1. DESCRIPTION of HHF28 Series High Reliability  DC/DC Converters

The HHF28 Series of dc dc converter  offers up to 15 watts of output power with high reliability. The HHF28 series’ small size, light weight, and hermetically sealed metal packages make them ideal for use in aviation aerospace and other high reliability applications.

The HHF 28 series of converters use forward pulse width modulated topology design. The operating principle is that the sampling signal of output voltage, coupled by the opto-coupler, works together with the sampling signal of input loop current to regulate the pulse width of the controller. The double close loop control can create constant voltage output and short circuit protection. The magnetic feedback technology can effectively prevent the magnetic saturation of transformer and also products reliability can be improved.

Thick film hybrid techniques provide the HHF28 Series of converters with reliability levels and optimum miniaturization. The design and manufacturing process of HHF28 Series of converters are in compliance with General Standards of Hybrid Integrated Circuits and detailed standards of manufacturing. Connected to a HFD-CE03 filter, the HHF Series of converters can achieve better electromagnetic compatibility (EMC) performance.

2. ELECTRICAL PERFORMANCE of HHF28 Series High Reliability  DC/DC Converters

ABSOLUTE MAXIMUM RATINGS

• Input Voltage: 16~44

• Power dissipation: 6W

• Lead Soldering Temperature : 300°C (10 sec per lead)

• Storage Temperature Range (Case): -55℃ ~ +125℃

• Inhibit voltage: ≤0.2V

• Outside Sync. Signal:

Frequency Range: 450~600kHz

Duty Cycle:40%~60%

TTL: 0.8≤V≤4.5V