This type of circuit has many applications, including audio level compression, synthesizers and amplitude modulation. In the last decade there is an ongoing interest to design lowpower linear vga. A this work was supported by national semiconductor inc. Ti helps you find the right programmable gain amplifier and variable gain amplifier products for your system design using a wide variety of commonly used parameters. Rf digital variable gain amplifier that offers an attenuation of 31. The xamp comprises a variable attenuator of 0 db to. Max4194 micropower, singlesupply, railtorail, precision. It can be realized by first creating a voltagecontrolled resistor, which is used to set the. Comparators 202 current sense amplifiers 125 current sense amplifiers. It provides a voltagecontrolled gain block coupled with a current feedback output amplifier.
This model is really a user model consisting of a dc controlled attenuator followed by a power amplifier. Pdf a novel method to design of variable gain amplifiers vgas is proposed. Moreover, the variable gain amplifier in the traditional columnparallel readout circuit is merged into the frontend of the ctsd modulator. A novel method to design of variable gain amplifiers vgas is proposed. White paper introduction to edfa technology june 2009 1 introduction shortly after their commercialization in the early 1990s, erbium doped fiber amplifiers edfas became a.
The second integrator is realized with a singleended inverterbased amplifier, instead of a standard ota. The puh141 provides a fully dttcompatible solution for feeding several tv points from one antenna. The vga block models a rf blockset variable gain amplifier. The control voltage is applied to one input, and the signal to the other. The maam011100 is an easytouse, broadband, general purpose variable gain amplifier.
In analog variable gain amplifiers, the gain in decibel is a linear function of the input voltage. The f2480 is a 400mhz to 3000mhz rf analog variable gain amplifier avga that can be used in receivers, transmitters and other applications. An all cmos 84dblinear lowpower variable gain amplifier. Analog high linearity low noise variable gain amplifier nxp. The cut off frequency can be 10khz to 150khz and the gain 0db to 24. One of the subjects which ive blogged about before was, the design of a variablegain amplifier stage, that was really a variableattenuation stage. A low power vga with a wide range of gain variation and appropriate. Variable gain amplifiers vgas announcements project. Abstract this paper reports the design of a highlylinear cmos. It has a gain span of 30 db in 3db steps and a 3db bandwidth of 230 mhz.
For example, if gain is set to 5 and you clear the check box for gain under ibisami parameters, the value of gain is hardcoded to 5. A variablegain or voltagecontrolled amplifier is an electronic amplifier that varies its gain depending on a control voltage often abbreviated cv vcas have many applications, including audio level compression, synthesizers and amplitude modulation a crude example is a typical inverting opamp configuration with a lightdependent resistor ldr in the feedback loop. If you deselect a parameter, the parameter is removed from the ami files, effectively hardcoding the parameter to its current value. Analog high linearity low noise variable gain amplifier. This device is known as a variable gain amplifier vga, or programmable gain amplifier.
A variable gain amplifier vga is an electronic amplifier that varies its gain, depending on control voltage 1, 2, 3. The gain of an amplifier is governed, not only by the components transistors etc. I want to have a very simple bjt signal amplifier with variable voltage gain. This variable gain amplifier is ideal for digital communications applications where excellent gain linearity and high efficiency at a 5 volt bias is required.
Adl5391, can be used as a variablegain amplifier, as shown in figure 3 below. The ad8557 has an adjustable gain using digital potentiometers and a programmable offset using a digital to analog converter dac. The weekly meetings i had with him and the other members of the ultra wideband group gave me invaluable insights into analog circuit design and helped me. The mps032701a82 variable gain amplifer is an internally matched gaas fet amplifier in a surface mount ceramic package. Variable gain amplifiers vgas are used in a variety of remote sensing and. Hello, i have designed vga using a railtorail amplifier.
High performance filter and variable gain amplifier design. We offer a wide range of variable and programmable gain amplifiers capable of improving the dynamic range of a circuit with the ability to adjust the amplitude of. Our vga product family covers frequencies from 5 mhz to 20 ghz. Its over 30 db gain range is controlled by a single control pin and 50 ohm match is maintained over all settings. Input power for 1 db compression for any gain setting p1db dbm 3 vdd supply voltage of amplifier vdd v 4. A variablegain or voltagecontrolled amplifier is an electronic amplifier that varies its gain depending on a control voltage. Digital variable gain amplifier is a combination of a gain device and an attenuator, packaged into a single module, and utilizes a digital control to modulate the gain. Equations are used to map the parameters entered by the user to those values used by the attenuator and voltage amplifier. The max4194 is a variablegain precision instrumentation amplifier that combines railtorail.
Noise and linearity face a tradeoff in the lna which can be dynamically adjusted depending on the input signal level. The vga output voltage is a function of the input voltage. The multiple gain varying stages lead to a higher amount ofpowerdissipation,which makes. Because of the attenuator, the amplifier never has to cope with large inputs and can use negative feedback to define its fixed gain and dynamic. A variable gain edfa is typically designed to have flat gain at the top of the required gain.
Inthe typicalreceiver, about20db is assigned to the rf stage, and 60db to the if andor baseband stages. A simplified vga circuit assuming one of the switches s9 is on, is shown in. If you circuit doesnt use an instrumentation amplifier or you need some adjustable gain after an instrumentation amplifier then you need to look at alternatives. There are 4 individual vga blocks, preceded by a fixed gain lna. A low power vga with a wide range of gain variation and appropriate bandwidth using new technique is presented in this paper. The variable gain amplifiers are used in a variety of network, commercial and aerospace and defense applications. Puh141 uhf 470862 mhz 1216db 4 way variable gain distribution amplifier masthead kit comes with psm114v variable gain power supply. High impedance inputs and minimum dependence of bandwidth on gain make the clc5523 easy to use in a wide range. As a result, the power consumption is reduced, without sacrificing the noise performance. Therefore, to cover thewidedynamic gainrange, the existing cmosbasedvgas that adopt1 and2 require at least 4 or 5 gainvarying stages. Variable gain amplifier for ad9850 dds variables, gain.
Dual, variable gain amplifier datasheet texas instruments. A variable gain amplifier is designed based on differential differen ce amplifier. The input signal is a sine wave and the signal amplitude is small enough to be considered as small signal around 500mv pkpk and rb,re and rc are selected properly to work in good bias condition. By circuit implementations of 1 and 2, wider gain ranges might be achieved, but the gain errors become significant.
Geiger department of electrical and computer engineering iowa state university, ames, ia 50011, u. Either the amplifier or voltage variable attenuator vva can be configured as the first stage in the cascade. Variable gain amplifier vga applications variable gain amplifiers vgas are employed in many applications in order to maximize the overall system dynamic range. Continuoustime adc with implicit variable gain amplifier. Variable gain amplifiers vgas market size, share, growth. Measurements of the complete analog frontend chip signal path blocks. The detailed schematic of the signal path can be found on sheet 1 and sheet 2 in the variable gain board documentation. Variable gain amplifiers vgas are signalconditioning amplifiers with electronically settable voltage gain. Yu, yue, design of a high dynamic range cmos variable gain amplifier for wireless. I would be glad if someone could help with the design and simulation of variable gain amplifier using orcad pspice. My first thought was to build two feedback resistors and switch one or the other off with a mosfet. Op amp variable gain amplifier circuit design electronics notes. A simple and effective variable gain op amp circuit using a minimum number of components.
The wiring can be mainly on the outside of the building, making this a popular solution. A highly linear cmos amplifier for variable gain amplifier applications yonghui tang and randall l. The focus of this research is on the design of a lowpass notch filter lpnf and a variable gain amplifier vga, which are both integrated into a selfcalibrated analog frontend for long acquisitions of biosignals scafelab system. Uhf variable gain masthead amplifiers installation. Our portfolio offers industryleading zero drift, highprecision solutions with wide range of frequency from dc to 4.
The dda provides a gain of 50 d b, gain bandwidth of 21. However, the mosfets have shunt diodes which are going to. In this configuration, the gain is directly proportional to the control voltage. These drawbacks can be addressed with a variable gain wdm amplifier. The max2057 generalpurpose, highperformance variablegain amplifier vga is designed to operate in the 0mhz to 2700mhz frequency range.
F2480 broadband rf analog vga, 400mhz to 3000mhz renesas. Digital controlled variable gain amplifier mini circuits. The max2027 highperformance, digitally controlled variablegain amplifier is designed for use from 50mhz to 400mhz. How does the input offset voltage vos of an amplifier affect my circuit. Vga3 is also outside the agc control loop and gets feed forward correction to achieve complete gain flattening.
Variable gain transimpedance general descriptions the comlinear clc5523 is a low power, wideband, dccoupled, voltagecontrolled gain amplifier. Variable gain amplifiers programmable gain amplifiers overview. Pdf a novel method to design variable gain amplifier. The device integrates a digitally controlled attenuator and a highlinearity if amplifier in one package. Variable gain amplifiers programmable gain amplifiers. In the case of voltagecontrolled vgas, it is common to make the. Frequency response amplifiers do not have the same gain at all frequencies. In this thesis, a variable gain commonsource amplifier is proposed to function as the frontend lna in a television receiver systemonchip soc. At macom we design, manufacture, and support a family of variable gain amplifiers vgas for rf, microwave, and millimeter wave applications. Variablegain amplifier, adapted for etching into silicon. This device is known as a variable gain amplifier vga, or programmable gain amplifier pga. This is due to the demand that portable equipment, biomedical devices and several wireless devices are. We offer a wide range of variable and programmable gain amplifiers capable of improving the dynamic range of a circuit with the ability to adjust the amplitude of the signal in real time.
Therefore small silicon area and low power consumption are the basic goals for the design. Such a device has a gain that is controlled by a dc voltage or, more commonly, a digital input. Max2057 0mhz to 2700mhz variablegain amplifier with. This amplifier is also offered in three fixedgain versions. Following a linearindb response, the vca2617 gain can be varied over a 48db range with a 0.