LM809M3X-4.63

Supervisors Overview

The LM809M3X-4.63/NOPB is a 3-pin microprocessor reset circuit manufactured by Texas Instruments, originally from the National Semiconductor portfolio. It functions as a voltage supervisor with a fixed threshold of 4.63 V. The device features an active low, push-pull output and provides a reset delay time of 240 ms. It operates within a supply voltage range up to 5.5 V and supports surface-mount installation in an SOT-23-3 package. The component is rated for operation between -40°C and +105°C.

Supervisors Feature Summary

• Provides automatic system reset when monitored voltage drops below the specified threshold
• Features active low push-pull output driver for direct processor interface
• Includes factory-prescribed reset timer delay to ensure stable power-up conditions

Supervisors Applications

• Digital system voltage monitoring
• Microprocessor reset signal generation
• Battery-powered equipment supervision

Supervisors Procurement Notes

Verify the exact suffix (e.g., NOPB) against the datasheet to confirm pinout and electrical specifications. Ensure the manufacturer source aligns with current Texas Instruments production status. Confirm RoHS compliance documentation matches the specific batch requirements for your assembly process.

Supervisors Selection Notes

Select this part when a fixed 4.63 V threshold is required for systems powered near 5 V. Compare the 240 ms delay against processor startup times. Verify that the SOT-23-3 package fits the PCB layout constraints. Check if the active low output polarity matches the target controller's reset input requirement.

Supervisors Part Context

This component belongs to the LM809/LM810 family of 3-pin microprocessor reset circuits. The LM809 variant specifically offers an active low reset output, whereas the LM810 provides an active high output. Both share similar electrical characteristics and packaging options, differing primarily in output logic state.

Supervisors Replacement Considerations

The MAX809SQ308T1G is a documented equivalent from Maxim Integrated offering similar 3-pin supervisor functionality. Verify threshold voltage compatibility and output polarity before substitution.