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CAT885
Five-Channel Power Supply Supervisors
FEATURES
Five-channel supply voltage detection
2 V
DD
inputs allow monitoring of
+5.0V, +3.3V, +3.0V, +2.5V or +1.8V supplies
3 adjustable voltage inputs allow monitoring
supplies > 0.6V
70ms minimum reset delay
Manual reset capability
Reset signals valid down to V
DD
= 1V
Accurate ± < 2% voltage threshold
Power-supply transients suppressed
Low 2µA maximum supply current at 5V
RoHS-compliant MSOP package
DESCRIPTION
The CAT885 is a five-channel power supply
supervisory circuit with high reset thereshold accuracy
and very low power consumption. The device features
an open-drain output, active-low function with manual
reset to perform basic system reset and monitoring
functions for a wide range of electronic products. The
CAT885 monitors five system voltages by maintaining a
reset output active until all the power supply voltages
exceed the specified trip values. The device then
maintains the reset output in an active condition until
the internal timer times out, which allows the system
power supplies to stabilize.
Two of the five voltage detectors are factory set for
standard supplies, while the threshold voltages of the
third, fourth, and fifth voltage monitors can be adjusted
for specific system design requirements using external
resistors.
The CAT885 lowers system costs and saves board
space by integrating five channels into a single, small
MSOP 8-lead package.
For Ordering Information details see page 7.
APPLICATIONS
Telecom & datacom systems
Routers & servers
Data storage equipment
Set-top boxes
Multi-voltage systems
PIN CONFIGURATION
MSOP 8-Lead (Z)
(top view)
¯¯¯
MR
V
DD
V
DD2
V
SS
1
2
3
4
CAT885
8 ¯¯¯¯
RST
7 V5MON
6 V4MON
5 V3MON
TYPICAL APPLICATION
V
DD
V
DD2
V3MON
CAT885
V4MON
MR
RST
Reset
Signal
See page 2 for pin functions
V5MON
PB
V
SS
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-3028 Rev. A
CAT885
FUNCTIONAL BLOCK DIAGRAM
V
DD
V
DD
POR
V
REF
V
DD2
V
DD
RST
Reset
Signal
MR
PB
V
REF
V3MON
V4MON
V
REF
V
REF
V5MON
V
SS
V
REF
PIN FUNCTIONS
Pin #
1
2
3
4
5
6
7
8
Pin
¯¯¯
MR
V
DD
V
DD2
V
SS
V3MON
V4MON
V5MON
¯¯¯¯
RST
Function
Active-low manual reset Input with internal pull-up resistor
Chip supply, first preset under-voltage detector input
Second preset under-voltage detector input
Ground
Adjustable third under-voltage detector input
Adjustable fourth under-voltage detector input
Adjustable fifth under-voltage detector input
Active-low open drain reset output, use external resistor
Doc. No. MD-3028 Rev. A
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT885
ABSOLUTE MAXIMUM RATINGS
(1)
Parameters
Temperature under Bias
Voltage on any Pin with Respect to V
SS
DC Output Current
Thermal Resistance
Ө
JA
for MSOP Package
(2)
Ratings
-40 to +125
-1.0 to +7.0
5
145
Units
ºC
V
mA
°C/W
RECOMMENDED OPERATING CONDITIONS
Parameters
Operating Temperature Range (Industrial)
Storage Temperature
Lead Soldering Temperature (10 seconds)
Ratings
-40 to +85
-65 to +150
+300
Units
ºC
ºC
ºC
ELECTRICAL CHARACTERISTICS
Over the recommended operating conditions unless otherwise specified.
Symbol
V
DD
I
DD1
I
DD2
I
DDX
V
TH1
V
TH1HYST
Parameter
Supply Voltage Range
V
DD
Supply Current
V
DD2
Input Current
V3, V4, V5MON Input Current
Fixed Voltage Trip Point for V
DD
Hysteresis of V
TH1
Conditions
V
DD
= 5.0V
V
DD2
= 3.3V
V3, V4, V5MON = 1.0V
CAT885Lx
CAT885Sx
V
TH1
= 4.63V
V
TH1
= 2.87V
CAT885xT
CAT885xS
CAT885xZ
CAT885xA
V
TH2
= 3.08V
V
TH2
= 2.95V
V
TH2
= 2.33V
V
TH2
= 1.68V
V
TH
for V3, V4, V5MON
4.55
2.81
Min
1.5
Typ.
2
0.5
15
4.63
2.87
50
30
3.08
2.95
2.33
1.68
40
30
25
20
0.598
3
Max
5.5
9
3
50
4.72
2.92
Units
V
µA
µA
nA
V
V
mV
mV
V
V
V
V
mV
mV
mV
mV
V
mV
Voltage Thresholds
V
TH2
Fixed Voltage Trip Point for V
DD2
3.02
2.90
2.29
1.65
3.13
3.01
2.37
1.71
V
TH2HYST
Hysteresis of V
TH2
V3MON, V4MON, V5MON Adj.
Reset Threshold Voltage
Hysteresis Voltage
V
REF
V
REFHYST
0.585
0.611
Notes:
(1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings
only and functional operation of the devices at these or any other conditions outside of those listed in the operational sections of this
specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device performance and reliability.
(2)
θ
JA
is measured with the component mounted on a high effective thermal conductivity test board in free air.
3
Doc. No. MD-3028 Rev. A
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT885
ELECTRICAL CHARACTERISTICS (continued)
Symbol
Reset
V
OL
t
RPD
t
PD
C
LOAD
Reset Output Voltage Low
V
TH
to Reset Asserted Delay
POR Timeout Delay
Load Capacitance on Reset Pin
V
DD
≥
3.3V, Sinking 2.5mA
V
DD
< 3.3V, Sinking 1.5mA
1
70
0.05
0.05
6
120
5
0.40
0.40
240
V
V
µs
ms
pF
V
V
µs
kΩ
Parameter
Conditions
Min
Typ.
Max
Units
Manual Reset
¯¯¯ Input Voltage Low
V
THL
MR
¯¯¯ Input Voltage High
V
THH
MR
¯¯¯ Minimum Pulse Width
T
PW
MR
R
IN
Internal Pull-Up Resistor
0.8
V
DD
- 0.6
1
8
16
OPERATION
The CAT885 is designed to monitor critical supply
voltages in line driven and battery powered
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
DD
, V2MON, V3MON, V4MON, and
V5MON. If the voltage on any of these five inputs falls
below their respective voltage trip points, a reset is
¯¯¯¯
asserted (RST = low) to prevent the microprocessor
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
PD
.
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
3MON
, V
4MON
and V
5MON
inputs. This is done
by connecting an external resistor divider network to
the V
xMON
pin in order to set the trip point to a voltage
above 600mV. Resistors R
1
and R
2
in Figure 1 are
selected by the formula: V
TRIP
= 0.6V x (R
1
+ R
2
) / R
2
.
VDD
V2MON
CAT885
R
1
VxMON
R
2
GND
Figure 1. CAT885 Programming Trip Voltage
Doc. No. MD-3028 Rev. A
4
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
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