NCP803
Very Low Supply Current
3-Pin Microprocessor
Reset Monitor
The NCP803 is a cost–effective system supervisor circuit designed
to monitor V
CC
in digital systems and provide a reset signal to the host
processor when necessary. No external components are required.
The reset output is driven active within 10
µsec
of V
CC
falling
through the reset voltage threshold. Reset is maintained active for a
minimum of 140 msec after V
CC
rises above the reset threshold. The
NCP803 has an open drain active–low RESET output. The output of
the NCP803 is guaranteed valid down to V
CC
= 1.0 V and is available
in a SOT–23 package.
The NCP803 is optimized to reject fast transient glitches on the V
CC
line. Low supply current of 1.0
µA
(V
CC
= 3.2 V) make this device
suitable for battery powered applications.
Features
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MARKING
DIAGRAM
3
1
2
3
SOT–23
(TO–236)
CASE 318
1
xxx = Specific Device Code
M = Monthly Date Code
xxxM
2
•
Precision V
CC
Monitor for 2.5 V, 3.0 V, 3.3 V, and 5.0 V Supplies
•
Precision Monitoring Voltages from 1.6 V to 4.9 V Available
•
•
•
•
•
•
•
•
•
•
•
in 100 mV Steps
140 msec Guaranteed Minimum RESET Output Duration
RESET Output Guaranteed to V
CC
= 1.0 V
Low 1.0
µA
Supply Current
V
CC
Transient Immunity
Small SOT–23 Package
No External Components
Wide Operating Temperature: –40°C to 105°C
Computers
Embedded Systems
Battery Powered Equipment
Critical
µP
Power Supply Monitoring
V
CC
V
CC
NCP803
C = 100 nF
RESET
GND
0
V
CC
R
pull–up
µP
RESET
GND
0
PIN CONFIGURATION
GND
1
3
V
CC
RESET
2
SOT–23*
(Top View)
Typical Applications
NOTE: *SOT–23 is equivalent to JEDEC (TO–236)
ORDERING INFORMATION
Device
NCP803SNxxxT1
Package
SOT–23
Shipping
3000/Tape & Reel
NOTE: The “xxx” denotes a suffix for V
cc
voltage threshold
options – see page 2777 for more details.
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 2777 of this data sheet.
Figure 1. Typical Application Diagram
Semiconductor Components Industries, LLC, 2001
2772
September, 2001 – Rev. 1
Publication Order Number:
NCP803/D
NCP803
ABSOLUTE MAXIMUM RATINGS*
(Note 1)
Rating
Supply Voltage (V
CC
to GND)
RESET
Input Current, V
CC
Output Current, RESET
dV/dt (V
CC
)
Thermal Resistance, Junction to Air
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 Seconds)
Latch–up performance:
Negative
*Maximum Ratings are those values beyond which damage to the device may occur.
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model 4000 V per MIL–STD–883, Method 3015.
Machine Model Method 400 V.
2. The maximum package power dissipation limit must not be exceeded.
TJ(max)
*
TA
with T
J(max)
= 150°C
PD
+
R
qJA
R
qJA
T
A
T
stg
T
sol
I
Latch–up
150
Symbol
V
CC
Value
6.0
–0.3 to (V
CC
+ 0.3)
20
20
100
491
–40 to +105
–65 to +150
+260
Unit
V
V
mA
mA
V/µsec
°C/W
°C
°C
°C
mA
ELECTRICAL CHARACTERISTICS
T
A
= –40°C to +105°C unless otherwise noted. Typical values are at T
A
= +25°C. (Note 3)
Characteristic
V
CC
Range
T
A
= 0°C to +70°C
T
A
= –40°C to +105°C
Supply Current
V
CC
= 3.3 V
T
A
= –40°C to +85°C
T
A
= 85°C to +105°C
V
CC
= 5.5 V
T
A
= –40°C to +85°C
T
A
= 85°C to +105°C
Reset Threshold (Note 4)
NCP803SN490
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN463
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN438
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN308
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
3. Production testing done at T
A
= 25°C, over temperature limits guaranteed by design.
4. Contact your ON Semiconductor sales representative for other threshold voltage options.
I
CC
–
–
–
–
V
TH
4.83
4.78
4.66
4.56
4.50
4.40
4.31
4.25
4.16
3.04
3.00
2.92
4.9
–
–
4.63
–
–
4.38
–
–
3.08
–
–
4.97
5.02
5.14
4.70
4.75
4.86
4.45
4.50
4.56
3.11
3.15
3.23
0.5
–
0.8
–
1.2
2.0
1.8
2.5
V
Symbol
Min
1.0
1.2
Typ
–
–
Max
5.5
5.5
µA
Unit
V
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2773
NCP803
ELECTRICAL CHARACTERISTICS
(continued)
T
A
= –40°C to +105°C unless otherwise noted. Typical values are at T
A
= +25°C.
(Note 5)
Characteristic
Reset Threshold (continued)
NCP803SN293
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN263
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN232
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
NCP803SN160
T
A
= +25°C
T
A
= –40°C to +85°C
T
A
= +85°C to +105°C
Reset Temperature Coefficient
V
CC
to Reset Delay V
CC
= V
TH
to (V
TH
– 100 mV)
Reset Active Timeout Period
RESET Output Voltage Low
V
CC
= V
TH
– 0.2 V
1.6 V
v
V
TH
v
2.0 V, I
SINK
= 0.5 mA
2.1 V
v
V
TH
v
4.0 V, I
SINK
= 1.2 mA
4.1 V
v
V
TH
v
4.9 V, I
SINK
= 3.2 mA
RESET Leakage Current
V
CC
u
V
TH
, RESET De–asserted
V
OL
Symbol
V
TH
2.89
2.85
2.78
2.59
2.55
2.50
2.28
2.25
2.21
1.58
1.56
1.52
–
–
140
–
2.93
–
–
2.63
–
–
2.32
–
–
1.6
–
–
30
10
240
–
2.96
3.00
3.08
2.66
2.70
2.76
2.35
2.38
2.45
1.62
1.64
1.68
–
–
460
0.3
ppm/°C
µsec
msec
V
Min
Typ
Max
Unit
V
I
LEAK
–
–
1
µA
5. Production testing done at T
A
= 25°C, over temperature limits guaranteed by design.
PIN DESCRIPTION
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Á
Á
1
2
3
GND
Ground
RESET
V
CC
RESET output remains low while V
CC
is below the reset voltage threshold, and for 240 msec (typ.)
after V
CC
rises above reset threshold.
Supply Voltage: C = 100 nF is recommended as a bypass capacitor between V
CC
and GND.
Pin No.
Symbol
Description
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2774
NCP803
APPLICATIONS INFORMATION
V
CC
Transient Rejection
The NCP803 provides accurate V
CC
monitoring and reset
timing during power–up, power–down, and brownout/sag
conditions, and rejects negative–going transients (glitches)
on the power supply line. Figure 2 shows the maximum
transient duration vs. maximum negative excursion
(overdrive) for glitch rejection. Any combination of
duration and overdrive which lies
under
the curve will
not
generate a reset signal. Combinations above the curve are
detected as a brownout or power–down. Typically, transient
that goes 100 mV below the reset threshold and lasts 5
µs
or
less will not cause a reset pulse. Transient immunity can be
improved by adding a capacitor in close proximity to the V
CC
pin.
V
CC
V
TH
Overdrive
Some
µP’s
(such as Motorola 68HC11) have
bi–directional reset pins which interface easily with the
Open Drain RESET output of the NCP803. As shown in
Figure 3, one can connect directly to the RESET output of
the NCP803 to the RESET pin of the
µP.
The pull–up resistor
avoids an undetermined voltage of the RESET pin.
V
CC
V
CC
NCP803
C = 100 nF
RESET
GND
0
RESET
GND
0
R
pull–up
V
CC
µP
Processors With Bidirectional I/O Pins
Figure 3. Interfacing to Bidirectional Reset I/O
Duration
MAXIMUM TRANSIENT DURATION (µs) I
300
250
200
150
100
50
0
10
V
TH
= 4.9 V
NCP803 RESET Output Allows Use With Two Power
Supplies
V
TH
= 3.08 V
V
TH
= 1.6 V
In numerous applications the pull–up resistor placed on
the RESET output is connected to the supply voltage
monitored by the IC. Nevertheless, a different supply
voltage can also power this output and so level–shift from
the monitored supply to reset the
µP.
However, if the
NCP803’s supply goes below 1 V, the RESET output ability
to sink current will decrease and the result is a high state on
the pin even though the supply’s IC is under the threshold
level. This occurs at a V
CC
level that depends on the R
pull–up
value and the voltage to which it is connected.
+3.3 V
+5.0 V
20
30
40
50
60
70
80
90 100
V
CC
NCP803
C = 100 nF
RESET
GND
0
RESET
GND
0
R
pull–up
V
CC
µP
RESET COMPARATOR OVERDRIVE (mV)
Figure 2. Maximum Transient Duration vs. Overdrive
for Glitch Rejection at 25°C
Figure 4. RESET Output with Two Power Supplies
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2775
NCP803
TYPICAL CHARACTERISTICS
1.8
1.6
SUPPLY CURRENT (mA)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0.5
1.5
2.5
3.5
4.5
5.5
25°C
0°C
–40°C
85°C
V
TH
= 1.60 V
105°C
1.4
1.2
SUPPLY CURRENT (mA)
1.0
0.8
0.6
0.4
0.2
0
0.5
V
TH
= 3.08 V
105°C
85°C
25°C
0°C
–40°C
1.5
2.5
3.5
4.5
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 5. Supply Current vs. Supply Voltage
Figure 6. Supply Current vs. Supply Voltage
1.6
1.4
SUPPLY CURRENT (mA)
1.2
1.0
0.8
0.6
0.4
–40°C
0.2
0
0.5
1.5
2.5
3.5
4.5
5.5
0°C
25°C
85°C
V
TH
= 4.90 V
105°C
1.001
1.000
NORMALIZED V
TH
VOLTAGE
0.999
0.998
0.997
0.996
0.995
0.994
0.993
–40
–20
0
20
40
60
80
100
120
V
TH
= 4.90 V
V
TH
= 3.08 V
V
TH
= 1.60 V
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
Figure 7. Supply Current vs. Supply Voltage
Figure 8. Normalized Reset Threshold Voltage
vs. Temperature
POWER–DOWN RESET TIMEOUT (mS)
350
300
250
200
150
100
50
0
–40
V
TH
= 1.60 V
–20
0
20
40
60
80
100
V
TH
= 3.08 V
V
TH
= 4.90 V
280
POWER–UP RESET TIMEOUT (mS)
270
260
250
240
230
220
210
200
–40
–20
0
20
40
60
80
100
120
V
TH
= 3.08 V
V
TH
= 1.60 V
V
TH
= 4.90 V
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 9. Power–up Reset Timeout vs. Temperature
Figure 10. Power–down Reset Timeout vs.
Temperature (Overdrive = 20 mV)
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2776
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