AFE5818_15 Datasheet, PDF (26/156 Pages) Texas Instruments – AFE5818 16-Channel, Ultrasound, Analog Front-End with 140-mW/Channel Power, 0.75-nV/√Hz Noise, 14-Bit, 65-MSPS or 12-Bit, 80-MSPS ADC, and Passive CW Mixer

AFE5818
SBAS687B – FEBRUARY 2015 – REVISED AUGUST 2015
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Typical Characteristics (continued)
At T_A = 25°C, AVDD_1P8 = 1.8 V, AVDD_3P3 = 3.3 V, AVDD_5V = 5 V, DVDD_1P2 = 1.2 V, DVDD_1P8 = 1.8 V, ac-
coupled with a 0.1-µF capacitor at INP, 15-nF capacitor to ground at INM, no active termination, VCNTLP = VCNTLM = 0 V,
LNA = 18 dB, PGA = 24 dB, LPF filter = 15 MHz, low-noise mode, internal 500-Ω CW feedback resistor, 14-bit ADC
resolution, ADC_CLKP and ADC_CLKM = 50-MHz differential, LVDS mode to capture ADC data, input signal frequency f_IN =
5 MHz, and output amplitude V_OUT = –1 dBFS, unless otherwise noted. Minimum and maximum values are specified across
the full temperature range.
300
280
LNA 12 dB
260
LNA 18 dB
LNA 24 dB
240
220
200
180
160
140
120
100
80
60
40
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
VCNTL (V)
D026
Across LNA gain for medium-power mode
360
340
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
0
LNA 12 dB
LNA 18 dB
LNA 24 dB
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
VCNTL (V)
D027
Across LNA gain for low-power mode
Figure 26. Output-Referred Noise vs VCNTL
250
Regsiter 203[3:2], 205[8] = 01, 1
225
Regsiter 203[3:2], 205[8] = 01, 0
Regsiter 203[3:2], 205[8] = 00, 0
Regsiter 203[3:2], 205[8] = 11, 0
200
Regsiter 203[3:2], 205[8] = 10, 0
Figure 27. Output-Referred Noise vs VCNTL
250
225
200
175
175
150
150
125
125
100
100
75
0 200 400 600 800 1000 1200 1400 1600
Frequency (kHz)
D028
Across LNA_HPF_PROG (register 203, bits 3-2) and
RED_LNA_HPF_3X (register 205, bit 8)
Figure 28. Low-Frequency Output-Referred Noise vs
Frequency
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
1 2 3 4 5 6 7 8 9 10 11 12
Frequency (MHz)
D030
75
50 250 450 650 850 1050 1250 1450 1650
Frequency (kHz)
D029
INMx capacitor = 1 µF, PGA_HPF_DIS (register 195, bit 4) = 1
Figure 29. Low-Frequency Output-Referred Noise vs
Frequency
180
160
140
120
100
80
60
40
1 2 3 4 5 6 7 8 9 10 11 12
Frequency (MHz)
D031
Figure 30. Input-Referred Noise vs Frequency
Figure 31. Output-Referred Noise vs Frequency
26
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