ADP3160 Analog Devices, ADP3160 Datasheet - Page 12

• Manufacturer Part Number: ADP3160
• Description: 5-Bit Programmable 2-Phase Synchronous Buck Controller
• Manufacturer: Analog Devices

ADP3160/ADP3167
sensing when the current threshold has been reached and when
the high-side MOSFET actually turns off. These two factors are
combined with the inherent voltage at the output of g
that commands a current sense threshold of 0 mV (V
The output voltage at no load (V
starting with the VID setting, adding in the positive offset (V+),
subtracting half the ripple voltage, and then subtracting the
dominant error terms:
With these two terms calculated, the divider resistors (R
for the upper and R
Assuming that the internal resistance of the g
(R
OGM
V
V
V
V
V
1 7
R
R
12
GNL
ONL
ONL
.
GNL
IN
k
B
B
) is 200 kW:
VID
V – .
V
=
600
=
-
L
=
=
V
V
2
¥
=
=
3
V
1 635
AVG
1
REF
V
+
1 7
V
7 57
nH
GNL
V +
VID
.
( .
.
Ê
Á
Ë
0 007
-
k
R
V
–
RT
0
¥
T
1 2
V
k
12 2
V
+
.
+
(
+
W
GNL
2
V
¥
V
I
0
. A
B
¥ ¥
)
¥
L RIPPLE
V
+
2
V
V
for the lower) can be calculated.
(
2 60
t
WIN
-
D
-
VID
+
-
=
V
-
2 2
Ê
Á
Ë
¥
¥
R I
g
10 73
REF
.
1 38
0 02
m
R
E O
4
ˆ
˜
¯
.
.
2
2
.
SENSE
¥
mmho
2
m
ns
)
(
3
D
V
¥
W
¥
m
2
¥
k
V
ONL
R
-
¥
94
W
ONL
W ¥
4
SENSE
1 7
2
V
¥
12 5
¥
m
.
VID
n
mV
( .
-
) can be calculated by
W
.
9 9
V
1 681
I
V
)
.
¥
VID
¥
–
¥
ˆ
˜ =
¯
12 5 1 201
A
2
n
I
)
V
. = .
–
-
1 681
– .
.
m
1 7
amplifier
GNL0
m
V
V
amplifier
)
V
):
(24)
(25)
A
(23)
–12–
Choosing the nearest 1% resistor value gives R
Finally, R
Again, choosing the nearest 1% resistor value gives R
The compensating capacitor can be calculated from the equation:
The closest standard value for C
The resistance of the zero-setting resistor in series with the
compensating capacitor is:
The nearest standard 5% resistor value is 470 W. Note that this
resistor is only required when C
25% or less). In this example, C
fore be omitted.
C
C
R
R
R
R
p
OC
OC
Z
Z
A
A
¥
=
=
400
=
=
A
=
=
C
3 3
R
7 57
is calculated:
C
19 8
1
OC
.
.
T
kHz
OUT
.
1
nF
-
¥ ¥
2
k
mF
7 57
R
W
p
¥
2
¥
R
.
¥ ¥
OGM
R
1
1
T
7 57
-
p
E MAX
¥
.
2
f
200
(
k
OSC
1 5
W
400
.
-
1
k
1
R
W
k
m
)
1
W
B
kHz
W
-
=
-
p
-
3 5
OUT
OUT
OC
11 3
.
¥
=
is 3.3 nF.
f
nF
.
approaches C
OSC
482
> C
1
2
k
W
¥
CRIT
W
R
=
T
25 86
, and R
B
.
= 11.0 kW.
CRIT
k
A
Z
W
can there-
= 26.1 kW.
(within
REV. B
(26)
(27)
(28)