Title :
A constant GM rail-to-rail opamp with a novel input stage for BiCMOS process
Author :
Rentala, Vijay ; Rout, Saroj ; Lee, Edward ; Weber, Robert J.
Author_Institution :
Dept. of Electr. & Comput. Eng., Iowa State Univ., Ames, IA, USA
Abstract :
A BiCMOS rail-to-rail operational amplifier capable of operating from supply voltages as low as 2.5 V is presented. A new technique of achieving a rail-to-rail input common mode range using a bipolar input stage is developed. The new technique avoids the use of complementary pairs at the input and thus avoids complicated schemes for monitoring the constant gm. The resulting variation of the gm is within +/-5.64%. The output stage is also rail-to-rail with a class AB control providing 5 mA of current to a 300 ohm resistor in parallel with a 20 pF load. The output stage can swing to within 50 mV of each supply rail. The opamp was realized in a conventional 1.2 μm BiCMOS process with a DC gain of 81 dB and a unity gain frequency of 7.9 MHz
Keywords :
BiCMOS analogue integrated circuits; compensation; operational amplifiers; 1.2 micron; 2.5 V; 5 mA; 7.9 MHz; 81 dB; BiCMOS process; bipolar input stage; class AB control; class AB output stage; constant GM rail-to-rail opamp; frequency compensation; rail-to-rail operational amplifier; rail-to-rail output stage; BiCMOS integrated circuits; Gain; Low voltage; Monitoring; Operational amplifiers; Rail to rail amplifiers; Rail to rail inputs; Rail to rail operation; Rail to rail outputs; Resistors;
Conference_Titel :
Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on
Conference_Location :
Sydney, NSW
Print_ISBN :
0-7803-6685-9
DOI :
10.1109/ISCAS.2001.921831
