---
# System prepended metadata

title: Design Outline of Hawdware
tags: [Major]

---

# Design Outline of Hawdware

![](https://i.imgur.com/JZo5MyN.png)

## Component part
* Photodiode
    * [BPW21R](https://www.vishay.com/docs/81519/bpw21r.pdf)
	  * R/F time ~ 6 us
	* [SFH250v](https://docs.broadcom.com/doc/AV02-3095EN)
	  * R/F time ~ 10 ns @ 5 Reverse Voltage
* OPA: 
	* [OPA192](https://www.ti.com/lit/gpn/opa192)
		* Price ~ 100NTD/1pcs
		* I/V Converter
		* Integrator
		* ADC Driver (necessary?)
		* ADC Ref.Voltage buffer (necessary?)
	* [OPA810](https://www.ti.com/lit/gpn/opa810)
		* Price ~ 150NTD/1pcs
		* GBP: 70 MHZ
		* PD input stage
	* [ADA4817-1](https://www.analog.com/media/en/technical-documentation/data-sheets/ADA4817-1_4817-2.pdf)
		* Price ~ 400NTD/1pcs
		* GBP: 500 MHZ (25MHz, 20V/V)
		* PD AMP stage
		* Problem: Result of simulation is so strange
	* [LTC6268-10](https://www.analog.com/media/en/technical-documentation/data-sheets/626810f.pdf)
	    * Price ~ 400NTD/1pcs
		* long DT: Feb.2023
		* GBP: 3500 MHZ (25MHz, 140V/V)
		* PD AMP stage
		* Problem: No spice model for simulation
    * [LMH6601](https://www.ti.com/lit/gpn/lmh6601)
      * Price < 100 NTD/1pcs
      * PD AMP stage
      * GBP: 150 MHZ
    * [OPA356](https://www.ti.com/lit/gpn/opa356)
      * Price < 100 NTD/1pcs
      * PD AMP stage
      * GBP: 450 MHZ
* ADC: 8ch.s input (Choose one)
	* ~~[AD7825](https://www.analog.com/media/en/technical-documentation/data-sheets/ad7822_7825_7829.pdf)~~
		* ~~Price ~ 500NTD/1pcs~~
		* ~~Sample rate: 2Mbps~~
		* ~~Resolution: 8bits~~
		* ~~Analog channels: 8~~
		* ~~Parallel(Digital) output~~
		* ~~3V/5V transfer(Digital buffer) is necessary~~
	* [ADS7961-Q1 or ADS790-Q1](https://www.ti.com/lit/gpn/ads7959)
		* Price ~ 200NTD/1pcs
		* Sample rate: 1Mbps
		* Resolution: 8bits
		* **Analog channels: 8 or 16**
		* **Serial(Digital) output**
* Voltage Reference for ADC ~~(necessary?)~~
  * [LM4132](https://www.ti.com/lit/gpn/lm4132)
    * Grade 
      * A: +-0.05%, 200NTD/PCS
      * B: +-0.1%, 160NTD/PCS
      * C: +-0.2%, 144NTD/PCS
      * C: +-0.4%, 98NTD/PCS
* Analog 1:4 Multiplexr (necessary?)
  * Usage: Gain selection for ADC
    * ![](https://i.imgur.com/Tg3xWWG.png)
  * [TMUX1204](https://www.ti.com/lit/gpn/tmux1204)
    * 30 NTD/PCS
    * On-Resistance: 15 ohm
* Digital Buffer for ADC ~~(necessary?)~~
	* ~~[sn74lxc8t245-Q1](https://www.ti.com/lit/gpn/sn74lxc8t245-q1)~~
		* ~~60NTD/1pcs~~
		* ~~With [Isolation](https://electronics.stackexchange.com/questions/643693/when-to-use-a-digital-isolation-buffer?noredirect=1#comment1706707_643693)~~
	* [TXU0304](https://www.ti.com/lit/gpn/txu0304)
		* 30NTD/1pcs
		* SPI Buffer
* FPGA/MCU
	* Since modern FPGA/MCU **has only 3.3V I/O max (digital)**, 
	  manipulating digital output of ADC to 3.3v is necessary
* Power Configure
  * ~~[MCP1726-5002](https://www.mouser.tw/datasheet/2/268/jp022884-1150097.pdf)~~
      * ~~30 NTD/1pcs~~
      * ~~5V/1A~~
      * ~~PSRR: 54dB(f = 100 Hz, C OUT = 10 μF, I OUT = 100 mA)~~
          * ~~Worse than TSP7A~~
      * ~~1st stage LDO for filtering noise~~
      * ~~Soft Start~~
          * ~~For real product reliability~~
          * ~~May add super-capacitor filter to reduce power noise~~
  * [TSP7A](https://www.ti.com/lit/gpn/tps7a20)
      * 30 NTD/1pcs
      * 3.3V/300mA, 5V/300mA
      * PSRR 95dB(f = 100 Hz, C OUT = 1 μF, I OUT = 20mA)
          * Better than MCP1726-5002
      * 2nd stage LDO taking ultra low noise of power
      * 3.3V -> Digital of ADC
      * 5V -> Analog and analog input of ADC
  * ~~[LP5907](https://www.ti.com/lit/gpn/lp5907)~~
    * ~~30 NTD/1pcs~~
    * ~~3.3V/250mA, 5V/250mA~~
    * ~~PSRR 90dB(f = 100 Hz, C OUT = 1 μF, I OUT = 20mA)~~
      * ~~Better than TSP7A~~
    * ~~Possible replacement of TSP7A~~
## Simulation
[Refer to here](https://github.com/curly-wei/PD-Driver-sim-beginning)

## Useful Resource

1. [Example design for PD Driver(TI)](https://www.ti.com/lit/pdf/tidu535)
2. Basical concept about photodiode
   * [The Physical Operation of Light-Sensitive pn Junctions](https://tinyurl.com/2h2ft8kc)
   * [Understanding Photovoltaic and Photoconductive Modes of Photodiode Operation](https://tinyurl.com/mr3n822d)
   * [Si photodiodes Handbook](https://tinyurl.com/ywbc2dx5)
3. [Instrument Amp(3 OPAs) for PD Driver](https://doi.org/10.1364/OE.27.002125)
4. How the voltage reference affects ADC performance
	* [Part 1](https://www.eeweb.com/wp-content/uploads/articles-app-notes-files-adc-performance-votlage-reference-part1-1315955297.pdf)
	* [Part 2](https://www.eeweb.com/wp-content/uploads/articles-app-notes-files-adc-performance-votlage-reference-part2-1316121303.pdf)
	* [Part 3](https://www.eeweb.com/wp-content/uploads/articles-app-notes-files-adc-performance-votlage-reference-part3-1316121526.pdf)
5. [Managing inrush current](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwimw-OsrcX7AhUG82EKHX4OCXcQFnoECAsQAQ&url=https%3A%2F%2Fwww.ti.com%2Flit%2Fpdf%2Fslva670&usg=AOvVaw1zMBpACFzPNdz70CO9qDPy) 

## Issues

1. [High Rfb of IV Converter](https://hackmd.io/@pd-driver-ntuhep/ryoQcyAUj)
2. [Change to High Speed PD and Circuit](https://hackmd.io/@pd-driver-ntuhep/By3s-oZDj)

## TechReport

1. [TechReport: Non-inverting PD AMP](https://hackmd.io/@pd-driver-ntuhep/HyBnq4Xvj)

###### tags: `Major`