Digi NS9750 - Manual (Page 818)

P o w e r s e q u e n c i n g
7 9 4 N S 9 7 5 0 H a r d w a r e R e f e r e n c e
Power sequencing
Use these requirements for power sequencing:
VDD
U3
R
E
S
E
T del
a
y
i
s
de
te
rm
in
e
d
by
ca
pac
it
o
r o
n
Ct
.
T
d
= 2.
1
x
10,00
0
0
x
C
t
T
d
=
s
e
c
.; C
t =
fa
ra
d
s
C
t =
0.
22
uF =
4
.6m
s
del
a
y
I/ O
3.3V
P
o
w
e
r
M
o
n
it
o
r
2.4K
EN
RES
E
T
A t
o
B
=
1.
5
V
a
t 80
%
,
or
abo
ve
,
pr
ec
ee
d
s
3.
3
V
at
8
0
%
, o
r abo
ve
,
by
1
-
1
0
0
m
s
Ra
mp
-D
o
w
n
OR
N
S
9750
P
o
w
e
r S
equ
en
ci
ng B
lo
c
k
D
ia
g
ra
m
-
5
V
o
r 3
V
sour
c
e
L
T
196
3AE
Q
-1
.5
Ra
m
p
-U
p
TPS2022
1 A
m
p
SEN
S
E
Per
iph
e
ral
s
co
nne
c
ted
to
N
S
975
0
I/
O
TI
LT
C7733
A
D
Po
w
e
r
Sw
it
c
h
DC
/D
C
C
P
o
we
r Do
wn
:
M
o
n
ito
r tu
rn
s
o
ff
3.
3
V
I
/O
b
e
fo
re
1
.5V
d
rop
s
.
3.
3V
_I
N
10
K
U4
B
LT17
65
R
ESI
N
3.3V
S
o
u
rce
A
=
3.
3
V
_
IN at
2.
0
V
B
=
3.
3
V
_
IN at
2.
9
3
V
+
Td (
R
E
S
ET
del
ay
)
C
= 3.
3V_I
N
a
t 2.
9
3
V
D
= 3.
3V_I
N
at
2.
0
V
R
e
gul
at
o
r
1.
0
W
Ma
x
.
C
to
D
=
1
.5
V
m
a
in
ta
in
e
d
a
t
8
0
%
, or
ab
ov
e,
unt
il
3
.3V
reac
hes
8
0
%
or
bel
o
w
.
Pow
e
r U
p
:
3.3V
I
/O
i
s
h
e
ld
of
f
by
m
o
n
it
o
r so
t
h
at
1.5V
co
re
com
e
s
u
p
fi
rs
t.
3
.3V
_I
N
3.
3V
5.
0
V
S
o
u
rc
e
NS
9
7
50
LD
O
CT
A t
o
B
1.
5
V
Regul
a
to
r
U1
CO
NT
ROL
Ct
C t
o
D
CO
RE
3
.3V_
PERPH
1.
5V
S
e
n
s
e =
2.9
3
V
5V/
3
.3
V @
2.
5
A
U2
3.
3
V
3
.3V
_I
N
JA
=
3
0
C/
W