ADP3208DJCPZ-RL ON Semiconductor, ADP3208DJCPZ-RL Datasheet - Page 32

• Manufacturer Part Number: ADP3208DJCPZ-RL
• Description: IC CTLR BUCK 7BIT 2PHASE 48LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADP3208DJCPZ-RL

• Applications: Controller, Power Supplies for Next-Generation Intel Processors
• Voltage - Input: 3.3 ~ 22 V
• Number Of Outputs: 1
• Voltage - Output: 0.01 ~ 1.5 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 48-LFCSP
• Output Voltage: 10 mV
• Output Current: 40 A
• Input Voltage: 19 V
• Supply Current: 6 mA
• Switching Frequency: 300 KHz
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 10 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

adequate for proper compensation of the output filter.
Figure 43 shows the Type III amplifier used in the
ADP3208D. Figure 44 shows the locations of the two poles
and two zeros created by this amplifier.
and zeros shown in Figure 44:
for the poles and zeros in the system and are intended to yield
an optimal starting point for the design; some adjustments
may be necessary to account for PCB and component
parasitic effects (see the Tuning Procedure for ADP3208D
section):
Figure 44. Poles and Zeros of Voltage Error Amplifier
A Type III compensator on the voltage feedback is
The following equations give the locations of the poles
The expressions that follow compute the time constants
R
E
GAIN
+ n
COMP
Figure 43. Voltage Error Amplifier
0dB
VOLTAGE ERROR
f
f
f
f
Z1
Z2
P1
P2
)
–20dB/DEC
R
AMPLIFIER
O
+
+
2
+
+
f
R
) A
P1
2p
2p
A
2p C
2p
n
L
C
D
B
A
C
C
C
R
C
(1 * ( n
C
1
) C
X
A
FB
A
A
R
A
1
FB
f
Z2
DS
) C
1
B
R
R
C
)
f
R
O
A
B
Z1
B
FB
R
REFERENCE
) C
–20dB/DEC
D) )
R
VOLTAGE
L
R
C
V
FB
f
V
FB
FB
P2
VID
A
ID
V
V
RT
RT
FREQUENCY
ADP3208D
VOLTAGE
OUTPUT
(eq. 29)
(eq. 30)
(eq. 31)
(eq. 32)
(eq. 33)
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32
where:
R’ is the PCB resistance from the bulk capacitors to the
ceramics and is approximately 0.4 mW (assuming an 8−layer
motherboard).
R
phase.
A
V
L
The compensation values can be calculated as follows:
the tuning procedure described in the Tuning Procedure for
ADP3208D section.
C
of the high−side MOSFET is approximately a square wave
with a duty ratio equal to n × V
is one−n
voltage transients, use a low ESR input capacitor sized for
the maximum RMS current. The maximum RMS capacitor
current occurs at the lowest input voltage and is given by:
is achieved by using MLC capacitors or a mixture of MLC
capacitors and bulk capacitors. In this example, the input
capacitor bank is formed by eight pieces of 10 mF, 25 V MLC
capacitors, with a ripple current rating of about 1.5 A each.
X
DS
IN
I
I
D
RT
The standard values for these components are subject to
In continuous inductor−current mode, the source current
In a typical notebook system, the battery rail decoupling
CRMS
CRMS
is 150 pH for the six Panasonic SP capacitors.
is 5.
Selection and Input Current DI/DT Reduction
T
T
T
T
where I
is 1.25 V.
is the total low−side MOSFET for on resistance per
A
B
C
D
+ C
+ (R
+
+
+ D
+ 0.18
th
V
C
of the maximum output current. To prevent large
X
RT
X
X
O
C
R
C
C
) R * R
is the output current.
A
A
B
FB
I
C
(R
V
(R
O
+
+
+
VID
X
+
40 A
O
O
L *
n
T
C
T
R
* R ) )
* R ) ) C
T
R
C
B
A
B
C
R
D
A
A
n
Z
E
R
O
2 f
D
R
)
E
1
O
SW
R
D
R
R
2
DS
R
C
L
O
* 1
B
T
X
O
X
Z
2
1
A
0.18
OUT
R
R
O
O
* 1 + 9.6 A
/V
R
* R
X
IN
and amplitude that
(eq. 42)
(eq. 34)
(eq. 35)
(eq. 36)
(eq. 37)
(eq. 38)
(eq. 39)
(eq. 40)
(eq. 41)