Lab Project: Design, simulation, and testing of TIA- EE 420L 

 

Author: Mario Verduzco

Email: Verdum1@unlv.nevada.edu

Date: 05/02/17

 

 

 

  

 

Introduction:

The objective of project is to design, simulate and build a transimpedance amplifier (TIA) using the ZVN3306A or ZP3306A MOSFETs. And as many resistors and capacitors as needed to drive a 10k resistive load with a gain of 30k

Design Parameters:

· The TIA must have a gain of at least 30k

· Must have an output swing as large as possible

· Must operate at as high speed as possible

· Operate with a 9v power supply

· Less than 0.3mA of quiescent current.

Design:

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Simulation:

100 mV at 1 KHz input

100 mV at 100 Hz input

Transresitance gain simulation

Output swing simulation

Quiescent current simulation

Testing:

100 mV at 1 KHz input

100 mV at 100 Hz input, Gain = 50k

100 mV at 90 kHz input, Gain = 31K

Lower Output swing, V=1.42v

Upper Output swing, V=2.96v

Summary:

Conclusion:

           The design of this TIA uses a push-pull amplifier with a feed back resistor going from the output to the input. After calculation the transresistive  gain of this topology is approximately equal to the value of the feed back resistor.  The two 10k resistors on the sources are used to bias the push pull amplifier by limiting the current through the device. This allows for low current and low power. The drawback to this design, is the fact that there will be a large voltage drop across these resistors therefore there will be a low output swing.

Quiescent current

Vout = purple, Vresistor = red, Vin = blue

Vout = purple, Vresistor = red, Vin = blue

Vout = purple, Vresistor = red, Vin = blue

Vout = purple, Vin = blue

Vout = purple, Vin = blue

           The amplifier has the theoretical gain of 50kHz and can operate down to 100 Hz. However, when the input is at 90KHz the gain drops to 30kHz. This is due to the capacitor on the output.

           The output swing is about 2.8Vpp before the waveform starts clipping. This low output swing is due to the large voltage drop across the source resistors. However, without a bias circuit these resistors are needed to limit the current flow and reduce the power consumption.         

           This amplifier design may not have had the largest output swing but it meets the other design requirements. Using discrete MOSFETs it is difficult to create a bias circuit to bias this amplifier, therefore resistors were used. An adaptation of this design would be to order a set of MOSFETs that where made from the same batch, and use them to create a bias circuit.