Micrel, Inc.

MIC841/2

March 2011

7

M9999-030811-B

OUT

0V

0V

OUT

0V

H AND N VERSIONS

L VERSION

Figure 2. Output Response and Hysteresis

Programming the MIC842 Thresholds

The voltage threshold is calculated using:

⎟

⎠

⎞

⎜

⎝

⎛

+

−

2

R

2

R

1

R

V

V

REF

)

LO

(

IN

where:

Figure 3. MIC842 Example Circuit

In order to provide the additional criteria needed to solve

for the resistor values, the resistors can be selected

such that they have a given total value, that is, R1 + R2

reasonable value because it draws minimum current but

has no significant effect on accuracy.

Input Transients

The MIC841/2 is inherently immune to very short

negative-going “glitches.” Very brief transients may

As shown in Figure 4, the narrower the transient, the

deeper the threshold overdrive that will be ignored by the

MIC841/2. The graph represents the typical allowable

transient duration for a given amount of threshold

overdrive that will not generate an output.

Figure 4. Input Transient Response