L4938ND

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

The L4938ND is a monolithic dual voltage regulator in a 20-SO package. It provides a precision 5V standby output with 50mA current capability and a second adjustable output ranging from 5V to 20V with 500mA capability. The device features very low dropout voltages (max 0.4V/0.6V), operating transient supply voltage up to 40V, and a power-on reset circuit. Quiescent current is less than 250μA in standby mode.

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

• Dual output architecture with precision 5V standby regulator and programmable high-current secondary output
• Integrated power-on reset circuit with externally defined delay pulse and early warning sense comparator
• Robust automotive-grade design supporting 40V transient input voltage without functional interruption
• Includes thermal shutdown and short-circuit protections for system reliability

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

• Microcomputer controlled systems
• Automotive applications
• Systems requiring two stabilized voltages

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

Verify component obsolescence status before procurement as the L4938ND is marked obsolete. Confirm that replacement components meet all electrical specifications including dropout voltage, current limits, and package dimensions. Ensure availability of suitable substitutes that maintain compatibility with existing board layouts and regulatory requirements.

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

Select this component when designing systems requiring a precise 5V reference alongside a higher current adjustable rail. The SO-20 package suits applications needing multiple control pins for enable, reset, and sense functions. Consider the low quiescent current benefit for battery-powered or efficiency-sensitive designs where standby modes are critical.

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

The L4938ND belongs to the L4938 family of dual multifunction voltage regulators by STMicroelectronics. It utilizes a modular approach to provide isolated collector vertical PNP transistor regulation for the standby output. This family is specifically engineered to meet the stringent demands of microprocessor power supplies in harsh environments.

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

NCV47411PAAJR2G onsemi

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

How is the Output 2 voltage programmed?

Output 2 voltage is settable from 5V to 20V using an external resistor divider connected to the ADJ pin.

What determines the reset pulse delay time?

The reset pulse delay time is defined by the charge time of an external capacitor connected to the CT pin.