Analog Devices Inc. LT3021EDH-1.5#PBF

Overview

LT3021EDH-1.5#PBF from Analog Devices (formerly Linear Technology) is a 500mA very low dropout (VLDO™) linear regulator in a 16-pin 5mm × 5mm DFN package with exposed pad, delivering a fixed 1.5V output. It operates from input voltages as low as 0.9V, achieves 160mV typical dropout at full load, and maintains 0.2% load regulation across 0–500mA - enabling efficient power delivery in space-constrained, battery-powered systems such as cellular handsets and wireless modems.

For engineers reviewing the LT3021EDH-1.5#PBF datasheet, LT3021EDH-1.5#PBF pinout, LT3021EDH-1.5#PBF application, or LT3021EDH-1.5#PBF equivalent, key selection criteria include its guaranteed 1.5V ±2% output accuracy over –40°C to 125°C, 3μA shutdown quiescent current, reverse-battery protection, and stable operation with ≥3.3μF ceramic output capacitors - all critical for low-voltage, high-reliability portable designs.

Technical Context

The LT3021EDH-1.5#PBF integrates an internal resistor divider (R1 = 20kΩ, R2 = 130kΩ) to fix the output at 1.5V, eliminating external feedback components. Its error amplifier references a precision 200mV bandgap, and the no-load recovery circuit activates when VOUT exceeds 1.59V (6% over nominal) to sink up to 15mA and suppress light-load overshoot.

Thermal protection uses hysteresis-based junction sensing (TJMAX = 125°C), and the exposed pad (Pin 17) must be soldered to PCB ground to achieve θJC = 3°C/W. Reverse-current protection prevents backflow when VIN = 0V and VOUT = 1.5V, limiting reverse output current to ≤10μA.

Key Specifications

Pinout & Package

LT3021EDH-1.5#PBF uses a 16-lead (5mm × 5mm) plastic DFN package with exposed thermal pad (Pin 17), rated for –40°C to 125°C operating junction temperature. The exposed pad must be soldered to PCB ground and connected to Pins 8 (AGND) and 10 (PGND) for optimal thermal performance (θJA = 35°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with TPS7A2015PDQNR and MCP1826-1502E/DB, the LT3021EDH-1.5#PBF uniquely combines 500mA capability, 160mV dropout, and reverse-battery protection - making it the only option viable for 1.5V rail generation in space-constrained, battery-fed RF devices requiring robust fault tolerance.

Availability

LT3021EDH-1.5#PBF is available at Aetrix Electronics and suitable for cellular handset power management, wireless modem core supplies, pager logic rails, and battery-powered sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for LT3021EDH-1.5#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LT3021 product line was designed specifically for ultra-low-voltage, high-current portable applications - emphasizing VLDO operation, reverse-protection, and ceramic-capacitor stability to replace inefficient switching solutions in noise-sensitive subsystems.

FAQ

What is the minimum input voltage required for LT3021EDH-1.5#PBF to deliver 500mA output current?

The LT3021EDH-1.5#PBF guarantees 500mA output with a minimum input voltage of 1.10V at temperatures below 0°C and 0.9V above 0°C. At room temperature, it typically regulates 500mA from a 1.655V input (1.5V + 155mV dropout). This ultra-low VIN capability enables direct use with partially discharged single-cell batteries or low-VIN DC/DC outputs.

Does LT3021EDH-1.5#PBF require an external feedback resistor network?

No, the LT3021EDH-1.5#PBF does not require external feedback resistors. It integrates a precision internal resistor divider (20kΩ/130kΩ) to fix the output at 1.5V, referencing the 200mV internal bandgap. This eliminates component count, layout area, and tolerance errors associated with external dividers - simplifying design for fixed-voltage applications.

How does the no-load recovery circuit in LT3021EDH-1.5#PBF improve transient response?

The LT3021EDH-1.5#PBF's no-load recovery circuit activates when VOUT exceeds 1.59V (6% above nominal 1.5V), sinking up to 15mA to rapidly discharge the output capacitor. This prevents millisecond-scale voltage recovery delays after sudden load removal - critical for maintaining stability in burst-mode communication systems where rapid load transitions occur.

Can LT3021EDH-1.5#PBF be used with input voltages below 1.0V?

Yes, the LT3021EDH-1.5#PBF is specified to operate from 0.9V input, and typical performance data shows regulation down to 0.9V at 500mA load above 0°C. However, at sub-1.0V inputs, dropout voltage increases slightly, and full 500mA delivery is only guaranteed above 0.9V per the datasheet's absolute minimum specification - making it one of few LDOs viable for near-dead-battery operation.

What thermal considerations apply to the exposed pad on LT3021EDH-1.5#PBF?

The exposed pad (Pin 17) of the LT3021EDH-1.5#PBF must be soldered to a PCB ground plane and electrically connected to Pins 8 (AGND) and 10 (PGND) to achieve the specified θJC = 3°C/W. Failure to do so degrades thermal performance significantly - increasing junction temperature by up to 40°C under 500mA load and risking thermal shutdown or long-term reliability loss.