LT1121IS8-3.3#TRPBF

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

The LT1121IS8-3.3#TRPBF is a micropower low dropout regulator with shutdown, manufactured by Analog Devices Inc. It provides a fixed 3.3V output at up to 150mA. The device operates within an input voltage range of 4.17V to 36V and maintains a typical dropout voltage of 0.4V at full load. Quiescent current is 30µA during operation and drops to 16µA in shutdown mode. It features reverse battery protection and is stable with output capacitors as small as 0.33µF. The component is housed in an 8-lead SOIC package and supports an operating temperature range from -40°C to +125°C.

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

• Micropower low dropout regulator with integrated shutdown control
• Capable of supplying 150mA output current with minimal quiescent consumption
• Stable with very small output capacitors, including ceramic types
• Provides reverse battery protection without requiring external diodes

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

• Battery-powered systems requiring extended operational life
• Backup power situations where input may be grounded or reversed
• Post-regulation for switching supplies

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

Verify the specific suffix #TRPBF indicates tape and reel packaging when sourcing this component. Confirm that the IS8 designation corresponds to the industrial temperature grade (-40°C to +125°C) and the 8-lead SOIC package type required for your design. Ensure compatibility with your PCB footprint before procurement.

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

Select this part for applications needing a fixed 3.3V rail with low standby current. The shutdown pin allows for system-wide power management. Consider thermal resistance values based on your copper area if high load currents are expected. Verify that the minimum input voltage requirement aligns with your source supply under all conditions.

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

This component belongs to the LT1121 series of micropower regulators. It shares core electrical characteristics with other variants like the LT1121CS8-3.3#TRPBF but differs in temperature rating and packaging style. The series is designed for efficiency in portable electronics and battery-operated devices.

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

LT1121IS8-3.3#PBF (Tube version)

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

What is the minimum recommended output capacitor value?

The device is stable with output capacitors as low as 0.33µF, though 1µF is generally recommended for optimal transient performance.

How does the shutdown pin function?

The shutdown pin is active-low; pulling it low turns off the output and reduces quiescent current to 16µA. It can be driven directly by 5V logic.