AME, Inc.
1
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
nn
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n Features
lSmall packages: SOT-23-5
l7 voltage threshold options
lTight voltage threshold tolerance --- ±1.50%
l 12 output driver configuration options
lWide temperature range -------- -45oC to 85oC
lLow temperature coefficient --- 100ppm/oC (max)
lLow quiescent current < 3.0µA
l3 bonding options
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n General Description
The AME8510/8520/8530 family allows the user to cus-
tomize the CPU monitoring function without any external
components. The user has a large choice of reset volt-
age thresholds and output driver configurations, all of
which are preset at the factory. Each wafer is trimmed
to the customer's specifications.
These circuits will ignore fast negative going transients
on VDD. The state of the reset output is guaranteed to be
correct down to 1V.
After VDD crosses above a factory preset threshold, the
AME8510/8520/8530 assert a reset signal. After a pre-
determined time (the “reset” interval) the reset is
deasserted. If VDD ever drops below the threshold volt-
age a reset is asserted immediately. In addition to a
supply monitoring function the AME8510/8520 also moni-
tor transitions at the watch dog (WDI) input. If a logic
transition does not occur at the WDI pin within a certain
time interval (the “watchdog” interval) then a reset is as-
serted. The reset deasserts after the reset interval, as
explained earlier.
The AME8510/8530 can both assert a reset manually
by pulling the MRB input to ground.
Space saving SOT25 packages and micropower quies-
cent current make this family a natural for portable bat-
tery powered equipment.
nn
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n Applications
lMotherboards
lComputer peripherals
lPortable electronics
lApplications using CPUs
lConsumer electronics
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n Pin Configuration
SOT-25 Top View
AME8510
AME8511
AME8510
V
DD
WDI
RESET/
RESETB GND MRB
AME8510
AME8511
AME8520
V
DD
WDI
GND
RESET/
RESETB RESETB/
RESET
V
DD
MRB
GND
RESET/
RESETB RESETB/
RESET
AME8530
AME851
AME8530
AME, Inc.
2
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
AME8530
AME851
8510/20/30
WDI/MRB
PIN 1 PIN 3
GND
V
DD
n O rd e ri n g In f ormat i on
AME8510AEEV X X X XX
AME8520AEEV X X X XX
AME8530AEEV X X X XX VDD Threshol d V oltage
22: VTH=2.19V
23: VTH=2.32V
26: VTH=2.63V
29: VTH=2.93V
31: VTH=3.08V
44: VTH=4.38V
46: VTH=4.63V
Watch Do g Interval (TWDNOM)
E: TD=1760mS
X: W ithout W DI option
Reset Time (TD2NOM)
F: TD=210mS
Outpu t Dr iver Optio n
Polarity * Polarity *
A: RESETB PP N/A N/A
B: RESETB OD N/A N/A
C: RESET PP N/A N/A
--F or example-- D: RESET OD N/A N/A
AME8520AEEVEF E29 means: E: RESET B PP R ESET PP
Output at pin 1 is RESETB, push pull F : RESET B PP R ESET OD
Output at pin 3 is RESET, push pull G: RESET B OD RES ET PP * O utput Driver Chart Explanation:
Reset time is 210mS H: RESET B O D RESET OD PP = Push pull output
W atch dog interval is 1760mS I : RESET PP RESET B PP OD = Open drain output
VDD threshold voltage is 2.93V J : RESET PP RESET B OD N/A = Not available (8510)
No temperature shutdown K: RESET OD RESET B PP RESET = Active high
L: RESET OD RESETB OD RESETB = Active low
Please cons ult AME sales office or authorized Rep. for other RESET TIME int erval and Watch D og time interval.
Pin 1 Pin 3
AME, Inc.
3
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
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n Absolute Maximum Ratings
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n Recommended Operating Conditions
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n Thermal Information
Caution: Stress above the listed absolute rating may cause permanent damage to the device
Maximum Unit
6V
B
Maximum Unit
256 oC / W
150 oC
300 oC
Parameter
Su ppl y Vol t age
ESD Classif icat ion
Parameter
Ambien t T em per at u r e R ange
Junct ion Tem perat ur e
Su ppl y Vol t age
Parameter Rating
0. 9 - 5 V
Th er m al R esistance (SO T - 25)
M axim um Lead Tem perat ure ( 10 Sec)
M axim u m Junct ion Temper atur e
- 40 to +85 oC
- 40 to +125 oC
AME, Inc.
4
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
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n Electrical Specifications
T
A
=
25
o
C unless otherwise noted
PARAMETER SYMBOL MIN TYP MAX UNITS
VDD Range VRANGE 15.5V
S upply Current IDD 310
µA
Reset Threshold* VTH VTH - 1.5% VTH + 1.5% V
ResetB O utput Voltage Hgh VDD>VTH ma x
Reset Output Voltage H gh VDD<VTH min
ResetB O utput Voltage Low VDD<VTH min
Reset Output Voltage Low VDD>VTH ma x
VDD to Reset Delay T D1 VDD = V TH - 100mV 40 µS
Reset Timeout P eriod* T D2 TA=-40~850CVersion F 140 210 280 mS
Watch Dog Timeout P eriod* T WD 1120 1760 2400 mS
WDI Pulse Width TWDI 50 nS
WDIIL 0.7 V
WDIIH 0.8VDD V
IIL WDI = 0V -15 -8
IIH WDI = VDD = 5.0V 8 15
MRBIL 0.7
MRBIH 0.8VDD
MRB Pulse W idth TWMRB 1µS
MRB Noise Immunity
(pulse width with no reset) 100 nS
MRB t o Reset Delay T DMRB 500 nS
MR B P ull Up R esistan ce 80 120 K ohm
* See th e ch art on page 2 for av ailable v alu es of th is param eter.
VOH V
VOL V0.5
0.8VDD
µA
VMR B I nput Threshold
W DI Input Threshold
W DI Input Current
VDD = V TH x 1.2
VDD = V TH x 1.2
Version E
TEST CONDITIONS
WDI and MRB unconn ected
ISOURCE= 0.5mA,
TA=-40~850C
ISNK= 1.2mA,
TA=-40~850C
AME, Inc.
5
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
n
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n Pin Description
Ground
Pin Numbe r
Thi s pi n m ay be eit her RE S E T or
RESETB. RESETB is active low. In the
c ase of t he A M E 8520 and A M E 8530 t hi s
pin wi ll alway s be t he opposite polarit y from
pin 3. This pin can be pus h/ pul l or open
drain.
111
RESET/
RESETB
222
This pin may be either RESETB or RESET.
RE S E T i s act ive high. In t he cas e of t he
A M E 8520 and A M E 8530 t hi s pi n wi ll
always be t he opposite pol ari t y from pi n 1.
Thi s pi n c an be eit her push/ pull or open
drain.
Wat c h Dog Input. A ny t rans i ti on on t hi s
pin wi ll reset t he wat c h dog t i mer. If thi s
pin rem ai ns high or low for longer t han t he
wat c h dog interval t hen a res et is as sert ed.
Fl oat or t ris t ate t his pi n t o disable t he
wat c h dog feat ure.
M anual Res et . A c t i ve low. P ul li ng t his pin
low forces a res et . A ft er a low t o hi gh
t rans i t ion res et rem ains as s ert ed for
exact l y one reset t i m eout period. Thi s pi n
is int ernal ly pulled hi gh. If thi s func t ion i s
unus ed t hen fl oat t hi s pin or t i e it t o V DD.
P os i t i ve power supply. A res et is as serted
aft er t his voltage drops below a
predeterm i ned level . A ft er V DD ris es above
t hat level res et rem ains as serted until t he
end of t he res et t i m eout period.
GND
N/A 3 3 RESET/
RESETB
34N/A MRB
44N/AWDI
555V
DD
Name Description
AME8510 AME8520 AME8530
AME, Inc.
6
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
nn
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n Detailed Description
The AME8510/8520/8530 are designed to interface with
the reset input of a microprocessor and to prevent CPU
execution errors due to power up, power down, and other
power supply errors. The AME8510/8520 also monitor
the CPU health by checking for signal transitions from
the CPU at the WDI input.
Reset Output
Each output pin in the family can be configured to be
either push/pull or open drain. In addition each output
may be either active high or active low with the condi-
tion that parts with two outputs must have opposite po-
larities. Active high reset outputs are denoted as RE-
SET. Active low reset outputs are denoted as RESETB.
The selection guide on page 2 of this data sheet shows
all possible combinations of output driver configuration.
A reset will be asserted if any of three things happen:
1) VDD drops below the threshold (VTH)
2) The MRB pin is pulled low .
3) The WDI pin does not detect a transition within
the watch dog interval (TWD).
The reset will remain asserted for the prescribed reset
interval after:
1) VDD rises above the threshold (VTH)
2) MRB goes high
3) The watch dog timer has timed out causing the
reset to assert.
Reset Timing Diagram
Manual Reset Input
The AME8510 and AME8530 feature a manual reset fea-
ture (MRB). A logic low on the MRB pin asserts a reset.
The reset remains asserted as long as the MRB pin re-
mains low . After the MRB pin transitions to a high state
the reset remains asserted for the prescribed reset inter-
val (TD2). The MRB pin is internally pulled up to VDD by
a 100kΩ resistor. It is internally debounced to reject
switching transients.
The MRB pin is ESD protected by diodes connected to
VDD and GND. So the MRB pin should never be driven
higher than VDD or lower than GND.
Watchdog Input
The AME8510 and AME8520 are equipped with a watch-
dog input (WDI). If the microprocessor does not produce
a valid logic edge at the the watchdog input (WDI) within
the prescribed watchdog interval (TWD) then a reset as-
serts. The reset remains asserted for the required reset
interval (TD2) At the end of the reset interval the reset is
deasserted and the watchdog interval timer starts again
from zero.
If the watchdog input is left unconnected or is connected
to a tri-stated buffer the watchdog function is disabled.
As soon as the WDI input is driven either low or high the
watchdog function resumes with the watchdog timer set
to zero.
Watchdog Timing Diagram
WDI
RESETB
VDD
T
WD
T
D2
T
D2
V
TH
V
DD
T
D2
V
Release
RESETB
V
TH
T
D1
T
D2
T
D1
RESET
50%
50%
50%
50%
AME, Inc.
7
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
Watchdog Input Current
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n Detailed Description (contd.)
The watchdog input pin (WDI) typically sources/sinks 8µA
when driven high or low. So from a power dissipation
point of view the duty cycle of the waveform at WDI is
unimportant. When the WDI pin is floating or tri-stated
the power supply current falls to less than 3.0µA.
Glitch Rejection
The AME8510/8520/8530 family will reject negative go-
ing transients on the VDD line to some extent. The smaller
the duration of the transient the larger its amplitude may
be without triggering a reset. The “Glitch Rejection” chart
in the graphs section of this datasheet shows the rela-
tion between glitch amplitude and allowable glitch dura-
tion to avoid unintended resets.
Accurate Output State at Low VDD
With VDD voltage on the order of the MOS transistor thresh-
old (<1.0V) the outputs of the AME8510/8520/8530 may
become undefined. For parts with active low output
(RESETB) a resistor placed between RESETB and GND
on the order of 100kΩ will ensure that the RESETB out-
put stays low when VDD is lower than the threshold volt-
age of the part. In a like manner a resistor on the order of
100kΩ when placed between RESET and VDD will en-
sure parts with active high output (RESET) will remain
high when VDD is lower than the threshold voltage of the
part.
AME, Inc.
8
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
0
20
40
60
80
100
120
140
0.01 0.1 1
Glitch Rejection
Glitch Duration (µ
µµ
µS)
Glitch Amplitude (V)
190
195
200
205
210
215
220
-45 -5 25 55 85 115
Temp erat ure (0C)
Reset Time (mS)
Reset time vs Temperature
Vth=2.63V
2.10
2.15
2.20
2.25
2.30
2.35
-45 -5 25 55 85 115
Temp er ature (0C)
Supply Current @ 5V (uA
)
IDD vs Temperature
Vth=2.63V
2.630
2.632
2.634
2.636
2.638
2.640
2.642
2.644
2.646
2.648
2.650
-45-5255585115
Temperature (0C)
Reset Vth (V)
Reset Vth vs Temperature
Vth=2.63V
0.220
0.225
0.230
0.235
0.240
0.245
0.250
0.255
0.260
0.265
-45 -5 25 55 85 115
Temperature (0C)
Reset VOL @ 0.8mA (V)
RESETB VOL vs Temperature
Vth=2.63V
AME, Inc.
9
AME8510 / 8520 / 8530 Micropower µµ
µµ
µP W atch Dog T imer
SOT-25
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n Package Dimension
MIN MAX MIN MAX
A 1.00 1.45 0.0394 0.0571
A10.00 0.15 0.0000 0.0591
A2 0.70 1.25 0.0276 0.0492
b 0.35 0.55 0.0138 0.0217
C 0.08 0.25 0.0031 0.0098
D 2.70 3.10 0.1063 0.1220
E 1.40 1.80 0.0551 0.0709
e
H 2.60 3.00 0.1024 0.1181
L 0.30 - 0.0118 -
θ1
θ1θ1
θ1 0°10°0°10°
S10.85 1.05 0.0335 0.0413
1.90 BSC 0.07480 BSC
SYMBOLS MILLIMETERS INCHES
Life Support Policy:
These products of AME, Inc. are not authorized for use as critical components in life-support devices or
systems, without the express written approval of the president
of AME, Inc.
AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and
advises its customers to obtain the latest version of relevant information.
AME, Inc., January 2002
Document: 2007-DS8510/8520/8530-B
U.S. Headquarters Corporate Headquarters
Analog Microelectronics, Inc. AME, Inc.
3100 De La Cruz Blvd. Suite 201 2F, 189 Kang-Chien Road, Nei-Hu Dist.
Santa Clara, CA. 95054-2046 Taipei 114, Taiwan, R.O.C.
Tel : (408) 988-2388 Tel : 886 2 2627-8687
Fax: (408) 988-2489 Fax: 886 2 2659-2989
www.ame.com.tw
E-Mail: info@ame.com.tw
