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university:courses:electronics:electronics-lab-20 [29 Oct 2012 16:18] – created Doug Merceruniversity:courses:electronics:electronics-lab-20 [02 Feb 2023 21:16] (current) – [Activity: CMOS Amplifier stages] Doug Mercer
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-====== Activity 20. CMOS Amplifier stages======+====== Activity: CMOS Amplifier stages - ADALM2000======
  
 ===== Objective: ===== ===== Objective: =====
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 The goal is to explore a high gain inverting amplifier constructed from complementary MOS devices. The goal is to explore a high gain inverting amplifier constructed from complementary MOS devices.
  
-====== 20.1 High gain inverting amplifier======+====== High gain inverting amplifier======
  
 ===== Materials: ===== ===== Materials: =====
-Analog Discovery Lab hardware\\+ADALM2000 Active Learning Module\\
 Solder-less breadboard\\ Solder-less breadboard\\
 Jumper wires\\ Jumper wires\\
-3 - 100KΩ Resistor\\ +3 - 100 KΩ Resistor\\ 
-1 - 10KΩ Resistor\\ +1 - 10 KΩ Resistor\\ 
-1 - 4.7KΩ Resistor\\  +1 - 4.7 KΩ Resistor\\  
-2 - 22uF capacitor\\ +2 - 22 uF capacitor\\ 
-2 - 1uF capacitor\\+2 - 1 uF capacitor\\
 1 - 10 pF capacitor\\ 1 - 10 pF capacitor\\
 1 - CD4069A, CD4069UB or 74HCU04 unbuffered hex inverter (be sure not to use the buffered 74HC04 version)\\ Alternatively a simple CMOS inverter can be built using the CD4007 transistor array. Note the appendix at the end. 1 - CD4069A, CD4069UB or 74HCU04 unbuffered hex inverter (be sure not to use the buffered 74HC04 version)\\ Alternatively a simple CMOS inverter can be built using the CD4007 transistor array. Note the appendix at the end.
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 ===== Directions: ===== ===== Directions: =====
  
-First build the simple example shown figure 2 to test the input to output transfer function of the simple CMOS amplifier. The green boxes indicate connections to the connector on Analog Discovery. Connect Vp (+5V) power to V<sub>CC</sub> (pin 14) and ground to GND (pin 7). Connect the output of the waveform generator to one of the inverter inputs (pin 1) along with scope input 1+ and connect the inverter output (pin 2) to scope input 2+. If you are using the CD4069A(UB) you can connect pin 7, V<sub>SS</sub> to the negative board supply, Vn, rather than ground because the CD4069A(UB) supports power supply voltages greater than +5 volts.+First build the simple example shown figure 2 to test the input to output transfer function of the simple CMOS amplifier. The green boxes indicate connections to the connector on ADALM2000. Connect Vp (+5V) power to V<sub>CC</sub> (pin 14) and ground to GND (pin 7). Connect the output of the waveform generator to one of the inverter inputs (pin 1) along with scope input 1+ and connect the inverter output (pin 2) to scope input 2+. If you are using the CD4069A(UB) you can connect pin 7, V<sub>SS</sub> to the negative board supply, Vn, rather than ground because the CD4069A(UB) supports power supply voltages greater than +5 volts.
  
 {{ :university:courses:electronics:a20_f2.png?500 |}} {{ :university:courses:electronics:a20_f2.png?500 |}}
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 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Configure the waveform generator for a 1 KHz triangle wave with 2V amplitude and 2.5V offset. Both scope channels should be set to 1V/Div. If you are using the CD4069A on the plus and minus power supplies you will need to use a larger 4V amplitude and 0V offset.+Configure the waveform generator for a 1 KHz triangle wave with 4V amplitude peak-to-peak and 2.5V offset. Both scope channels should be set to 1V/Div. If you are using the CD4069A on the plus and minus power supplies you will need to use a larger 8V amplitude peak-to-peak and 0V offset. 
 + 
 +{{ :university:courses:electronics:cmos_amplifier_hardware_setup_1.png|}} 
 +<WRAP centeralign> Figure 4 Hardware setup using CD4007 </WRAP> 
  
 ===== Procedure: ===== ===== Procedure: =====
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 Measure the slope of the output and calculate the DC gain of the amplifier as the ratio of the change in the output voltage to the change in input voltage at the center of the output swing (i.e. around 2.5V). Remember this should be a negative number because the amplifier inverts. Measure the slope of the output and calculate the DC gain of the amplifier as the ratio of the change in the output voltage to the change in input voltage at the center of the output swing (i.e. around 2.5V). Remember this should be a negative number because the amplifier inverts.
  
-====== 20.2 Adding negative feedback ======+{{ :university:courses:electronics:cmos_amplifier_scope_shot_1.png |}} 
 +<WRAP centeralign> Figure 5 CMOS inverting amplifier Scopy plot </WRAP>  
 + 
 +====== Adding negative feedback ======
  
-On your solder-less breadboard construct the amplifier circuit shown in figure 4 below. +On your solder-less breadboard construct the amplifier circuit shown in figure 6 below. 
  
 {{ :university:courses:electronics:a20_f4.png?500 |}} {{ :university:courses:electronics:a20_f4.png?500 |}}
  
-<WRAP centeralign> Figure 4 single stage amplifier </WRAP>+<WRAP centeralign> Figure 6 single stage amplifier </WRAP>
  
 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Configure the waveform generator for a 1 KHz sine wave with 1V amplitude and 0V offset. Both scope channels should be set to 1V/Div.+Configure the waveform generator for a 1 KHz sine wave with 2V amplitude peak-to-peak and 0V offset. Both scope channels should be set to 1V/Div.
  
 +{{ :university:courses:electronics:cmos_amplifier_hardware_setup_2a.png |}}
 +<WRAP centeralign> Figure 7 Hardware setup for single stage amplifier using CD4007 </WRAP>
 ===== Procedure: ===== ===== Procedure: =====
  
-Apply a sinusoidal signal of 1V amplitude with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system.+Apply a sinusoidal signal of 2V amplitude peak-to-peak with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system.
  
 +Figure 8 Plot for single stage amplifier using CD4007 </WRAP>
 ===== Questions: ===== ===== Questions: =====
  
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 What is the gain from the input source, W1, to the output seen at the inverter output? Which components set this gain and why? What is the gain from the input source, W1, to the output seen at the inverter output? Which components set this gain and why?
  
-====== 20.3 Adding more stages for higher gain ======+======  Adding more stages for higher gain ======
  
-On your solder-less breadboard construct the amplifier circuit shown in figure 5 below. +On your solder-less breadboard construct the amplifier circuit shown in figure 8 below. 
  
 {{ :university:courses:electronics:a20_f5.png?500 |}} {{ :university:courses:electronics:a20_f5.png?500 |}}
  
-<WRAP centeralign> Figure 5 three stage amplifier </WRAP>+<WRAP centeralign> Figure 8 three stage amplifier </WRAP>
  
 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-Configure the waveform generator for a 1 KHz sine wave with 1V amplitude and 0V offset. Both scope channels should be set to 1V/Div.+Configure the waveform generator for a 1 KHz sine wave with 2V amplitude peak-to-peak and 0V offset. Both scope channels should be set to 1V/Div.
  
 +{{ :university:courses:electronics:cmos_amplifier_hardware_setup_3a.png |}}
 +<WRAP centeralign> Figure 9 three stage amplifier hardware setup using CD4007 </WRAP>
 ===== Procedure: ===== ===== Procedure: =====
  
-Apply a sinusoidal signal of 1V amplitude with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system.+Apply a sinusoidal signal of 2V amplitude peak-to-peak with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system.
  
 +<WRAP centeralign> Figure 10. Plot for three stage amplifier hardware setup using CD4007 </WRAP>
 ===== Questions: ===== ===== Questions: =====
  
-====== 20.4 Chopper Amplifier ======+======  Chopper Amplifier ======
  
-In this part of the lab activity, the CD4069A(UB) un-buffered hex CMOS inverter and a CD4066 Quad analog switch are used as elements of a chopper amplifier. Reconnect the breadboard as indicated in figure 6. Referring to figure 6, the various functions of this circuit can be determined. The two inverters on the bottom left of figure 6 create a square wave and its complement to drive the switch controls of the CD4066. These square waves drive the switches, with switches A and B functioning as a single-pole, double-throw switch on the input, and switches C and D performing the same function on the output. The other inverter at the top of figure 6 is used as an AC coupled Amplifier similar to what we just looked at in figure 4.+In this part of the lab activity, the CD4069A(UB) un-buffered hex CMOS inverter and a CD4066 Quad analog switch are used as elements of a chopper amplifier. Reconnect the breadboard as indicated in figure 11. Referring to figure 11, the various functions of this circuit can be determined. The two inverters on the bottom left of figure 11 create a square wave and its complement to drive the switch controls of the CD4066. These square waves drive the switches, with switches A and B functioning as a single-pole, double-throw switch on the input, and switches C and D performing the same function on the output. The other inverter at the top of figure 6 is used as an AC coupled Amplifier similar to what we just looked at in figure 6.
  
-In operation, the input signal is modulated by the input switches, amplified by the ac amplifier, and then demodulated by the output switches. The 20 kO, 560 pF low pass filter minimizes the high frequency ripple in the output.+In operation, the input signal is modulated by the input switches, amplified by the ac amplifier, and then demodulated by the output switches. The 20 kΩ, 560 pF low pass filter minimizes the high frequency ripple in the output.
  
-{{ :university:courses:electronics:a20_f6.png?500 |}}+{{ :university:courses:electronics:a20_f6.png?530 |}}
  
-<WRAP centeralign> Figure 6 Chopper amplifier </WRAP>+<WRAP centeralign> Figure 11 Chopper amplifier </WRAP>
  
 ==== AC Amplifier Response to Pulse Modulated Signals ==== ==== AC Amplifier Response to Pulse Modulated Signals ====
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 ==== Chopper Amplifier DC Transfer Characteristic ==== ==== Chopper Amplifier DC Transfer Characteristic ====
  
-Measure the transfer characteristic (DC gain) of the chopper amplifier by applying DC voltages between about -2 V and +2 V to the input and measuring the output. This can be done manually using waveform generator W1 with a DC wave shape and setting the offset. Be sure to take sufficient data to determine the linear and nonlinear ranges of the transfer characteristic. To reduce data taking time, try using the waveform generator to provide a very low frequency (100 Hz) triangle signal with 0V offset. For example, a 2V amplitude setting will give outputs between +2V and -2V, respectively.+Measure the transfer characteristic (DC gain) of the chopper amplifier by applying DC voltages between about -2 V and +2 V to the input and measuring the output. This can be done manually using waveform generator W1 with a DC wave shape and setting the offset. Be sure to take sufficient data to determine the linear and nonlinear ranges of the transfer characteristic. To reduce data taking time, try using the waveform generator to provide a very low frequency (100 Hz) triangle signal with 0V offset. For example, a 4V amplitude peak-to-peak setting will give outputs between +2V and -2V, respectively.
  
 ==== Chopper Amplifier Frequency Response ==== ==== Chopper Amplifier Frequency Response ====
  
-Apply a sinusoidal signal of 200mV amplitude with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system, paying special attention to the 50KHz to 100KHz range and the region near the frequency of the chopping clock.+Apply a sinusoidal signal of 400mV amplitude peak-to-peak with zero offset voltage to the input and measure the gain of the entire system from 10 to 100 KHz. Use the Network (Bode) analyzer to plot gain and phase vs. frequency for the entire system, paying special attention to the 50KHz to 100KHz range and the region near the frequency of the chopping clock.
  
 ==== Chopper Amplifier Results ==== ==== Chopper Amplifier Results ====
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 Make a Bode plot (gain/phase versus frequency) of the Chopper Amplifier from the data taken above. Comment on the bandwidth of the chopper amplifier and the gain near the chopping frequency. Make a Bode plot (gain/phase versus frequency) of the Chopper Amplifier from the data taken above. Comment on the bandwidth of the chopper amplifier and the gain near the chopping frequency.
 +
 +==== For Further Study: ====
 +
 +ADI Mini Tutorial on [[adi>static/imported-files/tutorials/MT-055.pdf|Chopper Amplifiers]]
  
 ===== Circuit Additions: ===== ===== Circuit Additions: =====
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 These three inverters can be used to construct the three stage amplifier in section 20.3 for example. These three inverters can be used to construct the three stage amplifier in section 20.3 for example.
 +
 +<WRAP round download>
 +**Resources:**
 +  * Fritzing files: [[downgit>education_tools/tree/master/m2k/fritzing/cmos_amplifier_bb | cmos_amplifier_bb]]
 +  * LTspice files: [[downgit>education_tools/tree/master/m2k/ltspice/cmos_amplifier_ltspice | cmos_amplifier_ltspice]]
 +</WRAP>
 +
 +**Return to Lab Activity [[university:courses:electronics:labs|Table of Contents]]**
  
  
university/courses/electronics/electronics-lab-20.1351523908.txt.gz · Last modified: 29 Oct 2012 16:18 by Doug Mercer

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