VCA8500_0803 Datasheet, PDF (16/40 Pages) Texas Instruments – 8-Channel, Ultralow-Power, Variable Gain Amplifier with Low-Noise Pre-Amp

VCA8500
SBOS390A – JANUARY 2008 – REVISED MARCH 2008
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TYPICAL CHARACTERISTICS (continued)
All specifications at T_A = +25°C, AVDD2 = 5.0V, AVDD1 = DVDD = 3.3V; single-ended, ac-coupled (1µF) input configuration
to the preamp (LNA), f_IN = 5MHz, V_CNTL = 1.0V, clamp disabled (CL = 1), LPF = 15MHz, and R_LOAD = 1kΩ on each output to
ground, unless otherwise noted.
OUTPUT-REFERRED NOISE vs V_CNTRL
250
Frequency = 5MHz
200
150
PGA = 30dB
100
PGA = 20dB
50
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
V_CNTRL (V)
Figure 20.
120
110
100
90
80
70
60
50
40
30
20
10
0
0
INPUT-REFERRED NOISE vs V_CNTRL
Frequency = 5MHz
PGA = 20dB
PGA = 30dB
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
V_CNTRL (V)
Figure 22.
OUTPUT-REFERRED NOISE vs FREQUENCY OVER R_S
1500
1400
R_S = 1kW
V_CNTRL = 1.2V
1300
1200
1100
1000
R_S = 400W
900
800
700
600
500
400
R_S = 200W
300
200
R_S = 50W
100
0
1
10
20
Frequency (MHz)
Figure 24.
INPUT-REFERRED NOISE vs V_CNTRL
120
110
Frequency = 2MHz
100
90
80
PGA = 20dB
70
60
50
40
30
20
10 ^{PGA = 30dB}
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
V_CNTRL (V)
Figure 21.
CURRENT NOISE vs FREQUENCY OVER R_SOURCE
4.0
V_CNTRL = 1.2V
3.8
3.6
R_S = 1kW
3.4
R_S = 200W
3.2
3.0
R_S = 400W
2.8
2.6
2.4
2.2
2.0
1
10
20
Frequency (MHz)
Figure 23.
INPUT-REFERRED NOISE vs FREQUENCY OVER R_S
6.5
6.0
R_S = 1kW
5.5
5.0
4.5
V_CNTRL = 1.2V
4.0
3.5
R_S = 400W
3.0
2.5
R_S = 200W
2.0
1.5
1.0
0.5
R_S = 50W
0
1
10
20
Frequency (MHz)
Figure 25.
16
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