Datasheet

AD8260
Rev. A | Page 13 of 32
10
100
FREQUENCY (Hz)
OUTPUT-REFERRED NOISE (nV/√Hz)
10M100k 1M 50M
GAIN CODE = 1011
07192-033
Figure 33. Output-Referred Noise vs. Frequency for the VGA/Preamplifier at
Maximum Gain—See Figure 61
1
100
10
GAIN SELECT CODE
INPUT-REFERRED NOISE (nV/√Hz)
1010100110000111011001010001 010000110010 1011
07192-034
Figure 34. Input-Referred Noise vs. Gain Select Code for the VGA/Preamplifier
See Figure 61
1
10
FREQUENCY (Hz)
SHORT-CIRCUIT INPUT-REFERRED NOISE
(nV/√Hz)
10M100k 1M 50M
GAIN CODE = 1011
07192-035
Figure 35. Short-Circuit Input Noise vs. Frequency for the VGA/Preamplifier
See Figure 61
50
HARMONIC DISTORTION (dBc)
LOAD RESISTANCE (Ω)
1800160014001200200 10008004000 2000
30
40
60
80
70
600
HD
2
HD3
07192-036
V
OUT
= 1V p-p
GAIN CODE = 0110
Figure 36. Harmonic Distortion (HD2, HD3) vs. Load Resistance for the
VGA/Preamplifier—See Figure 62
LOAD CAPACITANCE (pF)
HARMONIC DISTORTION (dBc)
–70
–60
–50
–40
–30
–80
10 400 3020
50
V
OUT
= 1V p-p
GAIN CODE = 0110
HD2
HD3
07192-037
Figure 37. Harmonic Distortion (HD2, HD3) vs. Load Capacitance for the
VGA/Preamplifier—See Figure 62
–120
HARMONIC DISTORTION (dBc)
GAIN SELECT CODE
101010011000011101100101 1011
–20
–40
–60
–80
–100
0
MEASUREMENT OF
DISTORTION IS
LIMITED BY THE
MAXIMUM DYNAMIC
INPUT RANGE OF
THE PREAMPLIFIER
HD2, f
C
= 1MHz
V
OUT
= 1V p-p
HD3,
f
C
= 1MHz
HD2,
f
C
= 10MHz
HD3,
f
C
= 10MHz
07192-038
Figure 38. Harmonic Distortion (HD2, HD3) vs. Gain Select Code at 1 MHz
and 10 MHz for the VGA/Preamplifier—See Figure 62