ADP3163JRUZ-REEL Analog Devices Inc, ADP3163JRUZ-REEL Datasheet - Page 10

• Manufacturer Part Number: ADP3163JRUZ-REEL
• Description: IC REG BUCK 5BIT 2-3PHAS 20TSSOP
• Manufacturer: Analog Devices Inc

Specifications of ADP3163JRUZ-REEL

• Applications: Controller, Intel Pentium® IV
• Voltage - Input: 5V, 12V
• Number Of Outputs: 1
• Voltage - Output: 1.1 ~ 1.85 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ADP3163JRUZREELTR

ADP3163
At output voltages below 750 mV, the current sense threshold is
reduced to 108 mV, and the ripple current is negligible. There-
fore, at dead short the output current is reduced to:
To safely carry the current under maximum load conditions, the
sense resistor must have a power rating of at least:
where:
In this formula, n is the number of phases, and
verter efficiency, in this case assumed to be 85%. Combining
Equations 6 and 7 yields:
Output Resistance
This design requires that the regulator output voltage measured
at the CPU pins drops when the output current increases. The
specified voltage drop corresponds to a dc output resistance of:
The required dc output resistance can be achieved by terminating
the g
tion resistance that will yield the correct dc output resistance:
where n
g
ductance of the g
Output Offset
Intel’s specification requires that at no load the nominal output
voltage of the regulator be offset to a lower value than the nominal
voltage corresponding to the VID code. The offset is introduced
by realizing the total termination resistance of the g
with a divider connected between the REF pin and ground. The
resistive divider introduces an offset to the output of the g
amplifier that, when reflected back through the gain of the g
stage, accurately positions the output voltage near its allowed
maximum at light load. Furthermore, the output of the g
amplifier sets the current sense threshold voltage. At no load,
the current sense threshold is increased by the peak of the ripple
current in the inductor and reduced by the delay between sens-
ing 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 (V
g
m
m
R
R
amplifier to the PWM comparator CMP1, g
amplifier that commands a current sense threshold of 0 mV:
T
OUT
P
I
m
I
OUT SC
SENSE RMS
R
amplifier with a resistor. The value of the total termina-
SENSE
I
n
is the division ratio from the output voltage signal of the
P
n
(
R
V
I
(
SENSE
ONL
g
)
m
I
R
SENSE RMS
I
)
SENSE
2
O
m
n
R
65
V
amplifier itself, and n is the number of phases.
OUT
OFL
3
(
V
I
R
O
A
n
CS SC
SENSE
2
2
(
)
2
3 2 2
1 475
0 85 12
.
)
V
.
R
OUT
1 5
V
.
SENSE
12 5 5
3
.
IN
V
mmho
65
.
V
108
A
1 377
5
V
.
GNL0
m
m
mV
1 5
5
.
V
), at the output of the
m
m
m
65
1 5
is the transcon-
.
1 0
is the con-
A
.
6 31
m
m
.
W
amplifier
k
m
m
m
(6)
(7)
(5)
(8)
(9)
The divider resistors (R
can now be calculated, assuming that the internal resistance of
the g
Choosing the nearest 1% resistor value gives R
Finally, R
Choosing the nearest 1% resistor value gives R
C
The required equivalent series resistance (ESR) and capacitance
drive the selection of the type and quantity of the output capaci-
tors. The ESR must be less than or equal to the specified output
resistance (R
large enough that the voltage across the capacitors, which is the
sum of the resistive and capacitive voltage deviations, does not
deviate beyond the initial resistive step while the inductor cur-
rent ramps up or down to the value corresponding to the new
load current.
One can, for example, use nine MBZ-type capacitors from
Rubycon, with 2200 F capacitance, a 6.3 V voltage rating, and
13 m ESR. The nine capacitors have a maximum total ESR of
1.44 m when connected in parallel.
As long as the capacitance of the output capacitor bank is above
a critical value and the regulating loop is compensated with
Analog Devices’ proprietary compensation technique (ADOPT),
the actual capacitance value has no influence on the peak-to-
peak deviation of the output voltage to a full step change in the
load current. The critical capacitance can be calculated as follows:
R
OUT
A
V
V
C
n t
R
R
1 5
2 60
GNL
GNL
B
B
.
OUT CRIT
m
R
Selection
1
m
amplifier (R
D
T
V
3
(
65
REF
V
V
1
ns
A
6 31
R
R
V
GNL
.
is calculated:
A
R
OGM
SENSE
1 144
1
1 5
1
OUT
T
)
V
.
5
.
k
0
GNL
10 9
m
V
), in this case 1.5 m . The capacitance must be
R
V
.
I
R
OUT
OGM
1
L RIPPLE
V
B
n
(
A
g
REF
I
600
12 5 1 144
m
2 2
I
) is 1 M :
.
O
A
6 31
.
5
(
V
.
3
V
mmho
2
for the upper and R
3
m
nH
ONL
OUT
)
1
V
k
2
.
R
SENSE
V
12 5
( .
VID
1 475
5 78
1
L
n
.
.
V
M
1
)
1
V
mF
n
12
I
8 66
600
1 5
V
.
.
V
1
V
B
k
IN
nH
1 5
)
B
A
for the lower)
.
= 8.66 k .
= 23.7 k .
L
V
8 59
V
23 8
.
OUT
.
k
k
(12)
(10)
(11)
(13)