sp691a Exar Corporation, sp691a Datasheet - Page 15

• Manufacturer Part Number: sp691a
• Description: Low Power Microprocessor Supervisory With Battery Switch-over
• Manufacturer: Exar Corporation

Table 2. Input and Output Status in Battery-Backup Mode; to enter the Battery-Backup Mode, V
reset threshold and less than V
Figure 24. V
Date: 4/18/05
L
B
SW1
O
R
R
O
N
A
O
C
W
V
G
P
V
W
C
W
E
E
T
S
P
A
V
S
E
B
N
F
O
E
D
S
S
T
C
C
I F
M
A
I D
L
C
O
U
O
T
C
D
E
E
N I
O
S
U
T
N I
O
T
E
N I
E
T
V
T
T
L
N
E
OUT
CC
and V
S
V
B
i d
0
L
L
O
O
T
T
W
L
H
L
L
H
SP691A/693A/800L/800M Low Power Microprocessor Supervisor with Battery Switch-Over © Copyright 2005 Sipex Corporation
V
o
o
o
o
o
h
h
u
O
t a
g i
g i
c s
S
S
I D
U
g
g
e
e
g
g
g
p
C
C
T
e t
e r
- h
- h
V
c i
c i
c i
c i
c i
p
o
p
p
N I
S
c
s i
y l
y r
n
e f
. Z
. Z
BATT
BATT
E
o
o
o
I H
L
I H
I H
L
n
L
s i
w
w
n
e r
O
g i
O
c
e
s
s i
G
G
G
n
r u
e
e
D1
w
c
W
W
g i
n
n
to V
e
f - r
f - r
. H
. H
. H
e t
g i
o
c t i
c
e r
n
c
.
.
e r
e
d
n
l i a
l i a
e t
o
t n
h
OUT
o
e r
f
T
d
T
T
BATT
f
d
o
r o
V
0.1µF
o r
e r
h
c
c
h
h
s i
v
d
a
o t
o
o
CC
e
e
e
r e
Switch
m
d
n
l l a
.
a
m
m
1
d
o
o
o
a
D2
V
n
c
V
p
p
p
p
p
s
n
d
s i
A
B
o
r a
r a
O
e
e
e
A
g i
d
m
U
T
s i
- n
- n
- n
m
t a
t a
t a
T
T
n
s i
p
.
a
i c
i c
i c
a
h t
t a
r o
r o
r a
h
. s l
t a
i x
c r
c r
c r
o r
g i
t a
h
m
s i
s i
u
u
u
h
- h
u
g i
r o
t i
t i
t i
u
g i
SW2
g
d
d
- h
. Z
m
h
o
s i
s i
o
o
- h
m
. Z
u
u
u
a
a
a
w
. Z
p t
p t
p t
o
b
b
n
h
i n
e l
e l
t u
t u
t u
S
e
n i
o t
. d
. d
T
n
e t
v
v
v
A
s r
l o
l o
l o
V
n r
T
P
15
C
a t
a t
a t
V
U
C
F
l a
C
<
g
g
g
O
S
C
V (
e
e
e
P
f
Input Supply Voltage
The Input Supply Voltage (V
regulated +5V source. V
via a parallel diode and a large PMOS switch.
The switch carries the entire current load for
currents less than 250mA. The parallel diode
carries any current in excess of 250mA. Both
the switch and the diode have impedances
less than 1Ω each. Refer to Figure 24. The
maximum continuous current is 250mA, but
power-on transients may reach a maximum of 1A.
Backup-Battery Input
The Backup-Battery Input (V
to V
diode are much smaller. Refer to Figure 24.
Accordingly, the on-resistances of the diode and
the switch are each approximately 10Ω.
s i
M
r o
s i
s i
s i
B
A
O
o f
T
e
e
e
a
T
S
q
q
q
1 -
c
c r
CC
v i t
u
u
u
s
2 .
e
l a
l a
l a
w
d
e
, except the PMOS switch and parallel
V
c t i
o t
o t
o t
o t
. )
s
w
. h
V
V
V
o l
c t i
O
O
O
g
U
U
U
h
c i
T
T
T
o
.
.
.
v
L
e
O
. r
W
V
.
C
C
s i
CC
CC
connects to V
must be less than the
CC
BATT
) should be a
P
N I
) is similar
N
1
1
1
1
1
1
1
U
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
M
B
OUT
E
R