Better Simple Voltage Regulator Circuit than 78XX Series

1. The voltage drop across the LP295l is only 0.4 V at a load current of 100 mA, so a 6 V battery pack can be used to power a 5 V circuit. The quiescent cur- rent drain of the regulator is about 12 mA at an output current of 100 mA.
2. The former features an internal voltage divider with a 5 V tap bonded out to a pin, a logic compatible shutdown input, and an open- collector ERROR output which warns of a low output voltage, often due to an insufficient battery voltage at the input.
3. The recently introduced types LP295l and LP2950 from National Semiconductor are micropower voltage regulators with a variable output voltage of 1.24-29 V and a fixed output voltage of 5Vj respectively.
4. Note that both the LP2950 and LP295l feature internal current and thermal limiting circuits. The decoupling capacitor at the output of the regulator should be a good . quality tantalum type, fitted as l close as possible to pins
5. The application circuit shown in Fig. la should be fed from an input voltage of more than 5.4 lL while its maximum output current is 100 mA.
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7. The ERROR output is extremely useful for an early wanting system that arranges for a microprocessor to be reset properly before the supply voltage falls to a level that would upset the operation of the system it controls.
8. This is fairly high as compared with a conventional regulator from the 78XX family, and mainly due to the internal series regulator transistor being driven into saturation, which causes it to have a relatively low current amplification factor (the base current flows into the ground return line, instead of into the output load, as with the typical 18X`X regulator).
9. The fast spreading incorporation of CMOS, HC and HCT chips has created a need for voltage regulators with a very low internal drop to enable powering CMOS-based equipment from a set of batteries delivering 6V