DS1831C/D/E

4 of 14

PUSHBUTTON RESET SEQUENCING Figure 2

*NOTE:

Ω resistor in the push-button input and

therefore does not require a pull-up resistor (an addition pull up can be used to accelerate responses.) If

an external pull-up is used in this example it must be connected to the 3.3 volt power supply.

OPERATION - PUSHBUTTON RESET

The DS1831 provides 3 pushbutton inputs for manual reset of the device. Pushbutton inputs for the

3.3 volt reset, 2.5 volt reset, and a master pushbutton reset (DS1831C & DS1831D only) input; provide

multiple options for system control. The 3.3 volt pushbutton reset and 2.5 volt pushbutton resets provide

a simple manual reset for the associated reset output; while the master pushbutton reset forces all resets

and NMI outputs active low.

The 2.5 volt reset pushbutton input and the 3.3 volt reset pushbutton input provide manual reset control

for each associated reset output. When the output associated with a pushbutton input is not active, a

pushbutton is held low the reset will be forced active and will remain active for a reset cycle after the

pushbutton is released. See figure 2 for an application example that allows a user to sequence the reset

outputs.

in tolerance and at least 1 output is active.

A master pushbutton reset is generated by pulling the

MPBRST

pin low for at least 20 µs.

When the pushbutton is held low all outputs are forced active and

will remain active for a reset or NMI time delay after the pushbutton is released. The Master Pushbutton

input is pulled high through an internal 100 k

Ω pull up resistor and debounced via internal circuitry. See

figure 3 for an application example. Figures 4 and 5 for the timing diagram.

The 2.5 volt and 3.3 volt pushbutton reset inputs are pulled high through an internal 100 k

Ω pull up

resistor to the voltage input, which is associated with that pushbutton. The master pushbutton is pulled to

*Caution should be exercised to avoid pulling the pushbutton inputs above associated supply inputs.

Generally all pushbutton inputs should be driven low with open drain inputs.

GND

DS1831C

2.5V Supply

3.3V Supply

1

2

3

4

5

16

15

14

13

12

*