| US 7,573,331 B2 | ||
| Low power low noise amplifier for a magnetoresistive sensor | ||
| Elangovan Nainar, Longmont, Colo. (US) | ||
| Assigned to Agere Systems Inc., Allentown, Pa. (US) | ||
| Filed on Oct. 06, 2005, as Appl. No. 11/244,821. | ||
| Claims priority of provisional application 60/616863, filed on Oct. 06, 2004. | ||
| Prior Publication US 2006/0077584 A1, Apr. 13, 2006 | ||
| Int. Cl. H03F 3/45 (2006.01) | ||
| U.S. Cl. 330—253 [360/46] | 33 Claims |
| 1. An amplifier for amplifying differential input signals comprising a first and a second input signal, the amplifier comprising:
a first PMOSFET and a first NMOSFET each having a gate responsive to the first input signal;
a second PMOSFET and a second NMOSFET each having a gate responsive to the second input signal;
at a first node, a first source/drain of the first PMOSFET connected to a first source/drain of the first NMOSFET;
at a second node, a first source/drain of the second PMOSFET connected to a first source/drain of the second NMOSFET;
a first current source supplying a first DC bias current at a second source/drain of each of the first and the second PMOSFETS;
and
a second current source supplying a second DC bias current at a second source/drain of each of the first and the second NMOSFETS,
wherein the first DC bias current is different from the second DC bias current,
wherein a first load current at the first node is based on a current through the first PMOSFET and a current through the first
NMOSFET, and wherein a second load current at the second node is based on a current through the second PMOSFET and a current
through the second NMOSFET.
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