ADP3209CJCPZ-RL ON Semiconductor, ADP3209CJCPZ-RL Datasheet - Page 24

• Manufacturer Part Number: ADP3209CJCPZ-RL
• Description: IC CTLR BUCK 5BIT 1PH 32LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADP3209CJCPZ-RL

• Applications: Controller, Power Supplies for Next-Generation Intel Processors
• Voltage - Input: 3.3 ~ 22 V
• Number Of Outputs: 1
• Voltage - Output: 0.4 ~ 1.25 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The standard 1% resistor for R
If the DCR of the inductor is used as a sense element and
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.
If R
change in resistance, it cancels the temperature variation of the
inductor’s DCR. Due to the nonlinear nature of NTC thermistors,
series resistors R
the NTC and produce the desired temperature coefficient tracking.
The following procedure and expressions yield values for
R
R
1.
2.
CS1
CS
CS
, R
value.
Select an NTC to be used based on its type and value.
Because the value needed is not yet determined, start with
a thermistor with a value close to R
initial tolerance of better than 5%.
Find the relative resistance value of the NTC at 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
NTC is always 1 at 25°C.
is designed to have an opposite but equal percentage of
TH
CS2
ADP3209
(90°C)/R
, and R
Figure 35. Temperature-Compensation Circuit Values
≥
CSCOMP
1
5
TO INDUCTOR OR LOW-SIDE MOSFET
CSREF
3 .
1 .
CSFB
PLACE AS CLOSE AS POSSIBLE
mΩ
mΩ
CS1
TH
10
12
11
TH
and R
(the thermistor value at 25°C) for a given
C
(25°C)). Note that the relative value of the
×
CS1
200
CS2
TH
kΩ
(50°C)/R
(see Figure 35) are needed to linearize
=
C
PH
CS2
51
is 51.1 kΩ.
0 .
R
R
CS1
TH
kΩ
TH
(25°C)) and B (B is
AND AWAY FROM SWITCH
AS SHORT AS POSSIBLE
CS
KEEP THIS PATH
R
and an NTC with an
R
CS2
NODE LINES
SWITCH
PH
NODE
TO
Rev. 2 | Page 24 of 32 | www.onsemi.com
V
SENSE
CCGFX
TO
3.
4.
5.
6.
For example, if a thermistor value of 100 kΩ is selected in Step 1,
an available 0603-size thermistor with a value close to R
Vishay NTHS0603N04 NTC thermistor, which has resistance
values of A = 0.3359 and B = 0.0771. Using the equations in
Step 4, r
yields 219 kΩ, so a thermistor of 220 kΩ would be a reasonable
selection, making k equal to 1.005. Finally, R
found to be 72.2 kΩ and 146 kΩ. Choosing the closest 1%
resistor values yields a choice of 71.5 kΩ and 147 kΩ.
Find the relative value of R
temperatures. The relative value of R
percentage of change needed, which is initially assumed to
be 0.39%/°C in this example. The relative values are called
r
(
Compute the relative values for r
the following equations:
Calculate
the closest value available. In addition, compute a scaling
factor k based on the ratio of the actual thermistor value
used relative to the computed one:
Calculate values for R
equations:
1
(r
CS1
− 25))), where TC is 0.0039, T
1
=
=
=
is 1/(1+
is 0.359, r
1
(
1
=
−
−
1
−
1
=
=
1 (
×
1
)
(
×
1 (
−
−
−
(
CS2
×
×
−
× (
1
×
((
)
−
is 0.729, and r
×
1
)
×
−
CS1
−
)
− 25))) and r
)
)
−
, and then select a thermistor of
and R
+
×
(
CS
1 (
×
×
required for each of the two
−
1 (
CS2
−
CS1
)
TH
by using the following
×
1
))
is 50°C, and T
, r
)
is 1.094. Solving for r
2
×
CS
(r
CS2
+
2
is based on the
, and r
CS1
is 1/(1 +
−
×
(
and R
1 (
−
−
TH
)
by using
)
CS2
2
×
is 90°C.
CS
are
×
is the
(10)
(11)
TH
(9)