cat885 Catalyst Semiconductor, cat885 Datasheet - Page 4

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

CAT885
ELECTRICAL CHARACTERISTICS (continued)
OPERATION
The CAT885 is designed to monitor critical supply
voltages
microprocessor systems, providing Supply Voltage
Supervision, Power On Reset control and Manual
Reset Assertion. These features along with excellent
threshold accuracy and low power consumption make
the CAT885 device suitable for a wide variety of
applications needing multi-voltage monitoring.
During normal operation, the CAT885 monitors the
voltage levels of V
V5MON. If the voltage on any of these five inputs falls
below their respective voltage trip points, a reset is
asserted (RST
from operating during a power failure or brownout
condition. This reset signal remains low until the
voltages exceeds the voltage threshold settings for
the reset time delay period t
Doc. No. MD-3028 Rev. A
Reset
Manual Reset
Symbol
C
V
V
t
V
T
t
R
RPD
LOAD
PD
THH
THL
PW
OL
IN
¯¯¯¯ = low) to prevent the microprocessor
in
Reset Output Voltage Low
V
POR Timeout Delay
Load Capacitance on Reset Pin
Parameter
¯¯¯ Input Voltage Low
¯¯¯ Input Voltage High
¯¯¯ Minimum Pulse Width
Internal Pull-Up Resistor
MR
MR
MR
TH
line
to Reset Asserted Delay
DD
, V2MON, V3MON, V4MON, and
driven
PD
.
and
battery
powered
V
V
Conditions
DD
DD
≥ 3.3V, Sinking 2.5mA
< 3.3V, Sinking 1.5mA
4
CAT885 allows users to adjust the minimum voltage
sense level for three of the five monitored voltages.
For example, the user can adjust the voltage input trip
point for V
by connecting an external resistor divider network to
the V
above 600mV. Resistors R
selected by the formula: V
Figure 1. CAT885 Programming Trip Voltage
xMON
pin in order to set the trip point to a voltage
3MON
, V
R
1
4MON
V
DD
Min
V2MON
VxMON
70
1
1
8
R
and V
- 0.6
2
VDD
Characteristics subject to change without notice
TRIP
1
5MON
and R
= 0.6V x (R
Typ.
0.05
0.05
120
6
5
CAT885
inputs. This is done
© Catalyst Semiconductor, Inc.
2
Max
0.40
0.40
in Figure 1 are
240
GND
0.8
16
1
+ R
Units
2
ms
) / R
kΩ
pF
µs
µs
V
V
V
V
2
.