SP703 SIPEX [Sipex Corporation], SP703 Datasheet - Page 11

• Manufacturer Part Number: SP703
• Description: Low Power Microprocessor Supervisory with Battery Switch-Over
• Manufacturer: SIPEX [Sipex Corporation]

Figure 10. Input and Output Status in Battery-Backup Mode.
To enter the Battery-Backup mode, V
Reset threshold and less than V
Using a High Capacity Capacitor
as a Backup Power Source
V
V
ages are typically +20mV centered at V
allowing use of a capacitor and a simple charg-
ing circuit as a backup source (see Figure 12).
Figure 11. Allowable BACKUP-BATTERY Voltages
SP703/704DS/07
BATT
CC
I S
R
N
, and the battery-switchover threshold volt-
V
P
G
V
E
V
P
M
S
S
U
P
B
F
O
S
N
C
I F
A
R
P
P
has the same operating voltage range as
U
M
A
O
C
T
E
A
T
T
7
7
R
T
B
L
0
0
T
E
3
4
R
i D
C
a
C
d
e l
V
P
d
L
L
M
n
a r
s i
o
o
C
o
o
o
s s
a
c s
C
g
g
w
n
n
a
n
n i
w
c i
c i
<
n
n
b
o
e
u
h t
n
e t
B
e
e
e l
n
f - r
l a
V
o l
o l
c
c
a
n
n r
f
A
. d
BATT
o r
B
e t
e t
n
i a
w
w
e
R
A
V
C
l a
T
c
m
c l
d
d
.
0
e
S
T
O
K
e t
M
s
6 .
T
8
CC
o t
o t
-
o
h t
t e
L
U
d
A
A
1
must be less than the
m
T
e
- P
4
4
V
V
, A
T
f
. V
I X
s i
P
o r
p
A
8 .
5 .
U
B
O
b
r a
M
B
A
U
M
G
m
a
d
t a
S
T
0
5
T
A
T
O
s
t a
s i
.
SP703/704 Low Power Microprocessor Supervisory
U
E
e t
V
h t
a
T
S
o l
r o
C
M
y r
O
b
[
T
o r
n
] V
r u
U
s
e l
s i
E
T
g
w
s i
u
e r
d
BATT
R
g
c t i
a
h
t n
Y
s
h
,
11
Figure 12. Backup Power Source Using High Capacity
Capacitor with SP703 and a +5V 5% Supply
If V
is 0.5V above V
V
less than 0.5V above V
Leakage current through the capacitor charging
diode and the SP703/704 internal power
diode eventually discharges the capacitor to
V
above the reset threshold and power is lost
at V
through V
threshold; the SP703/704 then switches to
battery-backup mode.
Figure 13. Backup Power Source Using High Capacity
Capacitor with SP704 and a +5V 10% Supply
CC
CC
100K
CC
0.1F
. Also, if V
CC
from V
V
0.1F
BATT
is above the reset threshold and V
, the capacitor on V
V
CC
BATT
BATT
SP703
+5V
until V
GND
V
CC
SP704
CC
CC
+5V
until the voltage at V
GND
V
and V
, current flows to V
CC
V
RESET
BATT
OUT
© Copyright 2000 Sipex Corporation
CC
V
RESET
OUT
BATT
.
reaches the reset
BATT
CONNECT TO
STATIC RAM
start from 0.5V
CONNECT TO
STATIC RAM
CONNECT
CONNECT
TO P
discharges
TO P
OUT
BATT
BATT
and
is