Analog Devices Inc. LT1766IFE-5#PBF

Overview

LT1766IFE-5#PBF from Analog Devices (formerly Linear Technology) is a 5V fixed-output, 200kHz monolithic buck switching regulator with 1.5A peak switch current, 5.5V–60V input range, and thermally enhanced 16-pin TSSOP package. It integrates a 0.2Ω NPN power switch, current-mode control architecture, and internal feedback divider for industrial power conversion in battery-powered systems and distributed power supplies.

For engineers reviewing the LT1766IFE-5#PBF datasheet, LT1766IFE-5#PBF pinout, LT1766IFE-5#PBF application, or LT1766IFE-5#PBF equivalent, key selection considerations include its fixed 5V output, 25μA shutdown current, SYNC capability (228–700kHz), BOOST pin requirement for switch saturation, and thermal performance enabled by exposed GND pad (Pin 17).

Technical Context

The LT1766IFE-5#PBF employs current-mode control with cycle-by-cycle current limiting and a dedicated VC error amplifier output (0.9V–2.1V range) that sets switch current trip level. Its patented circuitry maintains constant 1.5A peak switch current across full duty cycle range, independent of input voltage or load.

It uses a BOOST capacitor to drive the internal NPN switch into saturation-reducing conduction loss to ~0.2Ω-and draws bias current from the BIAS pin when connected to VOUT ≥3V, improving efficiency at high VIN-to-VOUT ratios. Shutdown features dual thresholds: 2.38V UVLO lockout and 0.4V micropower shutdown.

Key Specifications

Pinout & Package

LT1766IFE-5#PBF is housed in a 16-pin plastic TSSOP package with exposed backside GND pad (Pin 17). The package provides θJA = 45°C/W and requires soldering of the exposed pad to a PCB ground plane for thermal performance and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3605EDE-5#PBF and LM5164QPWPRQ1, LT1766IFE-5#PBF uniquely combines 60V input tolerance, 1.5A capability, BOOST-enabled low-R_DS(on) NPN switch, and exposed-pad TSSOP for thermal robustness - making it optimal for industrial and high-reliability 5V buck applications where input transients and sustained load current are critical.

Availability

LT1766IFE-5#PBF is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered instrumentation, and automotive subsystems requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LT1766IFE-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 legacy Linear products including the LT1766 family.

The LT1766 series was designed as a high-voltage, current-mode monolithic buck regulator targeting rugged industrial, transportation, and battery-fed applications where wide input range, thermal resilience, and overload protection are essential.

FAQ

What is the function of the BOOST pin on the LT1766IFE-5#PBF?

The BOOST pin on the LT1766IFE-5#PBF connects to an external capacitor-diode network that generates a voltage higher than VIN, enabling full saturation of the internal NPN power switch. This reduces effective on-resistance to 0.2Ω and minimizes conduction losses - critical for maintaining high efficiency across the 5.5V–60V input range. Without BOOST, switch voltage drop would rise to ~1.5V, degrading thermal performance and efficiency.

Does the LT1766IFE-5#PBF require an external feedback resistor divider?

No, the LT1766IFE-5#PBF does not require an external feedback resistor divider. It integrates an internal resistor network configured for a precise 5V output, and Pin 12 functions as a SENSE input directly connected to the output. This eliminates external components, improves output accuracy (±1.2%), and reduces sensitivity to PCB leakage and noise - distinguishing it from the adjustable LT1766 variant.

How does the SHDN pin operate on the LT1766IFE-5#PBF?

The SHDN pin on the LT1766IFE-5#PBF implements dual-threshold control: at 2.38V it disables switching (UVLO mode), and at ≤0.4V it forces full micropower shutdown with 25μA supply current. This allows flexible system-level power sequencing - e.g., using a supervisor IC to assert SHDN at 0.4V after safe state entry. Leaving SHDN open defaults to active operation via internal bias current.

Can the LT1766IFE-5#PBF synchronize to an external clock?

Yes, the LT1766IFE-5#PBF supports external synchronization via its SYNC pin (Pin 14), which accepts logic-level signals from 228kHz to 700kHz with 10%–90% duty cycle. This feature enables EMI reduction through clock alignment, multi-rail phase interleaving, and deterministic noise placement - all without modifying the internal 200kHz oscillator's core timing behavior.

What thermal design considerations apply to the LT1766IFE-5#PBF package?

The LT1766IFE-5#PBF uses a 16-pin TSSOP with exposed GND pad (Pin 17), which serves as the primary thermal path. To achieve θJC = 10°C/W, the pad must be soldered to a minimum 100mm² copper area on the PCB, connected via ≥4 thermal vias to inner ground planes. Failure to solder the pad results in θJA degradation from 45°C/W to >85°C/W - risking thermal shutdown above ~0.8A continuous load.