Power dissipation advantage of optics: Experimental results
Design point: Low-power 2.5 Gb/s 0.5 mm CMOS / VCSEL opto-electronic Tx
- (a) VCSEL driver in 0.5 µm CMOS. 2.1 x 2.5 mm2 T8 test-die received at USC 5.8.97.
- (b) Upper trace is output of oxide-VCSEL (Ith = 0.2 mA, Vth = 1.5 V, Ib = 0.5 mA, Vb = 1.6 V, Lpp = 0.078 mW) driven by +Tx circuit. 1.5 mW power consumption at 1.25 Gb/s. Lower trace is -Tx electrical output. Input data is 50 mVpp 1.25 Gb/s NRZ 231 - 1 PRBS.
- (c) Upper trace detected output of oxide-VCSEL (Ith = 0.5 mA, Vth = 1.5 V, Ib = 1.9 mA, Vb = 1.7 V, Lpp = 0.744 mW) driven by + Tx circuit. 7 mW power consumption at 2.5 Gb/s. Lower trace is -Tx electrical output. Input data is 50 mVpp 2.5 Gb/s NRZ 231 - 1 PRBS.
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B. Madhavan and A. F. J. Levi, Low-power 2.5 Gbps VCSEL driver in 0.5 µm CMOS technology, Electron. Lett. 34, 178-179 (1998) and http://www.usc.edu/alevi
1.25 Gb/s 20x reduction in power consumption compared to load terminated LVDS (30 mW)
2.5 Gb/s more than 4x reduction in power consumption compared to load terminated LVDS (30 mW)