Description

CMOS VLSI. Analog Design. Outline. Overview Small signal model, biasing Amplifiers Common source, CMOS inverter Current mirrors, Differential pairs Operational amplifier Data converters DAC, ADC RF LNA, mixer. CMOS for Analog.

Transcripts

CMOS VLSI Analog Design Analog Design

Outline Overview Small flag show, biasing Amplifiers Common source, CMOS inverter Current mirrors, Differential sets Operational enhancer Data converters DAC, ADC RF LNA, blender Analog Design

CMOS for Analog MOS gadget can be utilized for intensification and exchanging Typical: work gadgets in immersion, entryway voltage sets current Benefits Cheap procedures (contrasted with BJT) Integrated bundles Challenges Low pick up Coupling issues Tolerances Analog Design

MOS Small Signal Model Analog Design

MOS Small Signal Model From first request immersion conditions: Rewrite regarding sensitivities: So Analog Design

Channel Length Modulation in actuality yield current does change with V ds Output resistance Analog Design

Bias Point Standard circuits for biasing Compute parameters from I-V bends Analog Design

Outline Overview Small flag demonstrate, biasing Amplifiers Common source, CMOS inverter Current mirrors, Differential sets Operational speaker Data converters DAC, ADC RF LNA, blender Analog Design

Common Source Amplifier Operate MOS in immersion Increase in V gs prompts drop in v out Gain A = v out/v in Analog Design

CMOS Inverter as an Amplifier Can utilize pMOS fixing to V dd for resistive load in like manner source intensifier Do better by having a "dynamic load": increment stack resistance when V in goes up Analog Design

AC Coupled CMOS Inverter How to get most extreme intensification? Inclination at V inv utilizing criticism resistor Use capacitor to AC couple the information Analog Design

AC Coupled CMOS Inverter Analog Design

Current Mirrors Replicate current at contribution at yield Ideally, I out = I in immersion, so unending yield impedance Channel length adjustment: utilize huge L Analog Design

Cascoded Current Mirror Key to comprehension: N1 and N2 have practically same deplete and door voltage Means high yield impedance Raise yield impedance utilizing a cascoded current reflect Analog Design

Current Mirror Can utilize numerous yield transistors to make numerous duplicates of info current Better than utilizing a solitary more extensive transistor, since indistinguishable transistors coordinate better Analog Design

Differential Pair Steers current to two yields in view of contrast between two voltages Common mode clamor dismissal Analog Design

Differential Amplifier Use resistive loads on differential match to assemble differential enhancer Analog Design

CMOS Opamp Differential intensifier with basic source speaker Diff amp utilizes pMOS current reflect as a heap to get high impedance in a little territory Common source amp is P3, stacked by nMOS current reflect N5 Bias voltage and current set by N3 and R A = v o/(v 2 – v 1 ) = g mn2 g mp3 (r on2 | r op2 ) (r op3 | r on5 ) Opamp: workhorse of simple plan Analog Design

Outline Overview Small flag demonstrate, biasing Amplifiers Common source, CMOS inverter Current mirrors, Differential sets Operational speaker Data converters DAC, ADC RF LNA, blender Analog Design

Data Converters DACs really simple to outline, ADCs harder Speed, linearity, control, estimate, simplicity of-outline Parameters Resolution, FSR Linearity: DNL, INL, Offset Analog Design

Noise and Distortion Measures DAC: apply computerized sine wave, measure craved flag vitality to music and commotion ADC: apply simple sine wave, do FFT on the put away specimens Measure add up to consonant bending (THD), and spurious free element go (SFDR) Analog Design

DAC Resistor String DACs Use a reference voltage stepping stool comprising of 2 N resistors from V DD to GND for a N-bit DAC Presents substantial RC, needs high load resistance Use: reference for opamp, support, comparator Analog Design

DAC R-2R DACs Conceptually, assessing parallel expression Much less resistors than resistor string DACs Analog Design

DAC Current DAC: quickest converters Basic guideline Different structures Analog Design

DAC Full execution: 4-bit current DAC Analog Design

ADC Speed of transformation, number of bits ( ¹ ENOBs) Easy ADC: Successive Approximation Analog Design

ADC Flash ADC: most elevated execution Analog Design

ADC Crucial segments: comparator, encoder Analog Design

ADC Pipeline ADC Amounts to a dispersed progressive approx ADC Trades streak speed and low inactivity for longer inertness and somewhat bring down speed Much less power Analog Design

ADC Sigma-delta converter Suitable for procedures where advanced is shabby CD players: sound frequencies, 20 bit exactness RF (10MHz): 8-10 bit accuracy Analog Design

Outline Overview Small flag display, biasing Amplifiers Common source, CMOS inverter Current mirrors, Differential sets Operational enhancer Data converters DAC, ADC RF LNA, blenders Analog Design

RF Low in gadget include, high exertion Sizing, segment choice extremely included Analog Design

Mixers Analog multiplier, ordinarily used to change over one recurrence to another Various approaches to actualize multipliers Quad FET switch Gilbert cell Analog Design

Noise Thermal commotion v^2 = 4kTR (Volt^2/Hz) Shot commotion i^2 = 2qI (Amp^2/Hz) 1/f clamor Very intricate wonder Proportional to 1/f Makes RF plan exceptionally troublesome Analog Design