Title: Device and method for controlling current gain
Application Number: 200610111021 Application Date: 2006.08.06
Publication Number: 1945980 Publication Date: 2007.04.11
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03M1/66
Applicant(s) Name: Broadcom Corp. Address:
Inventor(s) Name: Venes Arnoldus;Cong Yonghua
Attorney & Agent: caixiao gong
Abstract:
    A wide gain range current digital-to-analog converter (DAC) is presented that includes a unit current cell having a current source module biased by a current source voltage bias, a differential switch module, a main cascode module biased by a first bias voltage and an attenuation cascode module biased by a second bias voltage, configured such that a particular current gain range is obtained at the main cascode module output when a unit current cell current is at or above a current threshold. The output current at the attenuation cascode module output can be input into a current attenuator when the unit current cell current is below the current threshold to obtain additional current gain range. The current attenuator can include a plurality of attenuator cells that can be programmed to a desired level of current gain in linear decibels or linear step intervals. Smaller step sizes can be obtained by programming a current source within the step intervals.
Time: 13