Texas Instruments UCC27321D

Overview

UCC27321D from Texas Instruments is a single-channel, non-isolated, low-side MOSFET driver IC with enable functionality, delivering ±9 A peak output current at the Miller plateau region using TrueDrive hybrid bipolar-CMOS output stage. It operates from 4.5 V to 15 V supply, achieves 20 ns typical rise/fall times into 10 nF load, and supports –40°C to +105°C ambient operation in SOIC-8 (D) package - ideal for high-frequency synchronous rectification in buck-derived DC-DC converters.

For engineers reviewing the UCC27321D datasheet, UCC27321D pinout, UCC27321D application, or UCC27321D equivalent, key selection criteria include its inverting logic configuration, industry-standard 8-pin SOIC footprint with dedicated ENBL pin, thermal resistance of 42°C/W (θ_jc), and compatibility with PWM controllers requiring robust gate drive under high dV/dt conditions.

Technical Context

The UCC27321D implements an inverting logic function: high input yields low output, and low input yields high output. Its TrueDrive output stage combines parallel bipolar and MOSFET transistors to deliver symmetrical ±9 A peak current specifically during the Miller plateau, minimizing switching losses in large-power N-channel MOSFETs.

It features TTL/CMOS-compatible inputs independent of VDD, internal 100 kΩ pull-up on ENBL for active-high enable, and split ground architecture (AGND and PGND) to isolate control and power return paths - reducing noise coupling and improving stability in high-di/dt switching environments.

Key Specifications

Pinout & Package

UCC27321D is housed in an 8-pin SOIC (D) package with 3.91 mm × 4.90 mm body size and standard 1.27 mm lead pitch. Thermal resistance is 42°C/W (junction-to-case) and 56.6°C/W (junction-to-ambient).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-side MOSFET driver applications.

Compared with UCC27322D, UCC27321D provides essential inverting logic for synchronous rectifier control in buck topologies; compared with TPS2829DBVR, it delivers 4.5× higher peak current and integrated enable - making it irreplaceable in high-power, noise-immune, and sequenced-enable applications.

Availability

UCC27321D is available at Aetrix Electronics and suitable for switch-mode power supplies, motor controllers, and Class-D amplifiers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for UCC27321D 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 high-reliability power control solutions.

The UCC27321D belongs to TI's UCC2732x family of high-speed low-side MOSFET drivers, designed specifically for demanding gate-drive applications in high-efficiency, high-frequency power conversion systems.

FAQ

What is the logic configuration of the UCC27321D?

The UCC27321D implements inverting logic: a high input (IN = HIGH) results in a low output (OUT = LOW), and a low input (IN = LOW) produces a high output (OUT = HIGH). This behavior is confirmed in Table 8-1 of the official datasheet and is fundamental to its use in synchronous rectification circuits where inverted gate drive is required relative to the controller's PWM output. The UCC27321D maintains this inverting function across its full operating temperature and supply voltage range.

Does the UCC27321D require external pull-up or pull-down resistors on the ENBL pin?

No, the UCC27321D includes an internal 100 kΩ pull-up resistor on the ENBL pin, configured for active-high operation. When left unconnected, ENBL defaults to HIGH, enabling normal driver operation. External resistors are unnecessary unless specific timing delays (e.g., power-up sequencing) are needed - in which case a capacitor from ENBL to AGND may be used per Section 8.3.4 of the datasheet. The UCC27321D's ENBL threshold and hysteresis are fully specified and validated across temperature.

Can the UCC27321D drive both N-channel and P-channel MOSFETs effectively?

The UCC27321D is optimized as a low-side driver and is primarily intended for N-channel MOSFETs with source tied to PGND. While it can drive P-channel devices in low-side configurations, its inverting logic and output swing (0 V to VDD) make it especially effective for generating gate signals for ground-referenced N-channel synchronous rectifiers - as explicitly stated in Section 8.1. The UCC27321D does not support high-side floating bias or level-shifting, so direct P-channel high-side drive is not supported without external circuitry.

What is the maximum recommended load capacitance for stable operation of the UCC27321D?

The UCC27321D is characterized and guaranteed for stable operation with load capacitances up to 10 nF, as reflected in all switching specifications (rise/fall times, propagation delays). Figures 7-9 and 7-10 show rise/fall times increasing predictably beyond 10 nF - e.g., t_R ≈ 45 ns at 100 nF and VDD = 15 V - but no instability, oscillation, or thermal derating is reported up to at least 100 nF. For designs exceeding 10 nF, layout optimization (short traces, local decoupling) and thermal monitoring are advised, as the UCC27321D's SOIC-8 package has defined power dissipation limits.

How does the split-ground (AGND/PGND) design of the UCC27321D improve system performance?

The UCC27321D's separate AGND and PGND pins physically isolate control-circuit reference (AGND) from high-di/dt power return (PGND), minimizing ground-bounce-induced false triggering. Per Table 6-1, AGND must connect to controller ground and PGND to MOSFET source via a low-inductance path - this separation reduces noise coupling into input/enable thresholds and improves noise immunity in high-frequency switching environments. This architecture is a documented design requirement for stable UCC27321D operation, not optional best practice.