Unregulated DC-DC converter - DCP020515DU

The DCP02 series ,DCP01, DCV01 , DCR 01 and DCR02  are not designed for continuous isolated voltages greater than 60DC or 42VAC .

The statement below applies to continuous SELV isolation  limits .

The external continuous voltage difference limits are defined as voltages as measured between VIN (-) and Vout (-) ground). The converter is designed as ground fault isolation device. It is not designed to operate with a continuous voltage isolation barrier at greater than 60VDC. The isolation 1 second test validates only the magnetic coating separation between primary and secondary transformer wire.

The maximum potential difference ( Vin(+) to Vout ground ) as referenced to  a common ground is limited to continuous 60V DC or 42V Peak  AC transient between Vin(-) and Output ( ground). The primary and secondary transformer wires will  contact each other separated by magnet wire over-coating. The transformer magnet wires are single coating material and not double insulated . The UL listing, E199929, voltage limits are SELV or 60VDC continuous or 42V transient peak.

Stephan:

I reviewed your comments regarding in-rush current .

The typical in-rush  current  with any input voltage , DCP020515P=5Vin and DCP0212xx=12Vinis about 750mA. The input power source  dv/dt   and current limit have the critical influence on the in-rush current.

Additional factors influencing  in-rush current also  include the  required external  input  ceramic capacitance  and sync. pin capacitive load loading .

Send me an e-mail at  tguerin @ti.com  and I can call you to discuss this in-rush factor.

Do you means 750mA rms or 750mA peak-peak?

I'm experiencing more kind of 4Apeak-peak and 800mA to 1.6A rms. This measurement would be made on the same chip.

For the start-up time, I used another power supply, and my mean time shutdown from 80ms to 10ms . But the start-up time is still changing from 1ms to 20ms.

Sync pin is left floating.

I though power supplies were poorly rooted on the PCB so I soldered it very next to DCP02 pads. But the issue remains the same.

The inrush current when the power source (12V) has a current rating of 1 Amp or greater and power lines are large gauge wire, the current is typical   750MA Peak. If the 12 power source is current limited directly attached with long lossy  wire long power lines , the input in-rush current can be up to 2 amps.The power source /has a major impact on this in-rush current.

Call me at 630-836-2828 so we can discuss this question

Tom