Texas Instruments UCC2801DTRG4

Overview

UCC2801DTRG4 from Texas Instruments is a low-power BiCMOS current-mode PWM controller for fixed-frequency off-line and DC-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 voltage, 1.5% reference tolerance, and 70 ns current-sense-to-output response. It targets automotive and industrial PSU designs requiring robust fault handling and minimal external components.

For engineers reviewing the UCC2801DTRG4 datasheet, UCC2801DTRG4 pinout, UCC2801DTRG4 application, or UCC2801DTRG4 equivalent, key selection criteria include its 50% duty cycle limit, internal leading-edge blanking (100 ns), full-cycle soft start, 1 A totem-pole gate drive, and compatibility with UC3842/UC3842A PCB layouts - critical for retrofitting legacy SMPS designs while reducing component count.

Technical Context

The UCC2801DTRG4 implements a current-mode control architecture with dual comparators on the CS pin: one for PWM regulation and a separate overcurrent comparator that triggers full-cycle soft restart on fault. Its error amplifier is a true 2-MHz, low-impedance op-amp capable of sourcing/sinking COMP current - unlike the open-collector topology in UC3842.

Oscillator frequency is set via external RC network between REF and RC pins, supporting up to 1 MHz operation (with 2× output frequency for UCC2801). Internal leading-edge blanking digitally disconnects CS for 100 ns after OUT rising edge, eliminating need for external RC filtering in most applications and reducing propagation delay versus analog methods.

Key Specifications

Pinout & Package

UCC2801DTRG4 is housed in an SOIC-8 (D package), 3.91 mm × 4.90 mm body size, surface-mount package rated for –40°C to +125°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UC3842N, UCC2801DTRG4 reduces external component count and improves noise immunity via integrated blanking and soft start; compared with UCC2802DTR, it enforces stricter duty control for safety-critical or transformer-limited topologies - making it optimal for automotive and isolated DC-DC where conduction time must be capped.

Availability

UCC2801DTRG4 is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC-DC converters, and off-line flyback adapters requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-aligned reliability.

Supply support for UCC2801DTRG4 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 ICs, with deep expertise in high-reliability power conversion solutions.

The UCC280x product line was designed specifically for fixed-frequency current-mode switching power supplies - targeting automotive, industrial, and telecom applications where low quiescent current, robust fault handling, and minimal external component count are essential.

FAQ

What is the maximum operating frequency of the UCC2801DTRG4?

The UCC2801DTRG4 supports oscillator frequencies up to 1 MHz. Because UCC2801 uses a 2× frequency relationship (oscillator frequency = 2 × output switching frequency), the maximum practical switching frequency is 500 kHz. This is confirmed in Section 6.5 Electrical Characteristics and Figure 6-6 of the datasheet, where max duty cycle vs. frequency curves are plotted up to 1000 kHz oscillator frequency.

Does the UCC2801DTRG4 require an external soft-start circuit?

No, the UCC2801DTRG4 includes internal full-cycle soft start with a fixed 4 ms COMP voltage ramp to 5 V. As documented in Section 7.3.1.1 and Table 6-5, this eliminates the need for external resistors, capacitors, or transistors typically used in UC3842-based designs - directly reducing bill-of-materials and PCB area.

How does the CS pin functionality differ between UCC2801DTRG4 and UC3842?

The UCC2801DTRG4 CS pin connects to two independent comparators (PWM and overcurrent), with built-in 100 ns digital leading-edge blanking. In contrast, UC3842 has only one comparator on CS and requires external RC filtering. This difference is detailed in Section 7.3.1.3 and Table 5-1, enabling cleaner current sensing and faster fault response in UCC2801DTRG4.

What is the purpose of the REF pin on the UCC2801DTRG4?

The REF pin on the UCC2801DTRG4 provides a stable 5 V ±1.5% output used as the voltage reference for the error amplifier, oscillator, and internal logic. It can also power external circuitry up to 5 mA, but requires ≥0.1 μF ceramic bypass capacitance placed adjacent to the pin - as specified in Section 5 and Figure 5-1 of the datasheet.

Is the UCC2801DTRG4 pin-compatible with UC3842 and UC3842A?

Yes, the UCC2801DTRG4 has identical pin configuration and signal mapping to UC3842 and UC3842A, as explicitly stated in Section 1 Features and Section 7.1 Overview. However, it is not plug-in compatible due to differences in COMP topology and internal features - board layout reuse is supported, but schematic review is required before substitution.