Impala Linear Corporation
ILC705/706/707/708
mP Supervisory Circuit
General Description
The ILC705/ILC706/ILC707/ILC708 are low cost micro-
processor supervisory circuits that monitor power sup-
plies in microprocessor based systems. Circuit functions
include a watchdog timer, microprocessor reset, power
failure warning and a debounced manual reset input.
The ILC705 and ILC706 offer a watchdog timer function
while the ILC707 and ILC708 have an active high reset
output in addition to the active low reset output.
Supply voltage monitor levels of 4.65V and 4.4V are
available. The ILC705/ILC707 have a nominal reset
threshold level of 4.65V while the ILC706 and ILC708
have a 4.4V nominal reset threshold level. When the sup-
ply voltage drops below the respective reset threshold
level, RESET is asserted.
Features
!
4.4V or 4.65V Precision Voltage Monitor
!
200ms Reset Pulse Width
!
Debounced TTL/CMOS Compatible Manual Reset Input
!
Watchdog Timer with 1.6 sec Timeout (ILC705/ILC706)
!
Voltage Monitor for Early Power Fail Warning or Low
Battery Detect
!
8-Pin SOIC or DIP Package
Applications
!
Computers
!
Controllers
!
Critical Microprocessor Power Monitoring
!
Intelligent Instruments
!
Portable Equipment
!
Controllers
Pin Package Configuration
Typical Circuit
Top View
Manual
Reset
MR
1
8
7
6
5
+5 V (Regulated)
WDO
RESET
WDI
PFO
V
CC
MR
RESET
V
CC
RESET
V
CC
2
GND
3
PFI
4
ILC705
ILC706
DC Voltage
(Unregulated)
PFI
ILC705
ILC706
WDI
WDO
GND PFO
I/O Line
NMI
µ
P
Interrupt
MR
1
8
7
6
5
RESET
RESET
NC
PFO
V
CC
2
GND
3
PFI
4
ILC707
ILC708
Ordering Information
Part
ILC70_N
ILC70_M
Package
8-Lead PDIP
8-Lead SOIC
Temp. Range
-40°C to +85°C
-40°C to +85°C
N Package - 8 Lead Plastic DIP Package
M Package - 8 Lead Plastic SOIC Package
Impala Linear Corporation
ILC705-708 1.0
(408) 574-3939
www.impalalinear.com
Sept 1999
1
mP Supervisory Circuit
Absolute Maximum Ratings
Parameter
Terminal Voltage
Input Current
Output Current
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
Power Dissipation
Symbol
V
CC
All other inputs
V
CC,
GND
All outputs
T
A
Ratings
-0.3 to 6.0
-0.3 to (V
CC
+ 0.3)
25
20
-40 to +85
-65 to +150
300
475
400
Units
V
V
mA
mA
°C
°C
°C
mW
mW
PDIP
SOIC
Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality
at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device
reliability. Operating ranges define those limits between which the functionality of the device is guaranteed.
Electrical Characterisitcs
V
CC
= 4.75 V to 5.5 V for ILC705/ILC707, V
CC
= 4.5 V to 5.5 V for ILC706/ILC708, T
A
= Operating Temperature Range, unless
otherwise noted.
Parameter
Conditions
Min
Typ
Max
Units
Operating Voltage Range, V
CC
ILC70__
1.4
5.5
V
Supply Current, I
CC
ILC70__
60
µA
Reset Voltage Threshold
Reset Threshold Hysteresis
Reset Pulse Width, t
RS
RESET Output Voltage
ILC705, ILC707
ILC706, ILC708
4.5
4.25
140
V
CC
– 1.5V
4.65
4.4
40
200
4.75
4.5
280
0.4
0.3
V
CC
– 1.5V
1.0
50
3.5
-150
V
CC
– 1.5V
100
150
V
IL
V
IH
V
CC
= 5V
I
SINK
= 3.2mA
V
CC
= 5V, I
SOURCE
= 800 µA
0.8
2.0
1.2
-25
V
CC
- 1.5V
1.25
0.01
250
1.3
25
0.4
ns
V
nA
V
250
0.4
600
1.6
0.4
2.25
V
sec
ns
V
µA
150
V
µA
ns
V
V
mV
ms
V
RESET Output Voltage
Watchdog Timeout Period, t
WD
WDI Minimum Input Pulse, t
WP
WDI Threshold Voltage
WDI Input Current
WDO Output Voltage
MR Pull-Up Current
MR Pulse Width, t
MR
MR Input Threshold
MR to Reset Output Delay, t
MD
PFI Input Threshold
PFI Input Current
PFO Output Voltage
I
SOURCE
= 800 µA
I
SINK
= 3.2 mA
I
SINK
= 50 µA, V
CC
= 1.4V
I
SOURCE
= 800 µA
I
SINK
= 1.2 mA
V
IL
= 0.4V, V
IH
= 80% of V
CC
V
IH
, V
CC
= 5V
V
IL
, V
CC
= 5V
WDI = 0V
WDI = V
CC
I
SOURCE
800 µA
I
SINK
= 1.2 mA
MR = 0V
0.8
-50
50
Impala Linear Corporation
ILC705-708 1.0
(408) 574-3939
www.impalalinear.com
Sept 1999
2
mP Supervisory Circuit
Pin Functions
Pin Number
Pin
Name
MR
ILC705
ILC706
1
ILC707
ILC708
1
Manual reset input. MR forces RESET to assert when pulled below 0.8V.
An internal pull-up current of 250 mA on this input forces it high when
left floating. This input can also be driven from TTL or CMOS logic.
Power supply input, 5V.
Ground pin, 0 V reference.
Power fail input. Internally connected to the power fail comparator, which
is referenced to 1.25V. The power fail output (PFO) remains high if PFI
is above 1.25V. PFI should be connected to GND or V
OUT
if the power
fail comparator is not used.
Power fail output. The power fail comparator is independent of all other
functions on this device.
Watchdog input. The WDI input monitors microprocessor activity, an
internal watchdog timer resets itself with each transition on the watchdog
input. If the WDI pin is held high or low for longer than the watchdog
timeout period, WDO is forced to active low. The watchdog function can
be disabled by floating the WDI pin.
No Connect.
RESET output. RESET is asserted if either V
CC
goes below the reset
threshold or by a low signal on the manual reset input (MR). RESET
remains asserted for one reset timeout period (200ms) after V
CC
exceeds the reset threshold or after the manual reset pin transitions from
low to high. The watchdog timer will not assert RESET unless WDO is
connected to MR.
Watchdog timer output. The watchdog timer resets itself with each
transition on the watchdog input. If the WDI pin is held high or low for
longer than the watchdog timeout period, WDO is forced low. WDO will
also be forced low if V
CC
is below the reset threshold and will remain low
until V
CC
returns to a valid level.
RESET output. RESET is the compliment of RESET and is asserted if
either V
CC
goes below the reset threshold or by a low signal on the
manual reset input (MR). RESET is suitable for microprocessors
systems that use an active high reset.
Description
Vcc
GND
PFI
2
3
4
2
3
4
PFO
WDI
5
6
5
N/A
N/C
RESET
N/A
7
6
7
WDO
8
N/A
RESET
N/A
8
Impala Linear Corporation
ILC705-708 1.0
(408) 574-3939
www.impalalinear.com
Sept 1999
3
mP Supervisory Circuit
Circuit Description
Microprocessor Reset
The RESET pin is asserted whenever V
CC
falls below the
reset threshold voltage or when MR goes low. The reset pin
remains asserted for a period of 200ms after V
CC
has risen
above the reset threshold voltage and MR goes high. The
reset function ensures the microprocessor is properly reset
and powers up into a known condition after a power failure.
RESET will remain valid with V
CC
as low as 1.4V
fail comparator (PFI) can be chosen so as to trip the power
fail comparator a few milliseconds before V
CC
falls below
the maximum reset threshold voltage. The output of the
power fail comparator (PFO) can be used to interrupt the
microprocessor when used in this mode and execute shut-
down procedures prior to power loss
Unregulated DC
V
CC
t
MR
MR
t
MD
RESET
t
RS
V
RT
R1
PFI
R2
4
1.25 V
+
-
5
PFO
t
RS
WDO
Alternate Reference Guide
Watchdog Timer
The microprocessor can be monitored by connecting the
WDI pin (watchdog input) to a bus line or I/O line. If a tran-
sition does not occur on the WDI pin within the watchdog
timeout period, then WDO will go low. A minimum pulse of
50ns or any transition low-to-high or high-to-low on the WDI
pin will reset the watchdog timer. The output of the watch-
dog timer (WDO) will remain high if WDI sees a valid tran-
sition within the watchdog timeout period or if WDI is left
floating. If V
CC
falls below the reset threshold voltage then
WDO goes low immediately regardless of WDI. If WDI is left
floating, then WDO can be used as a low line indicator.
Manual Reset
The manual-reset input (MR) allows reset to be triggered by
a pushbutton switch which is debounced by the 140ms min-
imum reset pulse width. MR can be driven by external
TTL/CMOS compatible logic. By connecting WDO to MR a
watchdog timeout will generate a reset pulse in the
ILC705/ILC706.
Power Fail Warning
An additional comparator which is independent of other
functions on the ILC705/706/707/708 is provided for early
warning of power failure. An external voltage divider can be
used to compare unregulated DC to an internal 1.25V ref-
erence. The voltage divider ratio on the input of the power
Industry P/N
MAX705CPA
MAX705CSA
MAX705EPA
MAX705ESA
ADM705AN
DS1705
MAX706CPA
MAX706CSA
MAX706EPA
MAX706C/D
ADM706AN
DS1706
MAX707CPA
MAX707CSA
MAX707EPA
MAX707ESA
MAX707C/D
ADM707AN
DS1707
MAX708CPA
MAX708CSA
MAX708EPA
MAX708ESA
MAX708C/D
ADM708AN
DS1708
ILC Direct
Replacement
ILC705N
ILC705M
ILC705N
ILC705M
ILC705N
ILC705
ILC706N
ILC706M
ILC706N
ILC706D
ILC706N
ILC706
ILC707N
ILC707M
ILC707N
ILC707M
ILC707D
ILC707N
ILC707
ILC708N
ILC708M
ILC708N
ILC708M
ILC708D
ILC708N
ILC708
Impala Linear Corporation
ILC705-708 1.0
(408) 574-3939
www.impalalinear.com
Sept 1999
4
mP Supervisory Circuit
Packaging Information
0.197
0.190
M Package, 8-Pin Small Outline
Pin 1 identifier
0.155
0.150
0.244
0.228
0.069
0.053
0.060
0.040
0.019
0.013
0.012
0.009
0.8°
0.011
0.004
0.050
0.016
0.019
0.013
N Package, 8-Pin Plastic Dual In-line
0.260
0.240
0.260
0.240
0.260
0.240
0.260
0.240
0.260
0.240
0.260
0.240
0.260
0.240
0.260
0.240
Devices sold by Impala Linear Corporation are covered by the warranty and patent indemnification provisions appearing
in its Terms of Sale only. Impala Linear Corporation makes no warranty, express, statutory, implied, or by description
regarding the information set forth herein or regarding the freedom of the described devices from patent infringement.
Impala Linear Corporation makes no warranty of merchantability or fitness for any purpose. Impala Linear Corporation
reserves the right to discontinue production and change specifications and prices at any time and without notice.
This product is intended for use in normal commercial applications. Applications requiring an extended temperature
range, unusual environmental requirements, or high reliability applications, such as military and aerospace, are specif-
ically not recommended without additional processing by Impala Linear Corporation.
Impala Linear Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in an
Impala Linear Corporation product. No other circuits, patents, licenses are implied.
Life Support Policy
Impala Linear Corporation’s products are not authorized for use as critical components in life support devices or systems.
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use pro-
vided in the labelling, can be reasonably expected to result in a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reason-
bly expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
Impala Linear Corporation
ILC705-708 1.0
(408) 574-3939
www.impalalinear.com
Sept 1999
5
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