| US 7,501,887 B2 | ||
| Controllable amplifier and its use | ||
| Carl Stephelbauer, Ennsdorf (Austria); and Manfred Haberl, Linz (Austria) | ||
| Assigned to Infineon Technologies AG, Munich (Germany) | ||
| Filed on Feb. 23, 2006, as Appl. No. 11/360,720. | ||
| Claims priority of application No. 10 2005 008 507 (DE), filed on Feb. 24, 2005. | ||
| Prior Publication US 2006/0202752 A1, Sep. 14, 2006 | ||
| Int. Cl. H03F 1/14 (2006.01); H03F 3/45 (2006.01) | ||
| U.S. Cl. 330—51 [330/254; 330/278] | 18 Claims |
| 18. A controllable amplifier, comprising:
an input for supplying a radio-frequency signal (IN) which is to be amplified;
a control input for supplying a control signal for the desired overall gain (CTRL);
an output for provision of an amplified signal (OUT);
a first current path which comprises a first transistor connected as a source follower;
a second current path which comprises a second transistor connected as a source follower, with the second current path being
connected in parallel with the first current path; and
means for controlling the second current path which couples the control input to the second transistor,
where the input is connected to respective control inputs of the first and second transistors such that the control inputs
of the first and second transistors receive the same potential, and
where the output is formed in a connecting node of the first and second current paths.
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