Analog Devices Inc. LTC3118HFE#TRPBF

Overview

LTC3118HFE#TRPBF from Analog Devices (formerly Linear Technology) is a dual-input, synchronous buck-boost DC/DC converter with integrated PowerPath™ control. It delivers up to 2A output current across 2V–18V programmable VOUT, accepts 2.2V–18V inputs on either VIN1 or VIN2, and operates seamlessly in buck, boost, or pass-through modes. It is used in backup power systems where seamless switchover between wall adapter and Li-ion battery is required.

For engineers reviewing the LTC3118HFE#TRPBF datasheet, LTC3118HFE#TRPBF pinout, LTC3118HFE#TRPBF application, or LTC3118HFE#TRPBF equivalent, key selection criteria include dual-input priority/ideal-diode mode behavior, 1.2MHz fixed-frequency PWM vs. 50µA Burst Mode quiescent current, ±1.22V accurate RUN pin thresholds, and thermal-rated operation up to 150°C junction temperature.

Technical Context

The LTC3118HFE#TRPBF employs a current-mode, monolithic buck-boost architecture with independent N-channel MOSFET switch paths for VIN1→SW1 and VIN2→SW1, enabling true input source isolation. Its proprietary switching algorithm maintains regulation regardless of whether VIN1 or VIN2 is above, below, or equal to VOUT - eliminating subharmonic oscillation and output transients during mode transitions.

It integrates a 3.8V internal VCC regulator, dual charge-pump circuits (CP1/CN1 and CP2/CN2) for high-side gate drive, and separate CM1/CM2 filter pins for EMI suppression. The device supports pin-selectable PWM or Burst Mode operation, with automatic mode transition based on load, and features independent, resistor-programmable UVLO thresholds via RUN1/RUN2 with 170mV hysteresis.

Key Specifications

Pinout & Package

Package: 28-lead plastic TSSOP with exposed PGND pad (Pin 29). Thermal resistance θ_JA = 30°C/W; requires soldered exposed pad for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3115IUFD#TRPBF and MAX20404ATPA+T, the LTC3118HFE#TRPBF uniquely provides hardware-configurable dual-input arbitration, 150°C operation, and integrated PowerPath™ - making it the only option for high-reliability, analog-controlled backup power where thermal margin and zero-software switchover are mandatory.

Availability

LTC3118HFE#TRPBF is available at Aetrix Electronics and suitable for industrial backup power, automotive telematics, and medical portable monitors requiring stable component supply across extended temperature ranges.

Supply support for LTC3118HFE#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.

The LTC3118 belongs to Linear's high-efficiency PowerPath™ DC/DC converter family, designed specifically for systems requiring seamless dual-input power management with minimal external components and guaranteed operation in harsh thermal environments.

FAQ

What is the maximum junction temperature rating for the LTC3118HFE#TRPBF?

The LTC3118HFE#TRPBF is rated for operation up to +150°C junction temperature, verified across the full –40°C to +150°C ambient range. This H-grade qualification makes it suitable for under-hood automotive, industrial motor controls, and enclosed high-power systems where thermal derating is critical. The exposed pad (Pin 29) must be soldered to a thermal pad on the PCB to achieve specified θ_JA = 30°C/W.

How does the SEL pin configure input selection behavior in the LTC3118HFE#TRPBF?

The SEL pin on the LTC3118HFE#TRPBF determines input arbitration mode: logic low enables VIN1 priority mode (VIN1 used if valid; VIN2 only if VIN1 fails), while logic high enables ideal diode mode (automatically selects higher valid input). This hardware-selectable behavior eliminates software dependency and ensures deterministic switchover timing - a key advantage over I²C-configured alternatives.

Can the LTC3118HFE#TRPBF regulate output voltage when input is below, above, or equal to VOUT?

Yes, the LTC3118HFE#TRPBF supports true buck-boost operation across all three conditions: VIN < VOUT (boost), VIN > VOUT (buck), and VIN ≈ VOUT (pass-through). Its proprietary four-switch topology and current-mode control ensure seamless, transient-free transitions between modes - confirmed in typical performance graphs (Figures G29–G34) and block diagram analysis.

What is the purpose of the CM1 and CM2 pins on the LTC3118HFE#TRPBF?

The CM1 and CM2 pins on the LTC3118HFE#TRPBF serve as common-mode filter nodes for the VIN1→SW1 and VIN2→SW1 N-channel MOSFET paths, respectively. Each requires a 47nF capacitor to ground to suppress high-frequency switching noise and reduce EMI emissions - a design requirement explicitly called out in the Pin Functions section and validated in demo board layouts.

Does the LTC3118HFE#TRPBF support output disconnect during shutdown?

Yes, the LTC3118HFE#TRPBF provides internal output disconnect in shutdown mode: when both RUN1 and RUN2 are pulled below 0.2V, the device disables all power switches and isolates VOUT from VIN1 and VIN2. This prevents backfeeding, preserves downstream load state, and eliminates leakage paths - a feature explicitly listed in the Features section and confirmed in the Absolute Maximum Ratings table.