MB Page1Mihai Banu, July 2002 WCR #7 Nyquist rate ADC Main design motivation: Low Power Features: Pipeline arquitecture. Two interleaved ADCs with shared opamps: Efficient use of the most power demanding blocks. 1.5 bits/stage and digital correction: Relaxed comparator design. Good linearity. Target Specifications: 40 Msamples/sec. 10-bit resolution. Distortion and Noise below –60 dB.

MB Page2Mihai Banu, July 2002 WCR #7 Nyquist rate ADC Pipeline ADC Test chip 4K devices 0.25  m CMOS SIMULATION RESULTS Power: V (~2/3 less than publishied ADCs) INL: 0.38 LSB  -62 dB Harm. Dist.

MB Page3Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA Experimental Setup:

MB Page4Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA Measured Results: Sampling Rate: 40 MHz (still 60 MHz) Latency:12 cycles (300 ns) Power: ADC: mW ( V) Pin Drivers: 1.32 mW ( V) Distortion:0.3 to 0.65 LSBs ENOB:9.4 bits (from distortion)

MB Page5Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA Single-Tone test Low Freq. (20 KHz) Very low Distortion

MB Page6Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA 2-Tone test Low Freq. (100 KHz) Very low Distortion

MB Page7Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA 2-Tone test High Freq. (19.5 MHz) Still good Linearity

MB Page8Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA 2-Tone test High Freq. (20 MHz) 60 MHz CLK (50% Overclock) Still running

MB Page9Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA LINEARITY from Code Density Histogram (Doernberg et al.) 60 KHz input Too much ripples (bad code coverage?) Monotonic, no missing codes.

MB Page10Mihai Banu, July 2002 WCR #7 ADC: Experimental DATA LINEARITY from Code Density Histogram (Doernberg et al.) 20 KHz input (not full-scale) MAX DNL = 0.38 LSB MAX INL = 0.65 LSB  (INL) = 0.3 LSB