AAT3520/2/4
MicroPower Microprocessor Reset Circuit
Typical Application
*AAT3524 Only
AAT3520
AAT3522
AAT3524
uP
V
CC
V
CC
V
CC
RESET
(RESET)
GNDGND
RESET
INPUT
100k
(nominal)
*
Preliminary Information
3520.2002.2.0.9 1
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
VCC 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 VCC. 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
• 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
Applications
• Notebook Computers
• Cell Phones
• Portable Electronics
• Embedded Systems
• Intelligent Instruments
PowerManager™
Pin Descriptions
AAT3520, 3522, 3524 (SOT23-3)
Part Number Descriptions
Pin Configuration
SOT-23
(Top View)
1
2
3
(RESET) RESET
VCC
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 VCC is below the reset threshold
2
(AAT3520) and remains so for a fixed time period after VCC raises above the
reset threshold.
RESET RESET output remains low while VCC is below the reset threshold
(AAT3522, and remains so for a fixed time period after VCC raises above the
AAT3524) reset threshold
3 Vcc Supply Voltage (+1.2V to +5.5V)
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
23520.2002.2.0.9
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
3520.2002.2.0.9 3
Absolute Maximum Ratings (TA=25°C 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 (VIN = 5V, TA= -40 to 85°C unless otherwise noted. Typical values
are at TA=25°C, VCC = 5V for 4.63/4.38V versions, VCC = 3.3V for 3.08/2.93V versions, VCC = 3.0V for 2.63V
version and VCC = 2.5V for 2.32/2.2V versions )
Symbol Description Conditions Min Typ Max Units
VCC Operation Voltage TA= 0ºC to +70ºC 1.0 5.5 V
TA= -40ºC to +85ºC 1.2 5.5
IQQuiescent Current VCC = 5.5V 1.05 3 µA
VCC = 3V 0.85 2
VTH RESET Threshold (Table 1) TA= 25ºC VTH -1.5% VTH VTH +1.5% V
TA= -40ºC to +85ºC VTH -2.5% VTH VTH +2.5%
∆VTH/°C RESET Threshold Tempco 40 ppm/°C
tPRESET Propagation Delay VCC = VTH to (VTH -100mV) 15 µs
-50 option 30 50 100
tRDY RESET Active Timeout Period -200 option 150 250 400 ms
ISINK =1.6mA, VCC > 2.1V, 0.3
VOL
RESET Low Output Voltage RESET asserted V
AAT3522, AAT3524 ISINK =100µA, VCC >1.2V, 0.4
RESET asserted
VOH RESET High Output Voltage ISOURCE = 800 µA VCC -1.5 V
AAT3522
ISINK =1.2mA, VCC > 1.2V, 0.3
VOL
RESET Low Output Voltage RESET not asserted V
AAT3520 ISINK = 3.2mA, VCC > 4.5V, 0.4
RESET not asserted
ISOURCE = 500µA, VCC > 2.1V, 0.8VCC
VOH
RESET High Output Voltage RESET asserted V
AAT3520 ISOURCE = 50µA, VCC > 1.2V, 0.8VCC
RESET asserted
IDOFF RESET leakage current, AAT3524 VCC > VTH 1µA
Symbol Description Value Units
ΘJA Maximum Thermal Resistance (SOT23-3)1200 °C/W
PDMaximum Power Dissipation (SOT23-3)1320 mW
Symbol Description Value Units
VCC VCC to GND -0.3 to 5.5 V
VRESET
RESET to GND (Push-Pull Output) -0.3 to VCC+0.3 V
RESET to GND (Open Drain Output) -0.3 to 5.5
IMAX Maximum Continuous Input Current 20 mA
IRESET RESET/RESET Current 20 mA
dVcc/dt Rate of rise of Vcc 100 V/µs
TJOperating Junction Temperature Range -40 to 150 °C
TLEAD Maximum Soldering Temperature (at Leads) for 10s 300 °C
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
43520.2002.2.0.9
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,
VTH-VCC (mV)
Maximum Transient
Duration (µS)
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 (µs)
VOD=10mV
VOD=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 (µA)
VCC=5V
VCC=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
VCC 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 (tRDY) after VCC 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
VCC
GND
RESET
(RESET)
VREF
Figure 1: Reset Timing Diagram (AAT3522, AAT3524)
V
RESET
CC
V
TH
V
TH
V
TH
t
RDY
t
RDY
Applications Information
Reset Output Options
The AAT3524 has an active low open drain output
and the AAT3520/2 have a push-pull output. The
AAT3524 may be used in multiple voltage systems,
with an external pull-up resistor. This allows the
AAT3524 to interface to microprocessors with high-
er supply voltages up to 5.5V (Figure 2). In the
event of a power down or brown-out condition the
reset signal remains valid until the VCC drops below
1.2V. To ensure validity down to ground an external
100kΩ resistor should be connected between the
RESET output and GND.
Supply Voltage Transient Behavior
In some cases fast negative transients of short dura-
tion can appear on the VCC power supply. The
AAT3520 series devices provide some immunity to
line transients which can generate invalid reset puls-
es. Figure 1 shows typical behavior to short duration
pulses verses RESET comparator overdrive. As
shown in the Maximum Transient Duration vs. Reset
Threshold Overdrive graph, when the transient volt-
age becomes larger, the time allowed before assert-
ing a reset becomes shorter. e.g. typically a transient
of 100mV below the reset threshold would have to
present for more than 50µs to cause a reset.
Immunity can be increased by the addition of a small
by-pass capacitor of 0.1µF connected as close to
the VCC pin as possible.
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
63520.2002.2.0.9
Figure 2: Using AAT3524 Open Drain Output with Multiple Supplies
AAT3524 5V
System
+3.3V
VCC
VCC
RESET
100k
GNDGND
RESET
INPUT
+5.0V
Factory Trimmed Reset Thresholds* and Ordering Information Table 1
*Contact Local Sales Office for custom trimmed options
Reset Threshold Voltage, VTH (V)
Ordering Minimum TA= 25ºC TA= 40 to 85ºC
Part Number Marking Reset Active (ms) Min Typ Max Min Max
AAT3520IGY-2.32-200-T1 150
AAT3522IGY-2.32-200-T1 150 2.285 2.320 2.355 2.262 2.378
AAT3524IGY-2.32-200-T1 150
AAT3520IGY-2.63-200-T1 150
AAT3522IGY-2.63-200-T1 150 2.591 2.630 2.669 2.564 2.696
AAT3524IGY-2.63-200-T1 150
AAT3520IGY-2.93-200-T1 150
AAT3522IGY-2.93-200-T1 150 2.886 2.930 2.974 2.857 3.003
AAT3524IGY-2.93-200-T1 150
AAT3520IGY-3.08-50-T1 30
AAT3520IGY-3.08-200-T1 150
AAT3522IGY-3.08-50-T1 30 3.034 3.080 3.126 3.003 3.157
AAT3522IGY-3.08-200-T1 150
AAT3524IGY-3.08-200-T1 150
AAT3520IGY-4.38-200-T1 150
AAT3522IGY-4.38-200-T1 150 4.314 4.380 4.446 4.271 4.490
AAT3524IGY-4.38-200-T1 150
AAT3520IGY-4.63-200-T1 150
AAT3522IGY-4.63-200-T1 150 4.561 4.630 4.699 4.514 4.746
AAT3524IGY-4.63-200-T1 150
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
3520.2002.2.0.9 7
Package Information
SOT23-3
E
S1
D
Se
H
L
C
b
A1
A2 A
Θ1
AAT3520/2/4
MicroPower Microprocessor Reset Circuit
83520.2002.2.0.9
Advanced Analogic Technologies, Inc.
1250 Oakmead Parkway, Suite 310, Sunnyvale, CA 94086
Phone (408) 524-9684
Fax (408) 524-9689
Dim Millimeters Inches
Min Max Min Max
A .887 1.02 0.034 .040
A1 .013 0.10 0.0005 .004
A2 - - - -
b 0.37 0.51 0.015 0.020
C 0.085 0.180 0.003 0.007
D 2.80 3.04 0.110 0.120
E 1.20 1.40 0.047 0.055
e 1.78 2.05 0.070 0.080
H 2.10 2.64 0.083 0.104
L - 0.69 - 0.027
S 0.45 0.60 0.018 0.024
S1 0.89 1.03 0.035 0.040
θ1 0° 8° 0° 8°
Note:
1. PACKAGE BODY SIZE EXCLUDE MOLD FLASH
PROTRUSIONS OR GATE BURRS.
2. TOLERANCE ±0.1000 mm (4mi) UNLESS OTHER-
WISE SPECIFIED
3. COPLANARITY: 0.1000
4. DIMENSION L IS MEASURED IN GAGE PLANE
