AAT3520/2/4
MicroPower Microprocessor Reset Circuit
General Description
The AAT3520 Series of PowerManager™ products
is a member of AATI's Total Power Management
IC™ (TPMIC™) 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 1µA, 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 85°C oper-
ating temperature range.
Features
•
•
•
•
•
•
•
PowerManager
™
•
•
•
1.2V to 5.5V Input voltage range
Operation down to 1.2V
Extremely low quiescent current: less than 2µA
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 <20µs
Available output configurations:
• Open-drain output
• CMOS active high output
• CMOS active low output
Temp range -40 to 85°C
3 pin SOT23 package
Preliminary Information
Applications
•
•
•
•
•
Notebook Computers
Cell Phones
Portable Electronics
Embedded Systems
Intelligent Instruments
Typical Application
V
CC
V
CC
*
100k
(nominal)
V
CC
AAT3520
AAT3522
RESET
AAT3524
(RESET)
RESET
uP
INPUT
GND
GND
*AAT3524 Only
3520.2002.2.0.9
1
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Pin Descriptions
AAT3520, 3522, 3524 (SOT23-3)
Pin #
1
Symbol
GND
RESET
(AAT3520)
Function
Ground connection
RESET output remains high while V
CC
is below the reset threshold
and remains so for a fixed time period after V
CC
raises above the
reset threshold.
RESET output remains low while V
CC
is below the reset threshold
and remains so for a fixed time period after V
CC
raises above the
reset threshold
Supply Voltage (+1.2V to +5.5V)
2
RESET
(AAT3522,
AAT3524)
3
Vcc
Part Number Descriptions
SOT23-3 Part Number
AAT3520
AAT3522
AAT3524
Part Description
Reset Output Push Pull Active High with Delay
Reset Output Push Pull Active Low with Delay
Reset Output Open Drain Active Low with Delay
Pin Configuration
SOT-23
(Top View)
GND
(RESET) RESET
1
3
2
V
CC
2
3520.2002.2.0.9
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Absolute Maximum Ratings
Symbol
V
CC
V
RESET
I
MAX
I
RESET
dVcc/dt
T
J
T
LEAD
(T
A
=25°C unless otherwise noted)
Value
-0.3 to 5.5
-0.3 to V
CC
+0.3
-0.3 to 5.5
20
20
100
-40 to 150
300
Description
V
CC
to GND
RESET to GND (Push-Pull Output)
RESET to GND (Open Drain Output)
Maximum Continuous Input Current
RESET/RESET Current
Rate of rise of Vcc
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads) for 10s
Units
V
V
mA
mA
V/µs
°C
°C
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
Symbol
Θ
JA
P
D
Description
Maximum Thermal Resistance (SOT23-3)
1
Maximum Power Dissipation (SOT23-3)
1
Value
200
320
Units
°C/W
mW
Note 1: Mounted on an FR4 board.
Electrical Characteristics
Symbol
V
CC
I
Q
V
TH
∆V
TH
/°C
t
P
t
RDY
(V
IN
= 5V, T
A
= -40 to 85°C unless otherwise noted. Typical values
are at T
A
=25°C, 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 )
Description
Operation Voltage
Quiescent Current
RESET Threshold (Table 1)
RESET Threshold Tempco
RESET Propagation Delay
RESET Active Timeout Period
RESET Low Output Voltage
AAT3522, AAT3524
RESET High Output Voltage
AAT3522
RESET Low Output Voltage
AAT3520
Conditions
T
A
= 0ºC to +70ºC
T
A
= -40ºC to +85ºC
V
CC
= 5.5V
V
CC
= 3V
T
A
= 25ºC
T
A
= -40ºC to +85ºC
V
CC
= V
TH
to (V
TH
-100mV)
-50 option
-200 option
I
SINK
=1.6mA, V
CC
> 2.1V,
RESET asserted
I
SINK
=100µA, V
CC
>1.2V,
RESET asserted
I
SOURCE
= 800 µA
I
SINK
=1.2mA, V
CC
> 1.2V,
RESET not asserted
I
SINK
= 3.2mA, V
CC
> 4.5V,
RESET not asserted
I
SOURCE
= 500µA, V
CC
> 2.1V,
RESET asserted
I
SOURCE
= 50µA, V
CC
> 1.2V,
RESET asserted
V
CC
> V
TH
Min
1.0
1.2
Typ
Max
Units
V
TH
-1.5%
V
TH
-2.5%
30
150
5.5
V
5.5
1.05
3
µA
0.85
2
V
TH
V
TH
+1.5%
V
V
TH
V
TH
+2.5%
40
ppm/°C
15
µs
50
100
ms
250
400
0.3
0.4
V
V
0.3
0.4
V
V
OL
V
OH
V
CC
-1.5
V
OL
0.8V
CC
0.8V
CC
1
V
µA
V
OH
I
DOFF
3520.2002.2.0.9
RESET High Output Voltage
AAT3520
RESET leakage current, AAT3524
3
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Typical Characteristics
Supply Current vs. Temperature
1.40
Normalized Reset Threshold
vs. Temperature
Normalized Threshold
1.003
1.002
1.001
1.000
0.999
0.998
0.997
-40
-20
0
20
40
60
80
Supply Current (µA)
1.20
1.00
0.80
0.60
0.40
0.20
0.00
-40
-20
V
CC
=5V
V
CC
=3V
0
20
40
60
80
Temperature (°C)
Temperature (°C)
Normalized Power-Up Reset Timeout
vs. Temperature
Reset Propagation Delay (µs)
30
25
20
15
10
5
0
-40
Power-Down Reset Propagation
Delay vs. Temperature
Normalized Power-Up
Reset Timeout (ms)
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
-40
-20
0
20
40
60
80
100
V
OD
=10mV
V
OD
=100mV
Temperature (°C)
-20
0
20
40
60
80
Temperature (°C)
Maximum Transient Duration
vs. Reset Threshold Overdrive
400
Maximum Transient
Duration (µS)
350
300
250
200
150
100
50
0
1
10
100
1000
Reset Threshold Overdrive,
V
TH
-V
CC
(mV)
4
3520.2002.2.0.9
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Functional Block Diagram
V
CC
Reset
Generator
+ Timer
RESET
(RESET)
Oscillator
V
REF
GND
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 25ºC 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
V
CC
V
TH
V
TH
V
TH
RESET
t
RDY
t
RDY
Figure 1: Reset Timing Diagram (AAT3522, AAT3524)
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