Analog Devices Inc. LTC7860IMSE#PBF

Overview

LTC7860IMSE#PBF from Analog Devices is a high-efficiency switching surge stopper controller IC designed to protect downstream loads from input overvoltage transients (e.g., ISO 7637 load dump, MIL-STD-1275 surges) and overcurrent faults. It controls an external P-channel MOSFET in two modes: 100% duty-cycle SWITCH-ON mode for normal operation (VIN = 3.5V–60V), and PROTECTIVE PWM mode during faults, clamping VOUT to a user-adjustable safe level. Key confirmed parameters include 50kHz–850kHz programmable switching frequency, 0.8V feedback reference, 95mV current limit threshold, –40°C to 125°C operating junction temperature, and thermally enhanced 12-lead MSOP package.

For engineers reviewing the LTC7860IMSE#PBF datasheet, LTC7860IMSE#PBF pinout, LTC7860IMSE#PBF application, or LTC7860IMSE#PBF equivalent, this page delivers verified technical context, exact pin functions, real-world protection timing behavior, thermal design constraints, and validated alternative options - all grounded in Analog Devices' official Rev. G datasheet and functional diagrams.

Technical Context

The LTC7860IMSE#PBF implements peak current-mode control with a transconductance error amplifier (gm = 1.8 mS) and internal 0.8V reference. Its dual-mode operation-SWITCH-ON (dropout) and PROTECTIVE PWM-is governed by real-time monitoring of VIN–SENSE voltage and VFB feedback, with automatic transition triggered by overvoltage or overcurrent events. The TMR pin enables precise fault timing via programmable pull-up (–30 µA) and pull-down (1.3 µA cool-down, 40 µA reset) currents.

It features integrated gate drive with 8V regulated VCAP bias (VIN–VCAP), 2 Ω pull-up / 0.9 Ω pull-down gate resistance, and UVLO activation at 3.25V (typical) with 0.25V hysteresis. Frequency is set via FREQ pin: grounded (350 kHz), floating (535 kHz), or resistor-programmed (50–850 kHz), with foldback to 18% of set frequency when VFB < 0.4V.

Key Specifications

Pinout & Package

Package: 12-lead plastic MSOP with exposed PGND pad (Pin 13), requiring soldering to PCB for thermal and electrical performance (θJC = 10°C/W). Pin count, layout, and thermal pad mapping are confirmed per Analog Devices Rev. G datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-efficiency surge stopper applications.

Compared with LTC4365IMS#PBF and MAX16050ATJ+T, the LTC7860IMSE#PBF uniquely combines programmable fault timing, dual-mode operation, >60V extensibility via VFBN, and external MOSFET control - making it optimal for high-current, thermally constrained, or multi-voltage-range designs where efficiency and flexibility are mandatory.

Availability

LTC7860IMSE#PBF is available at Aetrix Electronics and suitable for automotive load dump protection, industrial 24V/48V power inputs, and MIL-STD-1275-compliant military systems requiring stable component supply across extended temperature and surge profiles.

Supply support for LTC7860IMSE#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, communications, and power management markets.

The LTC7860IMSE#PBF belongs to Analog Devices' Power by Linear™ surge protection controller family, engineered specifically for high-efficiency, thermally optimized transient suppression in automotive, industrial, and defense power systems.

FAQ

What is the primary function of the LTC7860IMSE#PBF in a power system?

The LTC7860IMSE#PBF is a high-efficiency switching surge stopper controller that protects downstream loads from input overvoltage transients (e.g., ISO 7637 load dumps) and overcurrent faults. It achieves this by controlling an external P-channel MOSFET in two distinct modes: 100% duty-cycle SWITCH-ON mode during normal operation and PROTECTIVE PWM mode during faults - regulating output voltage to a safe, user-adjustable level while strictly limiting fault duration via its TMR pin.

How does the LTC7860IMSE#PBF handle input voltage surges above 60V?

The LTC7860IMSE#PBF supports input voltages beyond 60V using external circuitry: a bootstrapped shunt regulator (e.g., Zener) creates a floating ground connected to PGND and SGND, enabling operation up to 200V+. Two feedback configurations are supported - Inverting Feedback (using VFBN pin) for simpler implementation with moderate accuracy, and Non-Inverting Feedback (VFBN > 2V) for higher accuracy and lower quiescent current - both confirmed in the LTC7860IMSE#PBF datasheet Rev. G.

What is the role of the TMR pin on the LTC7860IMSE#PBF, and how is it configured?

The TMR pin on the LTC7860IMSE#PBF implements a programmable fault timer that monitors time spent in PROTECTIVE PWM mode. A 30 µA internal current pulls TMR high during faults; shutdown occurs when TMR reaches 1.29V. After shutdown, a 1.3 µA current pulls TMR down to 240 mV for cool-down before automatic restart. The timer set time is calculated as 37–50 ms per µF of external capacitor, enabling precise thermal management during transients - a core safety feature of the LTC7860IMSE#PBF.

Can the LTC7860IMSE#PBF be used without an inductor, and what are the implications?

No - the LTC7860IMSE#PBF requires an external inductor for PROTECTIVE PWM mode operation, as it functions as a synchronous step-down controller during transients. However, in normal SWITCH-ON mode, the inductor serves primarily to reduce input EMI and has minimal impact on efficiency. Omitting the inductor disables surge protection functionality entirely; the LTC7860IMSE#PBF cannot operate as a linear regulator or ideal diode - its architecture fundamentally depends on inductive energy transfer during fault conditions.

What thermal considerations apply to the LTC7860IMSE#PBF's exposed PGND pad?

The exposed PGND pad (Pin 13) on the LTC7860IMSE#PBF is mandatory for thermal performance: it must be soldered to a PCB copper plane to achieve the specified θJC = 10°C/W. Without proper pad soldering, junction temperature can exceed 150°C during PROTECTIVE PWM operation, triggering thermal shutdown or permanent damage. Layout guidelines require direct thermal vias to inner ground planes and separation from noisy signal traces - all validated in the LTC7860IMSE#PBF's official thermal characterization data.