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Byoung-Han MIN Young-Jae CHO Hee-Sung CHAE Hee-Won PARK Seung-Hoon LEE
This work proposes a 10b 100 MS/s 1.4 mm2 CMOS ADC for low-power multimedia applications. The proposed two-step pipeline ADC minimizes chip area and power dissipation at the target resolution and sampling rate. The wide-band SHA employs a gate-bootstrapping circuit to handle both single-ended and differential inputs of 1.2 Vp-p at 10b accuracy while the second-stage flash ADC employs open-loop offset sampling techniques to achieve 6b resolution. A 3-D fully symmetrical layout reduces the capacitor and device mismatch of the first-stage MDAC. The low-noise references are integrated on chip with optional off-chip voltage references. The prototype 10b ADC implemented in a 0.18 µm CMOS shows the maximum measured DNL and INL of 0.59LSB and 0.77LSB, respectively. The ADC demonstrates an SNDR of 53.7 dB, an SFDR of 61.5 dB, and the power dissipation of 56 mW at 100 MS/s.
Young-Ju KIM Young-Jae CHO Doo-Hwan SA Seung-Hoon LEE
This work proposes a 10 b 200 MS/s 1.8 mm2 83 mW 0.13 µm CMOS ADC based on highly linear integrated capacitors for high-quality video system applications such as next-generation DTV and radar vision and wireless communication system applications such as WLAN, WiMax, SDR, LMDS, and MMDS simultaneously requiring low voltage, low power, and small area at high speed. The proposed 3-stage pipeline ADC optimizes chip area and power dissipation at the target resolution and sampling rate. The proposed ADC employs two versions of the SHA with gate-bootstrapped NMOS switches and conventional CMOS switches to verify and compare the input sampling effectiveness. Both of the two versions of the wide-band low-noise SHA maintain 10 b input accuracy at 200 MS/s. The proposed all signal-isolated 3-D completely symmetric capacitor layout reduces the device mismatch of two MDACs by isolating each unit capacitor from all neighboring signal lines with all the employed metal lines and by placing extra internal metal lines with a fixed internal bias voltage between signal lines connecting the bottom plate of each unit capacitor. The low-noise on-chip current and voltage references with internal RC filters can select optional off-chip voltage references. The prototype ADC is implemented in a 0.13 µm 1P8M CMOS process. The measured DNL and INL are within 0.24 LSB and 0.35 LSB while the ADC shows a maximum SNDR of 54 dB and 48 dB and a maximum SFDR of 67 dB and 61 dB at 200 MS/s and 250 MS/s, respectively. The ADC with an active die area of 1.8 mm2 consumes 83 mW at 200 MS/s and at a 1.2 V supply.
Young-Jae CHO Se-Won KIM Kyung-Hoon LEE Hee-Cheol CHOI Young-Lok KIM Seung-Hoon LEE
This work describes an 8b 240 MS/s CMOS ADC as one of embedded core circuits for high-performance displays based on low-noise on-chip references and dual-mode inputs with the requirements of limited pins, low power, and small size at high speed. The proposed ADC uses externally connected pins only for analog inputs, digital outputs, and supplies. The ADC employs (1) a two-step pipeline architecture to optimize power and chip size at the target sampling frequency of 240 MHz, (2) advanced bootstrapping techniques to achieve high signal bandwidth in the input SHA, and (3) RC filter-based on-chip current and voltage references to improve noise performance with a power-off function for portable applications. The prototype ADC is implemented in a 0.18 µm CMOS and simultaneously integrated in a DVD system with dual-mode inputs. The prototype ADC shows the measured DNL and INL within 0.49LSB and 0.69LSB, and the SNDR and SFDR exceeding 38 dB and 50 dB for inputs up to the Nyquist frequency at 240 MS/s. The ADC consumes 104 mW at 240 MS/s and an active die area is 1.36 mm2 .
Young-Jae CHO Hyuen-Hee BAE Seung-Hoon LEE
This work proposes an 8b 220 MS/s 230 mW 3-stage pipeline CMOS ADC with on-chip filters for temperature- and power supply- insensitive voltage references. The proposed RC low-pass filters reduce reference settling time at heavy R&C loads and improve switching noise performance without conventional off-chip bypass capacitors. The prototype ADC fabricated in a 0.25 µm CMOS occupies the active die area of 2.25 mm2 and shows the measured DNL and INL of maximum 0.43 LSB and 0.82 LSB, respectively. The ADC maintains the SNDR of 43 dB and 41 dB up to the 110 MHz input at 200 MS/s and 220 MS/s, respectively, while the SNDR at the 500 MHz input is degraded as much as only 3 dB than the SNDR at the 110 MHz input.