CAT853, CAT863
CAT859, CAT869
3-Pin Microprocessor Power Supply
Supervisors
FEATURES
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DESCRIPTION
The CAT853, CAT863, CAT859, and CAT869 are
supervisory circuits that monitor power supplies in digital
systems.
These devices generate a reset signal, which is asserted
while the power supply voltage is below a preset threshold
level and for at least 140 ms after the power supply level
has risen above that level. Industry standard threshold
levels are offered to support +3.3V or 5.0V systems.
The CAT859 and CAT869 feature a RESET push-pull
output (active low) for the two pinout options.
The CAT853 and CAT863 feature an open drain RESET
output (active low). Both require a pull-up resistor on
the RESET output.
Fast transients on the power supply are ignored and
the output is guaranteed to be in the correct state at V
cc
levels as low as 1.0V.
Precision monitoring of +3.3V (-5%, -10%), 5V
(-10% Power Supplies)
Active low reset output
Reset valid down to V
CC
= 1.0V
6μA power supply current
Power supply transient immunity
Industrial temperature range: -40ºC to +85ºC
RoHS-compliant SOT-23 package
APPLICATIONS
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Computers
Servers
Laptops
Cable modems
Wireless communications
Embedded control systems
White goods
Power meters
Intelligent instruments
PDAs and handheld equipment
For Ordering Information details, see page 8.
PIN CONFIGURATION
3-Lead SOT23
RESET
1
RESET
THRESHOLD SUFFIX SELECTOR
3-Lead SOT23
1
Nominal Threshold
Voltage
3.08V
GND
Threshold Suffix
Designation
T
S
M
CAT853
CAT859
GND
2
3
V
CC
V
CC
2
CAT863
CAT869
3
2.93V
4.38V
PIN DESCRIPTIONS
Name
Description
RESET Active low reset. RESET is asserted if V
CC
falls below the reset threshold and remains low for at least
140ms after V
CC
rises above the reset threshold.
GND
V
CC
Ground
Power supply voltage that is monitored.
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. 3026, Rev. B
CAT853, CAT863, CAT859, CAT869
ABSOLUTE MAXIMUM RATINGS
(1)
Any pin with respect to ground
Input Current, V
CC
Output Current, RESET
Rate of Rise, V
CC
Continuous Power Dissipation
Derate 4mW/ºC above 70ºC (SOT23)
Operating Temperature Range
Storage Temperature Range
Lead Soldering Temperature (10 sec)
Note:
(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 device 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.
-0.3V to +6.0V
20mA
20mA
100V/μs
320 mW
-40ºC to +85ºC
-65ºC to +105ºC
300ºC
ELECTRICAL CHARACTERISTICS
V
CC
= Full range, T
A
= -40ºC to +85ºC unless otherwise noted. Typical values at T
A
= +25ºC and V
CC
= 3.3V for the
T/S versions, V
CC
= 5V for the M version.
Parameter
V
CC
Range
Supply Current
Reset
Threshold
Voltage
I
CC
V
TH
Symbol
Conditions
T
A
= 0ºC to +70ºC
T
A
= -40ºC to +85ºC
T
A
= -40ºC to +85ºC
T Threshold
S Threshold
M Threshold
Reset
Threshold
Tempco
V
CC
to Reset
Delay
Reset Active
Timeout Period
RESET Output
Voltage Low
RESET Output
Voltage High
V
OL
V
OH
V
CC
= V
TH
to (V
TH
- 100 mV)
T
A
= -40ºC to +85ºC
V
CC
= V
TH
min, I
SINK
= 1.2mA
V
CC
> 1.0V, I
SINK
= 50μA
V
CC
= V
TH
max, I
SOURCE
= -500μA
(for CAT859/869 only)
0.8 V
CC
140
V
CC
< 3.6V, S/T
T
A
= +25ºC
T
A
= -40ºC to +85ºC
T
A
= +25ºC
T
A
= -40ºC to +85ºC
T
A
= +25ºC
T
A
= -40ºC to +85ºC
3.04
3.00
2.89
2.85
4.31
4.25
30
4.38
2.93
Min
1.0
1.2
6
3.08
Typ
(1)
Max
5.5
5.5
15
3.11
3.15
2.96
3.00
4.45
4.50
ppm/ºC
μA
V
Units
V
20
240
460
0.4
0.3
μs
ms
V
V
Note:
(1) Production testing done at T
A
= +25ºC; limits over temperature guaranteed by design only.
Doc. No. 3026, Rev. B
2
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT853, CAT863, CAT859, CAT869
TYPICAL OPERATING CHARACTERISTICS
V
CC
= Full range, T
A
= -40ºC to +85ºC unless otherwise noted. Typical values at T
A
= +25ºC, V
CC
=3.3V for T/S versions,
and V
CC
= 5V for the M version.
POWER-UP RESET TIMEOUT
VS. TEMPERATURE
POWER-UP RESET TIMEOUT (mS)
260
SUPPLY CURRENT VS. TEMPERATURE
(NO LOAD)
12
SUPPLY CURRENT (μA)
240
220
200
VCC=5V
10
8
6
4
2
0
V
CC
=5.5V
V
CC
=3.6V
VCC=2.5V
180
160
-50
0
50
100
150
-50
0
50
100
150
TEMPERATURE (°C)
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (μS)
POWER-DOWN RESET DELAY
VS. TEMPERATURE
NORMALIZED THRESHOLD
14
12
10
8
6
4
2
0
-50
0
50
100
150
1.0002
1
0.9998
0.9996
0.9994
0.9992
0.999
0.9988
NORMALIZED RESET THRESHOLD
VS. TEMPERATURE
0
20
40
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc No. 3026, Rev. B
CAT853, CAT863, CAT859, CAT869
DETAILED DESCRIPTIONS
RESET TIMING
The reset signal is asserted low for the CAT853, CAT863,
CAT859, and CAT869 when the power supply voltage falls
below the threshold trip voltage and remains asserted
for at least 140ms after the power supply voltage has
risen above the threshold.
Power 5V
Supply
Voltage 0V
Threshold
Voltage
Reset Timeout Period
140ms
minimum
RESET
5V
0V
Figure 1. Reset Timing Diagram
V
CC
TRANSIENT RESPONSE
The CAT853, CAT863, CAT859, and CAT869 protect
μPs
against brownout failure. Short duration transients
of 4μsec or less and 100mV amplitude typically do not
cause a false RESET.
Figure 2 shows the maximum pulse duration of negative-
going V
CC
transients that do not cause a reset condition.
As the amplitude of the transient goes further below
the threshold (increasing V
TH
- V
CC
), the maximum
pulse duration decreases. In this test, the V
CC
starts
from an initial voltage of 0.5V above the threshold and
drops below it by the amplitude of the overdrive voltage
(V
TH
- V
CC
).
Figure 2. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive
Doc. No. 3026, Rev. B
4
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT853, CAT863, CAT859, CAT869
VALID RESET WITH V
CC
UNDER 1.0V
To ensure that the CAT859 and CAT869 RESET pin
is in a known state when V
CC
is under 1.0V, a >10kΩ
pull-down resistor between RESET pin and GND is
recommended.
Power
Supply
V
CC
CAT8x9
RESET
GND
Figure 3. RESET Valid with V
CC
Under 1.0V
BI-DIRECTIONAL RESET PIN INTERFACING
The CAT859 and CAT869 can interface with
μP/μC
bi-directional reset pins by connecting a 4.7kΩ resistor
in series with the CAT859 and CAT869 reset output and
the
μP/μC
bi-directional reset pin.
BUF
Power
Supply
V
CC
V
CC
Buffered
RESET
CAT8x9
RESET
GND
RESET
INPUT
Bi-directional
I/O Pin
µP
(For example:
68HC11)
GND
Figure 4. Bi-directional Reset Pin Interfacing
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc No. 3026, Rev. B
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