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High quality Raspberry Pi I2S HAT - part 2 - hardware

Autor:

Schematic diagram


You can download pdf version here.


Schematic is very simple:

Design consists of three main parts: Q1, Q2 oscillators 45/49Mhz, U4 - Xilinx CPLD - main logic and reclocker circuit build on U5, U6 and U7.

Each part has its own LDO (U1, U2, U3). You can use many IC's in SOT23 package, also there is footprint on the PCB for bypass cap. In the prototype I'm using LP5907.

X1 is the input of the external power supply. In case of an external supply, JP3 should be open.

There is no need for a separate jtag port, as we will program Xilinx directly through Raspberry Pi gpio.

  PCB


 

 

 

 




  Assembled boards

Here with ordinary oscillators and xc9572xl


 

 

 

 

 


And here with CCHD-957 from Crystek and xc9536xl

 

 

 

 

 

 

Here is the BOM:


C1 47uF/10V SMB tantal.
C2, C5, C18 2.2uF/25V 1206 X7R
C3, C4, C19 10uF/16V 1206 X7R
C6, C7, C8, C9, C10, C14, C15, C16, C17 100nF/16V 0603 X7R
R1, R2, R4, R5, R6 47ohm 0603
R3 2.2k 0603
LED 0603
U1, U2, U3 LP5907 SOT23-5
U4 xc9572xl or xc9536xl VQ44
U5, U6, U7 74AUC1G79 TSSOP5
Q1 45.1584 oscillator 5x7 or CCHD-957
Q2 49.152 oscillator 5x7 or CCHD-957
J1 u.fl socket
JP1 10 pin strips, 2x5, male THT
JP2 40 pin strips, 2x20, female THT
JP3 2 pin strips, 1x2, male THT
X1 terminal AK300/2 THT


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