Related to : VWA 50030 AA

Functions : 40 Gbps, 800 mVpp Differential Limiter Amplifier

The VWA 00096 AB chip is a limiting - high gain differential amplifier for high data rate application, typically 10 to 40 Gb/s. The chip is designed in 0.18μm SiGe BiCMOS 150 GHz process.

The chip can be used in various ways:

• Single ended input to differential output transformer, by grounding through a capacitor one of the inputs.
• Limiting amplifier, using the high linear gain to saturate the input signal.
• Cross point adjustment can be done by tuning the DC levels between the two inputs.

The amplifier is a 6 stages amplifier, giving typically 60dB linear gain. When in saturation, the output amplitude is 400 mV pp single ended (800 mV
differential pp).

The different parts of the chip are internally biased using a voltage and currents reference circuit (Bandgap), in order to have the overall RF characteristics of the chip (especially the output amplitude), insensitive to the voltage supply, the temperature and the process spread. An enable input control pin is used to switch the chip ON or OFF.

Three separate pins are used to bias the chip: one dedicated to the reference circuit, the second for the amplifier core (input buffers and amplifier core) and the last for the 50Ω output driver. The 3 bias inputs can be separately filtered / decoupled in order to optimize the overall chip performances.