4-Pin, Low-Power

µP Reset Circuits with Manual Reset

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5

GND

MAX6804

RESET

MR

100k

Ω

(a)

GND

MAX6803

RESET

100k

Ω*

(b)

*ASSUMES HIGH-Z RESET INPUT TO THE

µP

MR

1V. For the MAX6804 application where RESET must be

valid down to 0, adding a pulldown resistor between

RESET and GND removes stray leakage currents, hold-

ing RESET low (Figure 2a). The pulldown resistor value

is not critical; 100k

Ω is large enough not to load RESET,

and small enough to pull it low. For the MAX6803, where

Ω pullup resistor

Since the MAX6805 has an open-drain, active-low out-

put, it typically uses a pullup resistor. With this device,

RESET will most likely not maintain an active condition,

but will drift to a non-active level due to the pullup

resistor and the reduced sinking capability of the open-

drain device. Therefore, this device is not recommend-

ed for applications where the RESET pin is required to

1

2

4

3

MR

(RESET)

GND

MAX6803

MAX6804

MAX6805

SOT143

TOP VIEW

RESET

( ) ARE FOR MAX6803

MAX6804

RESET

MR

RESET

GND

PUSHBUTTON

SWITCH

GND

µP

Pin Configuration

Typical Operating Circuit