Google Git
Sign in
foss-eda-tools / third_party / shuttle / sky130 / mpw-002 / slot-014 / f788bb2af33b8fe56334da5559f9c1472374c731
commitf788bb2af33b8fe56334da5559f9c1472374c731[log] [tgz]
authorJeff DiCorpo <jeffdi@efabless.com>Mon Dec 27 08:13:03 2021 +0000
committerJeff DiCorpo <jeffdi@efabless.com>Mon Dec 27 08:13:03 2021 +0000
tree6414ed93ab964c5e5c074f21a376764b0cb2e93a
parent49db5f550c8ca64185438a8eb7cc1e9fdc6f9024 [diff]
final gds oasis
2 files changed
tree: 6414ed93ab964c5e5c074f21a376764b0cb2e93a
  1. .github/
  2. checks/
  3. docs/
  4. gds/
  5. mag/
  6. netgen/
  7. oas/
  8. openlane/
  9. signoff/
  10. verilog/
  11. xschem/
  12. caravel
  13. .gitmodules
  14. info.yaml
  15. LICENSE
  16. Makefile
  17. README.md
README.md

Caravel Analog User - VCO IP, Comparator IP and Coil tests

License UPRJ_CI Caravan Build

VCO

The VCO is a 7 inverter ring oscillator. It can operate from 120MHz to 350 MHz. It has two tap points for external capacitors that can further reduce the frequence range.

Circuit

This is a ring oscillator with 7 invertors

Inputs to the circuit

  1. VCC - 3.3 v
  2. GND - Ground
  3. VADJ - Voltage to adjust the frequency output
  4. OUT1 - A tap point to add a capacitor
  5. OUT2 - Second tap point to add a capacitor to lower the frequency range.

Output of the circuit

  1. OUT - VCO output

Simulations

With no external capacitors Frequency range is 120 MHz to 350 MHz.

With 10 picoFarad External Capacitor Frequency range is 10 MHz to 40 MHz.

Comparator

A comparator is a device that compares two analog inputs and outputs a digital signal indicating which input is larger. So it has two analog input terminals and one binary digital output. When the difference between two analog input signals approach zero, noise on the inputs will cause spurious switching of digital output. This rapid change in output due to noise can be prevented by hysteresis. Hysteresis is switching the output high or low at different input signal levels. In place of one switching point, hysteresis introduces two: one for rising edge, and one for falling edge of voltage or current. The difference between the higher-level trip value (VH) and the lower-level trip value (VL) equals the hysteresis voltage (HYST).

Inputs to the circuit

  1. VCC - 3.3 v
  2. GND - Ground
  3. INN - Negative differential input
  4. INP - Positive differential input
  5. EN - Enable pin
  6. Ihyst - Current to control hysteresis

Output of the circuit

  1. VOUT - Comparator output

Circuit details

A comparator can be divided into three distinctive pieces – a frontend differential amplifier, amplifier stage and output stage.

Coil Tests

The coil is from the PDK. The fasthenry file is generated. The simulation is ongoing...

References

  1. P. Horowitz,and W. Hill, “The Art of Electronics,” Cambridge Press University, 3rd ed (references)
  2. P. Furth, Y. Tsen, V. Kulkarni,and T. Raju, On the Design of Low-Power CMOS Comparators with Programmable Hysteresis., IEEE, 2010, pp.1077–1080.