MIC834

Micrel

MIC834

4

September 2001

Functional Description

The MIC834 monitors the input voltage and detects when it

is higher than a programmed level (plus V

tion asserts the active-high output. An external pull-up resis-

tor is used to produce a logic-one output. When the input

voltage falls below the programmed threshold (V

the output stage is on.

Voltage Low Output

The voltage-low output (OUT) is an active-high, open-drain

output which sinks current when the MIC834 detects a low

input voltage.

Block Diagram

GND

OUT

1.24V

Bandgap

Reference

High-Voltage

Detect

INP

MIC834

4

2

1

5

VDD

Trip Points

Input voltage is monitored by a comparator via a voltage

divider network. The divided voltage is compared to an

internal reference voltage. When the voltage at the input pin

INP exceeds the internal reference voltage (plus V

output is pulled high by an external resistor.

V

threshold voltage for positive-going inputs. Decreasing in-

puts trip at the user-programmed threshold voltage.

The tolerance of the switching threshold on the falling edge

is equal to the tolerance of just the voltage reference. The

tolerance of the switching threshold on the rising edge is

equal to the tolerance of the voltage reference

plus the

tolerance of the hysteresis voltage.