Exclusive OR/NOR IC for 40-Gbit/s Clock Recovery Circuit

Taiichi OTSUJI
Takatomo ENOKI
Yohtaro UMEDA

IEICE TRANSACTIONS on Electronics   Vol.E82-C    No.3    pp.456-464
Publication Date: 1999/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Ultra-High-Speed IC and LSI Technology)
Category: Compound Semiconductor Devices
exclusive OR/NOR,  clock recovery circuit,  InP HEMT,  

Full Text: PDF>>
Buy this Article

The clock recovery circuit is a key component in high-speed electrical time-division multiplexing (ETDM) transmission systems. In the case of clock extraction from non-return-to-zero (NRZ) signals, differentiation and full-wave rectification are indispensable. Exclusive OR/NOR circuits (XOR) are widely used for this purpose. In this paper, we describe an XOR IC fabricated with 0. 1-µm gate-length InAlAs/InGaAs/InP HEMTs for a 40-Gbit/s class clock recovery circuit. The IC was configured with a symmetrical Gilbert cell type XOR gate and two types of peaking techniques are used to achieve its high bit-rate. On-wafer-measurements indicate that the IC operates as fast as 80 Gbit/s and can extract a 40-GHz frequency component from 40-Gbit/s NRZ input signals. To confirm the feasibility of using the packaged XOR IC in clock recovery circuits, the conversion gain of the IC, which was operated as a differentiater and full-wave rectifier, was evaluated. Assuming that the input to the clock recovery circuit is a 1 Vp-p signal, the relatively high output power of -17 dBm can be obtained with low dependency on the length of the input pseudo-random bit streams. Furthermore, a clock recovery circuit was assembled using the packaged XOR IC, a waveguide filter and a commercial amplifier; it offers the practical system-bit-rate of 39. 81312 GHz with the low rms jitter of 900 fs.