Analog Devices Inc. LTC3780MPUH

Overview

LTC3780MPUH from Analog Devices (formerly Linear Technology) is a high-efficiency, synchronous 4-switch buck-boost controller IC designed for wide-input DC-DC conversion where VIN may be above, below, or equal to VOUT. It delivers ±1% output voltage accuracy over 0.8V–30V range, supports phase-lockable 200–400kHz switching, and achieves up to 98% efficiency with quad N-channel MOSFET drive. It is used in automotive power systems requiring seamless mode transition across input transients.

For engineers reviewing the LTC3780MPUH datasheet, LTC3780MPUH pinout, LTC3780MPUH application, or LTC3780MPUH equivalent, key selection criteria include its –55°C to 125°C operating junction temperature, FCB-selectable low-current modes (Burst, Skip-Cycle, Forced CCM), integrated 6V LDO for gate drive, and robust fault protection including output overvoltage lockout and foldback current limiting.

Technical Context

The LTC3780MPUH implements a constant-frequency current-mode control architecture with dual independent gate drivers (TG1/BG1 and TG2/BG2) enabling true 4-switch synchronous buck-boost operation. Its control logic dynamically selects between buck, buck-boost, and boost regions based on duty cycle and input-output relationship, with sub-200ns mode transitions.

It integrates an error amplifier with 0.32mS transconductance and 0.6MHz GBW, a programmable oscillator via PLLFLTR pin (170–440kHz), and internal protection circuits including PGOOD monitoring (±7.5% window), undervoltage reset (4V), and reverse current detection via SENSE+/SENSE– differential inputs.

Key Specifications

Pinout & Package

The LTC3780MPUH is housed in a 32-lead (5mm × 5mm) plastic QFN package with exposed pad (Pin 33 = SGND), optimized for thermal performance (θJA = 34°C/W). The exposed pad must be soldered to PCB ground for electrical integrity and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost controller applications.

Compared with LTC3780IUH, the LTC3780MPUH adds guaranteed operation down to –55°C - critical for military or polar vehicle systems - while retaining identical electrical specs and layout compatibility. Against LT8705, it trades input voltage range for integrated FCB control and simpler compensation, making it more suitable for cost- and space-constrained automotive modules.

Availability

LTC3780MPUH is available at Aetrix Electronics and suitable for automotive power management, telecom intermediate bus conversion, and industrial DC distribution systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3780MPUH 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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, formed through the acquisition of Linear Technology in 2017.

The LTC3780MPUH belongs to ADI's Power by Linear™ controller family, engineered specifically for high-reliability DC-DC conversion in automotive, industrial, and telecom infrastructure where wide input range, seamless mode transition, and extended temperature operation are mandatory.

FAQ

What is the operating temperature range of the LTC3780MPUH?

The LTC3780MPUH is specified for a junction temperature range of –55°C to 125°C, making it suitable for extreme-environment applications such as under-hood automotive electronics, aerospace avionics, and outdoor industrial equipment. This MP-grade qualification exceeds commercial and industrial grades, and is verified per manufacturer test conditions in the datasheet.

How does the FCB pin configure operating modes in the LTC3780MPUH?

The FCB pin on the LTC3780MPUH selects among three distinct low-current modes: <0.8V enables forced continuous conduction mode (CCM); 0.85–5V activates skip-cycle mode in buck operation or Burst Mode® in boost operation; >5.3V selects discontinuous conduction mode (DCM) with constant frequency. Each setting directly alters gate drive timing and current-sense comparator behavior without external components.

Does the LTC3780MPUH support external frequency synchronization?

Yes, the LTC3780MPUH supports external synchronization via the PLLIN pin (Pin 10), which accepts a logic-level clock input. The internal phase-locked loop forces alignment of the rising edge of the bottom-gate driver signal to the rising edge of the PLLIN signal, enabling EMI reduction and multi-rail timing coordination in complex power systems.

What protection features are integrated into the LTC3780MPUH?

The LTC3780MPUH integrates output overvoltage lockout (triggered at 0.84–0.88V at VOSENSE), foldback current limiting, undervoltage reset (3.8–4V on VIN), and reverse current detection via SENSE+/SENSE–. It also provides a PGOOD output that asserts low when output voltage deviates beyond ±7.5% of regulation - eliminating need for most external protection circuitry.

Can the LTC3780MPUH operate with VIN equal to VOUT?

Yes, the LTC3780MPUH is explicitly designed for seamless operation when VIN equals VOUT - entering buck-boost mode with sub-200ns transition time between buck and boost states. In this region, all four switches participate in regulation, maintaining tight output voltage control without dropout or instability, as confirmed in typical performance curves and application schematics.