Datasheet
APPLICATION INFORMATION
ADJUSTING THE OUTPUT VOLTAGE
R
SET
+ 10 kW
0.69
V
O
* 0.69
* 1.43 kW
(1)
UDG−06043
R
SET
1%
0.05 W
V
O
+Sense
−Sense
VoAdjGND
3
4
5
6
7
+Sense
−Sense
GND
V
O
PTH04T260/261W
PTH04T260W , PTH04T261W
www.ti.com
.................................................................................................................................................. SLTS273E – SEPTEMBER 2006 – REVISED JULY 2009
The V
O
Adjust control (pin 7) sets the output voltage of the PTH04T260/261W. The adjustment range of the
PTH04T260/261W is 0.69V to 3.6V. The adjustment method requires the addition of a single external resistor,
R
SET
, that must be connected directly between the V
O
Adjust and the – Sense pins. Table 1 gives the standard
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 . Figure 9 shows the placement of the required
resistor.
Table 1. Preferred Values of R
SET
for Standard Output Voltages
V
O
(Standard) (V) R
SET
(Standard Value) (k Ω ) V
O
(Actual) (V)
3.3
(1)
1.21 3.304
2.5
(1)
2.37 2.506
1.8
(1)
4.75 1.807
1.5
(1)
6.98 1.510
1.2 12.1 1.200
1.0 20.5 1.004
0.7 681 0.700
(1) The minimum input voltage is 2.2 V or (V
O
+ 0.5) V, whichever is greater.
(1) R
SET
: Use a 0.05 W resistor with a tolerance of 1% and temperature stability of 100 ppm/ ° C (or better). Connect the
resistor directly between pins 7 and 6, as close to the regulator as possible, using dedicated PCB traces.
(2) Never connect capacitors from V
O
Adjust to either GND, V
O
, or +Sense. Any capacitance added to the V
O
Adjust pin
affects the stability of the regulator.
Figure 9. V
O
Adjust Resistor Placement
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