Tutorial: Create a circuit

NOTE: Before starting this tutorial, you should have installed and set up JITX.

You can follow along with this tutorial in the video above. Below is a transcript to make the code and text easier to read.

1. Searching for components

Open the JITX sidebar and click on Find Components. Search for:

TPS62080DSGR

Then click on the "Create Component" button. This adds a local code model of a component to your project.

To add it to your design, in main.stanza, change the my-design module to be:

pcb-module my-design:
   inst buck : components/Texas-Instruments/TPS62080DSGR/component

You have added this component to your design, run it to see it appear in the schematic and layout.

2. JITX component models

Open the components/Texas-Instruments/TPS62080DSGR.stanza file.

Delete the original pcb-symbol definition. In the pcb-component definition, shuffle the order of the pins, and replace the assign-symbol() line so that the new component body becomes:

  pin-properties :
    [pin:Ref | pads:Ref ... | side:Dir | electrical-type:String | bank:Int]
    [VIN | p[8] | Left | "power_in" | 0]
    [EN | p[1] | Left | "unspecified" | 0]
    [MODE | p[3] | Left | "unspecified" | 0]
    [GND | p[2] p[9] | Left | "power_in" | 0]
    [PG | p[6] | Right | "unspecified" | 0]
    [SW | p[7] | Right | "power_in" | 0]
    [VOS | p[5] | Right | "unspecified" | 0]
    [FB | p[4] | Right | "unspecified" | 0]

  assign-landpattern(lp)
  make-box-symbol()

3. Reusable circuits

Below the component definition in TPS62080DSGR.stanza, add:

public pcb-module module : 
  inst reg : components/Texas-Instruments/TPS62080DSGR/component

4. Using models from the database

Open the JITX sidebar and click on Find Components. Search for:

NR3015T1R0N

Then click on the "Copy Component" button, and paste it into the module:

public pcb-module module (-- output-voltage:Double = 3.3) :
  inst buck : components/Texas-Instruments/TPS62080DSGR/component
  inst L : database-part(["mpn" => "NR3015T1R0N", "manufacturer" => "Taiyo Yuden"])

To use the database-part function, you'll have to import generic-components at the top:

defpackage components/Texas-Instruments/TPS62080DSGR :
  import core
  import jitx
  import jitx/commands
  import ocdb/utils/box-symbol
  import ocdb/utils/generic-components

Change main.stanza to use the new module:

pcb-module my-design:
   inst buck : components/Texas-Instruments/TPS62080DSGR/module

5. Making connections with net

In the module definition in TPS62080DSGR.stanza, add ports and nets to build the circuit and expose an interface:

public pcb-module module (-- output-voltage:Double = 3.3) :
  pin vin
  pin vout
  pin en
  pin gnd

  inst buck : components/Texas-Instruments/TPS62080DSGR/component
  inst L : database-part(["mpn" => "NR3015T1R0N", "manufacturer" => "Taiyo Yuden"])
  
  net (buck.SW L.p[1])
  net (buck.VOS L.p[2] vout)
  net (buck.VIN vin)
  net (buck.EN en)
  net (buck.GND gnd buck.MODE)

In main.stanza you can now net the module pins:

pcb-module my-design:
   inst buck : components/Texas-Instruments/TPS62080DSGR/module
   net (buck.vin buck.en)

6. Parametric components

In the module definition in TPS62080DSGR.stanza, add the input and output capacitors:

  
  bypass-cap-strap(buck.VIN, buck.GND, 10.0e-6)
  bypass-cap-strap(L.p[2], buck.GND, 22.0e-6)

7. Reusing a smart sub-circuit

In the module definition in TPS62080DSGR.stanza, add the voltage divider and attach it:

  inst feedback : ocdb/modules/passive-circuits/voltage-divider(
    source-voltage = typ(3.3), 
    divider-output = 0.45 +/- (3 %), 
    current = 100.0 * 100.0e-9)

  net (feedback.in L.p[2])
  net (feedback.out buck.FB)
  net (feedback.lo buck.GND)

8. Making the parametric power regulator

Finally, change the module definition in TPS62080DSGR.stanza to accept an output-voltage argument, and pass that in to the voltage divider. Here is the completed module:

public pcb-module module (-- output-voltage:Double = 3.3) :
  pin vin
  pin vout
  pin en
  pin gnd

  inst buck : components/Texas-Instruments/TPS62080DSGR/component
  inst L : database-part(["mpn" => "NR3015T1R0N", "manufacturer" => "Taiyo Yuden"])
  
  net (buck.SW L.p[1])
  net (buck.VOS L.p[2] vout)
  net (buck.VIN vin)
  net (buck.EN en)
  net (buck.GND gnd buck.MODE)

  bypass-cap-strap(buck.VIN, buck.GND, 10.0e-6)
  bypass-cap-strap(L.p[2], buck.GND, 22.0e-6)

  inst feedback : ocdb/modules/passive-circuits/voltage-divider(
    source-voltage = typ(output-voltage), 
    divider-output = 0.45 +/- (3 %), 
    current = 100.0 * 100.0e-9)

  net (feedback.in L.p[2])
  net (feedback.out buck.FB)
  net (feedback.lo buck.GND)

Change main.stanza you can now net the module pins:

pcb-module my-design:
   inst buck : components/Texas-Instruments/TPS62080DSGR/module(output-voltage = 3.3)
   net (buck.vin buck.en)

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