LM350 variable voltage Regulator

The LM350 series of adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 3A over a 1.2V to 33V output range. They are exceptionally easy to use and require only 2 external resistors to set the output voltage. Further, both line and load regulation are comparable to discrete designs. Also, the LM350 is packaged in standard transistor packages which are easily mounted and handled. In addition to higher performance than fixed regulators, the LM350 series offers full overload protection available only in IC’s. Included on the chip are current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is accidentally disconnected. Normally, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors in which case an input bypass is needed. An output capacitor can be added to improve transient response, while bypassing the adjustment pin will increase the regulator’s ripple rejection. Besides replacing fixed regulators or discrete designs, the LM350 is useful in a wide variety of other applications. Since the regulator is “floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i.e., avoid short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM350 can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current. The part numbers in the LM350 series which have a K suffix are packaged in a standard Steel TO-3 package, while those with a T suffix are packaged in a TO-220 plastic package. The LM350 is rated for −55˚C≤TJ ≤+350˚C, while the LM350A is rated for −40˚C≤TJ≤+125˚C, and the LM350 is rated for 0˚C≤TJ≤+125˚C. 

Features of LM350

• Adjustable output down to 1.2V
• Guaranteed 3 Ampere output current
• Guaranteed thermal regulation
• Output is short circuit protected
• Current limit constant with temperature
• Product Enhancement tested
• 86 dB ripple rejection
• Guaranteed 1%output voltage tolerance (LM350A)
• Guaranteed max. 0.01%/V line regulation (LM350A)
• Guaranteed max. 0.3%load regulation (LM350A)

Application of LM350 

• Adjustable power supplies
• Constant current regulators
• Battery chargers