Innovative Circuits
Superpower compared to modern monolithic regulators
How does the superpower compare with modern 3 terminal regulators?
See the oscillograms below and judge for yourself. All devices
were tested using datasheet recommended application circuits, all
devices have a 10µF output capacitor and use the same input supply.
All were measured with 5Vout except the LT1585, which was
3.3Vout.
Superpower, 1A pulse
Superpower delivering 1A
into 0.5 Ohms, bottom trace is load voltage. The top trace shows Vout
transients, which are nearly invisible at 0.2V/div.
Superpower, 1A pulse magnified
LT1086, 1A pulse
The LT1086 has a
relatively quick transient at the leading edge of applied load and an
ugly settling transient on the trailing recovery edge.
LM1117T, 1A pulse
The LM1117 shows dynamics
similar to the LT1086, even though an examination of their data sheets
shows a different error amplifier and output schematic. There is a slow
transient at the leading edge of applied load and an ugly settling
transient on the trailing recovery edge. This device also requires a
2.5V overhead for dropout.
LT1585, 1A pulse
The LT1585 is billed as
"low dropout fast response" and it does have the best performance of
the monolithic devices. However, even at this magnification you can
see that the SPJ17 is faster with cleaner leading and trailing
edges. Note also that the maximum voltage across this regulator is 13V.
LT1585, 1A pulse magnified
LT1585
magnified output transient shows good performance relative to the others.
But not super, notice the lower recovery speed
compared to the Superpower magnified edges.
LM317, 1A pulse
OK, the LM317 is not "modern." However, it is still a great design after 30 years and
does well against most of the modern regulators. This one has significant
output ringing on the rising recovery transient and an odd wrinkle at the load.