LDO Voltage Regulator Texas Instruments LM1084 IT3.3 — Fixed 3.3V, Low-Dropout, TO-220

The Texas Instruments LM1084 IT3.3 is a linear low-dropout (LDO) voltage regulator providing a fixed 3.3 V output in a TO-220 package. It is designed to deliver a stable 3.3 V rail for digital circuits, microcontrollers and embedded systems where a compact, board-level regulator with low dropout is required. The device offers a straightforward solution for powering 3.3 V subsystems during prototyping and in production PCBs, combining thermal capability of the TO-220 package with the predictable behaviour of a fixed-output LDO.

Advantages

The LM1084 IT3.3 offers low dropout voltage for improved headroom in applications with limited input-output differential, reliable fixed 3.3 V regulation for consistent logic-level performance, and the thermal dissipation benefits of a TO-220 package for higher load currents. Its simple external component requirements and stable output under typical load conditions make it suitable for compact power-supply layouts and board-level replacements of switching converters where low noise is desired.

Suitable for

• Powering microcontrollers and digital logic that require a 3.3 V supply
• Embedded systems and single-board computers during prototyping and production
• Board-level voltage regulation for sensors, RF front-end modules and low-noise analog circuits
• Repair and upgrade of existing 3.3 V rails on PCBs

Key specifications

• Output voltage: fixed 3.3 V
• Regulator type: linear low-dropout (LDO)
• Package: through-hole TO-220 for improved thermal performance
• Typical use: single-supply board-level regulation for digital and analog loads
• Low dropout characteristic to minimize required input voltage above 3.3 V

How to use

Install the LM1084 in a TO-220 footprint on the PCB or mount it to a suitable heatsink when higher load currents or extended duty are expected. Provide the recommended input and output capacitors close to the device pins to ensure regulator stability and reduce output noise; follow the capacitor types and values indicated in the device datasheet. Connect the unregulated input voltage to the input pin, ground to the common pin, and take the regulated 3.3 V from the output pin. Observe the maximum input voltage and thermal dissipation limits to avoid overheating.

Recommendations

Use low ESR capacitors on the output as specified in the datasheet and place them close to the regulator pins. For loads with significant current draw, attach the TO-220 tab to a heatsink or a thermally capable PCB area and ensure adequate ventilation. Verify input voltage margin to maintain the required dropout headroom under worst-case conditions.