Analog Devices Inc. LT1372IS8#TRPBF

Overview

LT1372IS8#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 500kHz current-mode switching regulator IC in an 8-pin SOIC package, integrating a 1.5A power switch, oscillator, error amplifier, and protection circuitry. It operates in boost, buck, flyback, inverting, and Cuk topologies, supports ±2.7V to 25V input, regulates positive or negative outputs, and delivers up to 0.29A output current in boost configuration for laptop supplies and CCFL backlight drivers.

For engineers reviewing the LT1372IS8#TRPBF datasheet, LT1372IS8#TRPBF pinout, LT1372IS8#TRPBF application, or LT1372IS8#TRPBF equivalent, key selection criteria include its 500kHz fixed switching frequency, 1.245V internal reference, 12µA shutdown current, dual feedback architecture (FB/NFB), and thermal performance in industrial-grade (–40°C to 125°C) SO-8 packaging.

Technical Context

The LT1372IS8#TRPBF uses peak-current-mode control with adaptive anti-saturation driver logic, enabling immediate line transient response and simplified loop compensation. Its error amplifier features nonlinear transconductance (700–2300 µmho) that increases tenfold above 40mV FB overdrive to suppress startup/overload overshoot.

Oscillator frequency shifting (5:1 reduction when FB < 0.6V) protects external components during overload; the S/S pin provides both logic-level shutdown (1.3V threshold) and synchronization (600–800kHz range); VC pin serves as error amplifier output for compensation, soft-start, and current limit adjustment via external clamping.

Key Specifications

Pinout & Package

LT1372IS8#TRPBF is housed in an 8-lead plastic SOIC (SO-8) package with standard JEDEC MS-012AC footprint, 1.27mm pitch, and 120°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3872EMS#TRPBF and TPS61088RHLR, the LT1372IS8#TRPBF uniquely integrates dual-polarity feedback, industrial temperature range, and monolithic 1.5A switch in SO-8-making it optimal for compact, multi-rail embedded power where negative voltage regulation is essential.

Availability

LT1372IS8#TRPBF is available at Aetrix Electronics and suitable for laptop computer supplies, CCFL backlight drivers, inverting power supplies, and multiple-output flyback converters requiring stable component supply across industrial temperature ranges.

Supply support for LT1372IS8#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 its legacy of high-performance analog and power management ICs with rigorous qualification standards.

The LT1372IS8#TRPBF belongs to Linear's monolithic switching regulator product line, designed specifically for compact, high-efficiency DC-DC conversion in portable and industrial systems where integration, thermal robustness, and dual-polarity capability are critical.

FAQ

What is the maximum output current achievable with LT1372IS8#TRPBF in a boost configuration?

The LT1372IS8#TRPBF supports up to 0.29A output current in boost topology at 5V input to 12V output, as specified in the datasheet's "Typical Applications" section. This limit arises from the 1.5A switch current rating, duty cycle constraints, and thermal dissipation in the SO-8 package at 125°C junction temperature. Higher loads require heatsinking or lower ambient temperatures.

Does LT1372IS8#TRPBF support negative output voltage regulation, and how is it implemented?

Yes, the LT1372IS8#TRPBF supports negative output regulation via its dedicated NFB pin, which references an internal –2.49V bandgap. The user connects a resistor divider from the negative output to NFB, and the internal negative feedback amplifier drives the FB pin to 1.245V to maintain regulation-eliminating need for external op-amps or level shifters.

What is the purpose of the VC pin on LT1372IS8#TRPBF, and how is it used in design?

The VC pin on LT1372IS8#TRPBF is the error amplifier output and serves three functions: (1) frequency compensation via RC network to ground, (2) soft-start control via capacitor-coupled clamp, and (3) current limit adjustment via voltage clamping. Its voltage (1.0–1.9V under normal operation) directly sets switch current trip level and loop dynamics.

Can LT1372IS8#TRPBF be synchronized to an external clock, and what is the valid frequency range?

Yes, the S/S pin of LT1372IS8#TRPBF accepts external TTL/CMOS clock signals for synchronization. For the LT1372 variant, the guaranteed range is 600–800kHz; operation outside this range may cause instability or loss of regulation. The datasheet warns against synchronizing above 700kHz due to reduced slope compensation, which risks subharmonic oscillation at >50% duty cycle.

What are the thermal limitations of LT1372IS8#TRPBF in SO-8 package, and how is power dissipation calculated?

The LT1372IS8#TRPBF in SO-8 has θ_JA = 120°C/W. Total die power dissipation is calculated as P_D(TOTAL) = (I_IN × V_IN) + (I_SW² × R_SW × DC), where I_IN = 4mA + DC × (I_SW/60 + I_SW × 0.004). At worst-case 25V input and 1.5A switch current, junction temperature must be verified against 125°C max to avoid thermal shutdown.