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Texas Instruments UC2854BQ-TI
- Part No.:
- UC2854BQ-TI
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-LCC (J-Lead)
- Datasheet:
-
UC2854BQ-TI.pdf
- Description:
- 1.5A, 120KHZ BIPOLAR, PQCC20
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
UC2854BQ-TI from Texas Instruments is a high-performance active power factor correction (PFC) controller IC for boost preregulators, implementing fixed-frequency average current mode control to achieve near-unity power factor and limit line current distortion to <3%. It features a 5 MHz bandwidth current amplifier, 7.5 V ±1% reference, 10.5 V/10 V UVLO thresholds, and integrated voltage/current amplifiers with output clamps. Used in offline AC-DC front-end supplies for industrial and telecom power systems.
For engineers reviewing the UC2854BQ-TI datasheet, UC2854BQ-TI pinout, UC2854BQ-TI application, or UC2854BQ-TI equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, and two confirmed alternative PFC controllers with documented functional and application-level differences.
Technical Context
The UC2854BQ-TI implements average current mode control-eliminating slope compensation needs while maintaining stable, low-distortion sinusoidal input current tracking of AC line voltage. Its multiplier accepts IAC (500 mV offset), VRMS (0–5.5 V range), and VAOUT (clamped to 6 V) to generate precise current command signals.
It integrates a high-bandwidth (5 MHz typ.) current amplifier with ≤3 mV input offset and −0.3 V to 5 V common-mode output range, plus a voltage amplifier with 100 dB open-loop gain and soft-start capability. The gate driver delivers 0.5 A continuous / 1.5 A pulsed output with 35 ns rise/fall times into 1 nF load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Control Method | Average current mode-enables stable, low-distortion AC line current without slope compensation. |
| Oscillator Frequency | 80–120 kHz typical-fixed-frequency operation simplifies EMI filter design and enables predictable switching loss. |
| Current Amplifier BW | 5 MHz typical-supports clean current sensing at 400 Hz avionics inputs and fast transient response. |
| Voltage Reference | 7.5 V ±1%-provides stable feedback reference for output voltage regulation with <25 mV line regulation. |
| UVLO Thresholds | 10.5 V turn-on / 10 V turn-off-enables startup from auxiliary 12 V supply, reducing external bias complexity. |
| Gate Driver Output | 0.5 A continuous / 1.5 A pulsed-directly drives medium-power MOSFET gates without external buffer stages. |
| Startup Supply Current | 250 µA typical-lowers power dissipation in high-voltage startup resistors and improves light-load efficiency. |
Pinout & Package
UC2854BQ-TI is housed in a 20-pin PLCC (Q package) with gull-wing leads, rated for –40°C to +85°C operating temperature. Pin layout matches UC1854B/UC3854B family for board-level compatibility across temperature grades.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 11, 12, 16 | N/C | No internal connection-no routing or grounding required; floating pins must be left unconnected. |
| 2 | Gnd | Analog/digital ground reference for all internal amplifiers, comparators, and reference-requires low-impedance local return path. |
| 3 | PKLMT | Peak current limit threshold input-accepts up to 5 V; sets maximum switch current via external resistor divider. |
| 4 | CA Out | Current amplifier output-drives PWM comparator; clamped internally to prevent saturation during overcurrent events. |
| 5 | ISENSE | Inverting input of current amplifier-receives shunt-based current sense signal; high common-mode rejection supports high-side sensing. |
| 7 | IAC | Multiplier current input-regulated to 500 mV offset; eliminates need for external zero-crossing compensation resistor. |
| 8 | VA Out | Voltage amplifier output-feeds multiplier as third input; clamped to 6 V to avoid external zener protection. |
| 9 | VRMS | RMS-sensed line voltage input-0–5.5 V linear range enables accurate feedforward across 85–270 VAC inputs. |
| 13 | VSENSE | Voltage amplifier inverting input-connects to output voltage divider; bias current <±500 nA minimizes divider error. |
| 14 | RSET | Oscillator timing current set-controls frequency via external resistor; independent of multiplier current limiting. |
| 17 | CT | Oscillator timing capacitor-sets ramp amplitude (4.9–5.9 V p-p) and valley (0.8–1.3 V); defines switching frequency with RSET. |
| 18 | VCC | Supply input-22 V absolute max; internal 20 V clamp allows current-fed operation and protects against transients. |
| 19 | GT Drv | Gate drive output-push-pull stage capable of 1.5 A peak into capacitive loads; logic-compatible with standard MOSFETs. |
| 20 | SS | Soft-start capacitor node-linearly ramps VAOUT to prevent inrush current; charge current 10–24 µA typical. |
Key Features
| Feature | Design Value |
|---|---|
| 500 mV IAC offset | Eliminates external zero-crossing compensation resistor, reducing BOM count and improving line-current symmetry. |
| −0.3 V to 5 V Mult Out range | Supports larger current-sense signal amplitudes without clipping-enables direct use with high-value shunts or current transformers. |
| Integrated VREF "GOOD" comparator | Prevents GT Drv activation until 7.5 V reference stabilizes-removes need for external Schottky diodes on PKLMT/CA+ pins. |
| 10.5 V/10 V UVLO option | Enables reliable startup from auxiliary 12 V rails-ideal for systems with standby supplies or multi-rail architectures. |
| 250 µA startup supply current | Lowers power loss in high-voltage startup networks-extends hold-up time and reduces thermal stress on startup resistors. |
Applications
| Industrial AC-DC Power Supplies | Telecom Rectifier Modules |
|---|---|
Use Scenario: 3 kW rectifier for central office power systems operating from 85–264 VAC input. IC Role / Device Role / Timing Role: Primary PFC controller regulating boost stage to meet EN 61000-3-2 Class A harmonic limits. Use Value: Achieves <3% THD line current distortion and >0.99 power factor across full load and line range-reducing upstream transformer and fuse sizing. |
Use Scenario: Hot-swappable 48 V DC output module in distributed telecom power architecture. IC Role / Device Role / Timing Role: Average current mode PFC controller synchronizing boost converter to fixed 100 kHz clock for predictable EMI profile. Use Value: 5 MHz current amplifier bandwidth ensures stable current loop response during rapid load transients-maintaining output regulation during battery backup switchover. |
| Medical Imaging Power Front-Ends | Server PSU Active Front-Ends |
Use Scenario: High-reliability 1.5 kW power supply for MRI gradient amplifiers requiring low-noise, low-distortion input. IC Role / Device Role / Timing Role: Precision PFC controller shaping line current to match voltage waveform using VRMS feedforward and IAC sensing. Use Value: 0–5.5 V VRMS input range accommodates wide line sensing dividers-enabling accurate feedforward from 85 VAC to 270 VAC without recalibration. |
Use Scenario: 80 PLUS Titanium-certified 1.2 kW server PSU with digital control and analog PFC stage. IC Role / Device Role / Timing Role: Analog PFC controller providing robust, deterministic boost regulation independent of digital controller latency. Use Value: Integrated CA/VA output clamps and 10.5 V UVLO allow seamless integration with 12 V auxiliary rail-reducing system-level startup sequencing complexity. |
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 |
|---|---|---|---|
| UCC2854BDR | Same pinout, identical electrical specs, but offered in SOIC-16 (DW package) instead of PLCC-20; no SS pin-soft-start implemented externally. | Preferred for cost-sensitive, space-constrained designs where PLCC assembly is unavailable or thermal management favors SOIC. | Select UCC2854BDR when board assembly uses SOIC footprint and external soft-start is acceptable. |
| ICE2PCS01G | Fixed-frequency CCM PFC controller with integrated 600 V startup circuit; different pinout, no VRMS feedforward, lower current amplifier bandwidth (1.5 MHz). | Better suited for compact, single-stage PFC+LLC designs where integrated HV startup eliminates external resistor network. | Choose ICE2PCS01G when designing for simplified HV startup and reduced component count-not for high-precision feedforward applications. |
Compared with UC2854BQ-TI, UCC2854BDR offers identical functionality in SOIC-16 but requires external soft-start, while ICE2PCS01G trades feedforward accuracy and bandwidth for integrated HV startup and smaller footprint-making each suitable for distinct system-level trade-offs.
Availability
UC2854BQ-TI is available at Aetrix Electronics and suitable for industrial AC-DC power supplies, telecom rectifier modules, and medical imaging front-ends requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for UC2854BQ-TI 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 emphasis on reliability, precision, and energy efficiency.
The UC2854BQ-TI belongs to TI's legacy Unitrode PFC controller product line, designed specifically for high-accuracy, fixed-frequency average current mode active power factor correction in industrial and telecom offline power systems.
FAQ
What is the operating temperature range for UC2854BQ-TI?
The UC2854BQ-TI is specified for operation from –40°C to +85°C ambient temperature. This commercial-grade rating distinguishes it from the UC1854B (–55°C to +125°C) and UC3854B (0°C to +70°C), making it suitable for indoor industrial and telecom equipment where extended cold-start capability is not required but higher-temperature stability is needed over consumer-grade parts.
Does UC2854BQ-TI support line voltage feedforward, and how is it implemented?
Yes, UC2854BQ-TI supports line voltage feedforward via the VRMS pin, which accepts a 0–5.5 V analog signal proportional to RMS input voltage. Internally, this signal squares and divides into the multiplier to modulate current command amplitude-compensating for line-voltage variations and maintaining constant power delivery across 85–270 VAC inputs without software intervention.
How does the UC2854BQ-TI differ from UC2854AQ-TI in UVLO behavior?
The UC2854BQ-TI features a 10.5 V turn-on / 10 V turn-off UVLO threshold, optimized for startup from auxiliary 12 V supplies. In contrast, UC2854AQ-TI uses a 16 V/10 V UVLO pair intended for direct offline startup. This difference affects bias network design: UC2854BQ-TI enables simpler, lower-loss startup circuits when a regulated 12 V rail is present.
Can UC2854BQ-TI be used with high-side current sensing?
Yes, UC2854BQ-TI supports high-side current sensing via the ISENSE pin, which has a −0.3 V to 5 V common-mode input range and <±500 nA bias current. Combined with its 5 MHz current amplifier bandwidth and low 3 mV input offset, it maintains accuracy even with elevated common-mode voltages typical in high-side shunt configurations-eliminating need for isolated amplifiers in many designs.
What is the purpose of the 500 mV IAC pin offset in UC2854BQ-TI?
The 500 mV regulated offset on the IAC pin eliminates the external zero-crossing compensation resistor required by earlier UC1854 designs. This internal regulation ensures symmetrical positive/negative half-cycle current shaping-directly reducing total harmonic distortion (THD) and simplifying the line-sensing network while improving consistency across temperature and unit-to-unit variation.
UC2854BQ-TI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-LCC (J-Lead)
- Packaging:
- Bulk
- Product Status:
- Active
- Mode:
- Average Current
- Frequency - Switching:
- 80kHz ~ 120kHz
- Current - Startup:
- 250 µA
- Voltage - Supply:
- 10V ~ 20V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-PLCC (9x9)
UC2854BQ-TI FAQ
1.How can I place an order for UC2854BQ-TI through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2854BQ-TI 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 UC2854BQ-TI reliable?
The price and inventory of UC2854BQ-TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2854BQ-TI is usually 5 days.
3.What payment methods are accepted for UC2854BQ-TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2854BQ-TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2854BQ-TI?
UC2854BQ-TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2854BQ-TI 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 UC2854BQ-TI?
For technical support, including UC2854BQ-TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2854BQ-TI requirements.
6.How does Aetrix verify that UC2854BQ-TI is sourced from the original manufacturer or authorized distributors?
All UC2854BQ-TI 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 UC2854BQ-TI meets industry standards.
7.What is the process for return or replacement of UC2854BQ-TI?
All UC2854BQ-TI units undergo pre-shipment inspection (PSI). If there is an issue with UC2854BQ-TI, 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 UC2854BQ-TI part is unused and in its original packaging.
Return procedure for UC2854BQ-TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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