Texas Instruments UCC2802D

Overview

UCC2802D from Texas Instruments is a low-power, BiCMOS current-mode PWM controller for off-line and DC-DC switching power supplies. It features 100 μA start-up supply current, 500 μA typical operating supply current, 100% maximum duty cycle, 12.5 V turn-on UVLO threshold, and 70 ns current-sense-to-output response - enabling compact, high-efficiency AC/DC adapters and industrial PSU designs.

For engineers reviewing the UCC2802D datasheet, UCC2802D pinout, UCC2802D application, or UCC2802D equivalent, key selection considerations include its 12.5 V/8.3 V UVLO hysteresis, internal leading-edge blanking (100 ns), full-cycle soft start, 1.5% reference tolerance, and SOIC-8 package compatibility with UC3842-based layouts.

Technical Context

The UCC2802D implements fixed-frequency current-mode control using an internal oscillator (up to 1 MHz) with RC timing via REF–RC–GND network and delivers gate drive through a ±1 A totem-pole output stage. Its error amplifier is a true 2-MHz, low-impedance op-amp capable of sourcing/sinking COMP current - unlike open-collector UC3842 predecessors.

It integrates dual current-sense comparators (PWM + overcurrent fault), digital leading-edge blanking (disabling CS input for 100 ns post-OUT rise), and internal full-cycle soft start with 4 ms COMP ramp - eliminating external soft-start components. The device operates across –40°C to 125°C and supports minimal BOM count in isolated flyback and forward converters.

Key Specifications

Pinout & Package

UCC2802D is housed in an 8-pin SOIC (D package), 3.91 mm × 4.90 mm body size, with Gull-wing leads and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UC3842N and UCC2803D, the UCC2802D uniquely combines off-line-ready UVLO (12.5 V/8.3 V), 1 MHz capability, integrated blanking, and soft start - delivering higher efficiency, smaller magnetics, and lower component count in universal-input AC/DC designs.

Availability

UCC2802D is available at Aetrix Electronics and suitable for industrial AC/DC adapters, automotive onboard chargers, and telecom power modules requiring stable component supply, long-lifecycle support, and AEC-Q100-aligned reliability.

Supply support for UCC2802D 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 design heritage.

The UCC280x product line was engineered specifically for high-efficiency, low-component-count current-mode switching power supplies - targeting off-line AC/DC, DC/DC, and industrial PSU applications demanding wide temperature range and robust fault handling.

FAQ

What is the UVLO behavior of the UCC2802D?

The UCC2802D features a 12.5 V turn-on threshold and 8.3 V turn-off threshold, providing 4.2 V hysteresis. This ensures clean startup under rising AC line conditions and prevents oscillatory behavior during brownout events. The internal Zener clamp limits VCC to ~13.5 V, protecting the device during overvoltage transients. This UVLO profile is specifically optimized for universal-input (85–265 VAC) offline power supplies.

Does the UCC2802D require an external soft-start circuit?

No - the UCC2802D integrates full-cycle soft start with a fixed 4 ms COMP voltage ramp from 0.5 V to 5 V. This eliminates the need for external components such as a soft-start capacitor, resistor, and PNP transistor. The internal implementation ensures consistent startup timing across temperature and supply voltage, improving system reliability and reducing bill-of-materials cost.

How does the CS pin of the UCC2802D differ from the UC3842?

The UCC2802D CS pin connects to two comparators (PWM and overcurrent) and includes digital leading-edge blanking - disabling the input for 100 ns after each OUT rise. This replaces the analog RC filter required on UC3842 designs. Additionally, the UCC2802D's current-sense gain is 1.65 V/V (vs. ~3 V/V on UC3842), allowing direct use of lower-value, lower-power shunt resistors in high-current applications.

Can the UCC2802D replace a UC3842 in an existing PCB layout?

Yes - the UCC2802D uses identical SOIC-8 pinout and footprint as UC3842 and UC3842A. It supports direct drop-in replacement without PCB modification. However, due to lower operating current and integrated features, minor tuning of compensation (COMP network) and timing (RC values) may improve performance, especially when increasing switching frequency beyond 300 kHz.

What is the maximum recommended switching frequency for the UCC2802D?

The UCC2802D supports oscillator frequencies up to 1 MHz, as confirmed in its datasheet Features section and Electrical Characteristics table. At 1 MHz, propagation delays (e.g., 70 ns CS-to-OUT) and internal timing margins remain sufficient for stable current-mode operation. For best thermal performance and gate drive strength, TI recommends staying within 800 kHz for continuous high-load operation in SOIC-8 packages.