V REG ADJ +1.2/57V TO-220-3 317
The LMx17HV is an adjustable 3-terminal positive voltage regulator capable of supplying 1.5 A or more currents over a 1.25-V to 57-V output voltage range. It requires only two external resistors to set the output voltage. The LMx17HV is packaged in standard transistor packages that are easily mounted and handled. The LMx17HV offers overload protection like current limit, thermal overload protection and safe area protection, which make the device blowout proof. The overload protection circuitry remains fully functional even if the adjustment terminal is disconnected. Typically, 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 optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with standard 3-terminal regulators. Since the regulator is floating and sees only the inputto-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, or in other words, do not short the output to ground. By connecting a fixed resistor between the adjustment and output, the LMx17HV can also 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 1.25 V where most loads draw little current.