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CUI Inc

│ SERIES: PYB15-T & PYB15-U │ DESCRIPTION: DC-DC CONVERTER

date 06/15/2015

│ page 7 of 8

1. Recommended circuit

This series has been tested according to the following recommended testing circuit before leaving the factory. This series should be

tested under load (see Figure 2). If you want to further decrease the input/output ripple, you can increase the capacitance accord-

ingly or choose capacitors with low ESR (see Table 2). However, the capacitance of the output filter capacitor must be appropriate. If

the capacitance is too high, a startup problem might arise. For every channel of the output, to ensure safe and reliable operation, the

maximum capacitance must be less than the maximum capacitive load (see Table 3).

2. Output voltage trimming

Leave open if not used.

Application Circuit for Trim pin

Formula for Trim Resistor

(part in broken line is the interior of models)

Note: Value for R1, R2, R3, and Vref refer to Table 4

R

a: User-defined parameter, no actual meanings

Vo': The trim up/down voltage

APPLICATION NOTES

Figure 2

Figure 3

Table 2

Table 3

Table 4

Single Vout

(Vdc)

Cin

(µF)

Cout

(µF)

Dual Vout

(Vdc)

Cin

(µF)

(µF)

3.3

100

470

--

--

--

5

100

470

±5

100

220

12

100

220

±12

100

100

15

100

220

±15

100

100

24

100

100

--

--

--

Vout

(Vdc)

R1

(kΩ)

R2

(kΩ)

R3

(kΩ)

Vref

(V)

3.3

4.801

2.863

15

1.24

5

2.883

2.864

10

2.5

12

10.971 2.864 17.8

2.5

15

14.497 2.864 17.8

2.5

24

24.872 2.863

20

2.5

Note:

1. Minimum load shouldn't be less than 5%, otherwise ripple may increase dramatically. Operation under minimum load will not damage the converter, however, they may

not meet all specifications listed.

2. Maximum capacitive load is tested at input voltage range and full load.

3. All specifications are measured at Ta=25°C, humidity<75%, nominal input voltage and rated output load unless otherwise specified.

+Vo

0V

Trim

0V

Trim

+Vo

Trim up

Trim down

DC

DC

Vin

GND

+Vo

0V

Cin

Cout

Vin

GND

+Vo

0V

Cin

Cout

DC

DC

-Vo

Cout

Dual Output

Single Output

a

-a

a

-a

:

a=

Vref

Vref

Vo’ - Vref

Vo’ - Vref

R=

T

:

a=

R=

T

up

down

Note:

1. For each output.

Note:

1. For each output.

Single Vout

(Vdc)

Max. Capacitive Load

(μF)

Dual Vout

(Vdc)

(μF)

3.3

10200

--

--

5

4020

5

4800

12

1035

12

800

15

705

15

500

24

470

--

--

For more information, please visit the product page.