THS4012 EVM Inverting Operation

The gain of the EVM can easily be changed to support a particular application by changing the ratio of resistors R6 and R4 (channel 1) and R14 and R12 (channel 2) as described in the following equation:

Inverting Gain +±RF +±R6 and ±R14

RG R4 R12

In addition, some applications, such as those for video, may require the use of 75-Ωcable and 75-ΩEVM input termination and output isolation resistors.

Because the noninverting terminals are at ground potential, the inverting terminal becomes a virtual ground and is held to 0 V. This causes the input impedance to ground at the input terminal to look like two resistors in parallel (R1 and R4 for channel 1, and R9 and R12 for channel 2). As a result, if the source termination is changed, R1 and R9 must be adjusted in accordance with the following equations:

R1 +

R4 RT

(Channel 1)

and

R9 +

R12 RT

(Channel 2)

 

 

 

R4±RT

 

 

R4±RT

where RT is the source impedance.

Any resistor on the EVM board can be replaced with a resistor of a different value; however, care must be taken because the surface-mount solder pads on the board are somewhat fragile and will not survive many desoldering/soldering operations.

External factors can significantly affect the effective gain of the EVM. For example, connecting test equipment with 50-Ωinput impedance to the EVM output will divide the output signal level by a factor of 2 (assuming the output isolation resistor on the EVM board remains 50 Ω). Similar effects can occur at the input, depending upon how the input signal sources are configured. The gain equations given above assume no signal loss in either the input or the output.

Frequency compensation capacitors C3 and C6 may need to be installed to improve stability at lower gains. The appropriate value depends on the particular application.

The EVM circuit board is an excellent example of proper board layout for high-speed amplifier designs and can be used as a guide for user application board layouts.

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General

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Texas Instruments THS4012 manual Inverting Gain +±RF +±R6 and ±R14
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THS4012 specifications

The Texas Instruments THS4012 is a high-performance, dual-channel operational amplifier designed for a wide variety of applications requiring high speed and precision. This op-amp is particularly appreciated in the fields of signal processing, data acquisition, and instrumentation, thanks to its exceptional characteristics and innovative technologies.

One of the standout features of the THS4012 is its ultra-low input noise and high slew rate, which make it a compelling choice for applications that demand rapid response times without signal distortion. With a slew rate of up to 1200 V/µs, the THS4012 can handle rapid changes in input signals, making it ideal for high-frequency applications such as analog-to-digital converters and RF signal processing.

In terms of performance, the THS4012 boasts a wide bandwidth of approximately 100 MHz at a gain of 1, ensuring it can efficiently transmit fast signals without significant loss. The part also provides a high common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR), enhancing its stability in environments with fluctuating power supply conditions or varying signal levels.

Another important aspect of the THS4012 is its low total harmonic distortion (THD), which is crucial for high-fidelity applications. By minimizing distortions, it ensures that the output signal closely matches the input signal, preserving the integrity of the original waveform. This makes it especially suitable for audio applications and precision data acquisition systems.

The THS4012 operates on a single or dual power supply, with a voltage range from ±2.5 V to ±6 V, providing designers with the flexibility to integrate this op-amp into various circuit configurations. The device is available in compact packages, making it suitable for space-constrained designs in portable electronics.

Additionally, the THS4012 incorporates innovative features such as internal compensation, which simplifies the design process by reducing the need for external components. This enhances design efficiency and reliability, allowing engineers to focus on other critical aspects of their circuits.

In conclusion, the Texas Instruments THS4012 dual operational amplifier combines high-speed performance, low distortion, and flexible power supply options, making it a popular choice for engineers looking to enhance the capabilities of their electronic systems. Its advanced technologies and characteristics render it a strong option in a myriad of applications within today's demanding electronic landscape.
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