# Regular Meeting (2022.7.11)
* Zybo-z7
* CDCFE Fanout Baord

## 1 Zybo-Z7

[Trying here](https://qiita.com/yhmtmt/items/cba5330ad7ded151882d)

* Modify DT and rebuild
* RAM-DISK
* Boot ROOTDIR is RAMDISK
* After boot, `rm` folders boot time
* Very difference to x86 system

## 2 CDCFE Fanout Baord

## 2.1 Schedule:
1. Booking BOM (~2 weeks DT)
* Layout completed within 2 weeks
2. Print 1:1 board, put booked compoent on board (Jenny's suggestion)
2.5 Maybe verify each IC with SMD-DIP board
3. Delivered for manufacturing (~1 weeks)
4. Soldering

My Layout SW(KiCad) provide PCB calculator

### 2.2 BOM
#### 2.2.1 ICs

* OPA
0. Requrement
* 50 ohm(Fanout Board Ro) + 50 ohm(terminated Ri) line impedance, which output current 1/ch:
* For 10Vpp/dc=0 and
* 5V/(50 ohm + 50ohm) = 50mA (1/ch)
* 4 channels: 50mA\*4 = 200 mA
* 8 channels: 50mA\*8 = 400 mA
* OPA2674/OPA3694 can't achieve +5V/-5V when supply +-5V
* OPA2674: +-4.8V when supply +- 6V (worst case)
* OPA3674: +-3.3 when supply +- 5V (worst case)
* Date refer to datasheet
* So about +-3V, which is we guarentee swim for worst case (datasheet)
* For 1Vpp/dc=0 and
* 0.5V/(50 ohm + 50ohm) = 5mA (1/ch)
* 4 channels: 5mA\*4 = 20 mA
* 8 channels: 5mA\*8 = 40 mA
1. [OPA3692ID](https://www.ti.com/lit/ds/symlink/opa3692.pdf)
* Fixed resistor/gain video(analog) buffer
* Output current: 190mA/ch max
* ~ 300 NTD/pcs
2. [OPA2674ID](https://www.ti.com/lit/ds/symlink/opa2674.pdf)
* High current out OPA (500mA/ch)
* ~200 NTD/pcs
3. [OPA735](https://www.ti.com/lit/ds/symlink/opa735.pdf)
* For reference voltage: divide to 0.6V from 2.5V
* Reference voltage: [REF4321](https://www.ti.com/lit/ds/symlink/ref4132-q1.pdf), We have 10 pcs on lab521 presently.
* 
* [Difference between reference voltage and voltage regulator](https://electronics.stackexchange.com/questions/221312/voltage-regulator-vs-voltage-reference)
* ~150 NTD/pcs
* Also refer to here
* [How the voltage reference affects ADC performance, Part 1](https://www.ti.com/lit/an/slyt331/slyt331.pdf)
* [How the voltage reference affects ADC performance, Part 2](https://www.ti.com/lit/an/slyt339/slyt339.pdf)
* [How the voltage reference affects ADC performance, Part 3](https://www.ti.com/lit/an/slyt355/slyt355.pdf)
* Reference Voltage!!!????
* Previous test, he used
* 
* But [newest test](https://drive.google.com/file/d/1YFkMaBQrdKCMgRm2wFkOjw4l-dCjey0_/view), he did not use
* 
* LDO
0. Since I tried ~10-ohm@-5V load with [7905](https://www.ti.com/lit/gpn/lm79), input should rise to 12V
* Power loss: $(12V-5V)\cdot500mA=3.5W$ ----> **Very hot**
* I guess that *Power wires* generated 1 ohn resistor (I used 2), maybe *breadboard* also has problem, maybe... think wires...
* 7950 does not provied *Load(current) vs drop* chart
1. [LT3015](https://www.mouser.tw/datasheet/2/609/3015fb-1271510.pdf): -5V LDO
* ~ 300 NTD/1pcs
* 1.5A, 300mV drop volage
* 
2. [MCP1727-5002E/SN](https://ww1.microchip.com/downloads/en/DeviceDoc/21999b.pdf): +5V LDO
* ~ 40 NTD/1pcs
* 1.5A, 300mV drop volage
* 

#### 2.1.2 etc

* Wires
* [22awg dc cable (single wire)](https://shopee.tw/product/14138627/1326033617)
* [Current/AWG recommended](https://www.jst.fr/doc/jst/pdf/current_rating.pdf)
* [Ampacity(wiki)](https://en.wikipedia.org/wiki/Ampacity)
>Current rating: For electronic components (such as transistors, voltage regulators, and the like), the term current rating is more-commonly used than ampacity, but the considerations are broadly similar. However the tolerance of short-term overcurrent is near zero for semiconductor devices, as their thermal capacities are extremely small.
* U.FL connecotrs and wires
* [U.FL socket](https://www.mouser.tw/ProductDetail/Molex/73412-0110?qs=NlNVDDZd7xQHV8e0ilpSdQ%3D%3D)\*30 or \*50
* U.FL to BNC(50cm or 1M) \*15
* Clk source
* Signal source
* 8 channels Fanout Board to Scope (optional)
* U.FL to U.FL(15cm)\*10
* 8 channels Fanout Board to CDCFE-Prototype
* Price reference: 葰茂 sma-u.fl, 15cm 100NTD
* I wish this cables has double shielding and ~30 awg
* [Switches](https://shopee.tw/product/8481484/21619903574) for lab521 redecorate of cables
* Probe
* R/F time: 450 ps (Scope's freebie)
* We present SMA-BNC calbe, SMA/BNC connector
* For present func-gen (20MHz, 8ns R/F time): no problem

###### tags: `Regular Meeting` `DeWei`