Datasheet
Application Notes
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Adjusting the Output Voltage of the PTH12000x
Wide-Output Adjust Power Modules
The V
o
Adjust control (pin 4) sets the output voltage of
the PTH12000 product. The adjustment range is from
1.2 V to 5.5 V
for the W-suffix modules, and 0.8 V to
1.8 V for L-suffix modules. The adjustment method
requires the addition of a single external resistor, R
set
,
that must be connected directly between the V
o
Adjust
and GND pins
1
. Table 2-1 gives the preferred value of the
external resistor for a number of standard voltages, along
with the actual output voltage that this resistance value
provides. Figure 2-1 shows the placement of the required
resistor.
Figure 2-1; V
o
Adjust Resistor Placement
Notes:
1. A 0.05-W rated resistor may be used. The tolerance
should be 1 %, with a temperature stability of 100 ppm/°C
or better. Place the resistor as close to the regulator as
possible. Connect the resistor directly between pins 4
and 1 using dedicated PCB traces.
2. Never connect capacitors from V
o
Adjust to either GND or
V
out
. Any capacitance added to the V
o
Adjust pin will affect
the stability of the regulator.
PTH12000W PTH12000L
V
out
(Req’d) R
set
V
out
(Actual) R
set
V
out
(Actual)
5 V 280 Ω 5.009 V N/A N/A
3.3 V 2.0 kΩ 3.294 V N/A N/A
2.5 V 4.32 kΩ 2.503 V N/A N/A
2 V 8.06 kΩ 2.010 V N/A N/A
1.8 V 11.5 kΩ 1.801 V 130 Ω 1.800 V
1.5 V 24.3 kΩ 1.506 V 3.57 kΩ 1.499 V
1.2 V Open 1.200 V 12.1 kΩ 1.201 V
1.1 V N/A N/A 18.7 kΩ 1.101 V
1.0 V N/A N/A 32.4 kΩ 0.999 V
0.9 V N/A N/A 71.5 kΩ 0.901 V
0.8 V N/A N/A Open 0.800 V
Table 2-1; Preferred Values of R
set
for Standard Output Voltages
PTH12000 Series
PTH12000x
V
IN
1
4
5
2
3
C
IN
100µF
(Required)
+
C
OUT
100µF
(Optional)
+
Inhibit
GND
GND
V
OUT
R
SET
, 1 %
V
O
Adj
GNDInhibit
V
IN
V
O
For other output voltages the value of the required resistor
can either be calculated, or simply selected from the range
of values given in Table 2-3. The following formula may
be used for calculating the adjust resistor value. Select
the appropriate value for the parameters, R
s
and V
min
,
from Table 2.2.
R
set
= 10 kΩ ·
0.8 V
– R
s
kΩ
V
out
– V
min
Table 2.2; Adjust Formula Parameters
Pt. No. PTH12000W PTH12000L
V
min
1.2 V 0.8 V
V
max
5.5 V 1.8 V
R
s
1.82 kΩ 7.87 kΩ