LM809M3X-4.00/NOPB

Supervisors Overview

The LM809M3X-4.00/NOPB is a voltage supervisory circuit manufactured by Texas Instruments, originally part of the National Semiconductor portfolio. It operates within a supply voltage range up to 5.5 V and features a fixed threshold voltage of 4.00 V for monitoring system power rails. The device provides an active low, push-pull reset output with a typical reset delay time of 240 ms. It is housed in a SOT-23-3 surface-mount package and supports operation across a temperature range from -40°C to +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-set reset delay timer to ensure stable power-up conditions

Supervisors Applications

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

Supervisors Procurement Notes

Verify that the 'NOPB' suffix confirms lead-free and RoHS compliance as per manufacturer specifications. Confirm the 'X' designation in the part number aligns with current packaging or marking updates issued by Texas Instruments. Ensure the specific 4.00 V threshold matches the design requirement, as this variant differs from other threshold options in the LM809 family.

Supervisors Selection Notes

Select this component when a fixed 4.00 V threshold is required for systems operating at or below 5.5 V. The SOT-23-3 package is suitable for space-constrained designs. Consider the 240 ms reset delay duration to ensure compatibility with the target microcontroller's startup timing requirements. Verify that the active low output polarity matches the logic input of the controlled device.

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 counterpart provides an active high output. Both share similar electrical characteristics and are designed for cost-effective system monitoring without requiring external components.

Supervisors FAQ

Does the LM809M3X-4.00/NOPB include a manual reset input?

No, this specific device does not feature a manual reset pin; it relies solely on voltage threshold detection.

What is the maximum supply voltage for this supervisor?

The maximum supply voltage rating is 5.5 V.