271 TT05 Analog Testmacro (Ringo, DAC) :: Quicker, easier and cheaper to make your own chip!

271 : TT05 Analog Testmacro (Ringo, DAC)

Author: Harald Pretl and Jakob Ratschenberger

Description: For future analog enablement of TinyTapeout we designed a few simple analog blocks for testing the flow. The first block is a ca. 500kHz ring oscillator outputting a square-wave signal. The second block is a 3bit R-2R DAC outputting a programmable dc voltage. Both analog output signals can be gated or shorted using integrated transmission gates. To add a further level of madness, we have placed and routed this analog macro using an experimental automatic analog PnR tool, currently under development by the authors.

GitHub repository

Clock: 0 Hz

How it works

A ring oscillator (ca. 500kHz) produces a square-wave signal available at UA[0]. A 3-bit R-2R DAC produces a dc voltage availabel at UA[1].

How to test

Enable the respective blocks, and enable the transmission gates to connect the block outputs to UA[0] and UA[1], respectively. The DAC voltage can be changed by setting the digital inputs accordingly.

External hardware

scope, multimeter

#	Input	Output
0	dac_in[0]	UA[0]: Ringo output (when TG enabled)
1	dac_in[1]	UA[1]: DAC output (when TG enabled)
2	dac_in[2]
3	Enable TG for DAC output to UA[1]
4
5	Enable TG for ringo output to UA[0]
6	Enable ringo
7	Short UA[0] and UA[1] for testing

Input

Output

Bidirectional

dac_in[0]

UA[0]: Ringo output (when TG enabled)

dac_in[1]

UA[1]: DAC output (when TG enabled)

dac_in[2]

Enable TG for DAC output to UA[1]

Enable TG for ringo output to UA[0]

Enable ringo

Short UA[0] and UA[1] for testing

Chip location

271 TT05 Analog Testmacro (Ringo, DAC)