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Texas Instruments UC2852N
- Part No.:
- UC2852N
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
UC2852N.pdf
- Description:
- IC PFC CTRLR CCM 200KHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,446
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Product details
Overview
UC2852N from Texas Instruments is a high-power-factor preregulator controller IC designed for zero-current-switched (ZCS) boost PFC stages in AC-DC front-ends. It delivers >0.99 power factor, operates from –40°C to +85°C, supports controlled on-time PWM with min/max frequency limits, and drives external MOSFETs via a ±1.0A peak-current-capable output stage. It is used in 50–500W offline SMPS where harmonic compliance and cost-sensitive active PFC are required.
For engineers reviewing the UC2852N datasheet, UC2852N pinout, UC2852N application, or UC2852N equivalent, key selection criteria include its ZCS boost topology support, ISET-programmable ramp current (98 µA typ), ISNS fault threshold (–450 mV typ), UVLO thresholds (16.3 V turn-on / 11.5 V turn-off), and SOIC-8/PDIP-8 package compatibility for industrial-grade thermal operation.
Technical Context
The UC2852N implements a fixed-frequency-adjacent, variable-frequency zero-current-switched boost controller using a RAMP capacitor charged by an ISET-set current and discharged by inductor current sensing. Its PWM on-time is modulated by COMP voltage while off-time is determined by boost inductor zero-crossing detection via ISNS.
It integrates under-voltage lockout (UVLO), peak-current limiting (via ISNS fault comparator at –450 mV), output clamping (12.0 V typ), and maximum-frequency clamping (RAMP threshold = 1.02 V). The error amplifier features 5.0 V VFB input voltage and COMP clamp at 10.0 V, enabling stable bulk DC voltage regulation in high-line and low-line conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC UVLO Turn-On | 16.3 V - Ensures reliable startup only after sufficient bias supply is established |
| ISNS Fault Threshold | –450 mV - Triggers overcurrent protection before MOSFET stress exceeds safe limits |
| RAMP Charge Current | 98 µA - Sets timing capacitor charge rate for precise on-time control per cycle |
| OUT Peak Current | ±1.0 A - Directly drives gate of medium-power MOSFETs without external buffers |
| Power Factor | >0.99 - Meets IEC 61000-3-2 Class D harmonic limits for lighting and appliance applications |
| Operating Temp Range | –40°C to +85°C - Qualified for industrial ambient environments without derating |
| VFB Input Voltage | 5.0 V - Reference point for closed-loop bulk voltage regulation at 400 VDC output |
Pinout & Package
UC2852N is housed in an 8-pin plastic dual in-line package (PDIP-8, N package), with lead finish NIPDAU and RoHS-compliant construction. Pin 1 is GND; pin orientation follows standard DIP layout with notch-left marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Signal and power reference ground | Common return path for all internal circuits and external sense resistors |
| OUT (Pin 2) | High-current gate driver output | Drives MOSFET gate with ±1.0 A peak; actively held low during UVLO |
| ISET (Pin 3) | RAMP current programming & FAULT indicator | 5.0 V regulated reference; sets RAMP charge current; pulled to ~9 V during overcurrent fault |
| ISNS (Pin 4) | Zero- and over-current sensing input | Accepts ±5 V dynamic range; detects inductor zero-crossing and fault at –450 mV |
| RAMP (Pin 5) | Timing capacitor node | Charged by ISET current; discharge triggered by ISNS zero crossing; defines on-time |
| VCC (Pin 6) | Supply input | Operates from 16.3 V to 30 V; includes internal clamp at 33 V and UVLO hysteresis |
| VFB (Pin 7) | Error amplifier inverting input | 5.0 V reference input for feedback loop; connects to voltage divider from bulk output |
| COMP (Pin 8) | Error amplifier output / PWM comparator input | Clamped at 10.0 V to limit max on-time; interfaces with RAMP for duty control |
Key Features
| Feature | Design Value |
|---|---|
| Zero-current switching (ZCS) control | Reduces EMI and MOSFET switching losses by ensuring turn-on only at inductor current zero-crossing |
| Controlled on-time PWM architecture | Enables stable output regulation across wide line and load variations without complex compensation |
| Integrated UVLO with 5 V hysteresis | Prevents erratic operation during brown-out or soft-start; ensures clean power-up sequencing |
| High-current OUT driver (±1.0 A) | Eliminates need for external gate driver transistors in ≤300W designs |
| Programmable RAMP timing via ISET resistor | Allows flexible frequency tuning (10–100 kHz typical) using single external resistor |
Applications
| LED Driver Front-End | Industrial AC-DC Adapter |
|---|---|
|
Use Scenario: 150W constant-current LED driver operating from universal AC input (90–264 VAC). IC Role / Device Role / Timing Role: UC2852N serves as active PFC preregulator, generating sinusoidal input current and regulating 400 VDC bulk bus prior to downstream DC-DC conversion. Use Value: Achieves >0.99 PF and <10% THD, meeting IEC 61000-3-2 Class C requirements without additional filtering components. |
Use Scenario: 250W programmable bench power supply with adjustable output voltage and current limits. IC Role / Device Role / Timing Role: UC2852N controls ZCS boost stage to maintain stable 400 VDC rail across 50–100% load and full AC input range. Use Value: Enables compact magnetics (680 µH inductor) and eliminates need for auxiliary start-up circuitry due to <1 mA starting current. |
| PC Power Supply Auxiliary PFC | Appliance Motor Drive Input Stage |
|
Use Scenario: 300W ATX-compatible PSU auxiliary PFC stage feeding main LLC resonant converter. IC Role / Device Role / Timing Role: UC2852N regulates bulk voltage while coordinating with system supervisor IC for soft-start and fault signaling via ISET pin. Use Value: Delivers consistent >0.99 PF across 115/230 VAC inputs and enables fast transient response (<100 µs recovery) to load steps. |
Use Scenario: 400W variable-speed induction motor drive with integrated rectification and PFC for HVAC blower systems. IC Role / Device Role / Timing Role: UC2852N implements ruggedized ZCS boost to sustain 400 VDC bus under high-temperature, high-humidity conditions. Use Value: Supports –40°C to +85°C operation with no derating, and withstands line surges up to 30 V on VCC due to internal 33 V clamp. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power factor correction controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3852N | 0°C to +70°C temp range; identical pinout and electrical specs except narrower operating temperature | Suitable for commercial-grade equipment only; not rated for industrial ambient extremes | Select UC3852N only if ambient never exceeds 70°C and cost is primary constraint |
| L6561TR | Dual-mode (transition-mode + discontinuous conduction) PFC controller; higher integration (no external RAMP cap needed); different pinout and control architecture | Supports wider input range (85–265 VAC) and lower minimum load; requires different compensation network | Choose L6561TR when designing new platforms requiring TM/DCM flexibility and reduced BOM count |
Compared with UC3852N and L6561TR, the UC2852N offers the optimal balance of industrial temperature rating, proven ZCS boost performance, and minimal external component count-making it ideal for cost-sensitive, thermally demanding 50–500W PFC stages where reliability trumps feature richness.
Availability
UC2852N is available at Aetrix Electronics and suitable for industrial AC-DC adapters, LED driver front-ends, and appliance motor drive input stages requiring stable component supply and long-term manufacturability.
Supply support for UC2852N 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 specializing in analog, embedded processing, and power management technologies, with decades of expertise in power conversion IC design.
The UC2852N belongs to TI's legacy Unitrode PFC controller family, engineered specifically for cost-effective, high-efficiency active power factor correction in mid-power offline power supplies.
FAQ
What is the primary function of the UC2852N in a power supply design?
The UC2852N functions as a zero-current-switched (ZCS) boost power factor correction (PFC) controller. It regulates the bulk DC output voltage (typically 400 VDC) while shaping the input current to be sinusoidal and in-phase with the AC line voltage. In a typical design, the UC2852N drives an external MOSFET to implement the boost stage, achieving >0.99 power factor and meeting IEC 61000-3-2 harmonic standards. Its controlled on-time PWM and ISNS-based zero-current detection make the UC2852N especially effective in 50–500W industrial and commercial power supplies.
How does the UC2852N differ from the UC3852N in terms of operating conditions?
The UC2852N is specified for operation from –40°C to +85°C, whereas the UC3852N is rated only from 0°C to +70°C. All other electrical parameters-including pinout, UVLO thresholds, RAMP charge current (98 µA), ISNS fault threshold (–450 mV), and OUT drive capability (±1.0 A)-are identical between UC2852N and UC3852N. This makes the UC2852N the preferred choice for industrial environments where extended temperature range is mandatory, while the UC3852N suits cost-sensitive commercial applications with benign thermal conditions.
Can the UC2852N be used with a 100 pF RAMP capacitor, and what effect does that have on frequency?
Yes, the UC2852N supports RAMP capacitor values from 100 pF to 1 nF. Using a 100 pF capacitor with a 50 kΩ ISET resistor yields a typical RAMP charge current of 98 µA, resulting in a maximum switching frequency near 100 kHz (per UDG-92006 curve). This configuration enables compact magnetics and reduced core loss but requires careful PCB layout to minimize noise coupling into the sensitive ISNS and RAMP nodes. The UC2852N's min/max frequency limits ensure stable operation even with this high-frequency setup.
What protection features are built into the UC2852N?
The UC2852N integrates multiple hardware-level protections: under-voltage lockout (UVLO) with 16.3 V turn-on and 11.5 V turn-off, peak-current limiting via the ISNS input (fault threshold at –450 mV), output clamping (12.0 V typical), maximum-frequency clamping (RAMP threshold = 1.02 V), and thermal shutdown via package-limited power dissipation. During overcurrent, the ISET pin is pulled to ~9 V to signal external fault handling. These features collectively safeguard both the UC2852N and the external power stage without requiring additional supervisory circuitry.
Is the UC2852N pin-compatible with other members of the UCx852 family?
Yes, the UC2852N is fully pin-compatible with UC1852N and UC3852N across all 8-pin packages (PDIP-8 and SOIC-8). The three variants share identical pin functions, electrical characteristics, and block diagram architecture-the only differences are their specified operating temperature ranges: UC1852N (–55°C to +125°C), UC2852N (–40°C to +85°C), and UC3852N (0°C to +70°C). This allows direct substitution in existing layouts when thermal requirements change, provided the selected variant meets the target application's ambient specification.
UC2852N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Mode:
- Continuous Conduction (CCM)
- Frequency - Switching:
- 200kHz
- Current - Startup:
- 400 µA
- Voltage - Supply:
- 13V ~ 30V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
UC2852N FAQ
1.How can I place an order for UC2852N through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2852N 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 UC2852N reliable?
The price and inventory of UC2852N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2852N is usually 5 days.
3.What payment methods are accepted for UC2852N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2852N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2852N?
UC2852N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2852N 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 UC2852N?
For technical support, including UC2852N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2852N requirements.
6.How does Aetrix verify that UC2852N is sourced from the original manufacturer or authorized distributors?
All UC2852N 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 UC2852N meets industry standards.
7.What is the process for return or replacement of UC2852N?
All UC2852N units undergo pre-shipment inspection (PSI). If there is an issue with UC2852N, 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 UC2852N part is unused and in its original packaging.
Return procedure for UC2852N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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