For high frequency, we always talk about matching, and for low frequency, voltage is always as references. How about mixer from high frequency to low frequency, in low-IF topology , its input is at high frequency and output at low frequency. IP Logged. Eugene Senior Member Offline Posts: Re: 50 Ohm match in IC? Reply 1 - Oct 20 th , , pm. I can sympathize with your question. When I first started analyzing RF systems I struggled with the 50 ohm issue too. As long as you are aware of the differences between your the quantities you measure and how you specify your models, you should not have a problem.
However, that is harder than it sounds. There are factors of two lurking around every corner. For example, when talking about the receiver, I use input referred quantities. Then the issue of whether to use output dB or dBm is irrelevant. Everything is referred to input dBm,which are the units that matter.
Similarly, for transmitters I use output referred quantities. Then the input units become irrelevant.
An Analytical Approach for Fast Automatic Sizing of Narrow-Band RF CMOS LNAs with a Capacitive Load
All that matters are the output dBm. If you are working with ICs, chances are you can only measure end-to-end performance unless you have dedicated test circuits on the chip. In any event, at some point you will probably want to compare simulation or calculation against measurement. Let's take noise figure for example. You design each block for a specific gain and noise figure.
For the LNA, the 50 ohm source and load is physical. For the mixer, perhaps the load is a high impedance. I had to look at the chain very carefully with a manual calculation to realize that the Friis formula requires a slight modification when the chain switches from 50 ohm loads to high impedance loads.
I had to draw the linear circuit out with voltage sources, source impedances, and input impedances then derive the composite noise figure. An extra factor of 4 appears in the later stages. If you are using the Cadence RF behavioral library, I can say a few things about the 50 ohm assumption as it applies to the model specifications. Are you using that library?
Chi Guest. Reply 2 - Mar 3 rd , , pm. Actually, in the RF circuit, all the measurement is in the power term. However, in the analog circuit, all the measurement is in the voltage term. Which is make me so confused that as the next loading in the interstage circuit such as the output of the LNA to the input of the mixer is high enough, then much of the voltage will be loaded to the next stage by the voltage divider calculation. However, the power transfer is the lowest at this condition.
Therefore, in the RF IC circuit, I should use the power transfer or voltage transfer for consideration? If using Power transfer as the consideration, WHY? Is it due to the all measurement apparatuses are in power term? So, in RF circuit are using power for calculation? Best Regards,. Reply 3 - Mar 10 th , , am. Hi, I would suggest to use a different terminology for internal rf stages. First it is important to differentiate between voltage and current terminals. A terminal is a voltage terminal if the terminal voltage relative change is less than the current relative change if you attach the next stage.
For current it is vice verse. If you have identified the type of terminals you can define output and input resistance. So for a pair of stages you can estimate the attachment loos. So I would not say coupling loss. To drive the delay-block and verify its delay regulation, an mV test signal is applied to the proposed architecture. The strength of these test pulses can be tuned by adjusting the gain granted by the preceding amplifier. The primary objective of using two parallel sections in the circuit is to ensure uniform delay for all member pulses in the driving stream and power the delay block with a single bias rail V rail.
For a single-stage DB, as shown in Fig. The unit stage top. The driving stream for the bottom unit stage bot. Output from these parallel units at points x and y produces nearly uniform delays for bipolar pulses average of ps for a single block. In order to process negative pulses, the driving stream base was elevated to the 0.
As a result, a dc component of 1. This element is removed by an RC branch made of R f. R add. The overall delay achieved by the proposed single-stage DB is not fixated at ps but can be fine tuned with a number of design parameters , as will be explained in the following sections. The branched architecture of the delay-block allows extension of number of stages in each section up to eight during the testing process.
The device sizes mentioned in the figure remain consistent for the top section but need to be adjusted to deal with base elevated pulses in the bottom section. By controlling gain provided by the amplifier preceding the delay-block, the strength of input pulses and magnitude of dc offset needed in the bottom section can be predesigned. Since the wideband pulses are essentially regenerated in this scheme, no matching circuit will be needed for the delay-block as in the cases of LNA and RF mixer in the receiver chain. Further discussion on tuning and regulation of the proposed delay-block is documented in the result section.
The expression for propagation delay achieved by the complete delay chain indicates a non-linear relationship between overall delay and number of stages or individual delay units in top and bottom sections. The pair of cascaded inverters in a single-stage branch, as shown in Fig. For a single inverter gate, the value of saturation current flowing through the transistors I saturation is considered as average bias tree current and approximated by.
A mirror equation obtained for the pull-up device will produce the same magnitude for the bias current. If strength of input pulses and voltage of bias rail are regulated in the circuit then the following relationship can also be maintained. After we define t del. If R eq. When signal drops from high to low at inverter output, the reactive network is realized with R eq.
On the other hand, R eq. Therefore, propagation delays can be defined with the functions. Using these definitions and expressing 'on' resistance in terms of transistor sizes lead to . Derivation of equation 32 assumes an insignificant transition time for the driving signal at the input of the delay-block.
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Therefore, the final expression of inverter-delay for an individual gate will take the form of. If C shunt accounts for only design values of intermediate capacitors, external loading capacitance from a following RF component is modeled as C extra , input gate capacitance of the delay-block is defined with C gate , and equation 28 is modified as.
The power penalty suffered by a CMOS delay-block is expected to have three major components . They include a dynamically dissipated power element P dynamic arising from movement of charge through the shunt capacitor C shunt at a switching frequency of f op , a short-circuit power P sc component consumed when both transistors in an inverter gate are on simultaneously with a peak current I max and conduction duration t on , and a static power P static element dissipated by reverse leakage current I rev.
The overall power figure for a complete wideband delay-block will depend on number of stages used in the delay chain sections, optimized rail voltage, intermediate capacitance, and finger width of devices. After being processed by the delay-block, the received signal will leave the front-end and be fed to the following radio-frequency mixer in the TR-receiver. The proposed receiver blocks are designed with an RF simulator including layout parasites generated by 90 nm circuit components to facilitate accurate RF analysis. Wideband Differential Front-end.
As the first section of the proposed TR-receiver front-end, the design parameters of the differential wideband low noise amplifier are analyzed with the CMOS process. The 90 nm amplifier is able to achieve high small signal gain and keep noise ceiling and power penalty below 3 dB and 15 mW, respectively. During parameter extraction, the LNA is interfaced with balun-circuits and a matched 50 load.
It also shows that resistance to reverse isolation S 12 is always greater than The port return loss at the amplifier peak frequency Therefore, undesirable port-reflection remains insignificant over the concerned frequencies for the amplifier. At the compression point the amplifier is expected to deliver 2 dB m power to a matched load while still remaining in linear domain and the estimated output power at IIP 3 point is 12 dB m.
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NF settles around 2. Maintaining its compatibility with low power on-chip transceivers, dc power consumed by the font-end is measured as To assess this quality, the microwave stability factor B 1f is defined in terms of scattering parameters. When presented in Fig.
To verify this result with a second stability parameter, the Rollett stability factor K rollet is also plotted in the same figure with its value always being greater than a unit limit fulfilling its criterion of stability . This factor is also defined with s-parameters.
As a result, the amplifier will provide resistance to oscillation induced by white noise which may get accumulated in the circuit during its start-up mechanism. Wideband Delay-Block DB. The proposed wideband delay-block DB to follow the front-end amplifier is also built with 90 nm CMOS devices as a part of the TR-receiver architecture. To illustrate the progression of a driving bipolar pulse stream through a multi-stage delay chain, a six-stage delay-block built with the same principle presented in Fig.
Delayed versions ps of the positive half of the input pulse are collected from output nodes m 1 -m 6 of six successive stages See Fig. A symmetric balun produces identical replicas of the the driving pulse and feed them as sectional inputs at points b and c. Delayed versions for the elevated negative-half of the input signal show a progression of ps at output nodes of stages in the bottom section n 1 -n 6. The final response at node y gathered after six stages in the bottom section is decoupled dc component removed at node w as shown in Fig.
It also shows the signal produced by the output combiner culminating at node z which manifests an average delay of ps. Similar number of stages are employed in the DB branches to achieve identical and uniform delay for all pulse elements. The responses demonstrate that monotonic and quasi-linear rise in delay is available at output node of each of the six stages. To produce the response in Fig. The other five stages require manipulation of device dimensions to compensate for any signal drop at intermediate nodes.
Power dissipated by a single-stage delay-block is kept below 9 mW and for a six-stage delay unit power penalty reaches up to According to design requirement, number of stages in the DB can be varied to achieve regulated temporal shifts. The signal typically collected by a TR-receiver front-end is shown in Fig. In addition to the number of stages in a DB section, tuning of delay may also be controlled by shunt capacitors, ratio of transistors, and magnitude of rail voltage .
This phenomenon is further illustrated in tabular form for a single-stage delay-block in the following section. Front-End Amplifier. The synopsis of simulated performance extracted from the proposed differential front-end is summarized in Tables I and II where it is compared with simulated results of published wideband amplifier circuits -.
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To enable relative evaluation of amplifiers built on different scales of CMOS technology, a composite FOM figure-of-merit parameter is defined as. In summary, the proposed amplifier achieves a better figure of merit The literature on the proposed delay-block has estimated that tuning of shunt capacitors and transistor dimensions will raise the group-delay achieved by the chain and increasing the rail voltage will have an opposite effect.
To verify these predictions, performance of a single-stage delay-block under regulation is summarized in Table III where its specified controlling parameters including number of cascaded stages are varied. Among the four shunt capacitors of a single-stage DB, C 1.
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Progression of bipolar peaks through the delay-block becomes non-uniform when device dimension is varied as their negative peak suffers from higher group dispersion. The third control parameter of the DB rail voltage, V rail achieves a range of delay regulation which is nearly ps. With total number of stages varying between one and eight, range of coarse adjustment for overall delay is measured as ps.
Power requirement for the delay-block has a fixed component 7 mW for summer circuits and the remaining power element peak varies between 1. This paper proposes circuit-level implementation of a 22 GHz 90 nm CMOS receiver front-end suitable for the principle of transmitted-reference TR communication. Using an LC port-matching technique, the front-end amplifier realizes a differential topology with high simulated gain 11 dB to improve system noise performance below 3 dB.
Download Some Design Aspects On Rf Cmos Lnas And Mixers
Base NF ceiling for the wideband amplifier is expected to be 2. I am looking for useful tutorial for beginner in RF power. I am looking for useful tutorial for beginner in RF power and lna. Anyone can recommend? If you are new to broadband lna design. First read Gonzalez's book. There is chapter on broad band amplifier. It will be useful for you while designing in ADS.
Best of luck. Hi Guys Can anyone show me or give me a tutorial on how to simulate the noise figure on mixer? DO I have to use port to get noise figure like simulation in lna?
If I have to use port to do the simulation, The input port and output port resistor are 50 ohms and 1M ohms seperately. I followed the step in. Tutorials on Amplifier smulation using ADS software. But more ducument select the first. Which one i should select? Thank you,. Previous 1 2 Next.