A 1-mm2 CMOS-pipelined ADC with integrated folded cascode operational amplifier
Microelectronics International
ISSN: 1356-5362
Article publication date: 9 September 2020
Issue publication date: 29 September 2020
Abstract
Purpose
The purpose of this paper is to demonstrate the acceptable performance by using the limited input range towards lower open-loop DC gain operational amplifier (op-amp) of an 8-bit pipelined analog-to-digital converter (ADC) for mobile communication application.
Design/methodology/approach
An op-amp with folded cascode configuration is designed to provide the maximum open-loop DC gain without any gain-boosting technique. The impact of low open-loop DC gain is observed and analysed through the results of pre-, post-layout simulations and measurement of the ADC. The fabrication process technology used is Silterra 0.18-µm CMOS process. The silicon area by the ADC is 1.08 mm2.
Findings
Measured results show the differential non-linearity (DNL) error, integral non-linearity (INL) error, signal-to-noise ratio (SNR) and spurious-free dynamic range (SFDR) are within −0.2 to +0.2 LSB, −0.55 LSB for 0.4 Vpp input range, 22 and 27 dB, respectively, with 2 MHz input signal at the rate of 64 MS/s. The static power consumption is 40 mW with a supply voltage of 1.8 V.
Originality/value
The experimental results of ADC showed that by limiting the input range to ±0.2 V, this ADC is able to give a good reasonable performance. Open-loop DC gain of op-amp plays a critical role in ADC performance. Low open-loop DC gain results in stage-gain error of residue amplifier and, thus, leads to nonlinearity of output code. Nevertheless, lowering the input range enhances the linearity to ±0.2 LSB.
Keywords
Acknowledgements
Research University Individual Grant.1001/PCEDEC/8014079.USM Short Term Grant.304/PCEDEC/6315056.
Citation
Idros, N., Abdul Aziz, Z.A. and Rajendran, J. (2020), "A 1-mm2 CMOS-pipelined ADC with integrated folded cascode operational amplifier", Microelectronics International, Vol. 37 No. 4, pp. 205-213. https://doi.org/10.1108/MI-05-2020-0030
Publisher
:Emerald Publishing Limited
Copyright © 2020, Emerald Publishing Limited