Author: Michael Koltai

The OPA380 is an integrator-stabilized operational amplifier that was developed primarily for transimpedance amplifier applications. Its inverting input is that a 90MHz CMOS op amp but its non-inverting input is an integrator non-inverting input, allowing only very low frequency response through this input. In most dual- supply applications, the OPA380 non- inverting input is simply tied to ground. In single- supply applications, it can be used to provide a DC offset. By adding an input resistor, R1, a transimpedance amplifier is transformed into a conventional inverting amplifier. The usual op amp inverting gain equation  applies: Av = – (R2/R1) in V/V. The OPA380 is input offset voltage is specified as 4uV typical, 25uV maximum @ 25C, drift is 0.03uV/C typ, 0.1uV/C max.  (Circuit is created by Neil P. Albaugh  TI- Tucson)

 Very Low DC Offset Wideband Amplifier circuit:

Online Simulation of the Very Low DC Offset Wideband 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

Wideband 75MHz 28dB Gain Amplifier

This Wideband 75MHz 28dB Gain Amplifier circuit is based on two OPA355 gain stages in cascade. The dual version, OPA2355, can also be used. An OPA355 achieves low input bias current, +/-50pA MAZ, low voltage noise, 5.8nV/sq-rt Hz typical @ 1MHz, and it has good gain-bandwidth, 200MHz, and high slew rate, 300V/us. To maximize bandwidth in a 2-stage amplifier, each stage should be set to a gain of the square- root of the total cascaded amplifier gain. A triple op amp, OPA3355 can be cascaded to provide even higher BW at the same gain. (Created by Neil P. Albaugh  TI- Tucson)

Wideband amplifier circuit:

Online Simulation of the “Wideband 75MHz 28dB Gain 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

Avalanche Photodiode Driver

An avalanche photodiode (APD) typically requires a high reverse bias voltage to provide gain. An OPA445 can operate on +/-45V supplies but in this circuit we require only one polarity output voltage so the op amp is operated on assymetrical power supply voltages. This is permissable if the op amp common-mode voltage range is not exceeded. (Circuit is created by Neil P. Albaugh)

Avalanche Photodiode Driver circuit:

Online Simulation of the “Avalanche Photodiode Driver” 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

Graeme Double Integrator circuit:

Online Simulation of the “Graeme Double Integrator” 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

1kHz 2nd-Order Bessel High-Pass Filter

This filter was designed using TI’s “FilterPro” software. The cutoff frequency and gain can be changed by editing this circuit with new RC values determined by FilterPro. This filter topology is inherently a phase inverting configuration. For a non- inverting low- pass filter use a Sallen- Key type. As shown, this filter is designed for use on a single power supply. For bipolar supplies, Voffset is not needed. Large value resistors– typical in low frequency filters– require a CMOS or JFET input op amp to minimize offset voltage errors. (Circuit is created by Neil P. Albaugh  TI-Tucson)

1kHz 2nd-Order Bessel High-Pass Filter circuit:

Online Simulation of the “1kHz 2nd-Order Bessel High-Pass Filter” 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