NOT RECOMMENDED FOR NEW
DESIGN, USE (APX809/810)
AP1701/2/3/4
3-PIN MICROPROCESSOR RESET CIRCUITS
Features
•
•
•
•
•
•
•
•
•
•
•
•
Precision Monitoring of +2.5V, +3V, +3.3V, and +5V
Power-Supply Voltages
Fully Specified Over Temperature
Available in three Output Configurations
Push-Pull
RESET
Low Output (AP1701/3)
Push-Pull
RESET
High Output (AP1702/4)
200ms Min. Power-On Reset Pulse Width
20µA Supply Current (Typ.)
Guaranteed Reset Valid to V
CC
= +1V
Power Supply Transient Immunity
No External Components
Green Packages: SC59-3L and SOT23
Lead Free Finish / RoHS Compliant (Note 1)
General Description
The AP1701/2/3/4 are used for microprocessor (µP) supervisory
circuits to monitor the power supplies in µP and digital systems.
They provide excellent circuit reliability and low cost by
eliminating external components and adjustments when used
with +5V, +3.3V, +3.0V powered circuits.
These circuits perform a single function: they assert a reset
signal whenever the V
CC
supply voltage declines below a preset
threshold, keeping it asserted for at least 240ms after V
CC
has
risen above the reset threshold. Reset thresholds suitable for
operation with a variety of supply voltages are available. The
AP1701/2/3/4 have push pull outputs. The AP1701/3 have an
active low
RESET
output, while the AP1702/4 has an active
high RESET output. The reset comparator is designed to ignore
fast transients on V
CC
, and the outputs are guaranteed to be in
the correct logic state for V
CC
down to 1V. Low supply current
makes the AP1701/2/3/4 ideal for use in portable equipment. The
AP1701/2/3/4 is available in a 3-pin SC59 package.
Applications
•
•
•
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•
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Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery Powered Equipment
Automotive
Ordering Information
AP170 X X X X X
Enable
1
2
3
4
:
:
:
:
Active- Low
Active- High
Active- Low
Active- High
Voltage
A
B
C
D
E
F
G
: 4.63
: 4.38
: 4.00
: 3.08
: 2.93
: 2.63
: 2.25
Package
W
SA
:
:
SC59
SOT23
Lead Free
L : Lead Free
G : Green
Packing
-7 : Taping
Notes: 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see
EU Directive Annex Notes 5 and 7.
Device
AP170XXW
AP170XXSA
Package Packaging
Code
(Note 2)
W
SA
SC59
SOT23
7” Tape and Reel
Quantity
Part Number Suffix
3000/Tape & Reel
3000/Tape & Reel
-7
-7
Notes: 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
AP1701/2/3/4 Rev. 2
1 of 10
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©
Diodes Incorporated
NOT RECOMMENDED FOR NEW
DESIGN, USE (APX809/810)
AP1701/2/3/4
3-PIN MICROPROCESSOR RESET CIRCUITS
Pin Assignments
(Top View)
(Top View)
GND
1
AP1701
AP1702
3 V
CC
RESET (RESET)
1
AP1703
AP1704
3 V
CC
RESET (RESET)
2
GND
2
SC59-3L
SC59-3L
3 REF
ANODE 1
2
SOT23
CATHODE
Pin Descriptions
Name
GND
RESET
(RESET)
V
CC
Description
Ground
Reset Output Pin
L: for AP1701/3
H: for AP1702/4
Operating Voltage Input
AP1701/2/3/4 Rev. 2
2 of 10
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JANUARY 2007
©
Diodes Incorporated
NOT RECOMMENDED FOR NEW
DESIGN, USE (APX809/810)
AP1701/2/3/4
3-PIN MICROPROCESSOR RESET CIRCUITS
Absolute Maximum Ratings
Symbol
V
CC
V
RESET
I
CC
I
O
P
D
T
OP
T
ST
Parameter
Terminal Voltage (with respect to GND)
RESET,
RESET
(push-pull)
Input Current, V
CC
Output Current, RESET,
RESET
Continuous Power Dissipation (T
A
= +70°C),
de-rate 4mW/°C above +70°C
Operating Junction Temperature Range
Storage Temperature Range
Rating
-0.3 to +6.0
-0.3 to (V
CC
+ 0.3)
20
20
320
-40 to +105
-65 to +150
Unit
V
V
mA
mA
mW
°C
°C
Electrical Characteristics
Symbol
Parameter
V
CC
V
CC
Range
I
CC
Supply Current
(T
A
= 25ºC)
V
TH
T
S
T
DELAY
V
OL
V
OH
V
OL
V
OH
Conditions
T
A
= 0 C to +70 C
V
TH
+ 1.0V
AP1701/2/3/4A
AP1701/2/3/4B
AP1701/2/3/4C
Reset Threshold
AP1701/2/3/4D
T
A
= 25ºC
AP1701/2/3/4E
AP1701/2/3/4F
AP1701/2/3/4G
Reset Threshold
Tempco
Set-up Time
V
CC
= 0 to (V
TH
– 100mV)
Reset Active
T
A
= 0
o
C to +70
o
C
Timeout Period
V
CC
= V
TH
min, I
SINK
= 1.2mA, AP1701/3
RESET
Output V = V min, I
CC
TH
SINK
= 3.2mA
Voltage Low
V
CC
> 1.0V, I
SINK
= 50uA
RESET
Output V
CC
> V
TH
max, I
SOURCE
= 500uA, AP1701/3
V
CC
> V
TH
max, I
SOURCE
= 800uA
Voltage-High
RESET Output V
CC
= V
TH
max, I
SINK
= 1.2mA, AP1702/4
Voltage-Low
V
CC
= V
TH
max, I
SINK
= 3.2mA
RESET Output 1.8V < V
CC
< V
TH
min, I
SOURCE
= 150uA,
Voltage-High
AP1702/4
o
o
Min.
1.0
4.54
4.29
3.92
3.02
2.87
2.57
2.20
Typ.
20
4.63
4.38
4.00
3.08
2.93
2.63
2.25
30
Max.
5.5
30
4.72
4.47
4.08
3.14
2.99
2.68
2.30
Unit
V
μA
V
100
100
240
600
0.3
0.4
0.3
0.8V
CC
V
CC
–1.5
0.3
0.4
0.8 V
CC
ppm/
o
C
μs
ms
V
V
V
V
AP1701/2/3/4 Rev. 2
3 of 10
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©
Diodes Incorporated
NOT RECOMMENDED FOR NEW
DESIGN, USE (APX809/810)
AP1701/2/3/4
3-PIN MICROPROCESSOR RESET CIRCUITS
Typical Application Circuit
V
CC
Cin
0.1uF
V
CC
V
CC
AP170X
RESET
(RESET)
Microprocessor
RESET
INPUT
GND
GND
Function Description
A microprocessor’s (µP’s) reset input starts the µP in a
known state. The AP1701/2/3/4 assert reset to prevent
code-execution errors during power-up, power-down, or
brownout conditions. They assert a reset signal whenever the V
CC
supply voltage declines below a preset threshold, keeping it
asserted for at least 240ms after V
CC
has risen above the reset
threshold. The AP1701/2/3/4 have a push-pull output stage.
Applications Information
Negative-Going V
CC
Transients
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, the AP1701/2/3/4 are
relatively immune to short-duration negative-going V
CC
transients
(glitches).
The AP1701/2/3/4 do not generate a reset pulse. The
graph was generated using a negative going pulse applied to V
CC
,
starting 0.5V above the actual reset threshold and ending below it
by the magnitude indicated (reset comparator overdrive). The
graph indicates the maximum pulse width a negative going V
CC
transient can have without causing a reset pulse. As the
magnitude of the transient increases (goes farther below the
reset threshold), the maximum allowable pulse width decreases.
Typically, a V
CC
transient that goes 100mV below the reset
threshold and lasts 100µs or less will not cause a reset pulse. A
0.1µF bypass capacitor mounted as close as possible to the V
CC
pin provides additional transient immunity.
Ensuring a Valid Reset Output
Down to V
CC
= 0
is guaranteed to be a logic low for V
CC
> 1V.
Once V
CC
exceeds the reset threshold, an internal timer keeps
below the reset threshold),
RESET
goes low. Any time V
CC
goes below the reset threshold, the internal timer resets to zero,
and
RESET
goes low. The internal timer starts after V
CC
returns above the reset threshold, and
for the reset timeout period.
RESET
remains low
When V
CC
falls below 1V, the AP1701/3
RESET
output no longer sinks current—it becomes an open circuit.
Therefore, high-impedance CMOS logic inputs connected to
RESET
can drift to undetermined voltages.
This presents no problem in most applications since most µP and
other circuitry is inoperative with V
CC
below 1V. However, in
applications where
pull down resistor to
RESET
must be valid down to 0V, adding a
RESET
causes any stray leakage
currents to flow to ground, holding
RESET
low. R1’s value is
not critical; 100k are large enough not to load
small enough to pull
RESET
and
RESET
to ground. For the AP1702/4 if
RESET
is required to remain valid for V
CC
< 1V.
Benefits of Highly Accurate Reset Threshold
Most µP supervisor ICs has reset threshold voltages
between 5% and 10% below the value of nominal supply voltages.
This ensures a reset will not occur within 5% of the nominal
supply, but will occur when the supply is 10% below nominal.
When using ICs rated at only the nominal supply ±5%, this leaves
a zone of uncertainty where the supply is between 5% and 10%
low, and where the reset may or may not be asserted.
RESET
RESET
RESET
RESET
low for the reset timeout period; after this interval,
goes high.
If a brownout condition occurs (V
CC
dips
AP1701/2/3/4 Rev. 2
4 of 10
www.diodes.com
JANUARY 2007
©
Diodes Incorporated
NOT RECOMMENDED FOR NEW
DESIGN, USE (APX809/810)
AP1701/2/3/4
3-PIN MICROPROCESSOR RESET CIRCUITS
Block Diagram
Driver
Delay Circuit
V
REF
RESET
/ RESET
Performance Characteristics
Threshold
2.928
24
20
16
Iq 12
8
2.926
2.924
2.922
4
0 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
2.92
-40 -30 -20 -10
0
10 20 30 40 50 60 70 80 90
Temp ( C )
Iq vs. Temp
Temp
Threshold vs. Temp
AP1701/2/3/4 Rev. 2
5 of 10
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JANUARY 2007
©
Diodes Incorporated
