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发表于 2009-3-4 10:45:54
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原帖由 prof3 于 2009-3-4 09:43 发表
1. For 10bit, need about 7 tor. And Settling time=Ts/2=2ns, acutally only 1.8ns due to non-overlapped clock. For GBW=1.1Ghz, 7 tor about 7*1/(2*pi*GBW)=1.1ns1.8ns. It will harm your THD.
2. If your ...
Thank you very much.
1. The GBW of S/H opamp is lower than MDAC opamp. The GBW of MDAC opamp is about 1.8GHz.
2. Every MDAC have been tested. Gain = 2 mode was uesd. Input +/-0.25V sine wave signal and output +/-0.5V discrete sampled signal. 1024 DFT result is also good,
MDAC1 SFDR=-96dB THD=0.031%
MDAC2 SFDR=-100dB THD=0.030%
MDAC3 SFDR=-94dB THD=0.038%
It seems the MDAC linearity is very good from DFT analysis.
Now, I want to do some simulation.
1. ADC top level INL test, input a ramp siganl and measure the INL. It maybe helps me find problem
2. Increase power supply to 1.2V to make sure whether the opamp output range is too small |
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