Q.C. the DAC7822 concept

the non-neg. (bi-polar) multiplication wiring gave the better performance in the sense of speed

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8-bit ADC experiment

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Update about component pick

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500kHz DAC

the 2.5V ref. is provided for possible more exact v. of this -- for example -- forward normalizing the output as Uout=Uin*Vref/(Vsup/2)

Comparative ref. test

Experimental /// Alternative (the best) /// Datasheet (the 2-nd best)

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it seems that the inverter/comparator type ADC ↓↓ is the fastest here
now with CMOS-Comparators ((i tiled it up intuitively -- a top-down design -- surprisingly or not it came out the same as at the linked one ↑above↑))

(the chosen resistor values may be not the optimal or not the realistic 1-s)

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4-bit DAC and ADC test

src :: http://www.brown.edu/Departments/Engineering/Courses/En123/Lectures/DAconv.htm

modified

?? -- sounds "fun"

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best guess :: The Pipelined ADC-s

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src::not found at web

apx. guess of the ADC circuit layout and biasing resistors

related ::http://chpsndtch.blogspot.com.ee/2017/08/4-bit-adc-improvement.html

base/radix 3 ver. :: uses the same amount of ic-s per cascade -- but has "exponentially" higher resolution

↑ the radix 3 output can be converted to binary by summers -- for example ↑
something similar found at www :: https://www.researchgate.net/publication/220365717_A_Low-Power_Capacitive_Charge_Pump_Based_Pipelined_ADC

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at the sown  ADC-s when switched to 5V single supply and the CMOS comparators and op amp-s -- the least can be extended with 74HC125 or ↓ 74HC126 ↓ (to gain the OC OE functionality of LM311) . . . in other words by these changes the circuit can be made faster

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CMOS Radix-3 :: 2.5x faster than a "slow" LM324

↑ there's some optimistic 2.5µs read window ↑ to stay at the precision of the shown 0 to 26 e.g. 27 level of quantization . . .

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As a target of these tests -- i attempted to find suitable ADC - DAC combination to set up a successive approximation ADC

• as by adding cascades to shown cascaded(/pipelined) ADC-s -- the transition delay to LSB-s increases -- they don't much improve the final conversion speed
• basically the cascaded converters are a "Static SAR DAC" variants -- the SA delay still remains
• i must rethink the concept here
  
  • -- either should use a parallel converter
  • or try to incorporate/integrate a differential approach

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