cat885 Catalyst Semiconductor, cat885 Datasheet - Page 5

• Manufacturer Part Number: cat885
• Description: Five-channel Power Supply Supervisors
• Manufacturer: Catalyst Semiconductor

POWER ON RESET (POR)
Applying power to the CAT885 activates a POR circuit
which activates the reset output (active LOW). At
power-up POR prevents the system microprocessor
from starting to operate with insufficient voltage and
prior to stabilization of the clock oscillator. It ensures
that operation is precluded until internal registers are
properly loaded, FPGA’s have downloaded their
configuration data prior and all system power supplies
are above minimum operating levels and stable. The
reset signal remains active until V
minimum preset voltage level for time period t
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
V
V
V
V
RST
RST
DD2
MON
TH
MR
DD/
0
0
0
0
0
t
V
1V
PD
TH1/2
t
RPD
Figure 3. Auxillary Voltage Monitoring Diagram
Figure 2. Power Supply Monitoring Diagram
t
RPD
DD
rises above the
PD
.
t
PD
5
MANUAL RESET
The manual-reset input (MR
a reset by using a push-button switch or by
electronically driving the input low. The MR
active LOW debounced input. Reset is asserted
anytime the MR
for the minimum MR
output remains asserted low for t
and then is released. Figures 2 and 3 illustrate the
CAT885’s operation and RST
t
PD
¯¯¯ pin is pulled low to less than 100mV
¯¯¯ pulse width or longer. The reset
t
PD
t
RPD
>T
PW
¯¯¯ ) allows the user to trigger
¯¯¯¯ output response times.
PD
, typically 120ms
Doc. No. MD-3028 Rev. A
¯¯¯ input is an
CAT885