SUPPLY VOLTAGE
MONITOR
ISSUE
3
– JULY 2006
DEVICE DESCRIPTION
The ZSM380 is a three terminal under
v o l t a g e m o n i t or c ir c ui t fo r u s e i n
microprocessor systems. The threshold
voltage of the device has been set to 3.8 volts
making it ideal for 5 volt circuits.
Included in the device is a precise voltage
reference and a comparator with built in
hysteresis to prevent erratic operation. The
ZSM380 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 SOT223
for surface mount requirements.
ZSM380
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
3.8 volt threshold for 5 volt logic
20mV hysteresis prevents erratic operation
APPLICATIONS
Microprocessor systems
Computers
Computer peripherals
Instrumentation
Automotive
Battery powered equipment
SCHEMATIC DIAGRAM
4-349
Issue
3
-
July 2006
© Zetex Semiconductors plc 2006
ZSM380
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
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
High state output (V
cc
increasing)
Threshold Voltage
Low state output (V
cc
decreasing)
Hysteresis
SYMBOL
V
IH
V
IL
V
H
3.7
3.7
0.01
MIN
TYP.
MAX.
UNITS
V
V
V
3.81
3.79
0.02
3.9
3.9
0.05
OUPUT
Output sink saturation:
(V
cc
=3.3V, I
sink
=8.0mA)
(V
cc
=3.3V, I
sink
=2.0mA)
(V
cc
=1.0V, I
sink
=0.1mA)
Onstate output sink current
(V
cc
, Output=3.3V)
Offstate output leakage current
(V
cc
, Output=5V)
Clamp diode forward voltage
(I
f
=10mA)
Propagation delay
(V
in
5V to 3.3V, R
l
=10k, T
amb
=25°C)
I
sink
I
oh
V
f
T
d
0.6
10
27
0.02
1.2
3
V
OL
0.46
0.15
1.0
0.4
0.25
60
0.5
1.5
V
V
V
mA
µ
A
V
µ
s
TOTAL DEVICE
Operating input voltage range
Quiescent input current (V
cc
=5V)
V
cc
I
q
1.0 to 6.5
140
200
V
µ
A
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.
4-350
Issue
3
-
July 2006
© Zetex Semiconductors plc 2006
www.zetex.com
ZSM380
TYPICAL CHARACTERISTICS
500
10
R
l
=10K
T
a
=25°C
400
85°C
25°C
8
Input Current (µA)
300
Output Voltage (V)
-40°C
6
200
4
100
2
0
0
2
4
6
8
10
0
0
2
Input Voltage (V)
Input Voltage
(V)
4
6
8
10
Input Current vs. Input Voltage
50
Output Voltage vs. Input Voltage
R
l
=10K
V
in
=3.3V
40
5
V
in
(V)
Sink Current (mA)
30
-40°C
25°C
20
85°C
3.3
4
2
10
V
out
(V)
0
0
0
0.4
0.8
1.2
1.6
2.0
0
2
4
6
Output Saturation Voltage (V)
Time (µs)
Output I(sink) vs. Output V(sat)
50
V
in
=0V
3.82
Reset Delay Time
Upper Threshold
40
3.81
Forward Current (mA)
Threshold Voltage (V)
30
85°C
25°C
-40°C
3.80
20
3.79
Lower Threshold
10
3.78
0
0
0.4
0.8
1.2
1.6
2.0
3.77
-40
-20
0
20
40
60
80
Forward Voltage (V)
Temperature (
°C)
Clamp Diode I(forward) vs. Voltage
Threshold Voltage vs. Temperature
4-351
Issue
3
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July 2006
© Zetex Semiconductors plc 2006
www.zetex.com
100
ZSM380
TIMING DIAGRAM
Vcc
Threshold
Voltage
1V
Output
Output
Undefined
Output
Undefined
APPLICATION CIRCUIT
Note 4:
A time delayed reset can be accomplished with the additional Cd.
T
DY
=
RCd
ln
V
TH
(
mpu
)
V
in
ø
÷
÷
÷
ö
1
1
−
Issue
3
-
July 2006
© Zetex Semiconductors plc 2006
è
ç
ç
ç
æ
T
DY
=Time (Seconds)
V
TH
=Microprocessor Reset Threshold
V
in
=Power Supply Voltage
4-352
www.zetex.com
ZSM380
CONNECTION DIAGRAMS
SOT223
Package Suffix
–
G
TO92
Package Suffix
–
C
Top View –
Pin 4 floating or connected to pin 2
Bottom View
ORDERING INFORMATION
Part Number
ZSM380G
ZSM380C
Package
SOT223
TO92
Part Mark
ZSM380
ZSM380
Europe
Zetex GmbH
Streitfeldstraße 19
D-81673 München
Germany
Telefon: (49) 89 45 49 49 0
Fax: (49) 89 45 49 49 49
europe.sales@zetex.com
Americas
Zetex Inc
700 Veterans Memorial Highway
Hauppauge, NY 11788
USA
Telephone: (1) 631 360 2222
Fax: (1) 631 360 8222
usa.sales@zetex.com
Asia Pacific
Zetex (Asia Ltd)
3701-04 Metroplaza Tower 1
Hing Fong Road, Kwai Fong
Hong Kong
Telephone: (852) 26100 611
Fax: (852) 24250 494
asia.sales@zetex.com
Corporate Headquarters
Zetex Semiconductors plc
Zetex Technology Park, Chadderton
Oldham, OL9 9LL
United Kingdom
Telephone: (44) 161 622 4444
Fax: (44) 161 622 4446
hq@zetex.com
For international sales offices visit
www.zetex.com/offices
Zetex products are distributed worldwide. For details, see
www.zetex.com/salesnetwork
This publication is issued to provide outline information only which (unless agreed by the company in writing) may not be
used, applied or reproduced for any purpose or form part of any order or contact or be regarded as a representation relating
4-353
to the products or services concerned. The company reserves the right to alter without notice the specification, design, price
or conditions of supply of any product or service.
Issue
3
-
July 2006
© Zetex Semiconductors plc 2006
www.zetex.com
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