A 10/20/30/40 MHz feed-forward FIR DAC continuous-time ΔΣ ADC with robust blocker performance for radio receivers

The first (single-bit) feed-forward (FF) FIR DAC continuous-time (CT)-ΔΣ ADC is presented for cellular radio applications. It provides a robust loop delay compensation with no performance degradation in the presence of radio out-of-band blockers; a known drawback of FF CT-ΔΣ ADCs. At 20/30/40 MHz operation, the FOM is less than or equal to 36 fJ/conv. At 10 MHz operation, the FOM is 50 fJ/conv. The equivalent FOM for a 20-MHz-only design is 28 fJ/conv. It occupies 0.0194 mm2 in 40 nm CMOS.

[1]  Kathleen Philips,et al.  A continuous-time ΣΔ ADC with increased immunity to interferers , 2004 .

[2]  Shanthi Pavan,et al.  Design Techniques for Continuous-Time ΔΣ Modulators With Embedded Active Filtering , 2014, IEEE Journal of Solid-State Circuits.

[3]  Hung-Chieh Tsai,et al.  A 75.1dB SNDR 840MS/s CT ΔΣ modulator with 30MHz bandwidth and 46.4fJ/conv FOM in 55nm CMOS , 2013, 2013 Symposium on VLSI Circuits.

[4]  Bernard Mulgrew,et al.  On the design of high-performance wide-band continuous-time sigma-delta converters using numerical optimization , 2006, IEEE Transactions on Circuits and Systems I: Regular Papers.

[5]  José B. Silva,et al.  A 2.8 mW ΔΣ ADC with 83 dB DR and 1.92 MHz BW using FIR outer feedback and TIA-based integrator , 2011, 2011 Symposium on VLSI Circuits - Digest of Technical Papers.

[6]  Shanthi Pavan,et al.  Design Techniques for Wideband Single-Bit Continuous-Time $\Delta\Sigma$ Modulators With FIR Feedback DACs , 2012, IEEE Journal of Solid-State Circuits.

[7]  Maurits Ortmanns,et al.  A single DAC CT sigma-delta modulator with Butterworth STF characteristic , 2011, 2011 IEEE 54th International Midwest Symposium on Circuits and Systems (MWSCAS).

[8]  Pieter Rombouts,et al.  Controlled behaviour of STF in CT ΣΔ modulators , 2005 .

[9]  Ping Chen,et al.  A 28fJ/conv-step CT ΔΣ modulator with 78dB DR and 18MHz BW in 28nm CMOS using a highly digital multibit quantizer , 2013, 2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers.