C&D Technologies Debuts 78SR Series Voltage Regulators
C&D Technologies Inc. (Tucson, AZ) announced three new step-down voltage regulators that are pin-compatible and size-compatible with older and less-efficient LM78xx devices. Supplied in industry-standard TO-220 SIP packaging, the new 78SR regulators can be used as "drop-in" replacements that reduce the power consumption of applications without costly or time-consuming circuit redesign. As a result, the devices can be used to increase battery life in portable instrumentation and standby power applications.
The 78SR switching 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 V and 5 V regulators. Full-load operation from 9 V, 12 V, 24 V, 28 V or 36 V supplies – at ambient temperatures as high as 70 °C – requires no heatsinks, no forced-air cooling, and no temperature derating.
In addition to higher operating efficiencies, the new step-down voltage regulators offer a lower quiescent current of 3 mA (versus 5 mA), a higher operating input voltage of 36 V (versus 32 V), and a tighter output accuracy of ±1.5% (versus 5%). Line and load regulation of ±0.3% and ±0.2%, respectively, allow operation from poorly regulated dc supplies. In addition, the 78SR regulators do not require external input or output capacitors to provide stable, low-noise outputs.
The 78SR regulators are available in two package styles: a standard vertical-mount SIP that occupies less than 0.1 in² (64.5 mm²), and a horizontal-mount version that allows for an installed height of less than 0.35 in (8.9 mm). Pricing for the 78SR Series is $4.95 in OEM quantities.
