Texas Instruments UCC2801D

Overview

UCC2801D from Texas Instruments is a low-power BiCMOS current-mode PWM controller designed for fixed-frequency off-line and DC-to-DC switching power supplies. It features 50% maximum duty cycle, 9.4 V turn-on/7.4 V turn-off UVLO thresholds, 5 V reference with 1.5% tolerance, and 70 ns current-sense-to-output response - enabling compact, high-efficiency designs in automotive PSU and battery-operated systems.

For engineers reviewing the UCC2801D datasheet, UCC2801D pinout, UCC2801D application, or UCC2801D equivalent, key selection criteria include its dedicated 50% duty-cycle limit, internal leading-edge blanking (100 ns), full-cycle soft start, totem-pole 1 A output, and SOIC-8 package compatibility with UC3842-family layouts.

Technical Context

The UCC2801D implements a current-mode control architecture with dual comparators on the CS pin (PWM + overcurrent fault), digital leading-edge blanking synchronized to OUT rising edge, and a true low-impedance 2-MHz error amplifier at COMP that both sources and sinks current. Its oscillator uses REF-derived charging current into an external RC network, supporting up to 1 MHz operation with frequency set by Equation f = 1.5/(R × C).

Unlike UC3842 derivatives, the UCC2801D integrates full-cycle soft start (COMP ramp time: 4–10 ms), internal fault soft start, and a 1.5% precision 5 V reference shared across error amplifier, logic, and oscillator functions - all while maintaining pin compatibility but not plug-in equivalence with UC3842A.

Key Specifications

Pinout & Package

UCC2801D is housed in an 8-pin SOIC (D package), 3.91 mm × 4.90 mm body size, rated for –40°C to 125°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-mode PWM controller applications.

Compared with UC3842D, UCC2801D reduces component count via integrated soft start and blanking, while UCC2802D trades duty-cycle limitation for broader input range support - making UCC2801D optimal for constrained-space, medium-power applications needing deterministic 50% conduction control.

Availability

UCC2801D is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC-DC converters, battery-operated medical devices, and telecom power modules requiring stable component supply across extended temperature ranges.

Supply support for UCC2801D 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 power IC innovation.

The UCC280x product line was engineered specifically for high-efficiency, low-component-count current-mode switching power supplies - emphasizing reduced external parts, lower quiescent power, and enhanced noise immunity in demanding automotive and industrial environments.

FAQ

What is the maximum operating frequency of the UCC2801D?

The UCC2801D supports oscillator frequencies up to 1 MHz. Its actual output switching frequency depends on the external RC network connected to the RC pin and follows f = 1.5/(R × C). At typical configurations (e.g., 100 kΩ + 330 pF), it operates near 46 kHz; higher values enable scaling toward the 1 MHz limit while maintaining stable current-mode control.

Does the UCC2801D require an external soft-start circuit?

No, the UCC2801D includes internal full-cycle soft start that ramps the COMP voltage from 0.5 V to REF–1 V in 4–10 ms. This eliminates the need for external components like a PNP transistor, resistor, and capacitor - simplifying design and improving reliability in automotive and industrial power supplies using UCC2801D.

Is the UCC2801D pin-compatible with the UC3842 family?

Yes, the UCC2801D uses the same SOIC-8 pinout as UC3842 and UC3842A. However, it is not a plug-in replacement due to functional differences: UCC2801D has a true low-Z COMP amplifier (vs. open-collector), internal soft start, leading-edge blanking, and different UVLO thresholds - requiring validation of feedback and timing networks when migrating from UC3842 to UCC2801D.

What is the purpose of the CS pin's leading-edge blanking in the UCC2801D?

The CS pin in UCC2801D incorporates 100 ns digital leading-edge blanking synchronized to the rising edge of the OUT signal. This suppresses false overcurrent triggering caused by MOSFET switching spikes and transformer leakage, eliminating the need for external RC filtering in most applications - thereby reducing component count and improving response time compared to UC3842-based designs using UCC2801D.

Can the UCC2801D drive a MOSFET directly without a gate driver IC?

Yes, the UCC2801D features a ±1 A totem-pole output stage on the OUT pin, capable of directly driving medium-gate-charge MOSFETs (e.g., ≤50 nC Qg) in flyback or forward converters. Its <75 ns rise/fall times and low-impedance output reduce switching losses - making external gate drivers unnecessary in many UCC2801D-based power supply implementations.