Voltage regulators

The power electronics division of C&D Technologies has released three high-efficiency step-down voltage regulators that are pin- and size-compatible with older and less efficient LM78xx devices.

Supplied in TO-220 SIP packaging, the 78SR devices can be used as 'drop-in' replacements that allow engineers to reduce the power consumption of applications without costly or time-consuming circuit redesign.

The regulators are suitable for new and existing LM7805/LM7812 designs and other applications where maximum load current is 0.5 A or less and full load operation at elevated supply voltages is needed.

Output options are +5 V/0.5 A (7805SR), +12 V/0.4 A (7812SR) and +3.3 V/0.5 A (7803SR). A 260 kHz switching frequency produces efficiencies as high as 95% for the 12 V part and 85% for the 3.3 and 5 V regulators. Full load operation from 9, 12, 24, 28 or 36 V supplies - at ambient temperatures up to 70°C - requires no heat sinks, no forced air cooling, and no temperature derating. The regulators include a lower quiescent current of 3 mA (versus 5 mA), a higher operating input voltage of 36 (versus 32), and a tighter output accuracy of ±1.5% (versus 5%).

Line and load regulation of ±0.3 and ±0.2% allow operation from poorly regulated DC supplies. Unlike their linear counterparts, the regulators do not require external input or output capacitors to provide stable,low-noise outputs.