# Regular Meeting (2022.12.5)

## About 48 chs. Fanout board

* Some idea
* +-5V -> +7/+9/+12V...etc (?-> discussion)
* Dual rail must apply +V and -V regulator
* Single rail -> 1 +V regulator
* And FE-prototye only has +V
* Swining ISSEU of this [OPA](https://www.ti.com/lit/gpn/opa3692)
* It is due to saturation of transistor in OPA
* further reading: [*rail to rail OPA*](https://tinyurl.com/xmpw5md6)
* for the +-5V supplied -> +- 3.6V (original adopt)
* for the +5V supplied -> 1.3V ~ 3.8V output
* for the +12V supplied ->xV ~ 10V output
* USB supplies (5V/3A, GaN)
* 1 OPA fanout 4 channels
* 1 of OPA3692 can fanout 12 channels
* 48 channels only needs 4 OPA3692
* Internal fixed resistor
* About
* Should I add input OPA as buffer to drive 4 of OPA3692?
* Do simulation
* The new solution: *Rail to Rail OPA* and output >200mA per channels
* If we don't care about Bandwidth or R/F time
* Previous desing: 200MHz and R/F ~ 2ns
* External feedback(gain) resistor is necessary
* [AD8656](https://www.analog.com/media/en/technical-documentation/data-sheets/AD8655_8656.pdf)
* 200 NTD/1pcs
* 2chs.
* 28 MHz BW
* Lower noise: f = 1 kHz, 4nV/√Hz; f = 10 kHz, 2.7nV/√Hz
* Offset: 500uV
* Slew rate: 11V/us
* [AD8397](https://www.analog.com/media/en/technical-documentation/data-sheets/AD8397.pdf)
* 350 NTD/1pcs
* 2chs.
* 69 MHz BW
* Higher noise: f = 100 kHz, 4.5nV/√Hz;
* Offset: 2.5mV
* Slew rate: 32V/us
* [AD8534](https://www.analog.com/media/en/technical-documentation/data-sheets/AD8531_8532_8534.pdf)
* 68 NTD/1pcs
* 4chs.
* 3 MHz BW
* Give up noise: f = 1 kHz, 45nV/√Hz; f = 10 kHz, 30nV/√Hz
* Offset: 35mV
* Slew rate: 5V/us
###### tags: `Regular Meeting` `DeWei`