Hello,
I'm using AMC1210 to filter sigma-delta ADC for current sense application. The ADC is isolated, 5V voltage level, 10MHz clock, 16 bit resoluation. the AMC1210 connected to FPGA with a SPI interface.
When the current is 0A I see on the AD0 (MISO) 8-7 bits noise.The reason I use the AMC1210 in the first place was to "make room" in the FPGA. That noise seems weird to me, because with filter on the FPGA the noise was 3-2 bits. The SPI interface seems fine, voltage level is good. Then I got to think it's something to do with the
AMC1210 register map configuration. I check that I wrote the right values to the register map, and still it doen't help. I do think that may be the values of the register map are effecting the noise in some way. below you can the values i wrote to the register map. My question is according to ADC specifications are the values are good? and if there are good how can i reduce the noise?
Control Parameter Register: x"E000" - ACK is disable, INT enable, Master interrupt enable, patter count is zero.
Pattern Register: x"0000"- zero.
Clock Divider Register: x"0800" - PWM1 and PWM2 are off, signal generator is off, sinc is enable, no phase cakibration is preforming, signal generator clock divider is zero.
Control Parameter Register: x"0000" - CLK is input, SH1is chosen as sample-and-hold signal(though Imust say I didn't understand the fuction of the sample and hold in this register) , The time is measured from the last filter update to the last rising edge of the selected sample-and-hold signal, The clock speed is equal to the data rate from the modulator
Sinc Filter Parameter Register: x"0D7F"- sinc3 filter, no ACK flag, Filter anable, OSR is 128.
Integrator Parameter Register: x"0000"- Integrator disable.
High-Level Threshold Register: x"7530"
Low-Level Threshold Register: x"7AD0".
Control Filter Parameter Register: x"0374" - The modulator failure flag is enabled, Comparator filter runs with a Sinc2 structure,low-lwvwl and high-level enabled, OSR is 4.
I'll really appreciate your help.
best regards,
Tal
