LM809

RESET

RESET

INPUT

GND

GND

V

CC

V

CC

V

CC

µP

10

LM809, LM810

SNVS052E – SEPTEMBER 1999 – REVISED APRIL 2016

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Copyright © 1999–2016, Texas Instruments Incorporated

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM809 and LM810 are a supervisor circuit for microprocessor and digital systems. With a low supply current

of only 15 µA, the LM809 and LM810 are ideal for use in portable equipment.

8.2 Typical Application

Figure 10. Microprocessor RESET Circuit

8.2.1 Design Requirements

For this design example, use the parameters listed in Table 2 as the input parameters.

Table 2. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input supply voltage range

1 V to 5.5 V

Reset output voltage (high)

Input supply

Reset output voltage (low)

0 V

8.2.2 Detailed Design Procedure

For the typical application circuit, all that is required is the LM809 or LM810 IC, but TI recommends an input

capacitor to help with input voltage transients. A typical input capacitor value is 0.1 uF and must be rated for the

highest expected input voltage.