40-Gb/s Amplifiers Achieve 3-dB Bandwidth With High Gain

Feb. 13, 2008
MOST 40-Gb/s AMPLIFIERS suffer from limited gain, as the gain is often sacrificed for adequate bandwidth in high-speed operations. To conquer these design limitations, a circuit structure for broadband amplifiers has been proposed by Jun-Chau ...

MOST 40-Gb/s AMPLIFIERS suffer from limited gain, as the gain is often sacrificed for adequate bandwidth in high-speed operations. To conquer these design limitations, a circuit structure for broadband amplifiers has been proposed by Jun-Chau Chien and Liang-Hung Lu from the Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei. In this new architecture, the gain cells in the conventional distributed amplifiers are replaced with cascaded stages. The result is enhanced gain. Thanks to the use of inductive peaking with the staggertuning technique, a 3-dB bandwidth also can be achieved while maintaining impressive gain flatness across the entire frequency band.

In standard 0.18-m CMOS technology, two amplifiers are implemented for this proposed circuit architecture. The amplifier with a 3 x 3 configuration flaunts 16.2 dB of gain and a 3-dB bandwidth of 33.4 GHz. In contrast, the 2 x 4 amplifier demonstrates a gain of 20 dB and a bandwidth of 39.4 GHz. Both circuits consume 260 mW of direct-current (DC) power from a 2.8-V supply voltage. In doing so, they succeed in providing an eye diagram with a clear eye-opening with a pseudo-random bit sequence (PRBS) at 40 Gb/s.

For the cascade stage, a broadband technique is introduced that incorporates shunt as well as series peaking. For cascade stages with inductive peaking, the proposed design methodology incorporates the stagger-tuning technique. This approach should simplify the circuit implementation while minimizing undesirable gain ripples. See "40-Gb/s High-Gain Distributed Amplifiers with Cascaded Gain Stages in 0.18-m CMOS," IEEE Journal of Solid-State Circuits, Dec. 2007, p. 2715.

Sponsored Recommendations

Frequency Modulation Fundamentals

March 14, 2024
The development of crystal-clear FM communications was an innovation of genius and toil. Utilized today in applications such as radar, seismology, telemetry and two-way radios...

44 GHz Programmable Signal Generator

March 14, 2024
The Mini-Circuits SSG-44G-RC is a 0.1 to 44 GHz signal source with an RF output range of -40 to +17 dBm with fine resolution. This model supports CW and pulsed (? 0.5 ?s) outputs...

Webinar: Introduction to OTA Measurement for mmWave and Sub-THz

Feb. 19, 2024
Join Jeanmarc Laurent, a leading expert from MilliBox, for an exclusive live webinar showcasing a complete Over-the-Air (OTA) testing system setup. In this immersive session, ...

Using a CMT VNA with Socket Server

Feb. 19, 2024
This application note describes use of a software application CMT Socket Server which is distributed and supported by Aphena Ltd. Please email [email protected] regarding purchase...