ADAU1701 CLOCK DRIVER

Question

I am looking for a clock driver to drive 8 ADAU1701 and was looking @ the one in the link and was not sure if that circuit was suitable to drive 8 ADAU1701 over a 18 inch length of trace, DS1080CL datasheet, Pinout ,application circuits Spread- 
 Spectrum Crystal Multiplier 
 Is there an analog device ic I can use that is similar to the one in the link ? 
 Thanks in advance

KJBob · Accepted Answer

Hello izhmel, 
 The DS1080CL includes some interesting features, but may not be ideal for your application. It's a clock generator , not a clock driver -- so its output is only specified at a 15 pF load, and the data sheet gives no output impedance specification. Thus it's not clear how well it would do driving eight -1701s. You would definitely want to turn OFF its spread-spectrum feature, as such intentional clock variation would cause audible effects in the DSPs. If you're looking to minimize measured EMI, I'm afraid this will have to come instead from best-practices design, shielding, etc. Please see https://ez.analog.com/message/57200#57200 for an EMI example. 
 One of our prototypes is working fine with an ordinary 12.288 MHz packaged oscillator, buffered with a 74LVC2G34, to drive five DSPs. A 50 ohm series resistor placed near the buffer output reduces the ringing that would otherwise occur -- see, for example, https://ez.analog.com/message/130241#130241 
 Finally, the 18 inch trace length among your chips scares me. This may introduce issues not only with MCLK but also with any I2S you might be running between your -1701s. Our chips are tight together as shown. Perhaps another engineer having experience with the longer distance may suggest how to manage such issues. 
 Best regards. 
 Bob)

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ADAU1701 CLOCK DRIVER