---
# System prepended metadata

title: Regular Meeting (2023.2.6)
tags: [Regular Meeting, DeWei]

---

# Regular Meeting (2023.2.6)
* Fanout-48
	* Modify design: LDO

## Modify design: LDO 
* Before
  * ![](https://i.imgur.com/suZNVD0.png)
* After
  * ![](https://i.imgur.com/3AprUMR.png) 
* Reason
	* Layout is too awful because of *Voltage setup resistor*
      * Condider 16 -> 48 channels
        * 2 sets of LDOs -> 6 sets of LDOs
* Known issue
  * **Please set input swimming < 3.3 Vpp**
    * Because new LDO IoutMax = 300mA
      * Old: 500mA
    * Change Vs from 4.5V -> 3.3V for limit swimming of input signal??
      * Higher Vs would get better performance for most of OPAs
        * Especially for Slew Rate
        * ![](https://i.imgur.com/R9YJqXD.png)
        * ![](https://i.imgur.com/lFBY3y1.png)
      * 5Vusb -> 3.3V of LDO
        * (5-3.3)\*Iout = **Power dissipation on LDO**
        * Heat
        * ![](https://i.imgur.com/P5CB9tG.png)
      * 5V LDO -> 3.3V LDO -> OPA ??
        * Additional LDO and additional capacitor
        * Because I think this board is just what we'll use.
          * Don't need these protect/prevent
  

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