Lab 4 - EE 420L 

Authored by Sergio Covarrubias

covars1@unlv.nevada.edu

02/24/2016

Op-amps II, gain-bandwidth product and slewing

Again, this lab will utilize the LM324 op-amp (LM324.pdf).

For the following questions and experiments assume VCC+ = +5V and VCC- = 0V.

• Estimate, using the datasheet, the bandwidths for non-inverting op-amp topologies having gains of 1, 5, and 10.
• Experimentally verify these estimates assuming a common-mode voltage of 2.5 V.
• Your report should provide schematics of the topologies you are using for experimental verification along with scope pictures/results.
• Associated comments should include reasons for any differences between your estimates and experimental results.

• Repeat these steps using the inverting op-amp topology having gains of -1, -5, and -10. 

• Design two circuits for measuring the slew-rate of the LM324. One circuit should use a pulse input while the other should use a sinewave input.
• Provide comments to support your design decisions.
• Comment on any differences between your measurements and the datasheet’s specifications.

Ensure that your html lab report includes your name, the date, and your email address at the beginning of the report (the top of the webpage).
When finished backup your work.

Part #1

• Estimate, using the datasheet, the bandwidths for non-inverting op-amp topologies having gains of 1, 5, and 10.

Part #2

• Experimentally verify these estimates assuming a common-mode voltage of 2.5 V.
• Your report should provide schematics of the topologies you are using for experimental verification along with scope pictures/results.
• Associated comments should include reasons for any differences between your estimates and experimental results.

Gain of 1 (LTspice circuit)	Experimental Results of Gain 1:
Vin*GAIN*(0.7)=(360mV)(1)(0.7)=252mv=Vout Which is very close to our OUTPUT of 260mV	INPUT= 360mV OUTPUT = 260mv Which give us a gain of about 1. You can also see that our bandwidth frequency 350kHz

Gain of 5 (LTspice circuit)	Experimental Results of Gain 5:
Vin*GAIN*(0.7)=(360mV)(5)(0.7)=1.26v=Vout Which is very close to our OUTPUT of 1.26v	INPUT= 360mV OUTPUT = 1.26v Which give us a gain of about 5. You can also see that our bandwidth frequency 60kHz

Gain of 10 (LTspice circuit)	Experimental Results of Gain 10:
Vin*GAIN*(0.7)=(144mV)(10)(0.7)=1.008v=Vout Which is very close to our OUTPUT of 1.04V	INPUT= 144mV OUTPUT = 1.04v Which give us a gain of about 10.

Part #3  Repeat these steps using the inverting op-amp topology having gains of -1, -5, and -10. 

Gain of -1 (LTspice circuit)	Experimental Results of Gain -1:
Vin=  680mv Vout=640mv Bw=  450KHz

Gain of -5 (LTspice circuit)	Experimental Results of Gain -5:
Vin=  328mV Vout=1.48V Bw=  133kHz

Gain of -10 (LTspice circuit)	Experimental Results of Gain -10:
Vin=  440mV Vout=3.68V Bw=  68.40kHz

Part #4 

• Design two circuits for measuring the slew-rate of the LM324. One circuit should use a pulse input while the other should use a sinewave input.
• Provide comments to support your design decisions.
• Comment on any differences between your measurements and the datasheet’s specifications.

Non-Inverting Op-amp topology	PULSE WAVE INPUT	SINE WAVE INPUT