Texas Instruments UCC27518DBVT

Overview

UCC27518DBVT from Texas Instruments is a single-channel, high-speed, low-side gate driver IC designed to drive MOSFETs and IGBTs in power conversion stages. It delivers symmetrical 4-A peak source/sink current at 12 V supply, features 17-ns typical propagation delay, 8-ns/7-ns rise/fall times, and operates across 4.5 V–18 V supply with –40°C to 140°C junction temperature range - enabling robust control of GaN switches in high-frequency DC-DC converters.

For engineers reviewing the UCC27518DBVT datasheet, UCC27518DBVT pinout, UCC27518DBVT application, or UCC27518DBVT equivalent, key selection criteria include its inverting logic configuration (IN− input), CMOS-input threshold tracking VDD (55%/39% VDD), EN pin with fixed TTL-compatible thresholds (2.1 V/1.25 V), UVLO protection with 4.2 V turn-on and 300 mV hysteresis, and SOT-23-5 package suitability for space-constrained power stages.

Technical Context

The UCC27518DBVT implements an inverting-input architecture where output state follows the inverse of the IN− signal, with internal pull-down ensuring safe LOW output when IN− floats. Its CMOS-input threshold scales with VDD (VIN_H ≈ 55% VDD, VIN_L ≈ 39% VDD) and includes ~16% VDD hysteresis for noise immunity and RC-delay programmability.

Internally, it uses a hybrid output stage: a P-channel MOSFET for steady-state pull-up (ROH ≈ 0.5 Ω at 12 V), augmented by a brief N-channel boost during rising edge to achieve 4-A peak sourcing; the pull-down path uses a dedicated N-channel MOSFET (ROL ≈ 0.6 Ω at 12 V). UVLO holds OUT low below 4.2 V (rising) and releases above 4.5 V (falling), preventing glitchy startup.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads, thermal pad not present. Optimized for manual placement and reflow in compact power stages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC27519DBVT, the UCC27518DBVT provides inverting logic essential for direct interface with common PWM controllers, while TPS2828DBVR lacks VDD-scaled thresholds and exhibits slower timing - making UCC27518DBVT the optimal choice for high-noise, high-frequency GaN systems requiring precise delay control and fail-safe startup behavior.

Availability

UCC27518DBVT is available at Aetrix Electronics and suitable for high-frequency DC-DC converters, GaN-based AC-DC adapters, and industrial motor drive half-bridge stages requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for UCC27518DBVT 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 expertise in high-reliability power control ICs.

The UCC27518DBVT belongs to TI's UCC2751x family of high-speed low-side gate drivers, engineered specifically for efficient, robust switching in high-frequency power supplies, motor drives, and emerging wide-bandgap (GaN/SiC) applications.

FAQ

What logic configuration does the UCC27518DBVT use, and how does it affect system design?

The UCC27518DBVT uses inverting logic: its output is the logical inverse of the IN− input signal. This allows direct connection to PWM controllers whose output polarity matches the required gate drive sequence for low-side switches - eliminating external inverters or logic gates. The internal pull-down on IN− ensures the output remains LOW during floating or unconnected states, enhancing system safety. This configuration is confirmed in the functional block diagram and pin description of the UCC27518DBVT datasheet.

Does the UCC27518DBVT support GaN power devices, and what specifications enable this?

Yes, the UCC27518DBVT is explicitly designed for GaN power devices. Its 4.5 V minimum supply enables operation with low-voltage GaN gate drivers; its 4-A symmetrical peak current rapidly charges/discharge high dV/dt-sensitive GaN gate capacitances; and its 17-ns propagation delay and 8-ns rise time minimize switching losses at >1 MHz frequencies. TI's documentation cites GaN compatibility in both the feature list and application section of the UCC27518DBVT datasheet.

How does the UCC27518DBVT handle undervoltage conditions on the VDD pin?

The UCC27518DBVT incorporates an internal undervoltage lockout (UVLO) circuit that holds the OUT pin LOW whenever VDD falls below 4.2 V (rising threshold) or drops below 3.9 V (falling threshold), with ~300 mV hysteresis. This prevents erratic output behavior during power-up, brownouts, or transient supply droops - ensuring glitch-free operation in mission-critical power stages. The UVLO behavior is fully characterized in the Electrical Characteristics table of the UCC27518DBVT datasheet.

Can the EN pin of the UCC27518DBVT be left unconnected, and what is its default state?

Yes, the EN pin of the UCC27518DBVT can be left unconnected (no-connect), as it is internally pulled up to VDD. In this configuration, the device operates in its default enabled state - identical to connecting EN to VDD. The EN pin uses fixed TTL-compatible thresholds (2.1 V high, 1.25 V low), allowing direct interface with 3.3 V or 5 V logic without level shifting. This no-connect capability ensures pin-to-pin compatibility with TPS2828, as documented in the UCC27518DBVT Pin Functions table.

What is the thermal performance of the UCC27518DBVT in SOT-23-5 package?

The UCC27518DBVT in SOT-23-5 (DBV) package has a junction-to-ambient thermal resistance (RθJA) of 217.6°C/W, junction-to-board (RθJB) of 44.0°C/W, and junction-to-case (top) of 85.8°C/W. These values assume standard JEDEC 2-layer board layout per datasheet test conditions. At 4-A peak current and 1 MHz switching, thermal simulation shows junction temperature rise remains within the –40°C to 140°C operating limit when PCB copper area around the GND pad is ≥ 50 mm². Full thermal data appears in Section 8.4 of the UCC27518DBVT datasheet.