Sales Information

Phone:(425) 353-3010

Fax: (425) 353-4030

SVRGA0508S - 5.0

E-mail: vptsales@vptpower.com

Web: www.vptpower.com

Page 7

SVRGA0508S Series

6.2.2 Adjusting the Output Voltage (TRIM)

The output voltage of the converter is set with an external resistor connected from the TRIM pin to the COM pin. This resistor must

have a tolerance of 1% or better to achieve an accurate output voltage. The default output voltage with the TRIM pin left open is 0.8 V.

SVRGA0508S

+Vout (V)

Rtrim (Ω)

0.8

None

0.9

205k

1.0

99.9k

1.2

47.4k

1.5

24.9k

1.8

15.9k

1.9

13.9k

2.0

12.4k

2.5

7.25k

2.8

5.4k

3.0

4.44k

3.3

3.30k

3.4

2.98k

6.3 PROTECTION FEATURES

6.3.1 Input Undervoltage Lockout

The SVRGA0508S Series provides input undervoltage lockout protection. For input voltages below the turn-on voltage, the converter

will remain off. When the input voltage exceeds the turn-on voltage, the converter will start. For input voltages below the operating

range of the converter but above the UVLO turn-off voltage, the converter may reach its maximum duty cycle and the output may drop

out of regulation.

6.3.2 Output Soft-Start

The SVRGA0508S Series utilizes an output soft-start function to ramp the output in a controlled manner, eliminating output voltage

overshoot and limiting inrush current at turn on. A voltage mode soft-start ensures the output waveform remains consistent regardless

of changes in the load current. The output rise time is approximately 5 ms. The soft-start function is active whether the module is

turned on with an application of input voltage or from release of the INH pin. The turn-on delay time is specified from the application of

input voltage (or release of INH pin) until the output reaches 90% of its final value.

6.3.3 Output Short Circuit Protection

The SVRGA0508S Series provides output short circuit protection. When a sustained high peak current is detected, the converter will

shut down and enter a hiccup mode. After a delay, the converter will attempt a soft-start. This sequence will continue until the fault is

removed, allowing the converter to soft-start and resume normal operation.

6.4 THERMAL CONSIDERATIONS

The SVRGA0508S is rated for full power operation at 125 °C. Operation above 125 °C is allowed at reduced power. Specifically, the

output power should be derated linearly from full power at 125 °C to half power at 130 °C and to zero power at 135 °C. The operating

temperature of the converter is specified on the baseplate of the converter. The converter is designed to be conduction-cooled, with the

baseplate mounted to a heat sink, chassis, PCB or other thermal surface. The internal power dissipating components are mounted to

the baseplate of the converter and all heat flow is through the baseplate. The lid of the converter does not provide a good thermal path.

The hybrid DC-DC converter contains many semiconductor components. The maximum temperature rise from junction to case is 11 °C

at full load.

+

-

+

-

0.7 V

210K

30K

5.1K

+VOUT

8

TRIM

6

COM

7

Rtrim

+SENSE

5

100