AD8331_06 Datasheet, PDF (14/40 Pages) Analog Devices – Ultralow Noise VGAs with Preamplifier and Programmable RIN

AD8331/AD8332/AD8334
35
SAMPLE SIZE = 100
0.2V < V_GAIN < 0.7V
30
25
20
15
10
5
0
49.6 49.7 49.8 49.9 50.0 50.1 50.2 50.3 50.4 50.5
GAIN SCALING FACTOR
Figure 19. Gain Scaling Factor Histogram
100
SINGLE ENDED, PIN VOH OR VOL
R_L = ∞
10
1
0.1
100k
1M
10M
FREQUENCY (Hz)
Figure 20. Output Impedance vs. Frequency
10k
R_FB = ∞, C_SH = 0pF
R_FB = 6.65kΩ, C_SH = 0pF
R_FB = 3.01kΩ, C_SH = 0pF
1k
100M
R_FB = 1.1kΩ, C_SH = 1.2pF
R_FB = 549Ω, C_SH = 8.2pF
100
R_FB = 412Ω, C_SH = 12pF
R_FB = 270Ω, C_SH = 22pF
10
100k
1M
10M
FREQUENCY (Hz)
Figure 21. LNA Input Impedance vs.
Frequency for Various Values of RFB and CSH
100M
25j
RR_IFNB==6_∞kΩ,
0Ω
17Ω
50j
100j
R_IN = 50Ω,
R_FB = 270Ω
f = 100kHz
R_IN = 75Ω,
R_FB = 412Ω
R_IN = 100Ω,
R_FB = 549Ω _{RIN = 200Ω,}
R_FB = 1.1kΩ
–25j
–100j
–50j
Figure 22. Smith Chart, S11 vs. Frequency,
0.1 MHz to 200 MHz for Various Values of RFB
20
V_IN = 10mV p-p
15
R_IN = 50Ω
R_IN = 100Ω
10
R_IN = 200Ω
5
R_IN = 500Ω
0
R_IN = 1kΩ
–5
–10
–15
100k
1M
10M
FREQUENCY (Hz)
R_IN = 75Ω
100M
500M
Figure 23. LNA Frequency Response, Single Ended, for Various Values of RIN
20
15
R_FB = ∞
10
5
0
–5
–10
–15
100k
1M
10M
FREQUENCY (Hz)
100M
500M
Figure 24. Frequency Response for Unterminated LNA, Single Ended
Rev. E | Page 14 of 40