Analog Devices Inc. LTC7862IUFD#TRPBF

Overview

LTC7862IUFD#TRPBF from Analog Devices is a high-efficiency switching surge stopper controller designed to protect downstream loads from input overvoltage transients up to 140V. It controls two external N-channel MOSFETs to regulate output voltage during surges (e.g., ISO7637/ MIL-STD-1275), maintains 100% duty-cycle pass-through under normal operation, and delivers up to 20A output current with adjustable 28V clamp and 50kHz–900kHz switching frequency.

For engineers reviewing the LTC7862IUFD#TRPBF datasheet, LTC7862IUFD#TRPBF pinout, LTC7862IUFD#TRPBF application, or LTC7862IUFD#TRPBF equivalent, key selection criteria include its 4V–140V input range, programmable fault timer, RSENSE/DCR current sensing, open-drain WARNB fault indicator, and QFN-20 (4mm × 5mm) package with exposed thermal pad.

Technical Context

The LTC7862IUFD#TRPBF implements a peak-current-mode synchronous buck controller architecture during transient events, using fast comparator-based current limiting and adjustable soft-start. Its dual-mode operation-dropout (100% duty cycle) for normal input conditions and active switching for overvoltage/overcurrent-is governed by an internal fault timer that strictly limits cumulative switching duration.

It integrates independent LDOs for DRVCC (6V or 9V selectable via DRVUV) and INTVCC (5V), supports EXTVCC switchover at 4.7V/7.7V thresholds, and features gate drivers with <25ns rise/fall times, 1.0Ω pull-down on TG/BG, and charge-pump boosted high-side drive. The TMR pin sets both switching-on time and cooldown period via external capacitor.

Key Specifications

Pinout & Package

Package: 20-lead plastic QFN (4mm × 5mm), exposed thermal pad (Pin 21 = GND). Must be soldered to PCB ground plane for rated electrical and thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar surge protection controller applications.

Compared with LTC4365IMS#PBF and MAX16054ATJ+, the LTC7862IUFD#TRPBF uniquely combines ultra-wide 4V–140V input range, 20A scalable output via external MOSFETs, fully adjustable output clamp (up to 60V), and programmable fault timing - making it the only option for high-reliability, high-power automotive, military, and industrial surge protection where thermal management and design flexibility are critical.

Availability

LTC7862IUFD#TRPBF is available at Aetrix Electronics and suitable for automotive load dump protection, MIL-STD-1275 vehicle power systems, and industrial DC distribution requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LTC7862IUFD#TRPBF 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 aerospace markets.

The LTC7862IUFD#TRPBF belongs to Analog Devices' Power by Linear™ surge protection controller family, engineered specifically for high-efficiency, high-reliability pre-regulation in harsh 12V/28V/48V vehicle and military power systems subject to ISO7637 and MIL-STD-1275 transients.

FAQ

What is the primary function of the LTC7862IUFD#TRPBF in a power system?

The LTC7862IUFD#TRPBF functions as a high-efficiency switching surge stopper controller. During normal operation, it enables 100% duty-cycle pass-through of input voltage to the output with minimal drop. When input voltage exceeds a user-defined clamp level (e.g., 34V), the LTC7862IUFD#TRPBF actively switches two external N-channel MOSFETs to regulate the output, protecting downstream loads from destructive transients such as ISO7637 load dumps or MIL-STD-1275 surges.

How does the LTC7862IUFD#TRPBF handle overvoltage events without overheating?

The LTC7862IUFD#TRPBF uses a programmable fault timer (TMR pin) to strictly limit the cumulative time spent in switching mode during overvoltage, overcurrent, or startup events. After the timer expires, it enters a cooldown period before retrying. This duty-cycled approach allows thermal design and component selection to be optimized for the dominant pass-through mode, preventing thermal runaway even during prolonged high-power surges.

Can the LTC7862IUFD#TRPBF be used with both RSENSE and inductor DCR current sensing?

Yes, the LTC7862IUFD#TRPBF supports both RSENSE shunt resistor and inductor DCR sensing via its differential SENSE+ and SENSE– inputs. The device's current comparator has a typical trip threshold of 50mV with ±7mV tolerance, and its low input bias currents (±1µA on SENSE+, 900µA on SENSE– at 28V) ensure accuracy across both methods without requiring external amplification.

What is the role of the WARNB pin on the LTC7862IUFD#TRPBF?

The WARNB pin on the LTC7862IUFD#TRPBF is an open-drain logic output that pulls low during all active switching events - including overvoltage, overcurrent, startup, and cooldown periods. It transitions to high-impedance only during true dropout (100% pass-through) mode. This provides unambiguous system-level fault signaling, enabling host microcontrollers to log events, trigger alarms, or initiate safe shutdown sequences.

Does the LTC7862IUFD#TRPBF require external MOSFETs, and what type are supported?

Yes, the LTC7862IUFD#TRPBF requires two external N-channel MOSFETs: one high-side (MTOP) and one synchronous low-side (MBOT). It drives them via dedicated TG and BG pins with fast 1.0Ω pull-down strength and <25ns transition times. Compatible MOSFETs include Infineon BSC035N10NS5 (as referenced in the datasheet) and other logic-level or standard-gate-threshold devices with appropriate voltage rating (≥150V) and R_DS(on) for target current.