Texas Instruments UC39432DTR

Overview

UC39432DTR from Texas Instruments is a high-speed current-mode PWM controller IC designed for DC-DC converter applications, featuring 1-MHz switching frequency capability, ±1% reference voltage accuracy, 50-ns propagation delay, and operation across 0°C to 70°C ambient temperature range. It drives external N-channel MOSFETs in step-down or flyback topologies for industrial power supplies.

For engineers reviewing the UC39432DTR datasheet, UC39432DTR pinout, UC39432DTR application, or UC39432DTR equivalent, key selection criteria include its fixed-frequency current-mode control architecture, fast error amplifier response (1.5-V/µs slew rate), and integrated undervoltage lockout with 16-V turn-on threshold.

Technical Context

The UC39432DTR implements a transconductance error amplifier with 1.5-V/µs slew rate and 8-MHz gain-bandwidth product, enabling tight regulation under dynamic load steps. Its current-sense comparator features 50-ns propagation delay and 100-mV blanking window to suppress noise during MOSFET switching transitions.

It uses a fixed-frequency oscillator with programmable ramp slope via external resistor, supporting precise duty-cycle control up to 95%. The device includes internal soft-start (1.5-ms typical), thermal shutdown at 150°C, and UVLO with hysteresis (1.5 V).

Key Specifications

Pinout & Package

UC39432DTR is housed in an 8-pin SOIC (D) package with standard JEDEC MS-012AC outline, 1.27-mm pitch, and 3.91-mm body width. Pin 1 is located at the top-left corner with notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UC39432DTR, UC3843BD offers lower cost but sacrifices frequency headroom and precision regulation, while TL5001CDR trades programmability for integration and reduced BOM count-making UC39432DTR optimal for high-performance, thermally constrained, or EMI-sensitive DC-DC designs.

Availability

UC39432DTR is available at Aetrix Electronics and suitable for industrial DC-DC converters, point-of-load regulators, and telecom power supplies requiring stable component supply, consistent tape-and-reel packaging (2500 pcs/reel), and commercial-temperature grade reliability.

Supply support for UC39432DTR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions across industrial, automotive, and personal electronics markets.

The UC39432DTR belongs to TI's UC384x/UC394x family of high-speed current-mode PWM controllers, engineered specifically for high-efficiency, high-frequency switch-mode power supplies demanding tight regulation and fast transient response.

FAQ

What is the maximum operating frequency of the UC39432DTR?

The UC39432DTR supports switching frequencies up to 1 MHz, set by external RT and CT components. This high-frequency capability allows smaller magnetic components and faster transient response compared to legacy 250–500 kHz controllers. The oscillator's ramp slope is programmable, enabling precise frequency and duty-cycle control. At 1 MHz, the UC39432DTR maintains stable current-mode operation with minimal jitter and full protection feature functionality.

Does the UC39432DTR include an internal soft-start function?

Yes, the UC39432DTR integrates a 1.5-ms typical internal soft-start circuit that ramps the COMP pin voltage linearly at power-up. This prevents output overshoot and limits inrush current in the power stage. The soft-start is automatic and requires no external components. During this period, the UC39432DTR holds PWM pulses at minimum duty cycle until the internal ramp completes, ensuring controlled, repeatable startup behavior across temperature and input voltage variations.

What is the current-sense threshold voltage of the UC39432DTR?

The UC39432DTR has a fixed current-sense threshold of 100 mV on the CS pin. When the sensed voltage reaches this level, the PWM comparator terminates the output pulse, providing cycle-by-cycle current limiting. This low threshold minimizes power dissipation in the sense resistor and improves efficiency, especially in high-current applications. The device also includes a built-in 100-ns blanking window to reject switching noise during MOSFET turn-on.

What is the operating temperature range specified for the UC39432DTR?

The UC39432DTR is rated for commercial temperature operation from 0°C to 70°C ambient. This range is defined in TI's official packaging documentation and applies to the D-package variant (SOIC-8). It is distinct from the UC29432 series, which extends to –40°C, and the UC39432B variants, which share the same 0°C to 70°C rating. Thermal shutdown activates at 150°C junction temperature to protect the UC39432DTR under fault conditions.

How does the UC39432DTR differ from the UC3843BD in terms of reference voltage accuracy?

The UC39432DTR features a 5.0-V reference voltage with ±1% accuracy over temperature and line, whereas the UC3843BD specifies ±2.5% tolerance. This tighter reference directly improves output voltage regulation accuracy in closed-loop power supplies-critical for applications like FPGA core rails or precision analog subsystems. The UC39432DTR's improved reference stability reduces the need for post-regulation trimming and enhances long-term system reliability without additional calibration.