1999 IMP, Inc.
408-432-9100/www.impweb.com
1
Applications
N Computers and embedded controllers
N Battery-operated systems
N Intelligent instruments
N Wireless communication systems
N PDAs and handheld equipment
Block Diagrams
IMP705/6/7/8, 8
IMP705/6/7/8, 8
1
1
3L
3L
P
OWER
M
ANAGEMENT
RESET
RESET
V
CC
0.25mA
RESET
Generator
4.65V (IMP707)
4.40V (IMP708)
V
CC
+
+
MR
IMP707
IMP708
PFO
GND
1.25V
+
PFI
705_02.eps
1.25V
+
MR
WDI
IMP705
IMP706
IMP813L
WDO
RESET
(RESET)
(IMP813L)
PFO
GND
V
CC
0.25mA
RESET
Generator
4.65V (IMP705/813L)
4.40V (IMP706)
V
CC
+
+
PFI
Timebase
Watchdog
Timer
Transition
Detector
705_01.eps
Lo
Lo
w
w
-P
-P
o
o
w
w
er
er
P Super
P Super
visor Cir
visor Cir
cuits
cuits
W
W
atc
atc
hdog timer
hdog timer
Br
Br
o
o
wnout det
wnout det
ection
ection
P
P
o
o
w
w
er suppl
er suppl
y monit
y monit
or
or
The IMP705/706/707/708 and IMP813L CMOS supervisor circuits
monitor power-supply and battery voltage level, and
P/C operation.
Compared to pin-compatible devices offered by Maxim Integrated
Products, IMP devices feature 60 percent lower maximum supply current.
The family offers several functional options. Each device generates a
reset signal during power-up, power-down and during brownout
conditions. A reset is generated when the supply drops below
4.65V (IMP705/707/813L) or 4.40V (IMP706/708). For 3V power supply
applications, refer to the IMP705P/R/S/T data sheet. In addition, the
IMP705/706/813L feature a 1.6 second watchdog timer. The IMP707/708
have both active-HIGH and active-LOW reset outputs but no watchdog
function. The IMP813L has the same pin-out and functions as the IMP705
but has an active-HIGH reset output. A versatile power-fail circuit has a
1.25V threshold, useful in checking battery levels and non-5V supplies. All
devices have a manual reset (MR) input. The watchdog timer output will
trigger a reset if connected to MR.
All devices are available in 8-pin DIP, SO and MicroSO packages.
Key Features
N Improved replacements for the Maxim
MAX705/6/7/8, MAX813L
140A maximum supply current
60% improvement
N Precision power supply monitor
4.65V threshold (IMP705/707/813L)
4.40V threshold (IMP706/8)
N Debounced manual reset input
N Voltage monitor
1.25V threshold
Battery monitor/Auxiliary supply monitor
N Watchdog timer (IMP705/706/813L)
N 200ms reset pulse width
N Active HIGH reset output (IMP707/708/813L)
N MicroSO package
2
408-432-9100/www.impweb.com
1999 IMP, Inc.
IMP705/6/7/8, 8
IMP705/6/7/8, 8
1
1
3L
3L
Ordering Information
Pin Configuration
IMP707
IMP708
1
2
3
4
MR
V
CC
GND
PFI
RESET
RESET
NC
PFO
8
7
6
5
IMP707
IMP708
1
2
3
4
RESET
RESET
MR
V
CC
NC
PFO
PFI
GND
8
7
6
5
1
2
3
4
MR
V
CC
GND
PFI
WDO
RESET (RESET)
WDI
PFO
8
7
6
5
IMP705
IMP706
(IMP813L)
IMP705
IMP706
(IMP813L)
1
2
3
4
RESET (RESET)
WDO
MR
V
CC
WDI
PFO
PFI
GND
8
7
6
5
705_03.eps
DIP/SO
MicroSO
Part Number
Reset Threshold (V)
Temperature Range
Pins-Package
IMP705 Active LOW Reset, Watchdog Output and Manual RESET
IMP705CPA
4.65
0C to +70C
8-Plastic DIP
IMP705CSA
4.65
0C to +70C
8-SO
IMP705CUA
4.65
0C to +70C
8-MicroSO
IMP705C/D
4.65
25C
Dice
IMP705EPA
4.65
40C to +85C
8-Plastic DIP
IMP705ESA
4.65
40C to +85C
8-SO
IMP706ESA
4.40
40C to +85C
8-SO
IMP706 Active LOW Reset, Watchdog Output and Manual RESET
IMP706CPA
4.40
0C to +70C
8-Plastic DIP
IMP706CSA
4.40
0C to +70C
8-SO
IMP706CUA
4.40
0C to +70C
8-MicroSO
IMP706C/D
4.40
25C
Dice
IMP706EPA
4.40
40C to +85C
8-Plastic DIP
IMP706ESA
4.40
40C to +85C
8-SO
IMP707 Active LOW & HIGH Reset with Manual RESET
IMP707CPA
4.65
0C to +70C
8-Plastic DIP
IMP707CSA
4.65
0C to +70C
8-SO
IMP707CUA
4.65
0C to +70C
8-MicroSO
IMP707C/D
4.65
25C
Dice
IMP707EPA
4.65
40C to +85C
8-Plastic DIP
IMP707ESA
4.65
40C to +85C
8-SO
IMP708 Active LOW & HIGH Reset with Manual RESET
IMP708CPA
4.40
0C to +70C
8-Plastic DIP
IMP708CSA
4.40
0C to +70C
8-SO
IMP708CUA
4.40
0C to +70C
8-MicroSO
IMP708C/D
4.40
25C
Dice
IMP708EPA
4.40
40C to +85C
8-Plastic DIP
IMP708ESA
4.40
40C to +85C
8-SO
IMP813L Active HIGH Reset, Watchdog Output and Manual RESET
IMP813LCPA
4.65
0C to +70C
8-Plastic DIP
IMP813LCSA
4.65
0C to +70C
8-SO
IMP813LCUA
4.65
0C to +70C
8-MicroSO
IMP813LC/D
4.65
25C
Dice
IMP813LEPA
4.65
40C to +85C
8-Plastic DIP
IMP813LESA
4.65
40C to +85C
8-SO
1999 IMP, Inc.
408-432-9100/www.impweb.com
3
IMP705/6/7/8, 8
IMP705/6/7/8, 8
1
1
3L
3L
Electrical Characteristics
Absolute Maximum Ratings
Pin Terminal Voltage with Respect to Ground
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3V to 6.0V
All other inputs
1
. . . . . . . . . . . . . . . . . . . . . . . . 0.3V to (V
CC
+ 0.3V)
Input Current at V
CC
and GND . . . . . . . . . . 20mA
Output Current: All outputs . . . . . . . . . . . . . 20mA
Rate of Rise at V
CC
. . . . . . . . . . . . . . . . . . . . . 100V/s
Plastic DIP Power Dissipation . . . . . . . . . . . 700 mW
(Derate 9 mW/
C above 70C)
SO Power Dissipation . . . . . . . . . . . . . . . . . 470 mW
(Derate 5.9 mW/
C above 70C)
MicroSO Power Dissipation . . . . . . . . . . . . . 330mW
(Derate 4.1 mW/
C above 70C)
Operating Temperature Range
IMP705E/706E/707E/708E/813LE . . . . . . . 40
C to 85C
IMP706C/707C/708C/813LC . . . . . . . . . . . 0
C to 70C
Storage Temperature Range . . . . . . . . . . . . . . 65
C to 160C
Lead Temperature Soldering(10 sec) . . . . . . 300
C
Note: 1. The input voltage limits on PFI and MR can be exceeded if
the input current is less than 10mA.
These are stress ratings only and functional operation is not implied.
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Operating Voltage Range
V
CC
IMP705/6/7/8C
1.2
5.5
V
IMP813L
1.1
5.5
IMP705/6/7/8E, IMP813lE
1.2
5.5
Supply Current
I
CC
IMP705C/706C/813LC
75
140
A
IMP705E, IMP706E, IMP813LE
75
140
IMP707C, IMP708C
50
140
IMP707E, IMP708E
50
140
RESET Threshold
V
RT
IMP705, IMP707, IMP813L, Note 2
4.50
4.65
4.75
V
IMP706, IMP708, Note 2
4.25
4.40
4.50
RESET Threshold Hysteresis
Note 2
40
mV
RESET Pulse Width
t
RS
Note 2
140
200
280
ms
MR Pulse Width
t
MR
0.15
s
MR to RESET Out Delay
t
MD
Note 2
0.25
s
MR Input Threshold
V
IH
2.0
V
V
IL
0.8
MR Pull-up Current
MR = 0V
100
250
600
A
RESET Output Voltage
I
SOURCE
= 800
A
V
CC
- 1.5V
V
I
SINK
= 3.2mA
0.4
IMP705/6/7/8, V
CC
= 1.2V, I
SINK
= 100
A
0.3
RESET Output Voltage
IMP707/708/813L, I
SOURCE
= 800
A
V
CC
- 1.5V
V
IMP707/708, I
SINK
= 1.2mA
0.4
IMP813L, I
SINK
= 3.2mA
0.4
IMP813L, V
CC
=1.2V, I
SOURCE
= 4
A
0.9
Watchdog Timeout Period
t
WD
IMP705/706/813L
1.00
1.60
2.25
s
WDI Pulse Width
t
WP
V
IL
= 0.4V, V
IH
= 0.8V
CC
50
ns
WDI Input Threshold
V
IH
IMP705/706/813L, V
CC
= 5V
3.5
V
V
IL
0.8
WDI Input Current
IMP705/706/813L, WDI = V
CC
50
150
A
IMP705/706/813L, WDI = 0V
150
50
WDO Output Voltage
IMP705/706/813L, I
SOURCE
= 800
A
V
CC
- 1.5V
V
IMP705/706/813L, I
SINK
= 1.2mA
0.4
PFI Input Threshold
V
CC
= 5V
1.2
1.25
1.3
V
PFI Input Current
25
0.01
25
nA
PFO Output Voltage
I
SOURCE
= 800
A
V
CC
- 1.5V
V
I
SINK
= 3.2mA
0.4
Unless otherwise noted, V
CC
= 4.75V to 5.5V for the IMP705/707/813L. V
CC
= 4.5V to 5.5V for the IMP706/708 and over the
operating temperature range.
Notes: 2. RESET (IMP705/6/7/8), RESET (IMP707/8, IMP813L)
4
408-432-9100/www.impweb.com
1999 IMP, Inc.
IMP705/6/7/8, 8
IMP705/6/7/8, 8
1
1
3L
3L
Pin Descriptions
Feature Summary
Pin Number
IMP705/706
IMP707/708
IMP813L
DIP/SO MicroSO DIP/SO MicroSO DIP/SO MicroSO Name
Function
Manual RESET input. The active LOW input triggers a reset
1
3
1
3
1
3
MR
pulse. A 250
A pull-up current allows the pin to be driven
by TTL / CMOS logic or shorted to ground with a switch.
2
4
2
4
2
4
V
CC
+5V power supply input.
3
5
3
5
3
5
GND
Ground reference for all signals.
Power-fail voltage monitor input. With PFI less than
4
6
4
6
4
6
PFI
1.25V, PFO goes low. Connect PFI to ground or V
CC
when not used.
5
7
5
7
5
7
PFO
Power-fail output. The output is active LOW and sinks
current when PFI is less than 1.25V.
Watchdog input. WDI controls the internal watchdog
timer. A HIGH or LOW signal for 1.6sec at WDI
allows the internal timer to run-out, setting WDO LOW.
6
8
--
--
6
8
WDI
The watchdog function is disabled by floating WDI or
by connecting WDI to a high-impedance three-state
buffer. The internal watchdog timer clears when:
RESET is asserted; WDI is three-stated; or WDI sees
a rising or falling edge.
--
--
6
--
--
--
NC
Not connected.
Active-LOW reset output. Pulses LOW for 200ms
when triggered, and stays low whenever V
CC
is below
the reset threshold (IMP705: 4.65V, IMP705J: 4.00V,
7
1
7
1
--
--
RESET
IMP706: 4.40V). RESET remains LOW for 200ms
after V
CC
rises above the RESET threshold or MR
goes from LOW to HIGH. A watchdog timeout will not
trigger RESET unless WDO is connected to MR.
Watchdog output. WDO pulls LOW when the 1.6 sec
internal watchdog timer times-out and does not go
HIGH until the watchdog is cleared. In addition, when
8
2
--
--
8
2
WDO
V
CC
is below the reset threshold, WDO remains low.
Unlike RESET, WDO does not have a minimum pulse
width and as soon as V
CC
exceeds the reset
threshold, WDO goes HIGH with no delay.
--
--
8
2
7
1
RESET
Active-HIGH reset output
. RESET is the inverse of
RESET. The IMP813L has only a RESET output.
IMP705
IMP706
IMP707
IMP708
IMP813L
Power-fail detector
I
I
I
I
I
Brownout detection
I
I
I
I
I
Manual RESET input
I
I
I
I
I
Power-up/down RESET
I
I
I
I
I
Watchdog timer
I
I
I
Active-HIGH RESET output
I
I
I
Active-LOW RESET output
I
I
I
I
RESET threshold
4.65V/4.00V
4.40V
4.65V
4.40V
4.65V
1999 IMP, Inc.
408-432-9100/www.impweb.com
5
IMP705/6/7/8, 8
IMP705/6/7/8, 8
1
1
3L
3L
Detail Descriptions
RESET/RESET Operation
The RESET/RESET signals are designed to start a
P/C in a
known state or return the system to a known state.
The IMP707/708 have two RESET outputs, one active-HIGH
RESET and one active-LOW RESET output. The IMP813L has
only an active-HIGH output. RESET is simply the complement
of RESET.
RESET is guaranteed to be LOW with V
CC
above 1.2V. During a
power-up sequence, RESET remains low until the supply rises
above the threshold level, either 4.65V, 4.40V or 4.00V.. RESET goes
high approximately 200ms after crossing the threshold.
During power-down, RESET goes LOW as V
CC
falls below the
threshold level and is guaranteed to be under 0.4V with V
CC
above 1.2V.
In a brownout situation where V
CC
falls below the threshold
level, RESET pulses low. If a brownout occurs during an already-
initiated reset, the pulse will continue for a minimum of 140ms.
Auxiliary Comparator
All devices have an auxiliary comparator with 1.25V trip point
and uncommitted output (PFO) and noninverting input (PFI).
This comparator can be used as a supply voltage monitor with an
external resistor voltage divider. The attenuated voltage at PFI
should be set just below the 1.25 threshold. As the supply level
falls, PFI is reduced causing the PFO output to transit LOW.
Normally PFO interrupts the processor so the system can be shut
down in a controlled manner.
5V
0V
5V
t
WD
t
RS
t
WP
t
WD
t
WD
0V
5V
0V
5V
0V
RESET triggered by MR
WDI
WDO
RESET
IMP813L
(RESET)
705_05.eps
Figure 1. WDI Three-state operation
Figure 2. Watchdog Timing
5V
0V
5V
0V
5V
0V
5V
0V
V
CC
v
RT
WDO
RESET
MR
t
MD
t
RS
t
RS
t
MR
MR extermally
set low
705_04.eps
Manual Reset (MR)
The active-LOW manual reset input is pulled high by a 250
A
pull-up current and can be driven low by CMOS/TTL logic or a
mechanical switch to ground. An external debounce circuit is
unnecessary since the 140ms minimum reset time will debounce
mechanical pushbutton switches.
By connecting the watchdog output (WDO) and MR, a watchdog
timeout forces RESET to be generated. The IMP813L should be
used when an active-HIGH RESET is required.
Watchdog Timer
The watchdog timer available on the IMP705/706/813L monitors
P/C activity. If activity is not detected within 1.6 seconds, the
internal timer puts the watchdog output, WDO, into a LOW
state. WDO will remain LOW until activity is detected at WDI.
The watchdog function is disabled, meaning it is cleared and not
counting, if WDI is floated or connected to a three-stated circuit.
The watchdog timer is also disabled if RESET is asserted. When
RESET becomes inactive and the WDI input sees a high or low
transition as short as 50ns, the watchdog timer will begin a 1.6
second countdown. Additional transitions at WDI will reset the
watchdog timer and initiate a new countdown sequence.
WDO will also become LOW and remain so, whenever the
supply voltage, V
CC
, falls below the device threshold level. WDO
goes HIGH as soon as V
CC
transitions above the threshold. There
is no minimum pulse width for WDO as there is for the RESET
outputs. If WDI is floated, WDO essentially acts as a low-power
output indicator.
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