Datasheet

Application Notes
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Adjusting the Output Voltage of the PTH05000W
Wide-Output Adjust Power Modules
The V
o
Adjust control (pin 4) sets the output voltage of
the PTH05000Wproduct. The adjustment range is
from 0.9 V to 3.6 V. 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.
For other output voltages the value of the required resistor
can either be calculated using the following formula, or
simply selected from the range of values given in Table 2-2.
Figure 2-1 shows the placement of the required resistor.
R
set
= 10 kΩ ·
0.891 V
– 3.24 kΩ
V
out
– 0.9 V
Figure 2-1; V
o
Adjust Resistor Placement
Notes:
1. Use a 0.1 W resistor. 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.
0.900 Open
0.925 353 kΩ
0.950 175 kΩ
0.975 116 kΩ
1.000 85.9 kΩ
1.025 68.0 kΩ
1.050 56.2 kΩ
1.075 47.7 kΩ
1.100 41.3 kΩ
1.125 36.4 kΩ
1.150 32.4 kΩ
1.175 29.2 kΩ
1.200 26.5 kΩ
1.225 24.2 kΩ
1.250 22.2 kΩ
1.275 20.5 kΩ
1.300 19.0 kΩ
1.325 17.7 kΩ
1.350 16.6 kΩ
1.375 15.5 kΩ
1.400 14.6 kΩ
1.425 13.7 kΩ
1.450 13.0 kΩ
1.475 12.3 kΩ
1.50 11.6 kΩ
1.55 10.5 kΩ
1.60 9.49 kΩ
1.65 8.64 kΩ
1.70 7.90 kΩ
1.75 7.24 kΩ
1.80 6.66 kΩ
1.85 6.14 kΩ
1.90 5.67 kΩ
1.95 5.25 kΩ
V
out
(Standard) R
set
(Pref’d Value) V
out
(Actual)
3.3 V 475 Ω 3.298V
2.5 V 2.32 kΩ 2.502 V
2 V 4.87 kΩ 1.999 V
1.8 V 6.65 kΩ 1.801 V
1.5 V 11.5 kΩ 1.504 V
1.2 V 26.1 kΩ 1.204 V
1 V 84.5 kΩ 1.001 V
0.9 V Open 0.9 V
Table 2-1; Preferred Values of R
set
for Standard Output Voltages
Table 2-2; Output Voltage Set-Point Resistor Values
V
a
Req’dR
set
V
a
Req’dR
set
2.00 4.86 kΩ
2.05 4.51 kΩ
2.10 4.19 kΩ
2.15 3.89 kΩ
2.20 3.61 kΩ
2.25 3.36 kΩ
2.30 3.12 kΩ
2.35 2.90 kΩ
2.40 2.70 kΩ
2.45 2.51 kΩ
2.50 2.33 kΩ
2.55 2.16 kΩ
2.60 2.00 kΩ
2.65 1.85 kΩ
2.70 1.71 kΩ
2.75 1.58 kΩ
2.80 1.45 kΩ
2.85 1.33 kΩ
2.90 1.22 kΩ
2.95 1.11 kΩ
3.00 1.00 kΩ
3.05 904 Ω
3.10 810 Ω
3.15 720 Ω
3.20 634 Ω
3.25 551 Ω
3.30 473 Ω
3.35 397 Ω
3.40 324 Ω
3.45 254 Ω
3.50 187 Ω
3.55 122 Ω
3.60 60 Ω
PTH05000W
V
IN
1
4
5
2
3
C
IN
330µF
(Required)
+
C
OUT
100µF
(Optional)
+
Inhibit
GND
GND
V
OUT
R
SET
0.1 W, 1 %
V
O
Adj
GNDInhibit
V
IN
V
O
PTH05000W