Analog Devices Inc. LT1767EMS8E-5#PBF

Overview

LT1767EMS8E-5#PBF from Analog Devices (formerly Linear Technology) is a monolithic 1.25MHz, 1.5A step-down switching regulator in an exposed-pad MSOP-8E package, featuring a fixed 5V output, 0.22Ω internal NPN switch, 2% output tolerance, and 6µA shutdown current. It delivers high efficiency in battery-powered systems, wall adapters, and DSL modems requiring compact, thermally robust DC/DC conversion.

For engineers reviewing the LT1767EMS8E-5#PBF datasheet, LT1767EMS8E-5#PBF pinout, LT1767EMS8E-5#PBF application, or LT1767EMS8E-5#PBF equivalent, key selection criteria include its fixed 5V output, 3V–25V input range, exposed-pad thermal performance (θ_JA = 40°C/W), synchronization capability up to 2MHz, and current-mode control for fast transient response.

Technical Context

The LT1767EMS8E-5#PBF implements constant-frequency current-mode control with cycle-by-cycle peak current limiting and an internal 1.25MHz oscillator. Its BOOST pin enables saturation of the on-die NPN switch via external capacitor/diode, reducing conduction loss to ~330mV at 1.5A.

It integrates a 1.2V feedback reference (internally scaled for 5V output), error amplifier with 850µMho transconductance, and shutdown comparator with 1.33V threshold and 7µA hysteresis current. The VC pin serves as both error amplifier output and current-limit threshold input, enabling direct loop override or soft-start implementation.

Key Specifications

Pinout & Package

LT1767EMS8E-5#PBF uses an 8-lead plastic MSOP package with exposed thermal pad (MS8E), where the pad is electrically and thermally connected to GND. The package provides low thermal resistance (θ_JA = 40°C/W) when soldered to ≥1 cm² of PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3652EMSE-5#PBF and TPS54302DDAR, the LT1767EMS8E-5#PBF offers superior thermal performance in space-constrained 5V applications due to its exposed-pad MSOP-8E package and fixed-output simplicity, while trading off maximum input voltage and current headroom.

Availability

LT1767EMS8E-5#PBF is available at Aetrix Electronics and suitable for DSL modems, portable computers, wall adapters, battery-powered systems, and distributed power architectures requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for LT1767EMS8E-5#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 and maintains full technical and manufacturing continuity for the LT® product line, known for high-performance analog and power management ICs.

The LT1767EMS8E-5#PBF belongs to Linear's monolithic buck regulator family designed for high-efficiency, high-frequency DC/DC conversion in space- and thermally constrained applications where fixed-output simplicity and robust thermal performance are critical.

FAQ

What is the maximum continuous output current of the LT1767EMS8E-5#PBF?

The LT1767EMS8E-5#PBF guarantees a 1.5A maximum switch current limit across all duty cycles and temperatures. Actual continuous output current depends on thermal conditions: with proper PCB copper area (≥1 cm² under exposed pad), it delivers 1.5A at ambient ≤85°C. At 125°C junction temperature, derating applies per thermal calculations using θ_JA = 40°C/W.

Does the LT1767EMS8E-5#PBF require external feedback resistors?

No. The LT1767EMS8E-5#PBF is a fixed 5V output variant - its internal resistor divider connects the FB pin directly to VOUT, eliminating external resistors. This improves accuracy (±2% total output tolerance), reduces component count, and avoids noise coupling into the sensitive FB node that can occur with external dividers.

How does the BOOST pin function in the LT1767EMS8E-5#PBF?

The BOOST pin in the LT1767EMS8E-5#PBF supplies a voltage higher than VIN to the base of the internal NPN switch, ensuring saturation and minimizing conduction loss (~330mV at 1.5A). It requires an external 0.1µF capacitor and Schottky diode (e.g., CMDSH-3), typically tied to VOUT to generate VIN + VOUT - providing sufficient headroom for reliable switch drive.

Can the LT1767EMS8E-5#PBF be synchronized to an external clock?

Yes. The LT1767EMS8E-5#PBF supports synchronization via its SYNC pin, which accepts logic-level signals (20–80% duty cycle) from 1.5MHz to 2MHz. When synchronized, the internal oscillator locks to the external frequency, enabling EMI reduction through frequency alignment or dithering in multi-converter systems.

What thermal considerations apply to the LT1767EMS8E-5#PBF's exposed pad?

The exposed pad of the LT1767EMS8E-5#PBF is electrically connected to GND and must be soldered to a minimum 1 cm² copper area on the PCB for optimal thermal performance (θ_JA = 40°C/W). Thermal vias (≥4×0.3mm) to inner ground planes further reduce θ_JC; insufficient copper area causes junction temperature rise, triggering thermal shutdown above 125°C.