# Regular Meeting (2022.12.19)

* Simulation of fanout
* Basically, the circuit is the same to previous project
* https://hackmd.io/M-v_rjZKSKGRH43tHGPLxA
* Just change OPAs and Power
* [Code](https://github.com/curly-wei/sim-fanout64.git)
* Problem: Some *Analog Devive*\'s can't be simation
* This project and Dr.Ken's project both has that error
* AD8655 : This project (o)
* AD8397 : This project (x)
* ADA4817 : Dr.Huang project (x)
* ***TI*\'s OPAs has not this problem**
* 2 stage of LDO is not good choice
* [Refer to here](https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1179125/tps7a20-minimum-launch-voltage-of-tps7a20-5v/4445123#4445123)
* USB RC-Filter
* https://andybrown.me.uk/2015/07/24/usb-filtering/
## Simulation of fanout

* AD8655
* 2-stage OPAs
* 1 channels output
* 4.5Vcc for OPAs
* USB 5V (type-C) and PSU 5V (2 pins Euro terminal block)
* 1st: buffer (Emitter follower)
* 2nd: 2 V/V Gain
* with 50 ohm input and output
* Input pulse
* 20ns R/F time
* 1us width
* 100mV Amplitude
* Next week I'll do 8 or 48 channels output

### Tools: ngspice + python3 + make

* ngspice
* Crossplatform circuit simulation based on *spice* language
* Invoking OPAs modules(lib) which provided by vendor
* Describing my circuit with OPAs modules
* Describing testbench for my circuit
* Do simulation
* Export *.csv*-liked plotting data
* I called raw-data
* Python 3
* Plotting with *.csv*-liked raw-data from *ngspice* outputted
* make
* Invoke and interaction between *ngspice* and *python-3*
* Top file
* Just run `make adxx`, will invoke *ngspice* and *python-3* for simultion adxx

### Problem

* When I run :
* 
* This problem exist when I run Dr.Huang's project
* Raw-data(ngspice generated) is already incorrect data, which is the same to plotted data
* But some (Analog Decice 's)OPAs has no problem:
* AD8655(This project)

### Possible solution

* Compatibility mode for Pspice(TI) and LTSpice(Analog device and Linear Tech) of ngspice
* ngspice officially provided
* TI (o)
* Analog Device(x)

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