Analog Devices Inc. LT1074HVCK

Overview

LT1074HVCK from Analog Devices (formerly Linear Technology) is a 5A monolithic bipolar step-down switching regulator in a 4-lead TO-3 metal can package, operating from 8V to 60V input and delivering adjustable output voltages from 2.5V to 50V. It integrates a Darlington NPN power switch, oscillator, current limit, and analog multiplier-based feedback loop, enabling buck, positive-to-negative, and tapped-inductor topologies. Used in industrial power supplies requiring high-voltage input tolerance and robust overload protection.

For engineers reviewing the LT1074HVCK datasheet, LT1074HVCK pinout, LT1074HVCK application, or LT1074HVCK equivalent, key selection considerations include its 60V max input rating, 5A onboard switch, 100kHz fixed switching frequency, programmable current limit via ILIM pin, and operation down to –40°C ambient temperature for ruggedized DC-DC conversion.

Technical Context

The LT1074HVCK implements a classic buck topology enhanced with an on-chip true analog multiplier in the feedback path, making loop gain independent of input voltage and enabling near-instantaneous line transient response. Its Darlington NPN switch supports 40V swing below ground, enabling tapped-inductor configurations delivering up to 10A at 5V.

On-chip pulse-by-pulse current limiting-set by internal 320µA source and external resistor on ILIM pin-ensures robustness against output shorts. Frequency shifting (100kHz → 20kHz) activates when FB voltage drops below 1.3V, maintaining control under extreme duty-cycle conditions during overload or startup.

Key Specifications

Pinout & Package

LT1074HVCK is housed in a hermetically sealed 4-lead TO-3 metal can package (K package), with case connected to GND. The metal can provides superior thermal dissipation (θ_JC = 2.5°C/W) and EMI shielding for high-noise industrial settings.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3775 and LM5088MHX-SD/NOPB, the LT1074HVCK uniquely combines integrated 5A Darlington switching, analog multiplier-based line regulation, and –45V VSW rating-making it optimal for ruggedized 10A tapped-inductor or industrial negative-output converters where simplicity and transient immunity outweigh raw efficiency or frequency agility.

Availability

LT1074HVCK is available at Aetrix Electronics and suitable for industrial power supplies, telecom DC-DC conversion, and ruggedized embedded systems requiring stable component supply across extended temperature and high-input-voltage conditions.

Supply support for LT1074HVCK 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, datasheets, and application notes for legacy Linear parts including the LT1074HV series.

The LT1074HVCK belongs to Linear's high-voltage monolithic switching regulator family, designed specifically for industrial and telecom applications demanding wide input range, integrated power handling, and robust fault protection without external complexity.

FAQ

What is the maximum input voltage rating for the LT1074HVCK?

The LT1074HVCK has an absolute maximum input voltage rating of 60V, with guaranteed operation from 8V to 60V. This HV variant exceeds the standard LT1074 (45V max) and supports 48V telecom and industrial bus applications with margin for transients. Exceeding 60V risks permanent damage per Absolute Maximum Ratings table.

Does the LT1074HVCK include a shutdown pin?

No, the LT1074HVCK in the 4-lead TO-3 (K) package does not include a shutdown pin. Shutdown functionality is only available on 5-pin (T), 7-pin (T7/R), or DD (Q) packages. The K package retains the core 4-pin configuration (VIN, VSW, GND, FB) for minimal footprint and thermal performance-micropower shutdown is not supported in this variant.

How is output voltage set on the LT1074HVCK?

Output voltage is set externally using a resistive divider from VOUT to GND, with the FB pin connected to the midpoint. The internal 2.21V reference compares against FB voltage, so V_OUT = 2.21V × (1 + R1/R2). For example, R1 = 2.8kΩ and R2 = 2.21kΩ yields 5V output. Divider current should exceed FB bias current (≤2µA) for accuracy.

Can the LT1074HVCK drive a tapped-inductor for 10A output?

Yes-the LT1074HVCK's VSW pin is rated to swing 40V below ground (–45V absolute), enabling direct connection to the center tap of a custom inductor. Combined with its 5A switch and frequency-shifting protection, it reliably delivers 10A at 5V in tapped-buck configuration, as validated in Application Note AN44 and LT1074•TA02 schematic.

What thermal performance can be expected from the LT1074HVCK TO-3 package?

The LT1074HVCK's TO-3 metal can delivers θ_JC = 2.5°C/W and θ_JA = 35°C/W (with 0.5 in² copper pad). At 5A load and 25°C ambient, junction temperature rise is ~125°C above ambient-requiring heatsinking for continuous operation. Derating curves in the datasheet confirm 5A is sustainable up to 60°C ambient with proper board layout.