LP4951CMX/NAK2

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

The LP4951CMX/NAK2 is an adjustable micropower voltage regulator from Texas Instruments, housed in an 8-lead SOIC surface-mount package. It provides a maximum output current of 100 mA with a typical quiescent current of 75 μA and a dropout voltage of 380 mV at full load. The device features an error flag output to warn of low output voltage and a logic-controlled shutdown input for power management. Output voltage is programmable from 1.24 V to 29 V using external resistors or pin-strapped for 5 V.

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

• Features an error flag comparator output that signals when the regulated voltage drops out of regulation due to low input voltage or thermal limiting.
• Includes a logic-compatible shutdown input that allows the regulator to be switched on and off to conserve power.
• Offers high accuracy with tight initial tolerance and extremely low temperature coefficient, suitable for use as a low-power voltage reference.
• Requires only a 1 μF capacitor for stability, supporting operation with minimal external components.

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

• Battery-powered systems requiring extended battery life through low quiescent current consumption.
• Applications needing a warning signal for falling battery levels or system faults via the error flag output.
• Systems utilizing CMOS RAM keep-alive circuits where stable regulation at zero load is required.
• Portable electronics requiring a compact, adjustable voltage source with logic-controlled power switching.

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

Verify the specific suffix 'NAK2' against official Texas Instruments documentation to confirm exact packaging, lead finish, and environmental compliance details. Ensure the component matches the standard LP4951CMX/NOPB specifications if the suffix denotes a specific tape-and-reel configuration. Confirm RoHS status and moisture sensitivity level ratings prior to procurement to ensure compatibility with assembly processes.

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

Select this component for designs prioritizing low standby current and precise voltage regulation over a wide input range. The 8-pin SOIC package is suitable for space-constrained surface-mount applications. Consider the error flag feature if system monitoring for undervoltage conditions is necessary. Ensure the output capacitance meets stability requirements, particularly for lower output voltages or higher load currents.

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

The LP4951C belongs to the LP4950C/LP4951C family of micropower voltage regulators designed by Texas Instruments. While the LP4950C is available in a 3-pin TO-92 package, the LP4951C adds system-level functions like shutdown control and error detection in an 8-lead SOIC package. This family is engineered for battery-operated devices, offering performance comparable to older 5V regulators but with significantly reduced power consumption.

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

LP4951CM/NOPB

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

How does the error flag output function?

The error flag produces a logic low output whenever the regulator's output falls out of regulation by more than approximately 5%. This condition can be caused by low input voltage, current limiting, or thermal limiting.

What are the stability requirements for the output capacitor?

A 1.0 μF (or greater) capacitor is required between the output and ground for stability at output voltages of 5 V or more. For lower output voltages or specific load conditions, larger capacitance values such as 3.3 μF may be required to maintain stability.

Can the LP4951C operate with no load?

Yes, unlike many other regulators, the LP4951C remains stable and in regulation with no load in addition to the internal voltage divider, making it suitable for applications like CMOS RAM keep-alive.