APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Description
The APX823/APX824/APX825A family of supervisors
provides circuit initialization and timing supervision, primarily
for DSP and processor-based systems.
During power-on,
RESET
is asserted when supply voltage
V
CC
becomes higher than 1.1V. Thereafter, the supply
voltage supervisor monitors V
CC
and keeps
RESET
active as
long as V
CC
remains below the threshold voltage V
TH-
. An
internal timer delays the return of the output to the inactive
state (high) to ensure proper system reset. The delay time, t
d
starts after V
CC
has risen above the threshold voltage V
TH-
.
When the supply voltage drops below the threshold voltage
V
TH-
, the output becomes active (low) again. No external
components are required. All the devices of this family have a
fixed-sense threshold voltage V
TH-
set by an internal voltage
divider.
The APX823/APX825A devices incorporate a manual reset
input,
MR
. A low level at
MR
causes
RESET
to become
active. The APX824/APX825A devices include a high-level
output RESET. APX823/APX824/APX825A have a watchdog
timer that is periodically triggered by a positive or negative
transition at WDI. When the supervising system fails to
retrigger the watchdog circuit within the time-out interval,
ttout,
RESET
becomes active for the time period td. This
event also reinitializes the watchdog timer. Leaving WDI
unconnected disables the watchdog.
In applications where the input to the WDI pin may be active
(transitioning high and low) when the APX823/APX824/APX8
25A asserting
RESET
the APX823/APX824/APX825A does
not return to a non-reset state when the input voltage is
above Vt. The product spectrum is designed for supply
voltage of 2.5V, 3V, 3.3V and 5V. The circuits are available in
a
SOT25
and
SOT26
packages.
The
APX823/APX824/APX825A devices are characterized for
o
o
operation over a temperature range of -40 C to 105 C.
Pin Assignments
RESET
1
APX823
4 WDI
SOT25
(Top View)
5 V
CC
GND 2
MR
3
RESET 1
GND 2
RESET 3
(Top View)
5 V
CC
APX824
4 WDI
SOT25
RESET 1
GND 2
RESET 3
(Top View)
6 V
CC
APX825A
5 WDI
4 MR
SOT26
Features
•
•
•
Applications
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Note:
Power-on reset generator with fixed delay time of 200ms
Typ
Manual reset input (APX823/APX825A)
Reset output available in active-low
(APX823/APX824/APX825A), active-high
(APX824/APX825A)
Supply voltage supervision range 2.5V, 3V, 3.3V, 5V
Watchdog timer
Supply current of 30μA (Typ.)
Temperature range: -40°C to 85°C
SOT25 and SOT26: Available in “Green” Molding
Compound (No Br, Sb)
Lead Free Finish/RoHS Compliant (Note 1)
Applications Using DSPs, Microcontrollers, or
Microprocessors
Industrial Equipment
Programmable Controls
Automotive Systems
Portable/Battery-Powered Equipment
Intelligent Instruments
Wireless Communications Systems
Notebook/Desktop Computers
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see
EU Directive 2002/95/EC Annex Notes.
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2
1 of 12
www.diodes.com
May 2011
© Diodes Incorporated
APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Typical Application Circuit
V
CC
V
CC
RESET
APX8XX
MR
GND
WDI
C
IN
100nF
V
CC
RESET
Microprocessor
I/O
GND
Pin Descriptions
Pin Name
GND
Ground
Reset output pin
Operating voltage input
Watchdog input
Manual reset
Description
RESET
(RESET)
V
CC
WDI
MR
Functional Block Diagram
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2
2 of 12
www.diodes.com
May 2011
© Diodes Incorporated
APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Absolute Maximum Ratings
(Over operating ambient temperature range, unless otherwise noted)*
Symbol
Parameter
Rating
5
200
6.0
-0.3 to (V
CC
+0.3)
20
20
SOT25
SOT26
SOT25
SOT26
SOT25
SOT26
SOT25
SOT26
6.2
5.8
500
470
220
210
125
120
-40 to 105
-65 to 150
Derating Factor Above
T
A
= 25
o
C
Continuous Total Power
Dissipation
T
A
= 25 C Power Rating
T
A
= 70
o
C Power Rating
T
A
= 85
o
C Power Rating
T
OP
T
ST
Operating Junction Temperature Range
Storage Temperature Range
o
Unit
KV
V
V
V
mA
mA
mW/°C
mW
mW
mW
°C
°C
ESD HBM Human Body Model ESD Protection
ESD MM Machine Model ESD Protection
V
CC
V
RESET
I
CC
I
O
Supply Voltage
RESET,
RESET
,
MR
, WDI
Input Current V
CC
Maximum High Output Current
P
D
*
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-
maximum-rated conditions for extended periods may affect device reliability.
Recommended Operating Conditions
Symbol
V
CC
V
IN
V
IH
V
IL
Δt/ΔV
T
A
T
R
Supply Voltage
Input Voltage
High-level Input Voltage at
MR
and WDI
Low-level Voltage
Input Transition Rise and Fall Rate at
MR
or WDI
Operating Ambient Temperature Range
V
CC
Rising Time (V
CC
= 0~VT)
Parameter
Min
1.1
0
0.7
×
V
CC
-
-
-40
-
Max
5.5
(V
CC
+0.3)
-
0.3
×
V
CC
100
85
100
Unit
V
V
V
V
ns/V
o
C
V/ uS
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2
3 of 12
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May 2011
© Diodes Incorporated
APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Electrical Characteristics
(Over recommended operating ambient temperature range, unless otherwise noted)
Symbol
Parameter
APX823/APX824/APX825A -
29/26/23
APX823/APX824/APX825A -
RESET
40/31
V
OH
High-level
Output Voltage
APX823/APX824/APX825A
–46/44
APX824/APX825A
-29/26/23
APX824/APX825A -
46/44/40/31
APX824/APX825A
-29/26/23
RESET APX824/APX825A -40/31
APX824/APX825A -46/44
APX823/APX824/APX825A -
29/26/23
Test Conditions
V
CC
= V
TH-
+0.2V
I
OH
=-20μA
V
CC
= V
TH-
+0.2V
I
OH
=-30μA
V
CC
= V
TH-
+0.2V
I
OH
=-120μA
V
CC
> 1.8V,
I
OH
= -100μA
V
CC
> 1.8V,
I
OH
= -150μA
V
CC
= V
TH-
+0.2V
I
OL
=1mA
V
CC
= V
TH-
+0.2V
I
OL
=1.2mA
V
CC
= V
TH-
+0.2V
I
OL
=3mA
V
CC
= V
TH-
-0.2V
I
OL
=1mA
V
CC
= V
TH-
-0.2V
I
OL
=1.2mA
V
CC
= V
TH-
-0.2V
I
OL
=3mA
V
CC
> 1.1V,
I
OL
=20μA
-
2.21
2.59
2.88
3.02
3.93
4.31
4.56
2.20
2.57
2.86
3.00
3.92
4.29
4.54
-
2.25
2.63
2.93
3.08
4.00
4.38
4.63
2.25
2.63
2.93
3.08
4.00
4.38
4.63
0.4
2.30
2.69
3.00
3.15
4.08
4.47
4.72
2.30
2.69
3.00
3.15
4.08
4.47
4.72
V
-
-
0.4
V
-
-
0.4
V
0.8
×
V
CC
-
-
V
V
CC
-1.5V
-
-
V
0.8
×
V
CC
-
-
V
Min
Typ.
Max
Unit
RESET
V
OL
Low-level
Output Voltage
RESET
40/31
APX823/APX824/APX825A -
APX823/APX824/APX825A -
46/44
V
RESET
Power-up Reset Voltage (see Note 2)
APX823/APX824/APX825A -23
APX823/APX824/APX825A -26
APX823/APX824/APX825A -29
APX823/APX824/APX825A -31
APX823/APX824/APX825A -40
APX823/APX824/APX825A -44
APX823/APX824/APX825A -46
APX823/APX824/APX825A -23
APX823/APX824/APX825A -26
APX823/APX824/APX825A -29
APX823/APX824/APX825A -31
APX823/APX824/APX825A -40
APX823/APX824/APX825A -44
APX823/APX824/APX825A -46
o
o
T
A
= 0 C -85 C
V
V
TH-
Negative-going
Input Threshold
Voltage
(see Note 3)
o
o
T
A
= -40 C -85 C
V
Note:
2. The lowest supply voltage at which
RESET
becomes active. T
R
, V
CC
> 15μs/V.
3. To ensure best stability of the threshold voltage, a bypass capacitor (ceramic, 0.1μF) should be placed near the supply terminals.
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2
4 of 12
www.diodes.com
May 2011
© Diodes Incorporated
APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Electrical Characteristics
(cont.)
Symbol
Parameter
APX823/APX824/APX825A -23
APX823/APX824/APX825A -26
APX823/APX824/APX825A -29
APX823/APX824/APX825A -31
APX823/APX824/APX825A -40
APX823/APX824/APX825A -44
APX823/APX824/APX825A -46
V
CC
= V
TH
to (V
TH
– 100mV)
WDI=V
CC
,
Time average
(dc=88%)
WDI=0.3V,
V
CC
=5.5V time
average (dc=12%)
WDI=V
CC
WDI=0.3V,
V
CC
=5.5V
V
CC
= V
TH-
+0.2V
-
-
50
-
mV
-
50
20
120
-
-
μs
μA
Test Conditions
Min
Typ.
Max
Unit
V
hys
Hysteresis at V
CC
Input
T
S
I
IH(AV)
Set-up Time
Average High-
level Input
Current
Average Low-
level Input
Current
High-level Input
Current
Low-level Input
Current
Supply Current
WDI
I
IL(AV)
I
IH
I
IL
-
-15
-
μA
μA
μA
WDI
WDI
WDI and
MR
Unconnected, Outputs
unconnected
-
-
120
120
160
160
I
CC
-
-
30
60
50
40
-
-
-
o
μA
kΩ
o
ppm/ C
Internal Pull-up Resistor at
MR
TC
C
i
θ
JA
θ
JC
Note:
V
OUT
Temperature Coefficient
Input Capacitance at
MR
, WDI
Thermal Resistance Junction-to-Ambient
Thermal Resistance Junction-to-Case
V
I
= 0V to 5.5V
SOT25
SOT26
SOT25
SOT26
(Note 4)
(Note 4)
(Note 4)
(Note 4)
-
5
161
169
27
28
pF
C/W
C/W
o
4. Test condition for SOT25 and SOT26: Devices mounted on FR-4 substrate PC board, 2oz copper, with minimum recommended pad layout.
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2
5 of 12
www.diodes.com
May 2011
© Diodes Incorporated
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