ADP3208DJCPZ-RL ON Semiconductor, ADP3208DJCPZ-RL Datasheet - Page 28

• 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

a calculated ripple current of 9.0 A. The inductor should not
saturate at the peak current of 24.5 A, and it should be able
to handle the sum of the power dissipation caused by the
winding’s average current (20 A) plus the ac core loss. In this
example, 330 nH is used.
DCR, which is used for measuring the phase currents. Too
large of a DCR causes excessive power losses, whereas too
small of a value leads to increased measurement error. For
this example, an inductor with a DCR of 0.8 mW is used.
Selecting a Standard Inductor
standard inductor that best meets the overall design goals. It
is also important to specify the inductance and DCR
tolerance to maintain the accuracy of the system. Using 20%
tolerance for the inductance and 15% for the DCR at room
temperature are reasonable values that most manufacturers
can meet.
Power Inductor Manufacturers
inductors optimized for high power applications upon
request:
•
•
•
•
Output Droop Resistance
measured at the CPU pins decreases when the output current
increases. The specified voltage drop corresponds to the
droop resistance (R
of the resistors monitoring the voltage across each inductor
and by passing the signal through a low−pass filter. The
summing is implemented by the CS amplifier that is
configured with resistor R
and C
by the following equations:
Due to the current drive ability of the CSCOMP pin, the R
resistance should be greater than 100 kW. For example,
initially select R
Equation 9 to solve for C
example, if the optimal C
to 280 kW. For best accuracy, C
Another important factor in the inductor design is the
After the inductance and DCR are known, select a
The following companies provide surface−mount power
The design requires that the regulator output voltage
The output current is measured by summing the currents
Either R
If C
Vishay Dale Electronics, Inc.
Panasonic
Sumida Corporation
NEC Tokin Corporation
where R
CS
CS
(filters). The output resistance of the regulator is set
is not a standard capacitance, R
CS
SENSE
C
or R
CS
CS
PH(x)
+
O
is the DCR of the output inductors.
R
C
to be equal to 200 kW, and then use
0.8 mW
).
O
CS
can be chosen for added flexibility.
+
CS
+
CS
330 nH
PH(x)
R
R
R
:
capacitance is 1.5 nF, adjust R
PH(x)
CS
SENSE
200 kW
(summer) and resistors R
CS
L
R
should be a 5% NPO
SENSE
+ 2.1 nF
R
CS
CS
can be tuned. For
(eq. 10)
(eq. 8)
(eq. 9)
http://onsemi.com
CS
CS
CS
28
capacitor. In this example, a 220 kW is used for R
achieve optimal results.
follows:
The standard 1% resistor for R
Inductor DCR Temperature Correction
copper wire is the source of the DCR, the temperature
changes associated with the inductor’s winding must be
compensated for. Fortunately, copper has a well−known
temperature coefficient (TC) of 0.39%/°C.
percentage of change in resistance, it cancels the
temperature variation of the inductor’s DCR. Due to the
nonlinear nature of NTC thermistors, series resistors R
and R
produce the desired temperature coefficient tracking.
R
given R
ADP3208D
CS1
Next, solve for R
If the DCR of the inductor is used as a sense element and
If R
The following procedure and expressions yield values for
Figure 42. Temperature−Compensation Circuit
1. Select an NTC to be used based on its type and
2. Find the relative resistance value of the NTC at
3. Find the relative value of R
, R
CS2
-
+
Place as close as possible
CS
value. Because the value needed is not yet
determined, start with a thermistor with a value
close to R
of better than 5%.
two temperatures. The appropriate temperatures
will depend on the type of NTC, but 50°C and
90°C have been shown to work well for most types
of NTCs. The resistance values are called A (A is
R
R
value of the NTC is always 1 at 25°C.
the two temperatures. The relative value of R
based on the percentage of change needed, which
is initially assumed to be 0.39%/°C in this
example.
The relative values are called r
(T
where TC is 0.0039,
T
CSCOMP
CS
CS2
CSSUM
CSREF
TH
TH
1
R
(see Figure 42) are needed to linearize the NTC and
to nearest inductor
1
is 50°C, and T
value.
PH(X)
is designed to have an opposite but equal
− 25))) and r
, and R
(50°C)/R
(90°C)/R
17
19
18
w
C
CS
CS1
0.8 mW
2.1 mW
TH
and an NTC with an initial tolerance
TH
TH
PH(x)
(the thermistor value at 25°C) for a
(25°C)) and B (B is
(25°C)). Note that the relative
2
2
R
Values
(r
@ 220 kW + 83.8 kW
C
CS1
is 90°C.
R
CS2
2
by rearranging Equation 8 as
TH
is 1/(1 + TC × (T
R
PH(x)
CS2
CS
To Switch Nodes
is 86.6 kW.
R
As Possible And Well Away
required for each of
PH1
1
Keep This Path As Short
From Switch Node Lines
(r
1
is 1/(1+ TC ×
R
PH2
2
− 25))),
R
Sense
PH3
(eq. 11)
To V
CS
CS
OUT
CS1
is
to