging.
Return procedure for UC3854ADWTRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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