amplifier

Simple Absolute Value Amplifier

The rail- to- rail output characteristics of these CMOS op amps allow them to swing very close to their negative supply rails–ground. By using a non-inverting amplifier U1 to swing only positive (due to its not being capable of swinging below ground), this op amp acts like a perfect rectifier. For positive inputs, the input to the inverting amplifier U2 sees a voltage that is equal to the voltage on its non-inverting input (from follower U1), therefore the net gain of U2 is +1V/V. For negative inputs, the + input to the inverting amplifier U2 sees a voltage that is as close as U1 can swing to its negative supply rail (ground); therefore the net gain of U2 is -1V/V. This output of U1 is amplified by the noise gain of U2 and appears as an offset error on the output of the absolute value amplifier. This is the primary limitation to accuracy with very small input signals.This absolute- value amplifier has a gain of +1V/V and has an input range of +/- a few mV to -10V to +10V. (Circuit is created by Thomas Kugelstadt & Neil P. Albaugh, TI – Tucson)

Simple Absolute Value Amplifier circuit:

Simple absolute value amplifier

Online Simulation of the “Simple Absolute Value Amplifier” Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud and analyze the circuit, or watch our tutorial video! 

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Instrumentation Amplifier Offset Correction Loop

The feedback from integrator U2 provides a DC offset nulling function to the instrumentation amplifier (IA) U1. Although the IA response is similar to an AC- coupled amplifier, its input is, in fact, still DC- coupled and its input common-mode voltage limits must be observed.

Dc response can be preserved if a switch is added in series with R1. With the switch momentarily closed, the loop error is nulled and stored on C1 when the switch is open.
The switch converts the integrator into a sample/hold amplifier. To minimize correction voltage droop due to bias current, a JFET op amp such as an OPA132 is recommended for S/H use. Bypass capacitors are not shown. (Circuit is created by Neil P. Albaugh,  TI – Tucson)

Instrumentation Amplifier Offset Correction Loop circuit:

 Instrumentation Amplifier offset correction loop-blog

Online Simulation of the Instrumentation Amplifier Offset Correction Loop Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit, or watch our tutorial video!

You can send this link to any TINACloud customers and they can immediately load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Single-Supply Bipolar-Input Differential Output Amplifier

The rail- to- rail input and output characteristics of these CMOS op amps allow them to swing very close to their supply rails– +5V and ground.
By using both an inverting and noninverting amplifier output to swing only positive due to their not being capable of swinging below ground (0V), the op amps each act like a perfect rectifier. Due to its unique R-R input topology, the OPA364 exhibits very high linearity over its entire common- mode input voltage range. This absolute- value amplifier has a gain of 1V/V and has an input range of within a few mV of -5V to +5V. (Circuit is created by Neil P. Albaugh,  TI- Tucson)

Single-Supply Bipolar-Input Differential Output Amplifier circuit:

Single- Supply Bipolar- Input Differential Output Amplifier-blog

Online Simulation of the Single-Supply Bipolar-Input Differential Output Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit, or watch our tutorial video! 

You can send this link to any TINACloud customers and they can immediately load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Differential Amplifier Resistor Tolerance Analysis

Make all resistors “Control Objects” and use “Parameter Stepping” to step each resistor value from 9.9k (1% low) to 10.1k (1% high) in 3 linear steps. Run DC Analysis, “DC Transfer Characteristic” and sweep “Vcmv” from -1V to +1V. The resulting family of curves shows the differential amplifier output error due to the various resistor tolerance combinations. The OPA277 error contribution is nil. Note that using 1% resistors in a differential amplifier design can result in a worst- case CMRR error of 20mV per volt of common-mode voltage. This is only 36dB! (Circuit is created Neil P. Albaugh  TI-Tucson)

Differential Amplifier Resistor Tolerance Analysis Circuit:

Diff Amp R tolerance Analysis-blog

 

Online Simulation of the Differential Amplifier Resistor Tolerance Analysis Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or watch our tutorial video! 

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Online Simulation a Transimpedance Amplifier Circuit

This fast photodiode transimpedance amplifier is based on a high- speed JFET- input op amp OPA657. This op amp is compensated for a minimum closed- loop gain of 7V/V but the capacitance of the photodiode plus the op amp input capacitance together with the feedback resistor R1 provides a noise gain at high frequency that allows stable operation. Compensation capacitor C1 optimizes the amplifier bandwidth / gain peaking tradeoff. Achieving this level of performance requires very careful layout and the circuit must be shielded to prevent noise pickup. (Circuit is created by Neil P. Albaugh,  TI- Tucson)

Transimpedance amplifier circuit:

transimpedance amplifier-blog

Online Simulation a Transimpedance Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud and analyze the circuit yourself, or watch our tutorial video!  

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Zoom Amplifier

This “unusual zoom amplifier circuit” allows you to “zero out” a DC voltage and then amplify a small AC signal which is superimposed on the much larger DC level. When switch SW1 is closed, both INA128 inputs see the same AC + DC level and its high common- mode rejection results in zero volts output. When SW1 is opened, the DC level is stored on C1 but now the AC signal is applied to only the inverting input where it is amplified by a factor of 1000x. The droop rate of C1 depends on the leakage of SW1 and the input bias current of U1.Using a glass reed relay and an INA116 (Ib = 5fA typ), extremely low droop rate can be achieved. A high insulation resistance dielectric capacitor is necessary– teflon, polystyrene, etc. (Circuit is created by Neil P. Albaugh  TI- Tucson)

Zoom amplifier circuit:

Zoom amplifier-blog

 

Online Simulation of a Zoom  Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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Current Shunt Amplifier

This current shunt monitor circuit allows a current measurement to be made by measuring the voltage drop across a shunt resistor in the “high side” of a power supply. The INA193 is capable of operating with a common- mode voltage of up to +80V and its CMV range is not a function of
its supply voltage.  The INA193 provides a differential voltage gain of 20V/V and its recommended full- scale input  voltage is 100mV.  An INA194 provides a gain of 50V/V and an INA195 provides a gain of 100V/V. R1 & R2 together with C2, C3, & C4 provide differential and common-mode filtering and are recommended for switching power supplies. The two resistors should be carefully matched (1% tolerance) as well as capacitors C3 & C4 (5% or better tolerance). Resistors of 100 ohms will give a gain error of slightly under 2%. (Circuit is created by Neil P. Albaugh,  TI – Tucson)

Current Shunt Amplifier circuit:

Current shunt amplifier-blog

Online Simulation of the Current Shunt Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

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