A Current-Steering DAC Architecture with Novel Switching Scheme for GPON Burst-Mode Laser Drivers


IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.4   pp.877-884
Publication Date: 2007/04/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.4.877
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
current steering digital-to-analog converter,  DNL,  GPON,  cascade current mirror,  BiCMOS,  

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This paper describes a current-steering Digital-to-Analog Converter (IDAC) architecture with a novel switching scheme, designed for GPON Burst Mode Laser Drivers (BMLD) and realized in a 0.35 µm SiGe BiCMOS technology with 3.3 V power supply. The (4+6) segmented architecture of the proposed 10-bit IDAC is optimized for minimum DNL (Differential Nonlinearity). It combines a 4-bit MSBs (Most Significant Bits) unit-element sub-DAC and a 6-bit LSBs (Least Significant Bits) binary-weighted sub-DAC. A switching scheme based on this dedicated architecture yields a high monotony and a fast settling time. The linearity errors caused by systematic influences and random variations are reduced by the 2-D double centroid symmetrical architecture. Experimental results show that the DNL is below 0.5 LSB and that the settling time after the output current mirror is below 12 ns. Although the proposed IDAC architecture was designed for a BMLD chip, the design concept is generic and can be applied for developing other monotonic high-speed current-mode DACs.