202245A.pdf

DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
General Description
Features
The AAT3532 PowerManager is a member of Skyworks'
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 condition for
a minimum of 250ms while VCC is established 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 periodic strobe input from the microprocessor to ensure correct operation. The AAT3532 has
a programmable watchdog timer and voltage tolerance
level. The quiescent supply current is extremely low,
typically 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
The AAT3532 is available in a Pb-free, 8-pin SOP package and is specified over the -40°C to +85°C temperature range.
Applications
•Automotive
•Computers
•Controllers
• Embedded Systems
• Intelligent Instrumentation
• Telecom Equipment
Typical Application
VDD
VDD
VCC
PBRST
RST
AAT3532
TD
RESET
INPUT
µP
RST
ST
I/O
TOL
GND
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202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
1
DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
Pin Descriptions
Pin #
Symbol
1
PBRST
2
3
4
TD
TOL
GND
5
RST
6
RST
7
ST
8
VCC
Function
Push-button reset input. A de-bounced active low input for manual reset. Guaranteed to recognize inputs
20ms or greater.
Watchdog time delay set input. See Table 1 for watchdog timeout selections.
Tolerance set. Input selects 5% or 10% threshold detection.
IC ground connection.
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.
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.
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
GND
10%
5%
Table 2: Reset Voltage Threshold Programming Selections.
Pin Configuration
SOP-8
(Top View)
1
VCC
2
2
8
7
ST
3
6
RST
4
5
RST
PBRST
1
TD
2
TOL
GND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
VCC
VI/O
TA
TS
TLEAD
VESD
Description
VCC to GND
Voltage on I/O Pins Relative to GND
Operating Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at leads, 10 sec.)
ESD Rating2—HBM
Value
Units
-0.5 to 6
-0.5 to (VCC+0.5)
-40 to 85
-65 to 150
300
2000
V
V
°C
°C
°C
V
Value
Units
100
1.25
°C/W
W
Thermal Characteristics3
Symbol
QJA
PD
Description
Maximum Thermal Resistance
Maximum Power Dissipation
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions 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 1.5kW resistor into each pin.
3. Mounted on an FR4 board.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
3
DATA SHEET
AAT3532
MicroPowerTM 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
VCC
Supply Voltage
IQ
VCCTP
IIL
IOH
IOL
VIH
VIL
IRST
Conditions
Quiescent Current
VCC = 5.5V
Reset Threshold 5%
Reset Threshold 10%
Input Leakage ST, TOL
Output Current RST2
Current RST2, RST
ST and PBRST Input High
ST and PBRST Input Low
RST Output Leakage
TOL = GND
TOL = VCC
1
Min
Typ
Max
Units
4.5
5.0
23
160
4.62
4.37
5.5
50
500
4.74
4.49
1.0
V
CMOS Levels
TTL Levels
VOH = 2.4V
VOL = 0.4V
4.50
4.25
-1.0
-8.0
10.0
2.0
-0.3
VCC + 0.3
0.8
1.0
VOH = VCC
µA
V
µA
mA
mA
V
V
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
CIN
COUT
tPB
tPBD
tRST
tST
4
Conditions
Input Capacitance ST, TOL3
Output Capacitance RST, RST3
PBRST4
PBRST Delay
Reset Active Time
ST Pulse Width
TA = 25ºC
TA = 25ºC
See Figure 2
See Figure 2
tTD
ST Time-out Period
tf
tr
VCC
VCC
VCC
VCC
tRPD
tRPU
1.
2.
3.
4.
Description
Fall Time3
Rise Time3
Detect to RST High and RST Low
Detect to RST Low and RST Open
See Figure 3
TD Pin = 0V
TD Pin = Open
TD Pin = VCC
4.75V to 4.25V
4.25V to 4.75V
VCC Falling
VCC Rising
Min
20
1
250
20
62.5
250
500
10
0
250
Typ
Max
Units
5
7
pF
pF
ms
ms
ms
ns
4
610
20
1000
150
600
1200
250
1000
2000
5
610
50
1000
Measured with outputs open and ST toggling at 100kHz, 50% duty cycle.
RST is an open drain output.
Guaranteed by design and not subject to production testing.
PBRST must remain low for greater than 20ms to guarantee a reset.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
ms
µs
µs
µs
ms
DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
Functional Block Diagram
VCC
TOL
VCC
Tolerance
Select
Reset
Generator
RST
RST
VREF
PBRST
ST
De-Bounce
Circuit
Watchdog
Timer
Detector
Watchdog
Timer
TD
GND
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 voltages down to 1.4V.
The RST and RST pins are asserted whenever VCC drops
below the reset threshold voltage. This voltage 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.)
The RST output is an open drain output. For correct
operation, a pull-up resistor of 10kW should be connected between this output and VCC.
Manual Reset
The PBRST pin makes it possible to manually reset the
system by either directly connecting a mechanical pushbutton between the PBRST pin and GND or connecting to
a logic low output. Internal de-bounce circuitry is provided to reduce the effect of noise glitches at the input.
The signal should remain low for a minimum of 20ms for
correct operation. Once the PBRST signal is released (or
goes to a logic high), RESET (RESET) remains asserted
for a minimum of 250ms.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
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DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
+5V
+4.75V (5% Trip Point)
VCC
+4.50V (10% Trip Point)
0V
RESET Output Delay (VCC Rising)
RESET Output Delay (VCC Falling)
tRPU
tRPD
RST
RST
Figure 1: Reset Output Delay.
t PB
t PBD
PBRST
t RST
RESET
RESET
Figure 2: Push-Button Reset.
6
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
Watchdog Timer
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
starts once the RST signals become inactive. If the
watchdog timer does not receive a high-to-low transition
within the specified timeout period, then the RST signals
are activated for a minimum 250ms. In normal operation, the timer should receive a transition from the
microprocessor within the timeout period, in which case
the timer is reset and normal operation continues.
The AAT3532 will accept and recognize ST pulses down
to a minimum of 20ns wide.
t ST
ST
t TD
Figure 3: Watchdog Input.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012
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DATA SHEET
AAT3532
MicroPowerTM Microprocessor Reset Circuit
Ordering Information
Package
Marking
Part Number (Tape and Reel)1
SOP-8
3532
AAT3532IAS-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information
6.00 ± 0.20
3.90 ± 0.10
SOP-8
4.90 ± 0.10
0.42 ± 0.09 × 8
1.27 BSC
45°
4° ± 4°
0.175 ± 0.075
1.55 ± 0.20
0.375 ± 0.125
0.235 ± 0.045
0.825 ± 0.445
All dimensions in millimeters.
1. Sample stock is generally held on all part numbers listed in BOLD.
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202245A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 8, 2012