PT6510 datasheet(9/19 Pages) TI

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Application Notes

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PT6510 Series

Adjusting the Output Voltage of the

PT6510 5V/3.3V Bus Converters

The output voltage of the PT6510 series switching regula-

tors may be adjusted higher or lower than the factory

trimmed pre-set voltage with the addition of a single

external resistor. Table 4-1 gives the allowable adjust-

ment range for each model in the series as Va (min) and

Va (max).

Adjust Up:

An increase in the output voltage is obtained

by adding a resistor R2, between Vo Adjust (pin 14) and

GND (pins 7-10).

Adjust Down:

Add a resistor (R1), between Vo Adjust

(pin 14) and Vout (pins 11-13).

Refer to Figure 4-1 and Table 4-2 for both the placement and

value of the required resistor, either (R1) or R2 as appropriate.

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, Vout, or the Vo Sense pin. Any capacitance

added to the Vo Adjust pin will affect the stability of

the ISR.

3. If the remote sense feature is used, connecting the

resistor (R1) between Vo Adjust (pin 14) and Vo Sense

(pin 1) can benefit load regulation.

4. The minimum input voltage required by the part is

Vout + 1.2 or Vin(min) from Table 4-1, whichever is

higher.

Figure 4-1

The values of (R

1) [adjust down], and R2 [adjust up], can

also be calculated using the following formulae.

Ro (Va – 1.0)

(R1)

(Vo – Va)

– Rs kΩ

– Rs

kΩ

Va - Vo

Where: Vo = Original output voltage

Va = Adjusted output voltage

Ro = The resistance value in Table 4-1

Rs = The series resistance from Table 4-1

Table 4-1

PT6510 ADJUSTMENT AND FORMULA PARAMETERS

Series Pt #

PT6515

PT6512

PT6516

PT6513

PT6511

PT6514

Vo (nom)

1.2

1.5

1.8

2.5

3.3

3.6

Va (min)

1.14

1.27

1.4

1.8

2.25

2.5

Va (max)

2.35

2.65

2.95

3.5

4.2

4.3

Ro (k

Ω

Ω)

2.49

4.99

12.1

Rs (k

Ω

Ω)

4.22

12.1

Vin(min)

3.1

4.5

out

(R1)

Adj Down

Adjust Up

out

COM

Vin

COM

PT6510

11–13

7–10

4–6

out

GND

o(adj)

STBY

o(Sense)

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