Analog IC Design First – A OPAMP Design Example

1、Analog IC Design First A OPAMP Design Example.Date: 15th NOV, 2007報告人：何建興報告人：何建興2n1. What is Analog Signal?n2. Elements Used in Electronic Products.n3. Why OPAMP.n4. How an OPAMP works. n5. What is MOS? MOS Basic Characteristic.n6. A Design Example.n7. Is It the best design?n8. Is Direct Shrink Poss

2、ible?n9. Q&A3nAnalog signals in Integrated Circuits can be in the form of Voltage or Current (or Power). nThey are continuous signals, (amplitude vs. time). Voice and Audio signals are good examples of analog signals.nIf a threshold was set, then an Analog signal can be easily converted to Digit

3、al signal.nExample: A D AD_DA4nResistors, Capacitors, Inductors, Transistors and Diodes are basic devices (elements) in Integrated Circuit.nMany basic building blocks (IP) can be composed of these devices.nEx: 1. RAMs basic devices MOS(RAM cell + logic circuit, sense Amp.) + Capacitors.n 2. Logic ci

4、rcuit CMOS. (PMOS + NMOS)u 3. USB interface MOS + Resistors.5u 4. Recorder (ADC), Player (DAC) MOSu + Resistors + Capacitors. u 5. Regulator MOS + Resistors.n 6. ESD PAD MOS + Diode + Resistors. The IP (Intellectual Property ) listed above are able to construct a MP3 player Chip.nExample: 1 2 3 4uMa

5、ny Analog blocks need OPAMP.6n1. OPAMP (Operational Amplifier) are one of the most important building blocks in Analog IC design. It can be used to do addition, subtraction, multiplication, logarithm, operations.nFilters, Integrators, Oscillators Regulators, etc. all include OPAMP. nSymbol of OPAMPn

6、Examples:7n1. There are 5 nodes on an OPAMP, they are Positive (V+) terminal, Negative (V-) terminal, Output (Vo) terminal, Power (VDD) and Ground (GND). n2. An ideal OPAMP characteristic: (I) infinite input resistance. (II) infinite open loop gain. (III) v+ = v- when negative feedback configuration

7、. 8n3. An real CMOS OPAMP can have: (I) Very large input resistance (Ri) 1M ohm. input current =0 (II). Large but not finite open loop gain (A) 1000 (60dB). n4. Examples: n5. Insight9nMOS : Metal Oxide-SemiconductornExample10n1. Specification: given a voltage 1.25V, design a OPAMP to achieve 2.5V ou

8、tput. Precision +- 1mV, : means A01000. settling time 1M.n2. Schematic: 11n1. The MOS size (aspect ratio) which we just designed is not the unique solution. We can do it better.nBased on the design we just finished, we can tune the MOS size to achieve: (i) smaller area (ii) consume less current. Both goals are the popular topic