Analog Devices Inc. LTC4444EMS8E-5#PBF

Overview

LTC4444EMS8E-5#PBF from Analog Devices (formerly Linear Technology) is a high-frequency, high-voltage synchronous N-channel MOSFET gate driver IC designed for high-side and low-side drive in buck, boost, and buck-boost DC/DC converters. It supports up to 100V input supply, delivers 1.4A peak top-gate pull-up and 1.75A peak bottom-gate pull-up current, features adaptive shoot-through protection, and operates with VCC from 4.5V to 13.5V. It is used in high-density power modules requiring fast switching of high-gate-charge MOSFETs.

For engineers reviewing the LTC4444EMS8E-5#PBF datasheet, LTC4444EMS8E-5#PBF pinout, LTC4444EMS8E-5#PBF application, or LTC4444EMS8E-5#PBF equivalent, key selection criteria include bootstrap voltage capability (up to 114V above TS), undervoltage lockout thresholds (3.55V falling / 4.00V rising), thermal performance in MS8E package (θJA = 40°C/W), and nanosecond-scale rise/fall times under 1nF load.

Technical Context

The LTC4444EMS8E-5#PBF integrates independent CMOS-compatible inputs (TINP/BINP) with internal level-shifting for high-side operation, enabling ground-referenced PWM control of both N-channel MOSFETs. Its output stage uses bipolar pull-up transistors and MOSFET pull-down devices to achieve low RDS(on) drive strength: 1.5Ω top-gate and 0.75Ω bottom-gate pull-down resistance.

Adaptive shoot-through protection monitors TS voltage transitions and enforces non-overlapping gate drive timing-BG is held off until TS falls after TINP turns off, and TG is delayed if BG remains high. Undervoltage lockout disables outputs when VCC drops below 3.55V, preventing MOSFET partial turn-on and conduction loss.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic MSOP (MS8E) with exposed thermal pad (Pin 9 = GND). Requires soldering of exposed pad to PCB ground for thermal compliance (θJA = 40°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4444EMS8E-5#PBF, LTC4446 offers higher peak current but lacks adaptive timing control, while LTC4440-5 supports only high-side drive and lower voltage ratings-neither provides the same combination of 100V input support, dual N-MOSFET drive, and adaptive shoot-through protection in an MSOP package.

Availability

LTC4444EMS8E-5#PBF is available at Aetrix Electronics and suitable for distributed power architectures, automotive power supplies, and high-density power modules requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LTC4444EMS8E-5#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 acquired Linear Technology in 2017 and maintains its high-performance analog and power management portfolio. Linear pioneered precision power ICs with emphasis on ruggedness, accuracy, and thermal reliability.

The LTC4444EMS8E-5#PBF belongs to Linear's high-voltage gate driver product line, engineered specifically for synchronous DC/DC converters in telecom, industrial, and automotive applications demanding robust 100V operation and nanosecond timing precision.

FAQ

What is the maximum allowable voltage on the BOOST pin relative to TS for LTC4444EMS8E-5#PBF?

The absolute maximum BOOST–TS voltage for LTC4444EMS8E-5#PBF is 114V, as specified in the Absolute Maximum Ratings table. This enables reliable high-side gate drive in 100V-input synchronous buck converters. Exceeding this voltage risks permanent damage. The typical operating range aligns with standard bootstrap configurations using a 12V–15V VCC and appropriate diode/capacitor sizing.

Does LTC4444EMS8E-5#PBF require external bootstrap diode and capacitor?

Yes, LTC4444EMS8E-5#PBF requires an external bootstrap diode connected between VCC (Pin 3) and BOOST (Pin 6), and an external capacitor between BOOST (Pin 6) and TS (Pin 8). These components form the charge pump that supplies the high-side driver. The datasheet recommends low-forward-voltage, fast-recovery diodes and low-ESR ceramic capacitors placed close to the IC for optimal performance.

How does adaptive shoot-through protection work in LTC4444EMS8E-5#PBF?

LTC4444EMS8E-5#PBF monitors the TS pin voltage to detect when the high-side MOSFET turns off. If BINP commands BG turn-on while TS remains high (indicating high-side MOSFET still conducting), BG is delayed until TS falls. Similarly, if TINP asserts while BG is still high, TG activation is deferred. This real-time monitoring eliminates fixed dead-time tuning and prevents cross-conduction without external circuitry.

What is the purpose of the exposed pad (Pin 9) on LTC4444EMS8E-5#PBF?

The exposed pad (Pin 9) on LTC4444EMS8E-5#PBF is electrically and thermally connected to GND. It must be soldered to a PCB ground plane to achieve the specified θJA of 40°C/W. Failure to do so increases thermal resistance significantly-potentially exceeding 100°C/W-causing junction temperature rise, reduced reliability, and possible thermal shutdown during sustained 1.75A output current.

Can LTC4444EMS8E-5#PBF drive both high-side and low-side N-channel MOSFETs in a synchronous buck converter?

Yes, LTC4444EMS8E-5#PBF is explicitly designed for synchronous buck topologies. It drives the high-side N-MOSFET via TG (swinging between BOOST and TS) and the low-side N-MOSFET via BG (swinging between VCC and GND). Its dual-output architecture, adaptive shoot-through protection, and 100V input capability make it ideal for this role without requiring external level shifters or discrete logic.