ADP3207 ANALOG DEVICES, ADP3207 Datasheet - Page 27

• Manufacturer Part Number: ADP3207
• Description: 7-Bit Programmable Multiphase Mobile CPU Synchronous Buck Controller
• Manufacturer: ANALOG DEVICES

ADP3207
The number of hot spots monitored is not limited. The alarm
temperature of each hot spot can be set differently by playing
different RTTSET
TUNING PROCEDURE FOR ADP3207
1.
2.
DC Loadline Setting
3.
4.
5.
6.
7.
8.
9.
10. Measure output ripple at no load and full load with a scope
VRTT
Build the circuit based on compensation values computed
from Equation 1 to Equation 39.
Hook-up the dc load to the circuit. Turn the circuit on and
verify operation. Check for jitter at no load and full load.
Measure the output voltage at no load (V
is within tolerance.
Measure the output voltage at full load and at cold (V
Let the board set for a ~10 minutes at full load and measure
the output (V
millivolts, then adjust R
Equation 41.
Repeat Step 4 until cold and hot voltage measurements
remain the same.
Measure output voltage from no load to full load using 5 A
steps. Compute the load line slope for each change and
then average it to get the overall load line slope (R
If R
following to adjust the R
Repeat Step 6 and Step 7 to check load line and repeat
adjustments if necessary.
Once complete with dc load line adjustment, do not change
R
to make sure it is within specification.
R
R
PH
CS
PH
( 2
OMEAS
, R
(
NEW
NEW
R
R
CS1
)
)
Figure 13. Multiple-Point Thermal Monitoring
, R
=
=
is off from R
31
30
R
R
CS2
VCC
PH
CS
TTSENSE
1
FLHOT
, RTTSET
( 2
, or R
(
OLD
OLD
)
)
5V
). If there is a change of more than a few
×
×
TH
R
V
V
OMEAS
NL
O
R
NL
for the rest of procedure.
O
2
CS1
by more than 0.05 mΩ, use the
PH
, RTTSET
−
V
−
FD
V
V
and R
values:
FLCOLD
FLHOT
CS2
n
.
using Equation 40 and
R
TTSET1
R
TH1
NL
). Verify that it
R
TTSET2
…
R
TH2
OMEAS
FLCOLD
R
TTSETn
R
).
THn
(40)
(41)
Rev. 0 | Page 27 of 32
).
AC Loadline Setting
11. Remove the dc load from the circuit and hook up the dynamic
12. Hook up the scope to the output voltage and set it to dc
13. Set the dynamic load for a transient step of about 40 A at
14. Measure the output waveform (using the dc offset on scope
15. Users should see a waveform that similar to the one in
16. If the V
17. Repeat Steps15 and Step 16. Repeat adjustments if
18. Set dynamic load step to maximum step size. Do not use a
load.
coupling with the time scale at 100 µs/div.
1 kHz with a 50% duty cycle.
to see the waveform, if necessary). Try to use the vertical
scale of 100 mV/div or finer.
Figure 15. Use the horizontal cursors to measure V
and V
overshoot that occurs immediately after the step.
of mV, use the following to adjust C
need to parallel different values to get the right one due to
the limited standard capacitor values available. It is also wise
to have locations for two capacitors in the layout for this):
step size larger than needed. Verify that the output waveform
is square, which means V
Note: Make sure that the load step slew rate and turn-on
are set for a slew rate of ~150 A/µs to 250 A/µs (for
example, a load step of 50 A should take 200 ns to 300 ns)
with no overshoot. Some dynamic loads have an excessive
turn-on overshoot if a minimum current is not set properly
(this is an issue if you are using a VTT tool).
C
necessary. Once complete, do not change C
rest of the procedure.
CS
(
NEW
DCDRP
)
ACDRP
=
C
CS
as shown. Do not measure the undershoot or
and V
Figure 14. AC Loadline Waveform
(
OLD
)
×
DCDRP
V
V
DCDRP
ACDRP
are different by more than a couple
ACDRP
V
ACDRP
and V
CS
www.DataSheet4U.com
(note that users may
DCDRP
V
DCDRP
are equal.
CS
ADP3207
for the
ACDRP
(42)