Analog Devices Inc. LT3015ET-3#PBF

Overview

LT3015ET-3#PBF from Analog Devices (formerly Linear Technology) is a fixed-output –3V, 1.5A negative low-dropout linear regulator in a 5-lead TO-220 package. It delivers low noise (60µVRMS, 10Hz–100kHz), fast transient response, and precision current limit with foldback. Designed for post-regulation of switching supplies and noise-sensitive instrumentation requiring stable negative bias.

For engineers reviewing the LT3015ET-3#PBF datasheet, LT3015ET-3#PBF pinout, LT3015ET-3#PBF application, or LT3015ET-3#PBF equivalent, key selection criteria include guaranteed dropout voltage at 1.5A (≤320mV), controlled quiescent current in dropout (1.1mA typ), reverse output protection, thermal limit with hysteresis, and compatibility with 10µF ceramic output capacitors without ESR requirements.

Technical Context

The LT3015ET-3#PBF employs a PNP pass transistor architecture enabling true negative regulation with input-to-output differential as low as –310mV at full load. Its internal reference is trimmed to –3.0V (±1% over temperature), and the current limit folds back when |VIN – VOUT| ≥ 8V to protect under high-differential fault conditions.

Quiescent current remains tightly regulated across dropout (1.1mA typ), drops below 1µA in shutdown, and exhibits minimal variation over –40°C to 125°C. The device integrates reverse output protection and thermal shutdown with hysteresis, eliminating external diodes and simplifying system-level fault management.

Key Specifications

Pinout & Package

LT3015ET-3#PBF uses a 5-lead plastic TO-220 package with exposed tab connected to IN for optimal thermal performance (qJA = 50°C/W, qJC = 3°C/W). The tab must be soldered to PCB copper for thermal integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3015ET-3#PBF, LTC3015ET-3#PBF offers identical performance under the current Analog Devices product umbrella, while LT3015IT-3#PBF provides equivalent specification compliance with alternate temperature-grade labeling-both enable drop-in qualification without revalidation.

Availability

LT3015ET-3#PBF is available at Aetrix Electronics and suitable for industrial automation, precision test equipment, and embedded instrumentation requiring stable component supply, long-lifecycle support, and guaranteed TO-220 packaging consistency.

Supply support for LT3015ET-3#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, formed through the acquisition of Linear Technology in 2017.

The LT3015 series belongs to ADI's precision power management portfolio, designed specifically for noise-sensitive negative rail applications including post-regulation, instrumentation biasing, and industrial control where low dropout, low noise, and robust protection are mandatory.

FAQ

What is the minimum input voltage required for LT3015ET-3#PBF to maintain regulation at full load?

The LT3015ET-3#PBF requires a minimum input voltage of –3.31V (–3V output + 310mV dropout) at –1.5A load. Per datasheet specifications, it operates down to –1.8V input but cannot sustain 1.5A below –3.31V due to dropout constraints. For reliable full-load operation, –3.5V or lower is recommended.

Does LT3015ET-3#PBF require an external resistor network to set its output voltage?

No. LT3015ET-3#PBF is a fixed-output variant with internally trimmed –3.0V reference. Pin 2 (SENSE/ADJ) is pre-connected to the internal reference and requires no external components-unlike the adjustable LT3015 version, which needs an external resistor divider.

Can LT3015ET-3#PBF be used with ceramic output capacitors smaller than 10µF?

No. The LT3015ET-3#PBF is specified and tested for stability with a minimum 10µF ceramic output capacitor. Using smaller values may cause oscillation or degraded transient response. The 10µF requirement applies regardless of capacitor type (ceramic, tantalum, or aluminum).

What is the shutdown behavior of LT3015ET-3#PBF, and how much current does it draw in that state?

LT3015ET-3#PBF enters shutdown when SHDN pin voltage falls below 0.73V (typ). In shutdown, it draws ≤6µA (max) from VIN, with typical quiescent current below 1µA-enabling ultra-low-power retention in battery-powered systems without external disconnect switches.

How does the current limit foldback function in LT3015ET-3#PBF during overvoltage conditions?

The LT3015ET-3#PBF initiates current limit foldback when |VIN – VOUT| exceeds 8V. At that point, the current limit decreases gradually-from 1.7A minimum at low differential to ~1.2A at 12V differential-reducing power dissipation and thermal stress during sustained overvoltage faults while maintaining partial output capability.