L4938NPD

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

The L4938NPD is a monolithic dual voltage regulator in a PowerSO20 package, designed for microcomputer systems. It provides a precision 5V standby output with 50mA capability and a second output capable of 500mA, trackable to the standby rail or adjustable from 5V to 20V via an external divider. The device features very low dropout characteristics (max 0.4V/0.6V), operating transient supply voltage up to 40V, and integrated power-on reset with delay defined by an external capacitor. Additional functions include input voltage sensing and thermal shutdown.

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

• Dual low-dropout regulators with independent enable control for standby mode optimization
• Integrated power-on reset circuit with externally programmable delay timing
• Input voltage sense comparator for undervoltage warning and system supervision
• Robust protection mechanisms including thermal shutdown and short-circuit current limiting

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

• Microprocessor power supplies in automotive environments
• Systems requiring precise standby voltage regulation
• Applications needing early warning for supply undervoltage conditions

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

Verify component authenticity through official STMicroelectronics channels or authorized distributors. Confirm the specific PowerSO20 package marking matches the L4938NPD designation. Review the datasheet for absolute maximum ratings to ensure design compliance. Note that this product may be classified as obsolete; check current availability status before finalizing procurement plans.

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

Select the L4938NPD when a compact dual-output solution with high transient tolerance is required. The PowerSO20 package offers efficient thermal dissipation for the 500mA output stage. Ensure the application utilizes the ADJ pin correctly to configure Output 2 between fixed tracking and variable voltage modes. Verify that the external components meet the specified ESR requirements for stability.

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

This component belongs to the L4938 family of dual multifunction voltage regulators. It shares functional similarities with the L4938N and L4938ND variants, differing primarily in the physical packaging configuration. The family is engineered specifically for automotive-grade reliability and microcontroller power management tasks.

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

Direct substitutes include the L4938N (PowerDIP) and L4938ND (SO20). These alternatives provide identical electrical specifications but require different footprint layouts due to distinct package geometries. Verify mechanical clearance and soldering compatibility before transitioning between package types.

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

How is the Output 2 voltage configured?

Output 2 can be set to track the 5V standby output by connecting the ADJ pin directly to VO2. Alternatively, it can be adjusted between 5V and 20V using an external resistor divider connected to the ADJ pin.

What determines the reset pulse delay time?

The reset pulse delay is defined by the charge time of an external capacitor connected to the CT pin. The relationship is determined by the internal 2μA current source charging this capacitor.