Datasheet

Data Sheet ADP122/ADP123
Rev. E | Page 9 of 24
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
PSRR (dB)
I
OUT
= 100µA
V
IN
= V
OUT
+ 0.5V
V
RIPPLE
= 50mV
C
IN
= C
OUT
1µF
I
OUT
= 1mA
I
OUT
= 10mA
I
OUT
= 100mA
I
OUT
= 200mA
I
OUT
= 300mA
08399-017
Figure 21. Power Supply Rejection Ratio vs. Frequency, V
OUT
= 4.2 V, V
IN
= 4.7 V
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
PSRR (dB)
V
OUT
= 2.8V, I
OUT
= 1mA
V
IN
= V
OUT
+ 0.5V
V
RIPPLE
= 50mV
C
IN
= C
OUT
1µF
V
OUT
= 3.3V, I
OUT
= 1mA
V
OUT
= 4.2V, I
OUT
= 1mA
V
OUT
= 2.8V, I
OUT
= 300mA
V
OUT
= 3.3V, I
OUT
= 300mA
V
OUT
= 4.2V, I
OUT
= 300mA
08399-018
Figure 22. Power Supply Rejection Ratio vs. Frequency, Various Output
Voltages and Load Currents
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
PSRR (dB)
V
IN
= 3.1V, I
OUT
= 1mA
V
RIPPLE
= 50mV
C
IN
= C
OUT
1µF
V
IN
= 3.3V, I
OUT
= 1mA
V
IN
= 3.8V, I
OUT
= 1mA
V
IN
= 4.8V, I
OUT
= 1mA
V
IN
= 3.1V, I
OUT
= 300mA
V
IN
= 3.3V, I
OUT
= 300mA
V
IN
= 3.8V, I
OUT
= 300mA
V
IN
= 4.8V, I
OUT
= 300mA
08399-019
Figure 23. Power Supply Rejection Ratio vs. Headroom Voltage (V
IN
− V
OUT
),
V
OUT
= 2.8 V
0
1
2
3
4
5
10 100 1k 10k 100k
FREQUENCY (Hz)
NOISE (µv/√Hz)
08399-020
V
OUT
= 2.8V
V
OUT
= 3.3V
V
OUT
= 4.2V
Figure 24. Output Noise Spectrum
30
35
40
45
50
55
60
65
70
0.001 0.01 0.1 1
10 100 1000
I
OUT
(mA)
RMS NOISE (µV)
V
OUT
= 4.2V
V
OUT
= 3.3V
V
OUT
= 2.8V
08399-021
Figure 25. Output Noise vs. Load Current and Output Voltage
08399-022
CH1 200mA Ω
B
W
CH2 50.0mV
B
W
M 40.0µs A CH1 196mA
1
2
T 10.20%
V
OUT
V
IN
= 3.7V
V
OUT
= 3.3V
1mA TO 300mA LOAD STEP
I
OUT
Figure 26. Load Transient Response, C
OUT
= 1 μF