SUPPLY VOLTAGE
MONITOR
ISSUE 2- JANUARY 2003
DEVICE DESCRIPTION
The ZSH330 is a three terminal under voltage
monitor circuit for use in microprocessor
systems. The threshold voltage of the device
has been set to 3.1 volts making it ideal for
3.3 volt circuits.
Included in the device is a precise voltage
reference and a comparator with built in
hysteresis to prevent erratic operation. The
ZSH330 features an open collector output
capable of sourcing at least l0mA which only
requires a single external resistor to
interface to following circuits.
Operation of the device is guaranteed from
one volt upwards, from this level to the
device threshold voltage the output is held
high providing a power on reset function.
Should the supply voltage, once established,
at any time drop below the threshold level
then the output again will pull high.
The device is available in a TO92 package for
through hole applications as well as SOT223
for surface mount requirements.
ZSH330
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
SOT223 and TO92 packages
Power on reset generator
Automatic reset generation
Low standby current
Guaranteed operation from 1 volt
Wide supply voltage range
Internal clamp diode to discharge delay
capacitor
3.1 volt threshold for 3.3 volt logic
20mV hysteresis prevents erratic operation
APPLICATIONS
Microprocessor systems
Computers
Computer peripherals
Instrumentation
Automotive
Battery powered equipment
SCHEMATIC DIAGRAM
Vcc
Out
Gnd
4-329
ZSH330
ABSOLUTE MAXIMUM RATING
Input Supply Voltage
Offstate Output Voltage
Onstate Output
Source Current(
Note 1
)
Clamp Diode
Forward Current(
Note 1
)
Operating Junction
Temperature
Operating Temperature
Storage Temperature
-1 to 10V
10V
Internally limited
100mA
150°C
-40 to 85°C
-55 to 150°C
Power Dissipation
TO92
SOT223
780mW
2W(
Note 2
)
TEST CONDITIONS
(T
amb
=25°C for typical values, T
amb
=-40 to 85°C for min/max values (Note3))
COMPARATOR
PARAMETER
Threshold Voltage
Low state output (V
cc
increasing)
Threshold Voltage
High state output (V
cc
decreasing)
Hysteresis
SYMBOL
V
IL
V
IH
V
H
MIN
TYP.
MAX.
UNITS
V
V
V
3.01
3.01
0.01
3.09
3.07
0.02
3.15
3.15
0.05
OUPUT
PARAMETER
Output source saturation:
(V
cc
=2.7V, I
source
=8.0mA)
(V
cc
=2.7V, I
source
=2.0mA)
(V
cc
=1.0V, I
source
=2µA)
Onstate output source current
(V
cc
=2.7V, Output=0V)
Offstate output leakage current
(V
cc
=3.3V, Output=0V)
Clamp diode forward voltage (I
f
=10mA)
Propagation delay
(V
in
3.3V to 2.7V, R
l
=10k, T
amb
=25°C)
I
source
I
oh
V
f
T
d
0.6
10
21
0.02
1.2
1.4
SYMBOL
V
OH
V
CC
-1.3
V
CC
-1.2
V
CC
-0.4
50
0.5
1.5
V
V
V
mA
µA
V
µs
MIN
TYP.
MAX.
UNITS
TOTAL DEVICE
PARAMETER
Operating input voltage range
Quiescent input current (V
cc
=3.3V)
SYMBOL
V
cc
I
q
MIN
TYP.
MAX.
UNITS
V
1.0 to 6.5
130
180
µA
Note:
1. Maximum package power dissipation must be observed.
2. Maximum power dissipation for the SOT223 package is calculated assuming that the device
is mounted on a PCB measuring 2 inches square.
3. Low duty cycle pulse techniques are used during test to maintain junction temperatures as
close to ambient as possible.
4-330
ZSH330
TYPICAL CHARACTERISTICS
500
400
5.0
4.0
Input Current (µA)
Output Voltage (V)
4
6
8
10
300
200
100
0
0
2
3.0
2.0
85°C
25°C
-40°C
1.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
Input Voltage (V)
Input Voltage (V)
Input Current v Input Voltage
Output Voltage v Input Voltage
Rl=10k
Vin(V)
Vout(V)
2.0
Source Current (mA)
30
20
10
0
0.8
0.6
0.4
0.2
0.0
0.0
0.4
0.8
1.2
1.6
-40°C
25°C
85°C
85°C
25°C
-40°C
3.3
2.7
2.0
4.0
2.0
0.0
0
1
2
3
4
Output Saturation Voltage (V)
Time (µs)
Output Saturation Voltage v
Source Current
100
3.10
3.09
3.08
Reset Delay Time
Forward Current (mA)
60
40
20
0
0.0
85°C
25°C
-40°C
Threshold Voltage (V)
80
Upper
Threshold
3.07
3.06
Lower
Threshold
0.4
0.8
1.2
1.6
3.05
-40 -20
0
20
40
60
80
100
Forward Voltage (V)
Temperature (°C)
Clamp Diode Forward Current v Voltage
Threshold Voltage v Temperature
4-331
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