Analog Devices Inc. LTC4444HMS8E#PBF

Overview

LTC4444HMS8E#PBF from Analog Devices is a high-frequency, high-voltage synchronous N-channel MOSFET gate driver designed for buck and buck-boost DC/DC converters. It drives both high-side (TG) and low-side (BG) N-MOSFETs with 2.5A TG and 3A BG peak pull-up currents, 1.2Ω TG and 0.55Ω BG pull-down resistances, and supports up to 114V bootstrap voltage (BOOST–TS) - enabling operation in 100V-input automotive and telecom power supplies.

For engineers reviewing the LTC4444HMS8E#PBF datasheet, LTC4444HMS8E#PBF pinout, LTC4444HMS8E#PBF application, or LTC4444HMS8E#PBF equivalent, key selection criteria include adaptive shoot-through protection, –40°C to 150°C junction temperature rating, 5ns TG fall time (1nF load), undervoltage lockout thresholds (6.15V falling / 6.6V rising), and thermally enhanced MSOP-8 with exposed GND pad.

Technical Context

The LTC4444HMS8E#PBF implements supply-independent dual-input logic with internal level-shifting for high-side control: TINP (ground-referenced) controls TG output referenced to TS, while BINP controls BG referenced to GND. Its adaptive shoot-through protection monitors TS voltage and input timing to prevent simultaneous conduction - disabling TG if BG remains high, and delaying BG turn-on until TS falls or 150ns after TINP turns off.

Internally, the driver uses bipolar NPN pull-up transistors (Q1/Q2) and N-MOSFET pull-down devices (M1/M2), delivering rail-to-rail swing: TG swings between BOOST and TS (up to 114V differential), BG swings between VCC (7.2–13.5V) and GND. Undervoltage lockout disables outputs when VCC drops below 6.15V, and thermal shutdown activates above 160°C junction temperature.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic MSOP (MS8E) with exposed GND pad (Pin 9), thermally enhanced for θ_JA = 40°C/W when soldered to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage synchronous gate driver applications.

Compared with LTC4446 and LTC4440, the LTC4444HMS8E#PBF uniquely integrates adaptive shoot-through protection and 114V bootstrap support in a single dual-output package, enabling simpler, more robust high-voltage synchronous buck designs without external timing or level-shifting components.

Availability

LTC4444HMS8E#PBF is available at Aetrix Electronics and suitable for automotive power supplies, telecom intermediate bus converters, and high-density industrial power modules requiring stable component supply across extended temperature ranges.

Supply support for LTC4444HMS8E#PBF 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.

The LTC4444 belongs to Analog Devices' high-voltage power management IC family, engineered specifically for efficient, robust gate driving in synchronous DC/DC converters operating up to 100V input - emphasizing thermal resilience, noise immunity, and integrated protection.

FAQ

What is the maximum allowable voltage on the TS pin of the LTC4444HMS8E#PBF?

The TS pin of the LTC4444HMS8E#PBF has an absolute maximum rating of –5V to 100V. This allows direct connection to high-side switching nodes in 100V-input buck converters. Operation beyond 100V risks permanent damage; derating is recommended for reliability in transient-heavy environments. The LTC4444HMS8E#PBF's adaptive shoot-through protection relies on accurate TS voltage sensing, so proper PCB layout and grounding are critical for correct function.

Does the LTC4444HMS8E#PBF require external bootstrap diodes and capacitors?

Yes, the LTC4444HMS8E#PBF requires an external bootstrap diode (anode to VCC, cathode to BOOST) and a ceramic capacitor (typically 0.1µF, 100V) between BOOST and TS pins. The diode replenishes charge on the bootstrap capacitor during low-side conduction; its forward voltage drop affects achievable BOOST–TS voltage. The LTC4444HMS8E#PBF does not integrate these components, enabling design flexibility but requiring careful selection for 114V max BOOST–TS operation.

How does the adaptive shoot-through protection in the LTC4444HMS8E#PBF differ from fixed dead-time schemes?

The LTC4444HMS8E#PBF's adaptive shoot-through protection dynamically monitors the TS pin voltage and input timing to enforce non-overlapping gate drive - turning off TG if BG remains high, and delaying BG turn-on until TS falls or 150ns after TINP turns off. Unlike fixed dead-time, this eliminates unnecessary delay during light loads or slow transitions, maximizing efficiency without risking cross-conduction. The LTC4444HMS8E#PBF implements this entirely internally with no external components or configuration required.

What is the thermal performance advantage of the exposed pad on the LTC4444HMS8E#PBF MSOP-8 package?

The exposed GND pad (Pin 9) on the LTC4444HMS8E#PBF MSOP-8 package reduces thermal resistance from junction to ambient (θ_JA) to 40°C/W when properly soldered to a 2500mm² double-sided 1oz copper ground plane. Without soldering the pad, θ_JA degrades significantly - potentially exceeding 100°C/W - risking thermal shutdown above 125°C ambient. This feature enables continuous operation at 150°C junction temperature, critical for automotive and industrial applications. The LTC4444HMS8E#PBF datasheet mandates pad soldering for guaranteed specifications.

Can the LTC4444HMS8E#PBF drive both N-channel MOSFETs in a half-bridge configuration without additional level-shifting circuitry?

Yes, the LTC4444HMS8E#PBF is specifically designed to drive both high-side and low-side N-channel MOSFETs in a synchronous buck or half-bridge configuration without external level shifters. Its internal level-shifting circuitry translates the ground-referenced TINP signal to the floating TS domain for TG control, while BINP directly controls BG relative to GND. The BOOST–TS rail (up to 114V) provides sufficient gate drive voltage for high-side N-MOSFETs even with 100V input. This integrated capability is a core feature of the LTC4444HMS8E#PBF.