Datasheet

u
8CH_SNR
-
10
N
10 1 1
C
= x -
1CH_SNR
N + N 56 7
-
C
10
10
AFE5808A
SLOS729B –OCTOBER 2011–REVISED APRIL 2012 www.ti.com
ELECTRICAL CHARACTERISTICS
AVDD_5 V = 5 V, AVDD = 3.3 V, AVDD_ADC = 1.8 V, DVDD = 1.8 V, AC-coupled with 0.1 µF at INP and bypassed to
ground with 15 nF at INM, No active termination, V
CNTL
= 0 V, f
IN
= 5 MHz, LNA = 18 dB, PGA = 24 dB, 14Bit, sample
rate = 65 MSPS, LPF Filter = 15 MHz, low noise mode, V
OUT
= –1 dBFS, internal 500 Ω CW feedback resistor, CMOS CW
clocks, ADC configured in internal reference mode, single-ended VCNTL mode, VCNTLM = GND, at ambient temperature
T
A
= 25°C, unless otherwise noted. Min and max values are specified across full-temperature range with AVDD_5 V = 5 V,
AVDD = 3.3 V, AVDD_ADC = 1.8 V, DVDD = 1.8 V
PARAMETER TEST CONDITION MIN TYP MAX UNITS
TGC FULL SIGNAL CHANNEL (LNA+VCAT+LPF+ADC)
Rs = 0 Ω, f = 2 MHz, LNA =24/18/12 dB, PGA = 2 4dB 0.76/0.83/1.16
Input voltage noise over LNA Gain(low
nV/rtHz
noise mode)
Rs = 0 Ω, f = 2 MHz,LNA =24/18/12 dB, PGA = 30 dB 0.75/0.86/1.12
Rs = 0 Ω, f = 2 MHz,LNA =24/18/12 dB, PGA = 24 dB 1.1/1.2/1.45
Input voltage noise over LNA Gain(low
en (RTI) nV/rtHz
power mode)
Rs = 0 Ω, f = 2 MHz, LNA =24/18/12 dB, PGA = 30 dB 1.1/1.2/1.45
Rs = 0 Ω, f = 2 MHz,LNA = 24/18/12 dB, PGA = 24 dB 1/1.05/1.25
Input Voltage Noise over LNA
nV/rtHz
Gain(Medium Power Mode)
Rs = 0 Ω, f = 2 MHz, LNA = 24/18/12 dB, PGA = 30 dB 0.95/1.0/1.2
Input referred current noise Low Noise Mode/Medium Power Mode/Low Power Mode 2.7/2.1/2 pA/rtHz
Rs = 200 Ω, 200 Ω active termination, PGA = 24dB,LNA = 12/18/24 dB 3.85/2.4/1.8 dB
NF Noise figure
Rs = 100 Ω, 100 Ω active termination, PGA = 24dB,LNA = 12/18/24 dB 5.3/3.1/2.3 dB
V
MAX
Maximum Linear Input Voltage LNA gain = 24/18/12 dB 250/500/1000
mV
PP
V
CLAMP
Clamp Voltage Reg52[10:9] = 0, LNA = 24/18/12 dB 350/600/1150
Low noise mode 24/30
PGA Gain dB
Medium/Low power mode 24/28.5
LNA = 24 dB, PGA = 30 dB, Low noise mode 54
Total gain LNA = 2 4dB, PGA = 30 dB, Med power mode 52.5 dB
LNA = 24 dB, PGA = 30 dB, Low power mode 52.5
Ch-CH Noise Correlation Factor without
Summing of 8 channels 0
Signal
(1)
Full band (VCNTL = 0/0.8) 0.15/0.17
Ch-CH Noise Correlation Factor with
Signal
(1)
1MHz band over carrier (VCNTL= 0/0.8) 0.18/0.75
VCNTL = 0.6V(22 dB total channel gain) 68 70
Signal to Noise Ratio (SNR) VCNTL = 0, LNA = 18 dB, PGA =24 dB 59.3 63 dBFS
VCNTL = 0, LNA = 24 dB, PGA = 24 dB 58
SNR over 2 MHz band around carrier at VCNTL = 0.6 V ( 22 dB total
Narrow Band SNR 75 77 dBFS
gain)
Input Common-mode Voltage At INP and INM pins 2.4 V
8 kΩ
Input resistance
Preset active termination enabled 50/100/200/400 Ω
Input capacitance 20 pF
Input Control Voltage V
CNTLP
- V
CNTLM
0 1.5 V
Common-mode voltage V
CNTLP
and V
CNTLM
0.75 V
Gain Range -40 dB
Gain Slope V
CNTL
= 0.1 V to 1.1 V 35 dB/V
Input Resistance Between V
CNTLP
and V
CNTLM
200 KΩ
Input Capacitance Between V
CNTLP
and V
CNTLM
1 pF
TGC Response Time VCNT L= 0 V to 1.5 V step function 1.5 µs
3rd order-Low-pass Filter 10, 15, 20, 30 MHz
Settling time for change in LNA gain 14 µs
Settling time for change in active
1 µs
termination setting
(1) Noise correlation factor is defined as Nc/(Nu+Nc), where Nc is the correlated noise power in single channel; and Nu is the uncorrelated
noise power in single channel. Its measurement follows the below equation, in which the SNR of single channel signal and the SNR of
summed eight channel signal are measured.
6 Submit Documentation Feedback Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Links: AFE5808A