Texas Instruments UC3625QG4

Overview

UC3625QG4 from Texas Instruments is a brushless DC motor controller IC designed for fixed-frequency PWM voltage- or current-mode motor control. It integrates high-side (50-V open-collector) and low-side (push-pull) drivers, a high-speed current-sense amplifier with ideal diode, latched soft-start, tachometer output, and programmable cross-conduction protection. It operates in two- or four-quadrant mode and supports safe direction reversal via direction latch logic - used in industrial BLDC drives requiring closed-loop speed control and braking.

For engineers reviewing the UC3625QG4 datasheet, UC3625QG4 pinout, UC3625QG4 application, or UC3625QG4 equivalent, key selection considerations include its 0°C to +70°C operating range, 40–60 kHz oscillator frequency, 5 V ±2% reference, pulse-by-pulse and average current sensing capability, and compatibility with Hall-effect position sensors for commutation timing.

Technical Context

The UC3625QG4 implements a dedicated brushless DC motor control architecture with integrated position decoder logic that translates three 120°-spaced Hall sensor inputs (H1–H3) and DIR signal into six gate drive outputs (PUA/PUB/PUC and PDA/PDB/PDC). Its direction latch prevents instantaneous reversal by enforcing a minimum delay of one to two oscillator periods (25–50 µs at 40 kHz), while cross-conduction protection uses flip-flop-based blanking synchronized to the PWM clock.

It features dual current sensing paths: ISENSE1/ISENSE2 feed a fixed-gain (1.95 V/V typical) absolute-value amplifier with 2.5 V level shift, enabling both peak-current limiting (0.20 V threshold) and overcurrent shutdown (0.30 V threshold); RC-BRAKE input triggers active braking by disabling high-side drivers and enabling all low-side drivers simultaneously.

Key Specifications

Pinout & Package

UC3625QG4 is packaged in a 28-pin PLCC (Q) package with 1.27 mm pitch and gull-wing leads. Pin functions are identical across SOIC (DW), PLCC (Q), and LCC (L) variants per TI SLUS353C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar brushless DC motor controller applications.

Compared with UC2625QG4 and UC1625JG4, the UC3625QG4 offers cost-optimized commercial-grade performance with identical feature set and pin compatibility - making it ideal for volume production in non-extreme thermal environments.

Availability

UC3625QG4 is available at Aetrix Electronics and suitable for industrial BLDC motor drives, robotics actuator control, electric power tools, and automated HVAC blower systems requiring stable component supply and long-term design-in support.

Supply support for UC3625QG4 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 over 50 years of innovation in motor control ICs.

The UC3625QG4 belongs to TI's UCx625 family of integrated BLDC motor controllers - designed specifically for cost-sensitive, high-reliability industrial motion systems requiring robust Hall-based commutation and programmable protection features.

FAQ

What is the operating temperature range of the UC3625QG4?

The UC3625QG4 is characterized for operation from 0°C to +70°C - a commercial-grade temperature specification. This distinguishes it from the UC2625QG4 (–40°C to +105°C) and UC1625JG4 (–55°C to +125°C). The UC3625QG4's thermal limits are defined in the Absolute Maximum Ratings table of TI's SLUS353C datasheet, and derating is not specified beyond this range. Applications exceeding +70°C ambient must use alternative variants.

How does the UC3625QG4 implement safe direction reversal?

The UC3625QG4 uses a direction latch synchronized to the PWM oscillator to prevent unsafe reversal. When SPEED-IN exceeds 250 mV, the latch becomes opaque - blocking DIR input changes until motor speed drops. Direction changes then require at least one full oscillator period (25–50 µs at 40–60 kHz), enforced by a two-bit shift register. This ensures sufficient dead time to avoid cross-conduction, and is documented in the Terminal Functions section of the UC3625QG4 datasheet.

Can the UC3625QG4 support both two-quadrant and four-quadrant motor control?

Yes - the UC3625QG4 supports both modes via the QUAD SEL pin (Pin 22). When low, it enables two-quadrant operation (low-side chopping only), offering higher efficiency in unidirectional applications. When high, it enables four-quadrant operation (full six-driver chopping), delivering symmetrical acceleration and deceleration torque - essential for servo positioning and bidirectional braking. This behavior is confirmed in the Applications section of TI's SLUS353C.

What is the purpose of the RC-BRAKE pin on the UC3625QG4?

The RC-BRAKE pin (Pin 21) serves dual functions: (1) tachometer timing - discharging an external RC network to generate calibrated pulse widths; and (2) active brake mode - pulling below 1.0 V disables all high-side drivers (PUA/PUB/PUC) and enables all low-side drivers (PDA/PDB/PDC). Brake mode remains active until RC-BRAKE rises above threshold, and is independent of PWM or current-limit states - enabling controlled dynamic braking when ISENSE feedback is applied.

Does the UC3625QG4 include an integrated voltage reference, and what is its accuracy?

Yes - the UC3625QG4 includes an on-chip 5 V reference (VREF, Pin 2) with ±2% initial accuracy (4.9–5.1 V) over temperature and load (0 to –20 mA). It powers Hall sensors and stabilizes the ROSC/COSC timing network. Load regulation is –40 to –5 mV, and line regulation is ±10 mV across 10–18 V VCC. This reference is trimmed at wafer sort and does not require external components for basic operation, per Electrical Characteristics Table 1 in SLUS353C.