
AD9279
Rev. 0 | Page 13 of 44
TYPICAL PERFORMANCE CHARACTERISTICS
TGC MODE
fSAMPLE = 40 MSPS, fIN = 5 MHz, RS = 50 Ω, LNA gain = 21.3 dB, LNA bias = mid-high, PGA gain = 27 dB, GAIN = 0.8 V, AAF LPF
cutoff = fSAMPLE/3.0, HPF cutoff = LPF cutoff/12.00 (default).
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
GAIN+ (V)
G
A
IN
E
R
RO
R
(d
B
)
09
42
3-
00
6
Figure 6. Gain Error vs. GAIN+
600
550
500
450
400
350
300
250
200
150
100
50
0
–8 –7 –6 –5 –4 –3 –2 –1
0
1
2
3
4
5
6
7
8
CODES
N
U
M
B
E
R
OF
H
ITS
(
T
ho
us
a
n
ds
)
09
42
3-
00
7
1,000,000 TOTAL HITS
Figure 7. Output-Referred Noise Histogram, GAIN+ = 0.0 V
220
200
180
160
140
120
100
80
60
40
20
0
–8 –7 –6 –5 –4 –3 –2 –1
0
1
2
3
4
5
6
7
8
CODES
NUM
BE
R
O
F
HI
T
S
(
T
h
o
u
san
d
s
)
09
42
3-
00
8
1,000,000 TOTAL HITS
Figure 8. Output-Referred Noise Histogram, GAIN+ = 1.6 V
1.4
1.2
1.0
0.8
0.6
0.4
12
34
56
7
8
9
10
FREQUENCY (MHz)
IN
P
U
T
-R
E
F
E
R
E
D
N
OIS
E
(
n
V
/
Hz
)
09
42
3-
07
2
Figure 9. Short-Circuit, Input-Referred Noise vs. Frequency,
LNA Gain = 21.3 dB, PGA Gain = 30 dB, GAIN+ = 1.6 V
–128
–130
–132
–134
–136
–138
–140
–142
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
GAIN+ (V)
O
U
T
PU
T
-R
EF
ER
R
E
D
N
O
ISE
(
d
B
F
S
/
Hz
)
09
42
3-
00
9
LNA GAIN = 21.3dB
LNA GAIN = 17.9dB
LNA GAIN = 15.6dB
Figure 10. Short-Circuit, Output-Referred Noise vs. GAIN+
64
62
60
58
56
54
52
50
1.0
0.4
0.5
0.6
0.7
0.8
0.9
1.1
1.2
1.3
1.4
1.5
1.6
GAIN+ (V)
S
NR/
S
INA
D
(
d
BF
S
)
09
42
3-
01
0
SNR
SINAD
Figure 11. SNR/SINAD vs. GAIN+, AOUT = 1.0 dBFS