icroelectronic Circuits SJTU Yang Hua Chapter 10 Analog Integrated Circuits and its application Introduction The 741 Op-Amp Circuit The ideal Op Amp The inverting configuration The noninverting configuration Integrator and differentiator Other operation application
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Microelectronic Circuits SJTU Yang Hua Chapter 10 Analog Integrated Circuits and its application Introduction The 741 Op-Amp Circuit The ideal Op Amp.
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Microelectronic Circuits SJTU Yang Hua
Chapter 10 Analog Integrated Circuits and its application
IntroductionThe 741 Op-Amp CircuitThe ideal Op AmpThe inverting configuration The noninverting configurationIntegrator and differentiatorOther operation application
SJTU Yang HuaMicroelectronic Circuits
Introduction
信号的提取:传感器、接收器或信号发生器,通常信号比较微弱,且易受 干扰,甚至与噪声的幅度相当。信号预处理:信号的分离与放大(隔离、滤波与阻抗变换)信号的加工:信号的运算、转换和比较等。一般再经功放才能驱动负载, 或者经 A/D 转换到 PC 机信号的执行:一般为 CPU ( MCU , DSP , PC )
SJTU Yang HuaMicroelectronic Circuits
Part 1. The 741 Op-Amp Circuit and analysis.
Part 2. Analog integrated circuits’ application
_ the application of operational amplifier
_ the application of comparer circuits
Content
SJTU Yang HuaMicroelectronic Circuits
Part I:
Analog ICs include operational amplifiers, analog multipliers, A/D converters, D/A converters, PLL, etc.
A complete op amp is realized by combining analog circuit building blocks.
The bipolar op-amp has the general purpose variety and is designed to fit a wide range of specifications.
The terminal characteristics is nearly ideal.
SJTU Yang HuaMicroelectronic Circuits
The 741 Op-Amp Circuit
SJTU Yang HuaMicroelectronic Circuits
Structure
“ 化整为零”:划分偏置电路、输入级、中间级和输出级
“ 分析功能”:分别分析各部分的结构形式及特点
“ 统观整体” :研究各部分电路之间的联系 “ 定量估算”:必要时做定量分析
SJTU Yang HuaMicroelectronic Circuits
General Description
24 transistors, few resistors and only one capacitor
Two power supplies Short-circuit protection
SJTU Yang HuaMicroelectronic Circuits
SJTU Yang HuaMicroelectronic Circuits
SJTU Yang HuaMicroelectronic Circuits
The Input Stage
The input stage consists of transistors Q1 through Q7.
Q1-Q4 is the differential version of CC and CB configuration.
High input resistance. Current source (Q5-Q7) is the active load of input
stage. It not only provides a high-resistance load but also converts the signal from differential to single-ended form with no loss in gain or common-mode rejection.
SJTU Yang HuaMicroelectronic Circuits
The Intermediate Stage
The intermediate stage is composed of Q16, Q17 and Q13B.
Common-collector configuration for Q16 gives this stage a high input resistance as well as reduces the load effect on the input stage.
Common-emitter configuration for Q17 provides high voltage gain because of the active load Q13B.
Capacitor Cc introduces the miller compensation to insure that the op amp has a very high unit-gain frequency.
SJTU Yang HuaMicroelectronic Circuits
SJTU Yang HuaMicroelectronic Circuits
The Output Stage
The output stage is the efficient circuit called class AB output stage.
Voltage source composed of Q18 and Q19 supplies the DC voltage for Q14 and Q20 in order to reduce the cross-over distortion.
Q23 is the CC configuration to reduce the load effect on intermediate stage.
Short-circuit protection circuitry Forward protection is implemented by R6 and Q15. Reverse protection is implemented by R7, Q21,
current source(Q24, Q22) and intermediate stage.
SJTU Yang HuaMicroelectronic Circuits
The Output Stage
(a) The emitter follower is a class A output stage. (b) Class B output stage.
SJTU Yang HuaMicroelectronic Circuits
The Output Stage
Wave of a class B output stage fed with an input sinusoid.
Positive and negative cycles are unable to connect perfectly due to the turn-on voltage of the transistors.
This wave form has the nonlinear distortion called crossover distortion.
To reduce the crossover distortion can be implemented by supplying the constant DC voltage at the base terminals.
SJTU Yang HuaMicroelectronic Circuits
The Output Stage
QN and QP provides the voltage drop which equals to the summer of turn-on voltages of QN and QP.
This circuit is call Class AB output stage.
SJTU Yang HuaMicroelectronic Circuits
SJTU Yang HuaMicroelectronic Circuits
The Biasing Circuits
Reference current is generated by Q12, Q11 and R5.
Wilder current provides biasing current in the order of μA.
Double-collector transistor is similar to the two-output current mirror. Q13B provides biasing current for intermediate stage, Q13A for output stage.
Q5, Q6 and Q7 is composed of the current source to be an active load for input stage.
SJTU Yang HuaMicroelectronic Circuits
The Ideal Op Amplifier
symbol for the op amp
SJTU Yang HuaMicroelectronic Circuits
The Ideal Op Amplifier
The op amp shown connected to dc power supplies.
NP uu
ou
o
SJTU Yang HuaMicroelectronic Circuits
Characteristics of the Ideal Op Amplifier
Differential input resistance is infinite. Differential voltage gain is infinite. CMRR is infinite. Bandwidth is infinite. Output resistance is zero. Offset voltage and current is zero.
a) No difference voltage between inverting and noninverting terminals.
b) No input currents.
SJTU Yang HuaMicroelectronic Circuits
iiNN = = iiPP = = 00
uuNN = = uuPP
1. Differential input voltage is zero1. Differential input voltage is zero