Application Notes
For technical support and more information, see inside back cover or visit www.ti.com/powertrends
PT6100/6210/6300 Series
Adjusting the Output Voltage of Power Trends’
Wide Input Range Bus ISRs
The output voltage of the Power Trends’ Wide Input
Range Series ISRs may be adjusted higher or lower than
the factory trimmed pre-set voltage with the addition of a
single external resistor. Table 1 accordingly gives the
allowable adjustment range for each model for either
series as V
a (min) and Va (max).
Adjust Up:
An increase in the output voltage is obtained by
adding a resistor R2, between pin 12 (Vo adjust) and pins 5-8
(GND).
Adjust Down:
Add a resistor (R1), between pin 12 (Vo adjust)
and pins 9-11(Vout).
Figure 1
The values of (R1) [adjust down], and R2 [adjust up], can
also be calculated using the following formulas. Refer to
Figure 1 and Table 2 for both the placement and value of the
required resistor; either (R1) or R2 as appropriate.
Ro (Va – 1.25)
(R1)
=
Vo – Va
k
1.25 Ro
k
R2
=
Va – Vo
Where: Vo = Original output voltage
Va = Adjusted output voltage
Ro = The resistance value fromTable 1
Table 1
ISRADJUSTMENTRANGEANDFORMULAPARAMETERS
1Adc Rated
PT6102
PT6101
PT6103
2Adc Rated
PT6216
PT6213
PT6212
PT6214
3Adc Rated
PT6314
PT6303
PT6302
PT6304
Vo (nom)
1.5
3.3
5.0
12.0
Va (min)
1.3
1.8
1.88
2.18
2.43
Va (max)
1.9
6.07
11.25
8.5
22.12
Ro (k
)
8.25
66.5
150.0
90.9
243.0
R2
Adjust
Up
C1
1
F Ceramic
(Optional)
C2
100
F
(Req'd)
Vo
COM
Vin
+
(R1)
Adj Down
PT6100/6200/6300
9,10,11
12
5,6,7,8
2,3,4
Vin
Vo
G N D
Vo(adj)
Notes:
1. Use only a single 1% resistor in either the (R1) or R2
location. Place the resistor as close to the ISR as possible.
2. Never connect capacitors from Vo adjust to either GND
or Vout. Any capacitance added to the Vo adjust pin will
affect the stability of the ISR.
3. Adjustments to the output voltage may place additional
limits on the maximum and minimum input voltage for
the part. The revised maximum and minimum input
voltage limits must comply with the following
requirements. The limits are model dependant.
PT6216/PT6314:
Vin (max) = (10 x Va)V or 17V, whichever is less.
Vin (min) = 9.0V
All other models:
Vin (max) = (8 x Va)V or as specified.
Vin (min) = (Va + 4)V or 9V, whichever is greater.