3.3V 250mA Linear Voltage Regulator - L4931-3.3 TO-92

A low-dropout (LDO) 3.3 V linear voltage regulator based on the ST L4931 in a TO-92 package. With just 0.4 V dropout, it delivers a clean, regulated 3.3 V output from input voltages as low as 3.7 V — well suited for stepping down 5 V supplies or single-cell lithium batteries.

Built-in current limiting and thermal shutdown make the L4931 robust and reliable. The low 1 mA quiescent current (rising to ~5 mA at full load) keeps it efficient for portable and battery-powered projects.

Key Features

• Very Low Dropout – Only 0.4 V (vs 2 V for 78XX series regulators)
• 250 mA Output – Up to 250 mA peak current
• 3.3 V ±2% Regulation – Clean, stable output voltage
• Wide Input Range – 3.7–20 V DC input
• Built-In Protection – Current limiting and thermal shutdown
• Low Quiescent Current – 1 mA typical, ideal for battery use
• TO-92 Package – Compact through-hole form factor

Specifications

• Output Voltage – 3.3 V ±2%
• Max Output Current – 250 mA
• Dropout Voltage – 0.4 V
• Input Voltage – 3.7–20 V
• Quiescent Current – 1 mA (up to 5 mA at full load)
• Thermal Resistance – 200 °C/W junction-to-air (TO-92)
• Max Power Dissipation – ~0.6 W without heatsink

Ideal For

• Stepping 5 V supplies down to 3.3 V for sensors and modules
• Powering 3.3 V devices from lithium polymer/ion batteries
• Battery-powered and portable electronics
• Breadboard prototyping with 3.3 V logic

Package Contents

• 1× L4931-3.3 Voltage Regulator (TO-92)