Disadvantages of resistors

[hannover90]

• Hello all,

I am thinking to design a amplifier using resistors.

Have resistors any disadvantages in INTEGRATED circuits?

Thanks in advance for any advice.

 

[ud23]

what is the amplification unit?show us your schematic.

 

[D.A.(Tony)Stewart]

All passive components have to some degree imperfections due to geometry, so capacitors have inductance and resistance in series and parallel and resistors have tiny inductance and capacitance.

Usually it is not a problem till you get to very high RF (or VHF) and/or high impedance or high conductance and of course IC is smaller than discrete, so this is an advantage. Some resistor types make less noise than others, but this is NLA or RF Pre-Amps when there is a choice.

Then of course size matters for breakdown voltage of the resistor and power dissipation for such applications.

 

[hannover90]

All passive components have to some degree imperfections due to geometry, so capacitors have inductance and resistance in series and parallel and resistors have tiny inductance and capacitance.

Usually it is not a problem till you get to very high RF (or VHF) and/or high impedance or high conductance and of course IC is smaller than discrete, so this is an advantage. Some resistor types make less noise than others, but this is NLA or RF Pre-Amps when there is a choice.

Then of course size matters for breakdown voltage of the resistor and power dissipation for such applications.

Thanks for your reply.

I heard that resistors are affected by tempreture, which causes fluctuations of resistors. Do you know, how could it happen?

 

[D.A.(Tony)Stewart]

all conductor materials have a thermal temperature coefficient of resistance, even copper.. electrons move faster and usually cause more resistance or PTC... although some materials are NTC like semi-conductors voltages and most capacitance.

 

[hannover90]

Thank you very much for your help.

 

[crutschow]

Resistors are generally avoided as much as possible inside integrated circuits since they tend to take a lot of chip area (expensive) and have poor accuracy and temperature coefficient if made from the substrate semiconductor material. For example if you look at the schematics for typical IC op amps you will see few resistors.
Better resistors can be made using a thin film process to deposit resistive material on the chip surface but that adds even more cost. That is sometimes done for high accuracy analog circuits such as the ladder network in some D/A converters.