Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

2-Stage Operational Transconductance Amplifier

- Bias

- Differential Amplifier

- Cascode Amplifier

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Differential Amplifier

Parameter Value

Av > 20 dB

BW > 120 MHz

CMRR > 60 dB

ICMR > 1.4 V

Power < 1.25 mW

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

Set DC to 0Vdc

Set ACMAG to 1 (Important!)

• Differential input pair setting

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Differential input pair setting

Part name : E

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Output Plot

DC Gain > 20 dB

3dB Bandwidth > 120 MHz

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Gain measurement

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• BW measuement

-3dB

Your Bandwidth

Click Toggle cursor

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• CMRR

CMRR = |Adm/Acm|

But our gains are dB scale,

CMRR (dB) = Adm (dB) – Acm (dB)

< Common Mode Gain >

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• ICMR

Gain < 20dB

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Cascode Amplifier

Parameter Value

Av > 34 dB

BW > 250 kHz

Output Impedance > 30kΩ

Power < 1.25 mW

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Output Plot

DC Gain > 34 dB

3dB Bandwidth > 250 kHz

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Output Impedance

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

• Differentiation

DC Gain > 34 dB

3dB Bandwidth > 250 kHz

1) Click Add Trace

3) Choose signal what you want to differentiate

2) Select D( )

example

Then, your plot is differentiated by x-axis’ variable what you have sweeped.

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

DC Gain > 34 dB

3dB Bandwidth > 250 kHz

• 2 – Stage OTA

Parameter Value

Av > 76 dB

BW > 25 kHz

Phase Margin > 75 o

CMRR > 75 dB

ICMR > 0.4 V

Power < 2.5 mW

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

DC Gain > 34 dB

3dB Bandwidth > 250 kHz

PM > 75o

-180o

Gain = 0dB

• Phase margin measurement

Electronic Circuits 2 (17/1) W.-Y. Choi / H.-K. Kim

Lect. 18: Design Project

DC Gain > 34 dB

Deadline: 2:00 PM on May. 4, 2017