Testbenches for Analog Blocks

Purpose

I want a set of tests so I can set up testbenches quickly to easily compare different architectures/sizings of the basic analog building blocks.

There are a few aspects to this then:

1. basic testbench setup
2. datasheet generation
3. comparason of datasheets

I dunno. there's so many different things. comparators with hyst, without latched. etc. Is this mad?

Output

An example of the output can be found in the doc/cmos_24p2-ds/ directory.

Design

The initial design is NGSPICE, Python and TOML.

Each type of design, for example op-amp or comparator, has a python script to launch sims. This requires that the design under test (DUT) is wrapped in, for example opampwrapper.sp so that the testbench knows which nodes to connect to.

The design has a TOML file to specify supply voltages and path to things.

It's set up so that a single test can be run from the workarea directly if things need debugging.

Each design type has a testbench. Each testbench has one or more sims. Each sim has one or more measures.

Datasheet

Open Questions

• HTML with graphs and measurements?
• CVS file with raw data?
• How do I collate the results from multiple sims?

Regressions

How do I run a regression?

Maybe the easiest thing is just to write out loads of directories with the files?

Q: What do I need to specify a sweep?

1. The testbench to use
2. Each variable

Q: How do I specify what to sweep? A: In the TOML file?

[multicase.pvt]
var1 = ["P", "slow", "fast", "nominal"]
var2 = ["V", 0.9, 1.0, 1.1]
var3 = ["T", 0, 25, 125]

Would create a regression with 3x3x3 = 27 simulations.

Values verses ranges with stepsize?

Say I want to run the above, but have only three sims? Set?

Python would:

for analysis in config['multicase']:
    for var in analysis.values():


[multicase.pvt]
  label = "PVT Analysis of offset or something"
  testbench = ""
  measures = [ "offset", "input_range" ]
  [multicase.pvt.var1]
    label = "P"
    var = "library"
    list = ["slow", "fast", "nominal"]
  [multicase.pvt.var2]
    label = "V"
    var = "vdd"
    range = [0.9, 1.1, 0.05]
  [multicase.pvt.var3]
    label = "T"
    var = "tdegc"
	list = [0, 25, 125]


[multicase.trim]
  label = "PSSR at corners"
  testbench = ""
  measures = [ "psrr+", "pssr-" ]

  [multicase.trim.var1]
    label = "P"
    var = "library"
    list = ["slow", "fast", "nominal"]
    set = 0

  [multicase.trim.var2]
    label = "V"
    var = "vdd"
    range = [0.9, 1.1, 0.05]

  [multicase.trim.var3]
    label = "T"
    var = "tdegc"
	list = [0, 25, 125]

  [multicase.trim.var4]
    label = "Trim Setting"
    var = "trim"
	list = [4, 23, '0x34']
    set = 0

Still only 27 sims - trim setting moves with the process setting.

Limits

The toplevel testbench.toml for a design should be able to specify limits for each measurement.

Need to be able to list what measurements are taken:

opamp --measures

To update the .toml file automatically?

opamp --limits <measure> --max <> --min <>

PVT

Monte-Carlo