Broadcom ACPL-C799, Руководство пользователя

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ACPL-C799 Evaluation Kit Board
User Guide Measurement

Lab bench test: Apply input voltage signal from a function generator with 1

shunt resistor mounted on the input of
evaluation board.
When a voltage signal is sourced from a function generator to the evaluation board without a shunt resistor connected as
shown in
Figure 8 , input bias current of about 0.18mA from the ACPL-C799 will cause a 9mV offset on the function generator
output due to the 50

source impedance of the function generator.
Figure 8 Sourcing the Voltage Signal from a Function Generator to the Evaluation Board without a Shunt Resistor Connected
A more accurate method to measure the performance of the ACPL-C799 evaluation board is to connect a 1

shunt resistor,
then supply the voltage signal from a function generator that can drive sufficient current through the 1

shunt resistor until
an input signal level of ±50mV is reached. One such function generator is the ultra low distortion DS360 function generator
from Standford Research Systems.
Table 3 shows the SNR/SNDR performance using this method.
If such a function generator is not available, it is best to connect an actual shunt resistor and connect to customer's current sensing
system directly.
Table 2 SNR/SNDR Comparison
ACPL-C799 Board
Audio Signal from Dell Lattitude E7440 Laptop Audio Signal from Samsung Galaxy S6
signal freq=1kHz signal freq =500Hz signal freq =1kHz signal freq =500Hz
SNDR(dB) SNR(dB) SNDR(dB) SNR(dB) SNDR(dB) SNR(dB) SNDR(dB) SNR(dB)
Clock freq = 10MHz 67.55 68.44 66.27 68.06 72.31 74.26 72.05 74.76
Table 3 SNR/SNDR Performance
ACPL-C799 Board
DS360 Stanford Research Systems Ultra Low Distortion Function
Generator
signal freq=1kHz signal freq =500Hz
SNDR(dB) SNR(dB) SNDR(dB) SNR(dB)
Clock freq = 10MHz 74.53 77.42 74.97 78.35