Powersolve PS75W Series - Manual (Page 3)

Powersolve Electronics Ltd. 8A Arnhem Road, Newbury, RG14 5RU. England
Tel: 01635 521858 Fax: 01635 523771 Email: [email protected]
www.powersolve.co.uk
High Density DC-DC Modules
Application Note
Derating:
The case operating temperature range of the PS75W series is -40°C to +100°C. When operating the PS75W series, proper derating or
cooling is required.
Following is the derating curve for the PS75W without a heatsink; airflow along width (transverse).
Where:
The power dissipated (Pd):
Pd = Pi - Po = Po (1-n) / n
The thermal resistances are listed below:
AIR FLOW RATE TYPICAL Rca
Natural Convection 20ft/min. (0.1m/s) 7.12°C/W
100ft./min. (0.5m/s) 6.21°C/W
200ft./min. (1.0m/s) 5.17°C/W
300ft./min. (1.5m/s) 4.29°C/W
400ft./min. (2.0m/s) 3.64°C/W
500ft./min. (2.5m/s) 2.96°C/W
600ft./min. (3.0m/s) 2.53°C/W
700ft./min. (3.5m/s) 2.37°C/W
800ft./min. (4.0m/s) 2.19°C/W
The temperature rise (∆T):
∆T = Pd * Rca
External Output Trim Output Noise
The output can be trimmed externally (±10%) using a fixed resistor or
a trimpot as shown. The output noise is measured with a 10µF tantalum and a 1.0µF
ceramic capacitor across the output.