L4938E

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

The L4938E is a monolithic dual voltage regulator designed for microcomputer systems, particularly in automotive applications. It features two low dropout outputs: Output 1 provides a fixed 5V at up to 100mA, while Output 2 offers 400mA capability with an internally fixed 5V or adjustable voltage via external divider. The device includes power-on reset and input voltage sense functions. Operating DC supply voltage ranges from 5V to 28V, with transient tolerance up to 40V. Quiescent current is extremely low at 65μA, rising to less than 90μA in standby mode.

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

• Dual output architecture providing high precision standby regulation and higher current capability for main system loads
• Integrated power-on reset circuit with programmable threshold and delay timing capabilities
• Input voltage sense comparator for supervising supply levels and generating low voltage warnings
• Robust input protection on enable and sense pins against negative transients down to -5V

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

• Microprocessor power supply systems in automotive environments
• Standby voltage regulation for control units requiring low quiescent current
• Main system power distribution requiring adjustable secondary voltage rails
• Circuits requiring integrated input voltage supervision and reset generation

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

Verify component obsolescence status before procurement as the L4938E is listed as obsolete. Confirm package availability matches design requirements, specifically DIP, SO, or PowerSO formats. Ensure replacement components are sourced from authorized distributors to guarantee authenticity. Review datasheet revisions for any updates to electrical characteristics or pin configurations prior to finalizing orders.

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

Select this component when designing systems requiring simultaneous standby and active voltage regulation with minimal power consumption. Consider the adjustable nature of Output 2 if specific voltage levels other than 5V are needed. Evaluate thermal management needs based on the junction-to-ambient resistance values provided for the chosen package type. Ensure input voltage transients remain within the specified limits or implement external protection circuits.

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

The L4938E belongs to the L4938 family of advanced voltage regulators manufactured by STMicroelectronics. This series is engineered to meet the stringent demands of automotive electronics, offering reliability under varying temperature conditions. The device integrates multiple functions into a single chip to reduce board space and simplify power management designs for embedded microcontroller applications.

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

NCV47411PAAJR2G is documented as a similar substitute part number.