microelectronics(unibg)

MicroElectronics (UniBG)

The course started in 2004. Updates are very frequent while teaching (October-February).

The course is aimed to recall basic notion of Electronics and give a feel of advanced topics.

Lecture notes

• 1 Introduction (pdf 0.5Mb)
• 2 Passive elements: RLC (pdf 1Mb)
• 3 Active elements: diodes (pdf 0.5Mb)
• 4 BJT transistors (pdf 1.4Mb)
• 5 MOS transistors (pdf 1Mb)
• 6 Operational Amplifiers (pdf 0.6Mb)
• 7 Power Output stages (pdf 1Mb), additional notes for class D output stages (pdf 0.7 Mb)
• 8 Single/double transistor stages (pdf 1Mb)
• 9 Differential Input stages (pdf 1.1Mb)
• 10 Voltage feedback (pdf 0.6Mb)
• 11 Current feedback (pdf 0.3Mb)

1 Introduction (pdf 0.5Mb)

Course outline. Examples of 2-stage and 4-stage operation amplifiers. The famous uA741.

2 Passive elements: RLC (pdf 1Mb)

Fundamental units of measure. Kirchoff and Ohm laws. Resistances in series and in parallel. Voltage and current dividers. Thevenin and Norton equivalents. Effects superposition. Power transfer. Resistances connected as delta and wye.

Inductors and capacitors. Mutual inductance. Complex impedance. Single time constant circuits, basic RLC filters. Time response and frequency response. 1st and 2nd order RLC filters. Frequency response of 2 pole systems. Miller effect.

3 Active elements: diodes (pdf 0.5Mb)

Diode: accurate and simplified models. Equivalent circuits. Example of usage: logic. 2nd order effects. Small signal model. Zener diode. Examples of usage: clamping. Direct and inverse polarization. High frequency model. Example of usage: rectifiers and voltage regulators.

4 BJT transistors (pdf 1.4Mb)

Bipolar junction transistor (BJT). Symbols. Polarization: active, saturation, cutoff. Characteristics: collector current versus collector-emitter voltage and versus base-emitter voltage. T model and PI model. High frequency model. Small signal model. Basic amplifier / inverter.

1 stage and multiple stage amplifier. Feedback with emitter resistance (degeneration) and base resistance. High frequency model and cutoff frequency. Polarization circuits. 2nd order effects. Diode-connected transistors (transdiodes).

5 MOS transistors (pdf 1Mb)

Metal-Oxide Semiconductor transistor (MOS). Symbols. Polarization: triode, saturation, cutoff. Characteristics: drain current versus drain-source and versus gate-source voltage. T model and PI model. Small signal model. Basic amplifier / inverter: nMOS and CMOS. Latch-up in CMOS inverters.

1 stage and multiple stage amplifier. High frequency model and cutoff frequency. Polarization circuits. 2nd order effects. Diode-connected transistors (transdiodes). nMOS and CMOS pass-transistors.

6 Operational Amplifiers (pdf 0.6Mb)

Classical op.amp.: differential voltage input, voltage output. Internal model. Inverting and non-inverting configuration. Examples of usage: current/voltage amplifiers, weighted sum, differential amplifier, bridge / instrumentation amplifier, Miller integrator, derivator, logarithm/exponential (multipliers/dividers). Switched capacitor.

Pratical implementations. Limits on output voltage, output current. Input offset voltage, input bias current. 2-stage CMOS.

7 Power Output stages (pdf 1Mb)

Power output: class A. class B, class AB. Power consumption and efficiency. Dead zone and distortion. Thermal run-away. All npn, Darlington, quasi complementary stages. Complementary CMOS and BiCMOS class AB.

Safe operating area. Power dissipation. Input buffers. Output current boosters. Enhanced Darlington output. Short circuit protection. Thermal shutdown. Power BJT and power MOS. Examples: LM380 and uA741.

Class D. Pulse width modulation. Sawtooth and triangle carrier. Binary and ternary modulation. Phase-shift modulation in H-bridge power output stages. Digital driver with natural / uniform sampling. Sigma-delta modulation and noise-shaping. Digital interpolation, half-band filters. Additional notes for class D (pdf 0.7Mb)

8 Single/double transistor stages (pdf 1Mb)

BJT/MOS symbols and models.

Single transistor circuits: common emitter/source as amplifiers, common base/gate as current buffers, common collector/drain as voltage buffers.

Double transistor circuits: cascoded transistors (single, active, double and folded), wideband Darlington configuration, wideband buffered amplifiers.

Current mirrors (Wilson, Widlar, self-polarizing), mirrors for polarization, active loads. Differential input pairs. Output push-pull.

9 Differential Input stages (pdf 1.1Mb)

BJT/MOS resistance mirroring rules.

Differential pair, emitter degeneration, extended range. Differential input and common mode rejection. Passive load and active load, folded cascode load. Buffer on inputs, buffer on outputs. Examples: 2-stage and 4-stage amplifiers.

Current mirrors, cascoded current mirrors. Active load, depletion MOS, diode-connected enhancement MOS. Nano-ampere current reference. Self-polarizing current mirrors. Band-gap voltage reference. Temperature compensation.

Examples: folded cascode, active folded cascode.

10 Voltage feedback (pdf 0.6Mb)

Feedback purposes. Series/parallel connections to read current/voltage and to sum voltage/current. Use of emitter resistance to read current and sum voltage. Use of differential pair to sum voltages.

Examples of series-series, parallel-series, series-parallel and parallel-parallel connections.

Compensation by means of external capacitance, by internal capacitance exploiting the Miller effect. Nested Miller. Feed-forward.

11 Current feedback (pdf 0.3Mb)

Voltage feedback amplifiers (two high impedance inputs). Current feedback amplifiers (one low impedance input). Inverting and non-inverting configurations. Gain and bandwidth.

Examples. Current feedback amplifiers. Rail-to-rail voltage amplifiers.