| US 7,489,193 B2 | ||
| Operational amplifier | ||
| Kohichiroh Adachi, Osaka (Japan) | ||
| Assigned to Ricoh Company, Ltd., Tokyo (Japan) | ||
| Filed on Mar. 20, 2007, as Appl. No. 11/723,516. | ||
| Claims priority of application No. 2006-089414 (JP), filed on Mar. 28, 2006. | ||
| Prior Publication US 2007/0285164 A1, Dec. 13, 2007 | ||
| Int. Cl. H03F 3/45 (2006.01) | ||
| U.S. Cl. 330—253 [330/255; 330/263] | 18 Claims |
| 1. An operational amplifier comprising:
a pair of differential stages;
a cascode amplifier stage; and
an output stage, wherein
a threshold voltage of an output transistor constituting the output stage is higher than a threshold voltage of other transistors.
|