LT1129IS8-5#TRPBF

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The LT1129IS8-5#TRPBF is a micropower low dropout regulator with shutdown, manufactured by Analog Devices Inc. It provides a fixed 5V output at up to 700mA. Key electrical parameters include a maximum dropout voltage of 0.4V at full load, a quiescent current of 50μA during operation, and 16μA in shutdown mode. The device operates within an input voltage range of 5.5V to 30V and supports an extended temperature range from -40°C to 125°C. It features reverse battery protection and thermal limiting.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Micropower operation with controlled quiescent current that does not rise significantly in dropout conditions.
• Integrated shutdown capability allowing for deep sleep modes with minimal current consumption.
• Reverse battery protection enabling safe operation even if the input is connected backwards or grounded while the output is held high.
• Stable with small output capacitors, requiring only 3.3μF for stability compared to older devices needing larger values.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Battery-powered systems requiring low standby current
• Post-regulator for switching power supplies
• 5V to 3.3V logic level translation regulators
• Backup power situations where input may be reversed

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific suffix #TRPBF indicates tape and reel packaging and lead-free finish when ordering. Confirm the IS8 designation corresponds to the 8-lead SOIC package and the I-grade temperature rating (-40°C to 125°C). Ensure the -5 suffix matches the required fixed 5V output voltage. Cross-reference the manufacturer's latest datasheet for any potential pinout or marking changes.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component when a fixed 5V output is required with high efficiency under light loads due to low quiescent current. It is suitable for designs needing reverse input protection without external diodes. Consider the thermal resistance of the SOIC-8 package for heat dissipation at higher currents. Verify that the minimum input voltage requirement of 5.5V aligns with the system's supply rails.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

This part belongs to the LT1129 family of micropower LDOs, which also includes adjustable (LT1129) and 3.3V fixed (LT1129-3.3) variants. The family shares core features like low dropout voltage and shutdown functionality but differs in output configuration and package options such as TO-220, DD-Pak, and SOT-223. The IS8 variant specifically utilizes surface-mount technology for compact PCB layouts.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

LT1129IS8-5#PBF (Tube Packaging)

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

How does the LT1129 handle reverse input voltage?

The device acts as if there is a diode in series with its input, preventing reverse current flow into the regulator and protecting both itself and the load when the input is reversed or grounded.

What is the minimum output capacitance required for stability?

The LT1129 is stable with a minimum output capacitance of 3.3μF, typically a solid tantalum capacitor, which is significantly lower than many older LDO requirements.