Microprocessor
Supervisory Circuits
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
FEATURES
Upgrade for ADM690 to ADM695, MAX690 to MAX695
Specified over temperature
Low power consumption (0.7 mW)
Precision voltage monitor
Reset assertion down to 1 V V
CC
Low switch on resistance 0.7 Ω normal, 7 Ω in backup
High current drive (100 mA)
Watchdog timer: 100 ms, 1.6 s, or adjustable
400 nA standby current
Automatic battery backup power switching
Extremely fast gating of chip enable signals (3 ns)
Voltage monitor for power fail
Available in TSSOP package
V
BATT
V
OUT
V
CC
4.65V
1
RESET
GENERATOR
2
FUNCTIONAL BLOCK DIAGRAMS
RESET
WATCHDOG
INPUT (WDI)
POWER FAIL
INPUT (PFI)
WATCHDOG
TRANSITION DETECTOR
(1.6s)
ADM8690/
ADM8692/
ADM8694
POWER FAIL
OUTPUT (PFO)
1.3V
1
VOLTAGE DETECTOR = 4.65V (ADM8690, ADM8694)
2
RESET PULSE WIDTH = 50ms (AD8690, ADM8692)
Microprocessor systems
Computers
Controllers
Intelligent instruments
Automotive systems
200ms (ADM8694)
Figure 1. ADM8690/ADM8692/ADM8694
BATT ON
V
BATT
PRODUCT HIGHLIGHTS
The ADM8690, ADM8692, and ADM8694 are available in
8-lead, PDIP packages and provide:
1.
Power-on reset output during power-up, power-down, and
brownout conditions. The RESET output remains
operational with V
CC
as low as 1 V.
Battery backup switching for CMOS RAM, CMOS
microprocessor, or other low power logic.
A reset pulse if the optional watchdog timer has not been
toggled within a specified time.
A 1.3 V threshold detector for power-fail warning, low battery
detection, or to monitor a power supply other than 5 V.
V
CC
CE
IN
ADM8691/
ADM8693/
ADM8695
V
OUT
CE
OUT
4.65V
1
LOW LINE
RESET
2.
3.
4.
OSC IN
OSC SEL
RESET AND
WATCHDOG
TIME BASE
RESET
GENERATOR
RESET
WATCHDOG
INPUT (WDI)
POWER FAIL
INPUT (PFI)
WATCHDOG
TRANSITION DETECTOR
WATCHDOG
TIMER
WATCHDOG
OUTPUT (WDO)
POWER FAIL
OUTPUT (PFO)
00093-002
1.3V
1
VOLTAGE DETECTOR = 4.65V (ADM8691, ADM8695)
The ADM8691, ADM8693, and ADM8695 are available in 16-lead
PDIP and small outline packages (including TSSOP) and
provide three additional functions:
1.
2.
3.
Write protection of CMOS RAM or EEPROM.
Adjustable reset and watchdog timeout periods.
Separate watchdog timeout, backup battery switchover, and
low V
CC
status outputs.
4.40V (ADM8693)
Figure 2. ADM8691/ADM8693/ADM8695
Rev. A
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2006 Analog Devices, Inc. All rights reserved.
00093-001
APPLICATIONS
4.40V (ADM8692)
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Product Highlights ........................................................................... 1
Functional Block Diagrams............................................................. 1
Revision History ............................................................................... 2
General Description ......................................................................... 3
Specifications..................................................................................... 4
Absolute Maximum Ratings............................................................ 6
ESD Caution.................................................................................. 6
Pin Configurations and Function Descriptions ........................... 7
Typical Performance Characteristics ............................................. 8
Circuit Information ........................................................................ 10
Battery Switchover Section........................................................ 10
Power-Fail RESET Output......................................................... 10
Watchdog Timer RESET............................................................ 11
Watchdog Output (WDO) ........................................................ 12
CE Gating and RAM Write Protection
(ADM8691/ADM8693/ADM8695) ......................................... 12
Power-Fail Warning Comparator............................................. 13
Application Information................................................................ 14
Increasing the Drive Current.................................................... 14
Using a Rechargeable Battery for Backup ............................... 14
Adding Hysteresis to the Power-Fail Comparator ................. 14
Monitoring the Status of the Battery ....................................... 14
Alternate Watchdog Input Drive Circuits............................... 15
Typical Applications....................................................................... 16
ADM8690, ADM8692, and ADM8694 ................................... 16
ADM8691, ADM8693, and ADM8695 ................................... 16
RESET Output ............................................................................ 16
Power-Fail Detector ................................................................... 17
RAM Write Protection............................................................... 17
Watchdog Timer......................................................................... 17
Outline Dimensions ....................................................................... 18
Ordering Guide .......................................................................... 19
REVISION HISTORY
9/06—Rev.
0 to Rev. A
Updated Format..................................................................Universal
Changes to Absolute Maximum Ratings ....................................... 6
Updated Ordering Guide............................................................... 20
2/97—Revision 0: Initial Version
Rev. A | Page 2 of 20
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
GENERAL DESCRIPTION
The ADM869x family of supervisory circuits offers complete
single- chip solutions for power supply monitoring and battery
control functions in microprocessor systems. These functions
include microprocessor reset, backup battery switchover,
watchdog timer, CMOS RAM write protection, and power
failure warning. The complete family provides a variety of
configurations to satisfy most microprocessor system
requirements.
The ADM869x family is fabricated using an advanced epitaxial
CMOS process combining low power consumption (0.7 mW),
extremely fast chip enable gating (3 ns), and high reliability.
RESET assertion is guaranteed with V
CC
as low as 1 V. In
addition, the power switching circuitry is designed for minimal
voltage drop thereby permitting increased output current drive
of up to 100 mA without the need of an external pass transistor.
See Table 1 for a product selection guide listing the characteristics
of each device in the ADM869x family. To place an order, use
the Ordering Guide provided as the last section of this data sheet.
Table 1. Product Selection Guide
Part
Number
ADM8690
ADM8691
ADM8692
ADM8693
ADM8694
ADM8695
Nominal
Reset Time
50 ms
50 ms or ADJ
50 ms
50 ms or ADJ
200 ms
200 ms or ADJ
Nominal V
CC
Reset
Threshold
4.65 V
4.65 V
4.4 V
4.4 V
4.65 V
4.65 V
Nominal Watchdog
Timeout Period
1.6 s
100 ms, 1.6 s, ADJ
1.6 s
100 ms, 1.6 s, ADJ
1.6 s
100 ms, 1.6 s, ADJ
Battery Backup
Switching
Yes
Yes
Yes
Yes
Yes
Yes
Base Drive
Ext PNP
No
Yes
No
Yes
No
Yes
Chip Enable
Signals
No
Yes
No
Yes
No
Yes
Rev. A | Page 3 of 20
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
SPECIFICATIONS
V
CC
= full operating range, V
BATT
= 2.8 V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 2.
Parameter
BATTERY BACKUP SWITCHING
V
CC
Operating Voltage Range
ADM8690, ADM8691, ADM8694, ADM8695
ADM8692, ADM8693
V
BATT
Operating Voltage Range
ADM8690, ADM8691, ADM8694, ADM8695
ADM8692, ADM8693
V
OUT
Output Voltage
V
OUT
in Battery Backup Mode
Supply Current (Excludes I
OUT
)
Supply Current in Battery Backup Mode
Battery Standby Current
+ = Discharge, − = Charge
Battery Switchover Threshold
V
CC
– V
BATT
Battery Switchover Hysteresis
BATT ON Output Voltage
BATT ON Output Short-Circuit Current
RESET AND WATCHDOG TIMER
Reset Voltage Threshold
ADM8690, ADM8691, ADM8694, ADM8695
ADM8692, ADM8693
Reset Threshold Hysteresis
Reset Timeout Delay
ADM8690, ADM8691, ADM8692, ADM8693
ADM8694, ADM8695
Watchdog Timeout Period, Internal Oscillator
Watchdog Timeout Period, External Clock
Minimum WDI Input Pulse Width
RESET Output Voltage @ V
CC
= 1 V
RESET, LOW LINE Output Voltage
RESET, WDO Output Voltage
Output Short-Circuit Source Current
Output Short-Circuit Sink Current
WDI Input Threshold
1
Logic Low
Logic High
WDI Input Current
3.5
1
10
25
Min
Typ
Max
Unit
Test Conditions/Comments
4.75
4.5
2.0
2.0
V
CC
− 0.005
V
CC
− 0.2
V
BATT
− 0.005
5.5
5.5
4.25
4.0
V
CC
− 0.0025
V
CC
− 0.125
V
BATT
− 0.002
140
0.4
V
V
V
V
V
V
V
μA
μA
μA
mV
mV
mV
V
mA
μA
200
1
+0.02
−0.1
70
50
20
I
OUT
= 1 mA
I
OUT
≤ 100 mA
I
OUT
= 250 μA, V
CC
< V
BATT
− 0.2 V
I
OUT
= 100 μA
V
CC
= 0 V, V
BATT
= 2.8 V
5.5 V > V
CC
> V
BATT
+ 0.2 V
T
A
= 25°C
Power-up
Power-down
I
SINK
= 3.2 mA
BATT ON = V
OUT
= 4.5 V sink current
BATT ON = 0 V source current
0.3
0.5
55
2.5
25
4.5
4.25
4.65
4.4
40
50
200
1.6
100
4064
1011
4
0.05
4.73
4.48
V
V
mV
ms
ms
s
ms
cycles
cycles
ns
mV
V
V
V
V
μA
mA
V
V
μA
μA
OSC SEL = high
OSC SEL = high
Long period
Short period
Long period
Short period
V
IL
= 0.4, V
IH
= 3.5 V
I
SINK
= 10 μA, V
CC
= 1 V
I
SINK
= 1.6 mA, V
CC
= 4.25 V
I
SOURCE
= 1 μA
I
SINK
= 1.6 mA
I
SOURCE
= 1 μA
35
140
1.0
70
3840
768
50
70
280
2.25
140
4097
1025
20
0.4
0.4
25
3.5
0.8
3.5
−10
1
−1
10
WDI = V
OUT
WDI = 0 V
Rev. A | Page 4 of 20
ADM8690/ADM8691/ADM8692/ADM8693/ADM8694/ADM8695
Parameter
POWER-FAIL DETECTOR
PFI Input Threshold
PFI Input Current
PFO Output Voltage
PFO Short-Circuit Source Current
PFO Short-Circuit Sink Current
CHIP ENABLE GATING
CE
IN
Threshold
3.0
CE
IN
Pull-Up Current
CE
OUT
Output Voltage
V
OUT
− 1.5
V
OUT
− 0.05
CE Propagation Delay
OSCILLATOR
OSC IN Input Current
OSC SEL Input Pull-Up Current
OSC IN Frequency Range
OSC IN Frequency with External Capacitor
1
Min
1.25
−25
3.5
1
Typ
1.3
±0.01
Max
1.35
+25
0.4
25
Unit
V
nA
V
V
μA
mA
V
V
μA
V
V
V
ns
μA
μA
kHz
kHz
Test Conditions/Comments
V
CC
= 5 V
I
SINK
= 3.2 mA
I
SOURCE
= 1 μA
PFI = low, PFO = 0 V
PFI = high, PFO = V
OUT
V
IL
V
IH
I
SINK
= 3.2 mA
I
SOURCE
= 3.0 mA
I
SOURCE
= 1 μA, V
CC
= 0 V
3
25
0.8
3
0.4
3
±2
5
0
4
7
500
OSC SEL = 0 V
OSC SEL = 0 V, C
OSC
= 47 pF
WDI is a three-level input that is internally biased to 38% of V
CC
and has an input impedance of approximately 5 MΩ.
Rev. A | Page 5 of 20
