Texas Instruments UCC3817DWTR

Overview

UCC3817DWTR from Texas Instruments is a BiCMOS active power factor correction (PFC) controller for boost preregulators, implementing average current-mode control to achieve near-unity power factor and low line-current distortion. It features a 7.5-V reference, 16-V UVLO turn-on threshold, leading-edge PWM modulation, and integrated gate driver delivering up to 1.2-A peak sink current - used in IEC61000-3-2-compliant sub-300-W AC/DC supplies.

For engineers reviewing the UCC3817DWTR datasheet, UCC3817DWTR pinout, UCC3817DWTR application, or UCC3817DWTR equivalent, key selection considerations include its 0°C to 70°C operating temperature range, SOIC-16 package, 150-μA start-up current, and compatibility with universal AC input (85–265 VAC) in PC power, lighting, and industrial SMPS designs.

Technical Context

The UCC3817DWTR integrates an analog multiplier with three inputs (VAOUT, IAC, VFF), a wide-bandwidth current amplifier (±2-mV offset), and a voltage error amplifier (90-dB open-loop gain) to enable precise average current-mode control. Its oscillator uses RT/CT programming (f ≈ 0.6/(RT × CT)) and supports 6–220 kHz switching frequencies.

It implements overvoltage protection via OVP/EN pin (1.9-V enable threshold, ±500-mV hysteresis), zero-power detection (0.33-V comparator threshold), and peak current limiting via PKLMT pin referenced to GND. The DRVOUT gate driver employs totem-pole output with 5–12-Ω pullup and 2–10-Ω pulldown resistance for direct MOSFET drive.

Key Specifications

Pinout & Package

UCC3817DWTR is housed in a 16-pin SOIC (DW) package measuring 7.5 mm × 10.3 mm, with standard JEDEC MS-012AC footprint and 1.27-mm lead pitch. Thermal resistance R_θJA is 74.1°C/W on 5-in² FR4 board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PFC controller applications.

Compared with UCC2817DWTR and FAN7930C, the UCC3817DWTR offers superior line-voltage adaptability via VFF feed-forward and higher integration (on-chip 7.5-V reference, gate driver), reducing component count and improving light-load THD performance - critical for universal-input, low-THD designs.

Availability

UCC3817DWTR is available at Aetrix Electronics and suitable for PC power supplies, LED lighting drivers, industrial AC/DC modules, and consumer audio power supplies requiring stable component supply and long-term production continuity.

Supply support for UCC3817DWTR 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 ICs.

The UCC3817DWTR belongs to TI's BiCMOS PFC controller product line, designed specifically for cost-effective, high-performance active power factor correction in sub-300-W universal-input AC/DC power supplies.

FAQ

What is the operating temperature range for the UCC3817DWTR?

The UCC3817DWTR is specified for operation from 0°C to +70°C ambient temperature. This commercial-grade rating aligns with typical enclosed PC and consumer electronics environments. It differs from the UCC2817DWTR, which extends to −40°C to +85°C for industrial use. The UCC3817DWTR's thermal metrics - including R_θJA = 74.1°C/W - are validated under these conditions on standard FR4 PCBs.

Does the UCC3817DWTR support discontinuous conduction mode (DCM)?

No - the UCC3817DWTR is optimized for continuous conduction mode (CCM) operation in boost preregulators. Its average current-mode architecture, fixed-frequency oscillator, and multiplier-based feed-forward require CCM for stable, low-distortion line current shaping. For DCM or transition-mode (CRM) designs, TI recommends the UCC28019 or UCC28070 families instead of the UCC3817DWTR.

How does the OVP/EN pin function in the UCC3817DWTR?

The OVP/EN pin on the UCC3817DWTR serves as a dual-function window comparator. When pulled above the upper threshold (~VREF + 0.5 V), it disables DRVOUT to protect against output overvoltage. When pulled below 1.9 V (typical), it forces a full shutdown and resets the soft-start capacitor. This dual behavior makes the UCC3817DWTR suitable for systems requiring both output fault protection and controlled enable sequencing.

Can the UCC3817DWTR drive a 600-V MOSFET directly?

Yes - the UCC3817DWTR's DRVOUT pin provides 1.2-A peak sink and ~0.9-A source current, sufficient to drive common 600-V superjunction MOSFETs (e.g., STP16NF60, FDPF18N50) within typical gate charge (Q_g) ranges of 20–50 nC. A series gate resistor (e.g., 10–22 Ω) is required per TI's Figure 6 to suppress ringing, especially with longer PCB traces or high-C_iss devices.

What is the purpose of the VFF pin on the UCC3817DWTR?

The VFF pin on the UCC3817DWTR provides feed-forward voltage derived from half the IAC current through an external RC filter. It scales the analog multiplier's gain inversely with line voltage squared, enabling near-constant power delivery and improved line regulation. At low line (e.g., 85 VAC), VFF ≈ 1.4 V; at high line (265 VAC), VFF ≈ 4.7 V - ensuring the UCC3817DWTR maintains tight THD across universal input ranges.