ADP3211AMNR2G ON Semiconductor, ADP3211AMNR2G Datasheet - Page 23

• Manufacturer Part Number: ADP3211AMNR2G
• Description: IC CTLR BUCK 7BIT 2PHASE 32QFN
• Manufacturer: ON Semiconductor

Specifications of ADP3211AMNR2G

• Applications: Controller, Power Supplies for Next-Generation Intel Processors
• Voltage - Input: 3.3 ~ 22 V
• Number Of Outputs: 1
• Voltage - Output: 0.0125 ~ 1.5 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-TFQFN Exposed Pad
• Output Voltage: 1.1 V
• Output Current: 10 A
• Input Voltage: 19 V
• Supply Current: 6 mA
• Switching Frequency: 400 KHz
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

output capacitance, which results in an optimal transient
response. Solving Equation 6 for a 16 mV peak−to−peak
output ripple voltage yields:
selected value, the inductor can be changed to a smaller
value until the ripple value is met. This iteration allows
optimal
decoupling. In this example, the iteration showed that a
560 nH inductor was sufficient to achieve a good ripple.
minimize the number of output capacitors. Choosing a
560 nH inductor is a good choice for a starting point, and
it provides a calculated ripple current of 6.6 A. The
inductor should not saturate at the peak current of 18.3 A,
and it should be able to handle the sum of the power
dissipation caused by the winding’s average current (10 A)
plus the ac core loss.
DCR, which is used for measuring the inductor current. 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 1.3 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
10% tolerance for the inductance and 7% 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.
Vishay Dale Electronics, Inc.
(605) 665−9301
Panasonic
(714) 373−7334
Sumida Electric Company
(847) 545−6700
NEC Tokin Corporation
(510) 324−4110
In this example, R
If the resultant ripple voltage is less than the initially
The smallest possible inductor should be used to
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
L w
I
L w
R
1.1 V
+
V
transient
V
VID
400 kHz
VID
8 mW
f
SW
f
SW
R
(1 * D
O
O
response
V
L
RIPPLE
16 mV
is assumed to be the ESR of the
(1 * 0.054)
(1 * D
MIN
)
MIN
and
)
+ 1.4 mH
minimum
http://onsemi.com
(eq. 5)
(eq. 6)
(eq. 7)
output
23
Output Droop Resistance
measured at the chip−set pins decreases when the output
current increases. The specified voltage drop corresponds
to the droop resistance (R
voltage across the inductor or current sense resistor. The
filter is implemented by the CS amplifier that is configured
with R
regulator is set by the following equations:
where R
Due to the current drive ability of the CSCOMP pin, the
R
initially select R
Equation 9 to solve for C
In this case, the required C
tuning is required. For best accuracy, C
NPO capacitor.
follows:
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
and produce the desired temperature coefficient tracking.
CS
The design requires that the regulator output voltage
The output current is measured by low−pass filtering the
Either R
If C
Next, solve for R
The standard 1% resistor for R
If the DCR of the inductor is used as a sense element and
If R
resistance should be greater than 100 kW. For example,
CS2
CS
R
C
C
CS
PH
SENSE
R
O
CS
CS
is not a standard capacitance, R
, R
(see Figure 34) are needed to linearize the NTC
PH
+
CS
is designed to have an opposite but equal
+
+
CS
w
R
R
or R
R
1.3 mW
is the DCR of the output inductors.
CS
PH
, and C
1.3 mW
SENSE
8 mW
CS
PH
560 nH
to be equal to 200 kW, and then use
R
L
can be chosen for added flexibility.
PH
SENSE
CS
200 kW
R
CS
O
. The output resistance of the
by rearranging Equation 8 as
200 kW + 32.5 kW
CS
).
:
CS
is a standard value and no
+ 2.2 nF
PH
is 32.4 kW.
CS
CS
should be a 5%
can be tuned.
(eq. 10)
(eq. 11)
(eq. 8)
(eq. 9)
CS1