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AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Typical Application
*AAT3524 Only
AAT3520
AAT3522
AAT3524
uP
V
CC
V
CC
V
CC
RESET
(RESET)
GND
GND
RESET
INPUT
100k
(nominal)
*
Preliminary
Information
3520.2002.2.0.9
1
General Description
The AAT3520 Series of PowerManagerTM products
is a member of AATI's Total Power Management
ICTM (TPMICTM) product family. These micro-
processor reset circuits are ideal for monitoring volt-
age supplies in portable systems, where extended
battery life is critical. They provide a low cost, reli-
able solution by eliminating external components.
The AAT3520 series operates by monitoring the
system power supply voltage. When the input volt-
age drops below a fixed threshold, the device
asserts a reset signal for a fixed time period after
V
CC
has risen back above the fixed threshold; 30ms
and 150ms minimum periods are available. The
AAT3520 product series is guaranteed to operate
down to 1.2V and designed to ignore fast line tran-
sients appearing on V
CC
. The AAT3520 series is
available with three output stage versions: AAT3520
push-pull active high output, AAT3522 push-pull
active low output and AAT3524 open drain active
low output. The quiescent supply current is
extremely low, typically 1A, making it ideal for
portable battery operated equipment.
The AAT3520/2/4 are available in a 3 pin SOT23
package and are specified over -40 to 85C oper-
ating temperature range.
Features
1.2V to 5.5V Input voltage range
Operation down to 1.2V
Extremely low quiescent current: less than 2A
High accuracy detection threshold: 1.5%
Monitor Power Supply Voltages
Fixed thresholds from 2.2V to 4.6V
Reset pulse width options
Minimum 30 ms or 150ms
Fast propagation delay <20s
Available output configurations:
Open-drain output
CMOS active high output
CMOS active low output
Temp range -40 to 85C
3 pin SOT23 package
Applications
Notebook Computers
Cell Phones
Portable Electronics
Embedded Systems
Intelligent Instruments
PowerManager
TM
Pin Descriptions
AAT3520, 3522, 3524 (SOT23-3)
Part Number Descriptions
Pin Configuration
SOT-23
(Top View)
1
2
3
(RESET) RESET
V
CC
GND
SOT23-3 Part Number
Part Description
AAT3520
Reset Output Push Pull Active High with Delay
AAT3522
Reset Output Push Pull Active Low with Delay
AAT3524
Reset Output Open Drain Active Low with Delay
Pin #
Symbol
Function
1
GND
Ground connection
RESET
RESET output remains high while V
CC
is below the reset threshold
2
(AAT3520)
and remains so for a fixed time period after V
CC
raises above the
reset threshold.
RESET
RESET output remains low while V
CC
is below the reset threshold
(AAT3522,
and remains so for a fixed time period after V
CC
raises above the
AAT3524)
reset threshold
3
Vcc
Supply Voltage (+1.2V to +5.5V)
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
2
3520.2002.2.0.9
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
3520.2002.2.0.9
3
Absolute Maximum Ratings
(T
A
=25C unless otherwise noted)
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con-
ditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Thermal Information
Note 1: Mounted on an FR4 board.
Electrical Characteristics
(V
IN
= 5V, T
A
= -40 to 85C unless otherwise noted. Typical values
are at T
A
=25C, V
CC
= 5V for 4.63/4.38V versions, V
CC
= 3.3V for 3.08/2.93V versions, V
CC
= 3.0V for 2.63V
version and V
CC
= 2.5V for 2.32/2.2V versions )
Symbol
Description
Conditions
Min
Typ
Max
Units
V
CC
Operation Voltage
T
A
= 0C to +70C
1.0
5.5
V
T
A
= -40C to +85C
1.2
5.5
I
Q
Quiescent Current
V
CC
= 5.5V
1.05
3
A
V
CC
= 3V
0.85
2
V
TH
RESET Threshold (Table 1)
T
A
= 25C
V
TH
-1.5%
V
TH
V
TH
+1.5%
V
T
A
= -40C to +85C
V
TH
-2.5%
V
TH
V
TH
+2.5%
V
TH
/C
RESET Threshold Tempco
40
ppm/C
t
P
RESET Propagation Delay
V
CC
= V
TH
to (V
TH
-100mV)
15
s
-50 option
30
50
100
t
RDY
RESET Active Timeout Period
-200 option
150
250
400
ms
I
SINK
=1.6mA, V
CC
> 2.1V,
0.3
V
OL
RESET Low Output Voltage
RESET asserted
V
AAT3522, AAT3524
I
SINK
=100A, V
CC
>1.2V,
0.4
RESET asserted
V
OH
RESET High Output Voltage
I
SOURCE
= 800 A
V
CC
-1.5
V
AAT3522
I
SINK
=1.2mA, V
CC
> 1.2V,
0.3
V
OL
RESET Low Output Voltage
RESET not asserted
V
AAT3520
I
SINK
= 3.2mA, V
CC
> 4.5V,
0.4
RESET not asserted
I
SOURCE
= 500A, V
CC
> 2.1V,
0.8V
CC
V
OH
RESET High Output Voltage
RESET asserted
V
AAT3520
I
SOURCE
= 50A, V
CC
> 1.2V,
0.8V
CC
RESET asserted
I
DOFF
RESET leakage current, AAT3524
V
CC
> V
TH
1
A
Symbol
Description
Value
Units
JA
Maximum Thermal Resistance (SOT23-3)
1
200
C/W
P
D
Maximum Power Dissipation (SOT23-3)
1
320
mW
Symbol
Description
Value
Units
V
CC
V
CC
to GND
-0.3 to 5.5
V
V
RESET
RESET to GND (Push-Pull Output)
-0.3 to V
CC
+0.3
V
RESET to GND (Open Drain Output)
-0.3 to 5.5
I
MAX
Maximum Continuous Input Current
20
mA
I
RESET
RESET/RESET Current
20
mA
dVcc/dt
Rate of rise of Vcc
100
V/s
T
J
Operating Junction Temperature Range
-40 to 150
C
T
LEAD
Maximum Soldering Temperature (at Leads) for 10s
300
C
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
4
3520.2002.2.0.9
Typical Characteristics
Maximum Transient Duration
vs. Reset Threshold Overdrive
0
50
100
150
200
250
300
350
400
1
10
100
1000
Reset Threshold Overdrive,
V
TH
-V
CC
(mV)
Maximum Transient
Duration (
S)
Power-Down Reset Propagation
Delay vs. Temperature
0
5
10
15
20
25
30
-40
-20
0
20
40
60
80
Temperature (
C)
Reset Propagation Delay (
s)
V
OD
=10mV
V
OD
=100mV
Normalized Power-Up Reset Timeout
vs. Temperature
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
-40
-20
0
20
40
60
80
100
Temperature (
C)
Normalized Power-Up
Reset Timeout (ms)
Normalized Reset Threshold
vs. Temperature
0.997
0.998
0.999
1.000
1.001
1.002
1.003
-40
-20
0
20
40
60
80
Temperature (
C)
Normalized Threshold
Supply Current vs. Temperature
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
-40
-20
0
20
40
60
80
Temperature (
C)
Supply Current (
A)
V
CC
=5V
V
CC
=3V
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
3520.2002.2.0.9
5
Functional Description
General
During start-up, the reset pin on a microprocessor
ensures that it is fully reset and starts up in a known
condition. The AAT3520 series of microprocessor
reset devices monitor the supply voltage to a micro-
processor and assert a reset signal whenever the
V
CC
voltage falls below a factory programmed
threshold. This threshold is accurate within +/-1.5%
at 25C and within +/- 2.5% over the entire operat-
ing temperature range. The reset signal remains
asserted for a fixed time period (t
RDY
) after V
CC
has
risen above the threshold as shown in Figure 1.
See Ordering Information for available RESET
active timeout periods
Functional Block Diagram
Reset
Generator
+ Timer
Oscillator
V
CC
GND
RESET
(RESET)
V
REF
Figure 1: Reset Timing Diagram (AAT3522, AAT3524)
V
RESET
CC
V
TH
V
TH
V
TH
t
RDY
t
RDY
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