Analog Devices Inc. LT1376HVIS8#PBF

Overview

LT1376HVIS8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz, 1.5A monolithic step-down switching regulator in an 8-lead SOIC package with high-voltage rating (30V max input), fixed 5V output, and integrated 0.4Ω NPN power switch. It delivers up to 1.25A at 5V from 6V–25V input, features cycle-by-cycle current limiting, thermal shutdown, and operates across –40°C to 125°C junction temperature.

For engineers reviewing the LT1376HVIS8#PBF datasheet, LT1376HVIS8#PBF pinout, LT1376HVIS8#PBF application, or LT1376HVIS8#PBF equivalent, key selection criteria include its HV-rated input range, fixed 5V output accuracy (±2%), 20µA shutdown current, BIAS pin efficiency optimization, and compatibility with standard 5µH surface-mount inductors in compact DC/DC designs.

Technical Context

The LT1376HVIS8#PBF implements current-mode control with a 500kHz oscillator, internal error amplifier (2000 µMho transconductance), and peak-current sensing for fast transient response and stable loop behavior. Its bipolar NPN switch uses BOOST-pin-driven saturation to achieve low on-resistance (0.4Ω typ) without MOSFET die area penalty.

It integrates undervoltage lockout (2.38V UVLO threshold), dual shutdown thresholds (0.4V full shutdown, 2.38V standby), and FB/SENSE pin functionality for 5V regulation with ±0.6% sense voltage tolerance (4.94–5.06V). The BIAS pin enables output-sourced biasing to improve light-load efficiency when VIN ≫ VOUT.

Key Specifications

Pinout & Package

LT1376HVIS8#PBF is housed in an 8-lead plastic SOIC (S8) package with θ_JA = 120–150°C/W depending on PCB layout. Pin 1 is marked with a dot; pins are arranged in standard SOIC configuration with GND on pins 3 and 6 for low-impedance return paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LTC3605EDE#TRPBF and TPS54202DRCT, LT1376HVIS8#PBF offers superior HV input margin (30V abs max), tighter 5V regulation (±2%), and BIAS-enabled efficiency gain at high VIN/VOUT ratios - making it preferred for industrial and automotive 24V-rail applications where precision and ruggedness outweigh raw current or frequency specs.

Availability

LT1376HVIS8#PBF is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, portable medical devices, and test equipment requiring stable component supply with extended temperature support and long-term lifecycle assurance.

Supply support for LT1376HVIS8#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) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving industrial, automotive, communications, and healthcare markets with rigorous quality and reliability standards.

The LT1376 series belongs to Linear's legacy monolithic buck regulator product line, designed specifically for rugged, high-efficiency 5V conversion from wide-input industrial and automotive supplies - emphasizing HV tolerance, thermal robustness, and minimal external component count.

FAQ

What is the maximum continuous output current of the LT1376HVIS8#PBF?

The LT1376HVIS8#PBF delivers up to 1.25A continuous output current at 5V when using a 10µH inductor and 10V input, as specified in the Typical Application Circuit (Figure TA01). Peak switch current is rated at 1.5A ≤50% duty cycle, decreasing to 1.35A at 80% duty cycle. Actual achievable load depends on input voltage, inductor value, and thermal design - e.g., at VIN=25V and L=5µH, max continuous output drops to ~0.8A due to ripple current and thermal limits. The LT1376HVIS8#PBF datasheet provides detailed load-current vs. input-voltage curves (Figures G13–G15).

Does the LT1376HVIS8#PBF require an external BOOST capacitor and diode?

Yes, the LT1376HVIS8#PBF requires an external BOOST capacitor and Schottky diode (e.g., 1N5818) connected between VIN and BOOST pins to generate the boosted gate drive voltage needed for NPN switch saturation. Without this network, the internal switch cannot achieve its specified 0.4Ω on-resistance, resulting in excessive conduction loss and reduced efficiency. The BOOST capacitor must be rated for ≥16V and placed close to the IC; typical values range from 10nF to 100nF depending on layout and ripple requirements. This is a mandatory part of the LT1376HVIS8#PBF application circuit.

How does the BIAS pin improve efficiency in the LT1376HVIS8#PBF?

The BIAS pin on the LT1376HVIS8#PBF allows internal bias circuitry to draw operating current from the regulated 5V output instead of the higher VIN rail - reducing total input-referred quiescent current. At VIN=20V, VOUT=5V, and IOUT=25mA, this yields >10% efficiency improvement. The BIAS pin must be connected directly to the 5V output (not through a resistor or ferrite bead) and is only functional when VOUT ≥3.3V. This feature makes the LT1376HVIS8#PBF especially valuable in high-input-voltage, low-power applications like industrial sensors and automotive modules where standby power matters.

What is the purpose of the FB/SENSE pin on the LT1376HVIS8#PBF?

On the LT1376HVIS8#PBF, the FB/SENSE pin serves as the direct 5V output sense input - internally connected to the regulated output via precision resistors. It enables accurate 5V regulation (±2%) without external components. Additionally, it provides fault protection: when voltage drops below 1.7V, the switch current limit folds back; below 1V, switching frequency reduces ~5:1 to limit power dissipation during short circuits. This dual-function pin eliminates external feedback dividers while adding intelligent overload response - a core safety feature of the LT1376HVIS8#PBF architecture.

Is the LT1376HVIS8#PBF RoHS-compliant and lead-free?

Yes, the LT1376HVIS8#PBF is RoHS-compliant and lead-free, as indicated by the "#PBF" suffix in the part number (Pb-Free). It meets JEDEC J-STD-020 moisture sensitivity level 3 (MSL3) and is qualified for reflow soldering per IPC/JEDEC J-STD-020. The device uses matte tin lead finish and is compatible with standard Pb-free assembly processes. Full compliance documentation, including material declarations and test reports, is available from Analog Devices' official product page for LT1376HVIS8#PBF.