LM350 Datasheet, PDF (5/8 Pages) Motorola, Inc – THREE.TERMINAL ADJUSTABLE POSITIVE VOLTAGE REGULATOR

Typical Application
Input
LM350
LM350
Output
Figure 13.
CI : CI is required if the regulator is located an appreciable distance from power supply filter.
CO : Output capacitors in the range of 1µF to 100µF of aluminum or tantalum electronic are commonly used to provide
improved output impedance and rejection of transients.
In operation, the LM350 develops a nominal 1.25V reference voltage, VREF, between the output and adjustment terminal. The
reference voltage is impressed across program resistor R1 and, since the voltage is constant, a constant current I1 then flows
through the output set resistor R2, giving an output voltage of
VO = 1.25V(1+R2/R1) + IADJ R2
Since IADJ current (less than 100µF) from the adjustment terminal represents an error term, the LM350 was designed to mini-
mize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current is returned to the
output establishing a minimum load current requirement. If there is insufficient load on the output, the output voltage will rise.
Since the LM350 is a floating regulator, it is only the voltage differential across the circuit which is important to performance,
and operation at high voltage with respect to ground is possible.
Since IADJ is controlled to less than 100µA, the error associated with this term is negligible in most applications.
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