Hi Team,
Customer used the LME49720 as the I/V translator.The currunt source is from ES9018.
The high frequency after 15KHz voltage decrease heavily.
If you think the problem is resulted from the ES9018 DAC, please suggest how to clarify the issues.
Can you help check the RD design and recommend how to improve the frequency response?
Here is the schematic and audio performance.
LME49720 schematic.zipplease drop me mail for the schematic password.
performance
1. THD, you can see the THD from 20~20KHz is good.
D:\PC Audio\5. THD+N_20Hz-20kHz_client.at27, 10/13/16 10:14:53 DGen.Freq, Anlr.THD+N Ampl, Anlr.THD+N Ampl, ,,,,, Source 1, Data 1, Data 2, ,,,,, Hz, dBr A, dBr B, ,,,,, 20.001411438, -102.550585708, -102.580750896, ,,,,, 25.1798629761, -102.463069707, -102.493234895, ,,,,, 31.6972732544, -102.841260362, -102.87142555, ,,,,, 39.9055480957, -102.978770722, -103.00893591, ,,,,, 50.2367019653, -102.484866179, -102.515031367, ,,,,, 63.2457733154, -103.189206335, -103.219371524, ,,,,, 79.6222686768, -103.165571247, -103.195736435, ,,,,, 100.238800049, -104.739760111, -104.769925299, ,,,,, 126.191139221, -103.955742073, -103.985907261, ,,,,, 158.866882324, -103.929929603, -103.960094791, ,,,,, 199.999809265, -104.112248823, -104.142414011, ,,,,, 251.784324646, -104.516316545, -104.546481733, ,,,,, 316.97845459, -105.234567662, -105.264732851, ,,,,, 399.052619934, -105.38563042, -105.415795608, ,,,,, 502.378463745, -106.628588555, -106.658753743, ,,,,, 632.454872131, -106.489053191, -106.519218379, ,,,,, 796.214103699, -106.950988479, -106.981153668, ,,,,, 1002.37369537, -106.370668162, -106.400833351, ,,,,, 1261.91425323, -107.285817974, -107.315983162, ,,,,, 1588.65737915, -107.673645324, -107.703810512, ,,,,, 2000.00095367, -107.753332943, -107.783498132, ,,,,, 2517.85182953, -108.593203097, -108.623368285, ,,,,, 3169.78740692, -109.621766647, -109.651931835, ,,,,, 3990.52333832, -110.788699004, -110.818864192, ,,,,, 5023.77319336, -112.54432736, -112.574492548, ,,,,, 6324.55444336, -113.733997662, -113.76416285, ,,,,, 7962.14389801, -117.216070418, -117.246235606, ,,,,, 10023.7455368, -115.019970548, -115.050135737, ,,,,, 12619.1482544, -118.63469383, -118.664859019, ,,,,, 15886.5652084, -108.121260921, -108.151426109, ,,,,, 20000.0009537, -91.9145422461, -91.9447074343, ,,,,,
2. Frequency response. please see the green line, red line is the upper and lower limitation.
Thnaks,
SHH
