STMicroelectronics L6741TR

Overview

L6741TR from STMicroelectronics is a dual high-current N-channel MOSFET driver for synchronous-rectified buck converters, featuring integrated bootstrap diode, adaptive dead-time control, 5–12 V flexible gate-drive voltage, preliminary overvoltage (OV) protection, and SO-8 package. It drives both high-side and low-side MOSFETs in high-current VRM/VRD applications for desktop/server CPUs.

For engineers reviewing the L6741TR datasheet, L6741TR pinout, L6741TR application, or L6741TR equivalent, key selection criteria include HS/LS source/sink current capability (2 A / 3 A), adaptive anti-shoot-through timing, HiZ shutdown behavior, PVCC/VCC supply flexibility, and PHASE-pin-based OV threshold (1.8 V).

Technical Context

The L6741TR implements independent high-side and low-side drivers with separate supply rails (PVCC for HS, VCC for LS), enabling optimized gate voltage selection per MOSFET. Its adaptive dead-time logic monitors PHASE voltage transitions to dynamically adjust turn-on timing-activating LS when PHASE falls below ~2 V and HS when LGATE drops below ~1 V-to minimize body-diode conduction.

HiZ management uses internal resistor divider on PWM input to detect floating state (VPWM between 1 V and 2.3 V); after 150 ns hold-off, both outputs disable. Preliminary OV protection activates only during HiZ post-UVLO (VCC > 4.1 V), latching LS ON if PHASE exceeds 1.8 V-providing autonomous load protection before controller engagement.

Key Specifications

Pinout & Package

Package: SO-8 (ECOPACK®, lead-free, 1.27 mm pitch). Thermal resistance R_thJA = 85 °C/W on 2s2p PCB (67 mm × 67 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IR2110PbF and LM5109BMAX, L6741TR uniquely combines integrated bootstrap diode, adaptive dead-time, and preliminary OV protection-making it purpose-built for high-reliability CPU VRM systems where autonomous fault containment and minimal BOM are critical.

Availability

L6741TR is available at Aetrix Electronics and suitable for desktop CPU VRM, server VRD, and workstation GPU power applications requiring stable component supply, long-lifecycle support, and compatibility with ST's legacy power management ecosystem.

Supply support for L6741TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and computing markets.

L6741TR belongs to ST's high-current gate driver product line, engineered specifically for synchronous buck converters in high-performance computing power delivery-emphasizing integration, protection autonomy, and thermal robustness.

FAQ

What is the function of the PHASE pin beyond being the HS return path?

The PHASE pin serves three critical roles: (1) return path for the high-side driver, (2) input for adaptive dead-time control (triggering LS turn-on when voltage falls below ~2 V), and (3) sensing node for preliminary OV protection (latching LS ON if voltage exceeds 1.8 V during HiZ). It is not a passive connection-it actively enables timing and safety functions.

Can L6741TR operate with only a single 12 V supply for both VCC and PVCC?

Yes-L6741TR supports single-supply operation: tie VCC and PVCC together at 12 V. This configures both drivers for 12 V gate drive, maximizing R_DS(on) reduction in high-current MOSFETs. Layout must ensure low-inductance connections and separate BOOT capacitor routing to avoid coupling noise into the PHASE node.

How does the preliminary OV protection differ from standard overvoltage protection?

Preliminary OV is a pre-controller safety mechanism: it activates only during HiZ (after UVLO but before first PWM edge) and latches LS ON if PHASE > 1.8 V-clamping output before the main PWM controller powers up. Unlike system-level OV, it operates autonomously without external feedback or controller involvement, protecting against HS MOSFET short-circuit failures during startup.

Is the integrated bootstrap diode rated for continuous operation at high frequency?

Yes-the integrated diode is designed for continuous operation in synchronous buck topologies up to 1 MHz. Its forward voltage and thermal design accommodate typical BOOT capacitor recharge cycles; however, at >500 kHz with high-Qg MOSFETs, adding a small series resistor (R_BOOT ≈ 2–5 Ω) limits peak current and prevents overcharge during negative PHASE spikes.