AAT3532IAS-T1 [AAT]
MicroPower™ Microprocessor Reset Circuit; 微功耗™微处理器复位电路
| 型号： | AAT3532IAS-T1 |
| 厂家： | 
ADVANCED ANALOG TECHNOLOGY, INC. |
| 描述： | MicroPower™ Microprocessor Reset Circuit |
| 文件： | 总8页 (文件大小：99K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AAT3532
MicroPower™ Microprocessor Reset Circuit
™
PowerManager
General Description
Features
The AAT3532 PowerManager is a member of
AnalogicTech’s Total Power Management IC™
(TPMIC™) product family. It is a fully integrated
device for monitoring microprocessor activity,
external reset, and power supply conditions. The
device holds the microprocessor in a reset condi-
tion for a minimum of 250ms while VCC is estab-
lished to ensure correct system start-up. A manual
reset can be initiated via a de-bounced input pin.
As an additional level of protection, the AAT3532
includes a watchdog timer which requires a period-
ic strobe input from the microprocessor to ensure
correct operation. The AAT3532 has a programma-
ble watchdog timer and voltage tolerance level.
The quiescent supply current is extremely low, typ-
ically 23µA.
•
•
•
•
Adjustable 4.5V or 4.75V Voltage Monitor
250ms (min) Reset Pulse Width
Low Quiescent Current: Typically 23µA
Adjustable Watchdog Timer (150ms, 600ms,
or 1200ms)
De-bounced Manual Reset Input
Operates Down to 20ns Strobe Input Pulse
Width
•
•
•
•
•
•
No External Components
Temperature Range: -40° to +85°C
Standard 8-Pin SOP Package
Pin Compatible with MAX1232
Applications
The AAT3532 is available in a Pb-free, 8-pin SOP
package and is specified over the -40°C to +85°C
temperature range.
•
•
•
•
•
•
Automotive
Computers
Controllers
Embedded Systems
Intelligent Instrumentation
Telecom Equipment
Typical Application
VDD
VCC
VDD
RESET
INPUT
PBRST
AAT3532
TD
RST
RST
µP
ST
I/O
TOL
GND
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AAT3532
MicroPower™ Microprocessor Reset Circuit
Pin Descriptions
Pin #
Symbol
Function
1
PBRST
Push-button reset input. A de-bounced active low input for manual reset. Guaranteed
to recognize inputs 20ms or greater.
2
3
4
5
TD
Watchdog time delay set input. See Table 1 for watchdog timeout selections.
Tolerance set. Input selects 5% or 10% threshold detection.
IC ground connection.
TOL
GND
RST
Reset output (active high). Activated when either: VCC falls below the reset voltage
threshold; PBRST is forced low; ST is not strobed within the minimum timeout period;
or during power-up.
6
7
RST
ST
Reset output (active low, open drain). Inverse of RST.
Strobe input to watchdog timer. A pulse is required within the watchdog timeout period
to prevent RST and RST entering active state.
8
VCC
5V supply.
Pin Programming Selections
Timeout
TD Pin
Min
Typ
Max
GND
Float
VCC
62.5ms
250ms
500ms
150ms
600ms
1200ms
250ms
1000ms
2000ms
Table 1: TD Pin Programming for Watchdog Timeout Selections.
TOL Pin
Tolerance
VCC
10%
5%
GND
Table 2: Reset Voltage Threshold Programming Selections.
Pin Configuration
SOP-8
(Top View)
1
8
VCC
PBRST
2
3
4
7
6
5
TD
TOL
GND
ST
RST
RST
2
3532.2005.12.1.2
AAT3532
MicroPower™ Microprocessor Reset Circuit
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
Description
Value
Units
VCC
VI/O
TA
VCC to GND
-0.5 to 6
-0.5 to (VCC+0.5)
-40 to 85
-65 to 150
300
V
V
Voltage on I/O Pins Relative to GND
Operating Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at leads) for 10s
ESD Rating2—HBM
°C
°C
°C
V
TS
TLEAD
VESD
2000
Thermal Characteristics3
Symbol
Description
Value
Units
ΘJA
PD
Maximum Thermal Resistance
Maximum Power Dissipation
100
°C/W
W
1.25
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.
3. Mounted on an FR4 board.
3532.2005.12.1.2
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AAT3532
MicroPower™ Microprocessor Reset Circuit
DC Electrical Characteristics
VIN = 4.5V to 5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
VCC
Supply Voltage
4.5
5.0
23
5.5
50
V
CMOS Levels
TTL Levels
IQ
Quiescent Current1
VCC = 5.5V
µA
V
160
4.62
4.37
500
4.74
4.49
1.0
Reset Threshold 5%
Reset Threshold 10%
Input Leakage ST, TOL
Output Current RST2
Current RST2, RST
TOL = GND
TOL = VCC
4.50
4.25
-1.0
-8.0
10.0
2.0
VCCTP
IIL
IOH
IOL
µA
mA
mA
V
VOH = 2.4V
VOL = 0.4V
VIH
VIL
IRST
ST and PBRST Input High
ST and PBRST Input Low
RST Output Leakage
VCC + 0.3
0.8
-0.3
V
VOH = VCC
1.0
µA
AC Electrical Characteristics
VIN = 4.5V to 5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
CIN
COUT
tPB
Input Capacitance ST, TOL3
Output Capacitance RST, RST3
PBRST4
TA = 25ºC
5
7
pF
pF
ms
ms
ms
ns
TA = 25ºC
See Figure 2
See Figure 2
20
1
tPBD
tRST
tST
PBRST Delay
4
20
Reset Active Time
ST Pulse Width
250
20
610
1000
See Figure 3
TD Pin = 0V
TD Pin = Open
TD Pin = VCC
4.75V to 4.25V
4.25V to 4.75V
VCC Falling
62.5
250
500
10
150
600
250
1000
2000
tTD
ST Time-out Period
ms
1200
tf
VCC Fall Time3
VCC Rise Time3
µs
µs
µs
ms
tr
0
5
tRPD
tRPU
VCC Detect to RST High and RST Low
VCC Detect to RST Low and RST Open
50
VCC Rising
250
610
1000
1. Measured with outputs open and ST toggling at 100kHz, 50% duty cycle.
2. RST is an open drain output.
3. Guaranteed by design and not subject to production testing.
4. PBRST must remain low for greater than 20ms to guarantee a reset.
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3532.2005.12.1.2
AAT3532
MicroPower™ Microprocessor Reset Circuit
Functional Block Diagram
VCC
VCC
Tolerance
Select
TOL
RST
RST
Reset
Generator
VREF
De-Bounce
Circuit
PBRST
ST
Watchdog
Timer
Detector
Watchdog
Timer
TD
GND
age can be set by programming the TOL pin.
Connecting TOL to VCC sets the 10% tolerance of
the VCC supply (typically 4.37V for VCC = 5V).
Connecting TOL to GND sets the 5% tolerance of
the VCC supply (typically 4.62V for VCC = 5V). The
reset pin is guaranteed to remain asserted for a
minimum period of 250ms after VCC has risen
above the reset threshold voltage. (See Figure 1.)
Applications Information
Power Monitor
The reset function monitors the VCC supply to ensure
a microprocessor is correctly reset and is powered
up into a known condition following a power supply
failure. RST and RST will remain valid for VCC volt-
ages down to 1.4V.
RST output is an open drain output. For correct
The RST and RST pins are asserted whenever VCC
drops below the reset threshold voltage. This volt-
operation, a pull-up resistor of 10kΩ should be con-
nected between this output and VCC
.
+5V
+4.75V (5% Trip Point)
+4.50V (10% Trip Point)
VCC
0V
RESET Output Delay (VCC Falling)
tRPD
RESET Output Delay (VCC Rising)
RST
tRPU
RST
Figure 1: Reset Output Delay.
3532.2005.12.1.2
5
AAT3532
MicroPower™ Microprocessor Reset Circuit
the effect of noise glitches at the input. The signal
should remain low for a minimum of 20ms for cor-
rect operation. Once the PBRST signal is released
(or goes to a logic high), RESET (RESET) remains
asserted for a minimum of 250ms.
Manual Reset
The PBRST pin makes it possible to manually
reset the system by either directly connecting a
mechanical push-button between the PBRST pin
and GND or connecting to a logic low output.
Internal de-bounce circuitry is provided to reduce
tPB
tPBD
PBRST
tRST
RESET
RESET
Figure 2: Push-Button Reset.
starts once the RST signals become inactive. If the
Watchdog Timer
watchdog timer does not receive a high-to-low tran-
sition within the specified timeout period, then the
RST signals are activated for a minimum 250ms. In
normal operation, the timer should receive a transi-
tion from the microprocessor within the timeout
period, in which case the timer is reset and normal
operation continues.
The watchdog timer monitors the microprocessor
to ensure that the system is functioning correctly.
The ST pin of the AAT3532 can be derived from the
microprocessor data signals, address signals,
and/or I/O signals. The watchdog timer function
forces the RST and RST signals into the active
state when the ST input is not toggled by a pre-
determined time. This time period is set by the logic
state of the TD pin, as shown in Table 1. The timer
The AAT3532 will accept and recognize ST pulses
down to a minimum of 20ns wide.
tST
ST
tTD
Figure 3: Watchdog Input.
6
3532.2005.12.1.2
AAT3532
MicroPower™ Microprocessor Reset Circuit
Ordering Information
Package
Marking
Part Number (Tape and Reel)1
AAT3532IAS-T1
SOP-8
3532
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Package Information
SOP-8
4.90 0.10
0.375 0.125
45°
0.235 0.045
0.825 0.445
0.42 0.09 × 8
1.27 BSC
All dimensions in millimeters.
1. Sample stock is generally held on all part numbers listed in BOLD.
3532.2005.12.1.2
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AAT3532
MicroPower™ Microprocessor Reset Circuit
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,
or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.
Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech
warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-
trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
8
3532.2005.12.1.2
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