3-Terminal Adjustable Regulator
The LM117HV/LM317HV are adjustable 3-terminal positive
voltage regulators capable of supplying in excess of 1.5A
over a 1.2V to 57V output range. They are exceptionally
easy to use and require only two external resistors to set the
output voltage. Further, both line and load regulation are bet-
ter than standard fixed regulators. Also, the LM117HV is
packaged in standard transistor packages which are easily
mounted and handled.
In addition to higher performance than fixed regulators, the
LM117HV series offers full overload protection available only
in IC’s. Included on the chip are current limit, thermal over-
load protection and safe area protection. All overload protec-
tion circuitry remains fully functional even if the adjustment
terminal is disconnected.
Normally, no capacitors are needed unless the device is situ-
ated 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 rejections ratios which are difficult to achieve with
standard 3-terminal regulators.
Besides replacing fixed regulators, the LM117HV is useful in
a wide variety of other applications. Since the regulator is
“floating” and sees only the input-to-output differential volt-
age, supplies of several hundred volts can be regulated as
long as the maximum input to output differential is not ex-
ceeded, i.e. do not short the output to ground.
Also, it makes an especially simple adjustable switching
regulator, a programmable output regulator, or by connecting
a fixed resistor between the adjustment and output, the
LM117HV can be used as a precision current regulator. Sup-
plies with electronic shutdown can be achieved by clamping
the adjustment terminal to ground which programs the out-
put to 1.2V where most loads draw little current.
The LM117HVK STEEL and LM317HVK STEEL are pack-
aged in standard TO-3 transistor packages, while the
LM117HVH and LM317HVH are packaged in a solid Kovar
base TO-39 transistor package. The LM317HVT uses a TO-
220 plastic package. The LM117HV is rated for operation
from −55˚C to +150˚C, and the LM317HV from 0˚C to
n Adjustable output down to 1.2V
n Guaranteed 1.5A output current
n Line regulation typically 0.01%/V
n Load regulation typically 0.1%
n Current limit constant with temperature
n 100% electrical burn-in
n Eliminates the need to stock many voltages
n Standard 3-lead transistor package
n 80 dB ripple rejection
n Output is short-circuit protected
n P+ Product Enhancement tested
1.2V-45V Adjustable Regulator
Full output current not available at high input-output voltages
†Optional — improves transient response. Output capacitors in the range of 1 µF to 1000 µF of aluminum or tantalum electrolytic
are commonly used to provide improved output impedance and rejection of transients.
*Needed if device is more than 6 inches from filter capacitors.
© 2000 National Semiconductor Corporation DS009062