UC3855BDWTR Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
Texas Instruments UC3855BDWTR is a high-performance active power factor correction controller IC using current-mode PWM control. It operates from 15 V to 20 V bias supply and drives boost PFC stages with integrated gate drive and protection in a 20-pin SOIC package. Available from stock worldwide for AC-DC power supply and industrial PFC pre-regulator designs.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 20
- Lifecycle
- ACTIVE
- Datasheet
- UC3855BDWTR Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $13.1200(MOQ 2000)
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of UC3855BDWTR?
- Average current-mode PWM control achieving power factor above 0.99 and THD below 5% in boost PFC topologies
- Integrated gate driver with 1 A peak output current for directly driving power MOSFETs in 300 W to 3 kW PFC stages
- High-bandwidth multiplier and error amplifier enabling fast line transient response in universal 85 V to 265 V AC input designs
- Cycle-by-cycle current limiting with programmable over-current threshold for robust short-circuit protection of PFC inductor and switch
What is UC3855BDWTR used for?
The UC3855BDWTR is used as the primary control IC in active PFC boost pre-regulators for industrial AC-DC power supplies requiring IEC 61000-3-2 Class D harmonic compliance at power levels from 75 W to 3 kW. It drives the power stage in server power supplies, telecommunications rectifiers, and motor drive front-ends where regulated 400 V DC bus voltage must be maintained across 85 V to 265 V AC input range. The device also controls PFC stages in uninterruptible power supplies and EV charging station on-board chargers where high power factor reduces utility infrastructure loading.
What are the specifications of UC3855BDWTR?
| Pbfree Code | Yes |
| Date Of Intro | 1999-11-03 |
| YTEOL | 15 |
| Analog IC - Other Type | POWER FACTOR CONTROLLER |
| Control Mode | CURRENT-MODE |
| Control Technique | PULSE WIDTH MODULATION |
| Input Voltage-Max | 20V |
| Input Voltage-Min | 15V |
| Input Voltage-Nom | 18V |
| JESD-30 Code | R-PDSO-G20 |
| JESD-609 Code | e4 |
| Number of Functions | 1 |
| Output Current-Max | 1.5A |
| Output Voltage-Max | 7.688V |
| Output Voltage-Min | 7.313V |
| Output Voltage-Nom | 7.5V |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP20,.4 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Peak Reflow Temperature (Cel) | 260 |
| Qualification Status | Not Qualified |
| Supply Current-Max (Isup) | 17mA |
| Supply Voltage-Max (Vsup) | 20V |
| Supply Voltage-Nom (Vsup) | 18V |
| Surface Mount | YES |
| Switcher Configuration | BOOST |
| Switching Frequency-Max | 500kHz |
| Technology | BIPOLAR |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | Nickel/Palladium/Gold (Ni/Pd/Au) |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 2 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.90 |
Where can I find the UC3855BDWTR datasheet?
UC3855BDWTR Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for UC3855BDWTR?
Compatible alternatives and drop-in replacements for UC3855BDWTR:
Power Factor Controller, Current-mode, 1.5A, 500kHz Switching Freq-Max, BIPolar, PDSO20
Rochester Electronics LLC 1.5A POWER FACTOR CONTROLLER, 500kHz SWITCHING FREQ-MAX, PDSO20, GREEN, PLASTIC, SOIC-20
Frequently Asked Questions
What power factor and harmonic distortion performance does UC3855BDWTR achieve in a boost PFC design?
The UC3855BDWTR uses average current-mode control to shape the input inductor current as a sinusoid synchronized to the AC line voltage, achieving power factor greater than 0.99 and total harmonic distortion below 5% across the 85 V to 265 V AC input range. This performance meets IEC 61000-3-2 Class D limits for equipment above 75 W without additional passive filtering, reducing EMI filter component count.
What bias supply voltage does UC3855BDWTR require and how is it typically derived in a PFC pre-regulator circuit?
The UC3855BDWTR requires a 15 V to 20 V bias supply for normal operation, with 18 V as the nominal design point. In a PFC boost converter, this bias rail is typically derived from a small auxiliary winding on the boost inductor or from a separate flyback winding, providing 500 mA to support the 1 A peak gate driver output. An undervoltage lockout circuit inside the IC prevents operation below 10.5 V startup threshold, protecting the MOSFET from partial gate drive during initial startup.
How does UC3855BDWTR implement overcurrent protection for the PFC boost switch?
The UC3855BDWTR performs cycle-by-cycle current limiting by comparing the boost inductor current sense voltage against an internal threshold. When the sensed peak current exceeds the programmed limit, the current PWM cycle terminates immediately, clamping peak switch current to a safe level. The threshold is set by an external resistor, and at 200 mV sense voltage the protection activates within 200 ns propagation delay, preventing transformer saturation or switch destruction during input surge or output overload conditions.
For a server power supply designer, when is UC3855BDWTR preferable over newer digital PFC controllers?
The UC3855BDWTR offers fully analog average current-mode control with predictable loop dynamics, no firmware development, and no software-induced latency in protection response. For server power supply designs in the 500 W to 1500 W range where IEC 61000-3-2 compliance and 0.99 power factor are required without DSP resources, the UC3855BDWTR reduces design cycle time. Its 20-pin SOIC package and well-documented transfer function make it suitable for high-volume production where analog control reliability over -40°C to 125°C is valued over digital flexibility.
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Why Buy from FindMyChip
About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
More from Texas Instruments
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 2000+ | $13.1200 | $26240.00 |
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