Application Notes

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PT6680 Series

Adjusting the Output Voltage of the

PT6680 5Amp 18-36V Bus Converter Series

The output voltage of the Power Trends PT6680 Series

ISRs may be adjusted higher or lower than the factory

trimmed pre-set voltage with the addition of a single

adjustment range for each model in the series as V

and V

Adjust Up:

An increase in the output voltage is

obtained by adding a resistor R2, between pin 14 (V

just) and pins 7-10 (GND).

Adjust Down:

Add a resistor (R1), between pin 14 (V

o

adjust) and pins 11-13 (V

Refer to Figure 1 and Table 2 for both the placement and value

Notes:

location. Place the resistor as close to the ISR as possible.

2. Never connect capacitors from V

V

the V

3. If the Remote Sense feature is being used, connecting the

Sense) can benefit load regulation.

4. For output voltages above 10.0Vdc, the maximum output

current must be limited to 4Adc.

5. Adjustments to the output voltage may place additional

limits on the input voltage for the part. The revised limits

must comply with the following requirements.

V

= (V

whichever is higher.

V

= (10 x V

whichever is less.

also be calculated using the following formulae.

(R1)

=

R2

=

Where: V

o

= Original output voltage

V

a

= Adjusted output voltage

R

o

= The resistance value in Table 1

R

s

= The series resistance from Table 1

Figure 1

Table 1

PT6680 ADJUSTMENT AND FORMULA PARAMETERS

Series Pt #

PT6682

PT6681

PT6683

PT6684

PT6686

PT6685

Vo (nom)

2.5V

3.3V

5.0V

9.0V

12.0V

15.0V

Va (min)

1.8V

2.2V

3.0V

6.0V

9.0V

10.0V

Va (max)

4.3V

4.7V

6.5V

10.2V

13.6V

17.0V

Ro (k

Ω

Ω

Ω

Ω

Ω)

4.99

4.22

2.49

2.02.02.0

Rs (k

Ω

Ω

Ω

Ω

Ω)

2.49

4.99

4.99

12.7

12.7

12.7

C

in

+

C

out

+

(R1)

Adj Down

R2

Adjust

Up

Vo

COM

COM

Vin

L

O

A

D

PT6680

11,12,13

14

7,8,9,10

4,5,6

Vin

V o

G N D

Vo(adj)

STBY

3

Vsense

1