ADP5070RE-EVALZ/ADP5071RE-EVALZ User Guide UG-848
Rev. 0 | Page 7 of 13
LOAD REGULATION
For load regulation measurements, monitor the regulator output
while the load is varied. For good load regulation, the output
must change as little as possible with varying loads. The input
voltage must be held constant during this measurement. Figure 7
and Figure 8 show the typical load regulation performance of the
ADP5070/ADP5071 at both the output and feedback pins. Keep
power leads short during this test and use a power supply with
remote sense.
Figure 7. Boost Regulator Load Regulation, V
IN
= 5 V, V
POS
= 15 V (Nominal
Defined as Average Value Within a Range of 65% to 75% Maximum Load)
Figure 8. Inverting Regulator Load Regulation, V
IN
= 5 V, V
NEG
= −15 V (Nominal
Defined as Average Value Within a Range of 65% to 75% Maximum Load)
EFFICIENCY
For efficiency measurements, monitor the regulator input and
output while the load is varied. The input voltage must be held
constant during this measurement. Keep power leads short during
this test and use a power supply with remote sense. Connect
ammeters in series with the input and output. Connect voltmeters
to the PCB side of the ammeter and measure the voltage across the
input and output terminals. For the best results, measure the
voltage across the input and output capacitors. If possible, par-
ticularly at low current, trigger the meters simultaneously and set
to average readings for a period of a few hundred milliseconds or
more. Averaging the readings removes the switching ripple and
skip mode effects. Figure 9 and Figure 10 show typical efficiency
curves using a 5 V input.
Figure 9. Boost Regulator Efficiency vs. Current Load, V
POS
= 15 V, T
A
= 25°C
Figure 10. Inverting Regulator Efficiency vs. Current Load, V
NEG
= −15 V, T
A
= 25°C
–0.5
–0.3
–0.1
0.1
0.3
0.5
0 0.05 0.10 0.15 0.20 0.25
LOAD REGULATION (% CHANGE IN V
FB1
)
LOAD (A)
13281-007
1.2MHz
2.4MHz
–0.5
–0.3
–0.1
0
0.3
0.5
0 0.05 0.10
LOAD (A)
1.2MHz
2.4MHz
LOAD REGULATION (% VARIATION IN V
REF
TO V
FB2
)
13281-008
0
20
40
60
80
100
0.001 0.01
0.1
1
EFFICIENCY (%)
LOAD (A)
V
IN
= 5V, 1.2MHz
V
IN
= 5V, 2.4MHz
13281-009
0
20
40
60
80
100
0.001 0.01 0.1 1
EFFICIENCY (%)
V
IN
= 5V, 1.2MHz
V
IN
= 5V, 2.4MHz
LOAD (A)
13281-010
