Analog Devices Inc. LTC4440AMPMS8E-5#PBF

Overview

LTC4440AMPMS8E-5#PBF from Analog Devices (formerly Linear Technology) is a high-frequency, high-voltage, high-side N-channel MOSFET gate driver optimized for isolated full-bridge and phase-modulated converters. It operates with input supply voltages up to 80V (with 100V/100ms transient tolerance), delivers 1.1A peak pull-up current and 1.85Ω pull-down impedance at 6V BOOST–TS, and drives 1nF loads with 10ns rise and 7ns fall times - enabling low-loss switching in telecom and server power supplies.

For engineers reviewing the LTC4440AMPMS8E-5#PBF datasheet, LTC4440AMPMS8E-5#PBF pinout, LTC4440AMPMS8E-5#PBF application, or LTC4440AMPMS8E-5#PBF equivalent, key selection criteria include its –55°C to 150°C operating junction temperature range, bootstrapped high-side drive capability (up to 95V above ground), TTL/CMOS-compatible input with 350mV hysteresis, undervoltage lockout (3.04V falling threshold), and thermally enhanced 8-lead MSOP package with exposed GND pad.

Technical Context

The LTC4440AMPMS8E-5#PBF uses a bipolar-NMOS hybrid output stage: an NPN transistor (Q1) for high-current pull-up and an NMOS (N1) for low-impedance pull-down. Its level-shifted input accepts ground-referenced logic signals and internally shifts them to the bootstrapped domain, supporting operation with TS floating up to 80V above GND. The device features nonoverlapping predriver control to prevent cross-conduction.

It integrates an undervoltage lockout circuit that disables TG when VCC falls below 3.04V, pulling TG to TS. Input thresholds (VIH = 1.55V typ, VIL = 1.25V typ) are supply-independent due to internal regulation, and hysteresis ensures noise immunity in high-dV/dt environments typical of high-density power converters.

Key Specifications

Pinout & Package

The LTC4440AMPMS8E-5#PBF is housed in an 8-lead plastic MSOP package (MS8E) with an exposed GND pad (Pin 9) that must be soldered to PCB ground for thermal performance (θJA = 40°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC4444-5 and LTC4446, the LTC4440AMPMS8E-5#PBF provides broader VCC compatibility (4V vs 7.2V minimum), extended temperature range (–55°C to 150°C), and superior low-VCC functionality - making it optimal for cold-start and wide-input industrial power systems.

Availability

LTC4440AMPMS8E-5#PBF is available at Aetrix Electronics and suitable for telecom power supplies, server power modules, and industrial motor drives requiring stable component supply, long-term lifecycle support, and guaranteed extended temperature performance.

Supply support for LTC4440AMPMS8E-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 with rigorous reliability standards and military/aerospace-grade qualification processes.

The LTC4440A family is designed for high-voltage, high-frequency gate driving in isolated DC/DC converters - specifically targeting full-bridge, phase-modulated, and resonant topologies where bootstrapped high-side drive, transient resilience, and precise timing are critical.

FAQ

What is the maximum continuous input voltage the LTC4440AMPMS8E-5#PBF can withstand on the TS pin?

The LTC4440AMPMS8E-5#PBF supports continuous operation with TS pin voltage up to 80V above ground. Its absolute maximum rating allows 100V for 100ms transients without functional interruption or damage, making it suitable for 48V and 60V DC bus applications with surge requirements. This rating is confirmed in the Absolute Maximum Ratings table on page 2 of the official datasheet.

Does the LTC4440AMPMS8E-5#PBF require an external bootstrap diode, and what is its function?

Yes, the LTC4440AMPMS8E-5#PBF requires an external bootstrap diode connected between VCC (Pin 3) and BOOST (Pin 6). Its function is to charge the external bootstrap capacitor during the low-side switch conduction period, enabling the driver to generate a gate drive voltage referenced to the floating TS node. Without this diode, the BOOST rail cannot be replenished, causing gate drive collapse during sustained high-side conduction.

What is the purpose of the exposed pad (Pin 9) on the LTC4440AMPMS8E-5#PBF MS8E package?

The exposed pad (Pin 9) on the LTC4440AMPMS8E-5#PBF is electrically and thermally connected to GND. It must be soldered to a PCB ground plane of ≥2500mm² to achieve the specified thermal resistance of 40°C/W. Failure to do so results in significantly higher junction temperatures, derating output current capability and long-term reliability - especially under continuous 1.1A peak drive conditions.

How does the undervoltage lockout (UVLO) circuit behave in the LTC4440AMPMS8E-5#PBF?

The LTC4440AMPMS8E-5#PBF UVLO circuit disables the TG output and actively pulls it to TS when VCC falls below 3.04V (falling threshold). This prevents weak or partially enhanced MOSFET operation that could cause excessive heating or shoot-through. The hysteresis (160mV) ensures clean re-enablement at 3.20V rising, avoiding oscillation near the threshold. This behavior is verified in Electrical Characteristics Table 1 (page 3).

Can the LTC4440AMPMS8E-5#PBF drive both high-side and low-side N-channel MOSFETs?

Yes, the LTC4440AMPMS8E-5#PBF can drive low-side N-channel MOSFETs by connecting TS to GND - effectively converting it into a ground-referenced driver. In this configuration, TG swings from GND to BOOST (4–15V), maintaining full 1.1A pull-up and 1.85Ω pull-down capability. This dual-mode flexibility is explicitly supported in the Applications Information section (page 7) and Pin Functions description.