SUPPLY VOLTAGE
MONITOR
ISSUE 1 – NOVEMBER 1995
DEVICE DESCRIPTION
The ZSM300 is a three terminal under
vo l ta ge mo ni t or ci rc ui t f or use i n
microprocessor systems. The threshold
voltage of the device has been set to 2.63
volts making it ideal for 3 volt circuits.
Included in the device is a precise voltage
reference and a comparator with built in
hysteresis to prevent erratic operation. The
ZSM300 features an open collector output
capable of sinking 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
low 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 low.
The device is available in a TO92 package for
through hole applications as well as SO8 and
SOT223 for surface mount requirements.
ZSM300
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
SO8, 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
2.63 volt threshold for 3 volt logic
20mV hysteresis prevents erratic operation
APPLICATIONS
Microprocessor systems
Computers
Computer peripherals
Instrumentation
Automotive
Battery powered equipment
SCHEMATIC DIAGRAM
4-339
ZSM300
ABSOLUTE MAXIMUM RATING
Input Supply Voltage
Offstate Output Voltage
Onstate Output
Sink 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
SO8
780mW
2W(
Note 2
)
780mW(
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
High state output (V
cc
increasing)
Threshold Voltage
Low state output (V
cc
decreasing)
Hysteresis
SYMBOL
V
IH
V
IL
V
H
MIN
TYP.
MAX.
UNITS
V
V
V
2.56
2.56
0.01
2.64
2.62
0.02
2.7
2.7
0.05
OUPUT
Output sink saturation:
(V
cc
=2.2V, I
sink
=8.0mA)
(V
cc
=2.2V, I
sink
=2.0mA)
(V
cc
=1.0V, I
sink
=0.1mA)
Onstate output sink current
(V
cc
, Output=2.2V)
Offstate output leakage current
(V
cc
, Output=3V)
Clamp diode forward voltage
(I
f
=10mA)
Propagation delay
(V
in
3V to 2.2V, R
l
=10k, T
amb
=25°C)
I
sink
I
oh
V
f
T
d
0.6
10
27
0.02
1.2
2.5
V
OL
0.46
0.15
1.0
0.4
0.25
60
0.5
1.5
V
V
V
mA
µA
V
µs
TOTAL DEVICE
Operating input voltage range
Quiescent input current (V
cc
=3V)
V
cc
I
q
1.0 to 6.5
125
190
V
µA
Note:
1. Maximum package power dissipation must be observed.
2. Maximum power dissipation, for the SOT223 and SO8 packages, 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.
4-340
ZSM300
TYPICAL CHARACTERISTICS
500
5
R =10K
T
A
=25 °C
400
4
Input Current (µA)
85 °C
200
-40 °C 25 °C
100
Output Voltage
300
(V)
3
2
1
0
0
2
4
6
8
10
0
0
1
2
3
4
5
Input Voltage
(V)
Input Voltage
(V)
Input Current vs. Input Voltage
50
V
in
=2.4V
Output Voltage vs. Input Voltage
R
L
=10K
40
V
in
(V)
3.0
2.4
2
4
Sink Current (mA)
30
-40 °C
25 °C
20
85 °C
V
out
(V)
2
10
0
0
0.4
0.8
1.2
1.6
2.0
0
0
1
2
3
4
Output Saturation Voltage (V)
Time (µs)
Output Saturation Voltage vs. Sink Current
100
V
in
=0V
2.65
Reset Delay Time
Upper Threshold
80
2.64
Forward Current (mA)
Threshold Voltage (V)
60
85 °C
40
25 °C
-40 °C
20
2.63
2.62
Lower Threshold
2.61
0
0
0.4
0.8
1.2
1.6
2.0
2.60
-40
-20
0
20
40
60
80
100
Forward Voltage (V)
Temperature (°C)
Clamp Diode Forward Current vs. Voltage
Threshold Voltage vs. Temperature
4-341
PCB Design
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