Analysis and Design of Analog Integrated Circuits UQSTC Chapter2 Amplifiers,source followers and cascodes ---Single-transistor amplifiers ---Source followers ---Cascode 2019/9/3 UESTC Luo Ping
Analysis and Design of Analog Integrated Circuits 2019/9/3 UESTC Luo Ping 1 Chapter2 Amplifiers, source followers and cascodes --- Single-transistor amplifiers --- Source followers --- Cascode
Analysis and Design of Analog Integrated Circuits Operational amplifier 1:B Current mirror Differential pair 8年g年089导8g年年 Operational VOUT amplifier is the most versatile circuit block. Current mirror Single- transistor amplifier First stage:a differential pair loaded by a current source. Second stage:a single-transistor amplifier with a DC current source as load. 2019/9/3 UESTC-Luo Ping
Analysis and Design of Analog Integrated Circuits 2019/9/3 UESTC – Luo Ping 2 Operational amplifier is the most versatile circuit block. First stage: a differential pair loaded by a current source. Second stage: a single-transistor amplifier with a DC current source as load
Analysis and Design of Analog Integrated Circuits UQSTC Types of Single Transistor Amplifiers VCC VCC Rc Rc Rc VIN VOUT VOUT VOUT VOUT 0 0 VIN Q RE RE VIN O Common Emitter Common Base Common Collector Emitter Degeneration ◆VDD AVDD VDD RD> RD RD VIN VOUT VOUT VOUT VOUT p VIN 0 Rs Rs VIN Common Source Common Gate Common Drain Source Degeneration 2019/9/3 UESTC-Luo Ping 3
Analysis and Design of Analog Integrated Circuits 2019/9/3 UESTC – Luo Ping 3 Types of Single Transistor Amplifiers
Analysis and Design of Analog Integrated Circuits 2.1 Single-transistor amplifiers One single transistor can be used as an amplifier,a source follower or a cascode.Moreover,gain boosting can be applied by a cascode,which is little more than a cascode combined with an amplifier. With two transistors two more configurations can be differential pair and the current mirror.Combined,they give rise to a full four-transistor differential voltage and current amplifier. 2019/9/3 UESTC-Luo Ping
Analysis and Design of Analog Integrated Circuits 2019/9/3 4 One single transistor can be used as an amplifier, a source follower or a cascode. Moreover, gain boosting can be applied by a cascode, which is little more than a cascode combined with an amplifier. With two transistors two more configurations can be differential pair and the current mirror. Combined, they give rise to a full four-transistor differential voltage and current amplifier. UESTC – Luo Ping 2.1 Single-transistor amplifiers
Analysis and Design of Analog Integrated Circuits UQSTC An amplifier is normally loaded by a DC current source. In this way the maximum gain can be obtained. Single-transistor amplifier Vout VGS out 9mVGS ros Ay gmTDs= 2 los VEL_2VEL VGs-VT IDs Ves-VT Ay≈100 if VEL÷10 V and VGS-V-=0.2v For large gain Av,we must choose VGs-V as small as possible and L as large as possible. L=(4-5)*Lmin.VGS-Vr=0.15-0.2V. 2019/9/3 UESTC-Luo Ping 5
Analysis and Design of Analog Integrated Circuits 2019/9/3 UESTC – Luo Ping 5 An amplifier is normally loaded by a DC current source. In this way the maximum gain can be obtained. For large gain Av, we must choose VGS-VT as small as possible and L as large as possible. L=(4~5)*Lmin. VGS-VT =0.15~0.2V