page

date

DESCRIPTION: dc-dc converter

3 of 3

02/2008

20050

phone

phone 503.612.2300 fax

fax 503.612.2382

PART NUMBER: VAT0.25-SMT Series

Application Notes:

- To ensure this module can operate efficiently and

reliably during operation, the minimum output load

should not be less than 10% of the full load. This

product should never be operated under no load

conditions. If the actual output power is very low you

should increase the load by connecting a resistor

with the proper resistance at the output end in

parallel.

- Recommended Circuit

If you want to further decrease the input/output

ripple, an “LC” filtering network may be connected to

the input and output ends of the dc-dc converter, see

(Figure 1).

- Overload Protection

Under normal operating conditions, the output circuit

of these products has no protection against overload.

The simplest method is to connect a self-recovery

fuse in series at the input end or add a circuit

breaker to the circuit.

DC DC

DC

+Vin

-Vin

+Vin

-Vin

REG

+Vout

Com

-Vout

+Vout

Com

-Vout

DC

REG

REG

- Output Voltage Regulation and Over-voltage

Protection Circuit

The simplest device for output voltage regulation,

over-voltage and over-current protection is a linear

voltage regulator with overheat protection that is

connected to the input or output end in series

(Figure 2).

No parallel connection or plug and play.

Figure 2

DC

L

L

DC

L

+Vout

Com

-Vout

+Vin

-Vin

C

C

C

Figure 1

It should also be noted that the inductance and

the frequency of the “LC” filtering network should

be staggered with the dc-dc frequency to avoid

mutual interference. However, the capacitance of

the output filter capacitor must be proper. If the

capacitance is too large, a startup problem might

arise. It is not recommended to connect any

external capacitor in the application field .

250

200

150

100

50

0

90 Sec. max

(>220°C)

220°C

Peak Temperature

260°C for 10 Sec. Max

Time (Seconds)

Reflow Profile