Macro-model for MPY634

Arun,

        Currently we don't have a PSPICE or TINA macromodel for the MPY634KP, however if you are in need of a behavioral macro for a "proof of concept" project you are working on, I might be able to help you. If you are more interested in things such as bandwidth, noise, cmrr and a more detailed circuit you will have to submit a model request so that we can work on developing such model.

Regards,

-Marcos

ADC2011 in India has a preliminary phase1A, where we are to solve analogue design problems given by TI first.

Here are the problem statements: http://uniti.in/analog-design-contest/analog-design-contest-2011/76

ProblemD requires a macromodel for MPY634KP, so do all team 'D's from the country. (Each univ has 3 or more teams-ABCD)

We cannot proceed without a macro-model now.....

Are there alternatives or can a model be made available immediately?

hello everyone..Even our team is facing the same problem..There is no Macro for MPY634KP analog multiplier IC which is required for our design in ADC India 2011.It was given that  we can find the macro in Ti website..but v dint get it..how r v supposed to simulate the circuit that has this analog multiplier in it..?Please upload the macro for this IC as soon in TI website...Every one here is facing the same problem...

sir i too need a macro for MPY634KP to work with in TINA TI... pl help...

Davidson,

Currently, the MPY634KP does not have a TINA model available. If you would like to request a model for this device, please contact the Product Information Center at support@ti.com.

Flora

thank you sir..

Thanks a lot for timely response...

thanks a lot sir...

thank you for giving the link to download MPY634 but we are having problem in simulating the macro model. we are getting an error stating "this circuit is too big for this trial demo version". we are using TINA 9 DEMO VERSION.CAN U GIVE US SOME SOLUTION?

2630.MPY634_prova.TSC

Dear Marcos,

I've a problem with your MPY634 model.

I've attacched a simple schematic and I've got problem of saturation on the out port.

Can you help me?

Davide 

Davide,

        I looked at the schematic you provided and there are two things that are causing the saturation of the output port. Recall that the transfer function of the multiplier is given by

                        Vout = A*[(X1 - X2)*(Y1 - Y2)/SF - (Z1 - Z2)]

where A is the open loop gain of the multiplier. Looking closely at the multiplier transfer function we notice that it resembles the transfer function of an open loop operational amplifier,

                        Vout = A(V+ - V-)

thus, Vout will track any infinitesimally small change in the differential input V+ - V-. In the case of the multiplier, since A is large (~85dB) any small change in the variables inside the bracket [] will produce a very high voltage at Vout which is limited to swing between [-Vs, +Vs]. Now, how do we overcome this? Similar to the amplifier case, we use feedback =). Consider what happens if we connect input Z1 to Vout and Z2 to ground,

let X1 - X2 = X, Y1 - Y2 = Y, and SF = 1 then

                      Vout = A[X*Y - Vout]

rearranging and solving for Vout yields

                       Vout = X*Y*A/(1 + A) ~= X*Y

which is a bit more controlled than A*X*Y. In your schematic you could connect Z1 to Vout to obtain the closed loop response of the system.

The second detail is that the SF used is too small. Bear in mind that since this is a behavioral model, the way the SF pin is implemented differs slightly from the real circuit to provide ease of use.SF goes from 0.1 to 10 internally, but is controlled by an external DC voltage. The voltage at the SF pin is clamped internally so it won't go below 3 or 10 V regardless of what the user connects to this pin. In the data sheet is says that a resistor must be connected but this is where the real circuit and the model disagree. In our case to make things a bit simpler we decided to connect a DC voltage source to the SF pin and provide the voltage that way. The voltage on the DC source can be calculated for a given SF using,

        V(SF) = (7*SF + 29) / 9.9

Similarly,

        SF(V) = (9.9*V - 29)/7

I hope this answers your question. Should you have any further questions or concerns please feel free to re-post.

PS. Also if SF is chosen to be 0.1 the product of (X1 - X2)*(Y1 - Y2)/0.1!! can easily hit the supplies. I have attached an schematic with the suggested modifications. In my schematic I have used an SF of 4 to avoid hitting the supplies since Xpeak = 5 and Ypeak = 5.

Regards,

-Marcos. 

Thanks, very nice!

were u able to get macromodel for mpy634 for ur contest. we too are in need of it..

Hi maneesha,

See the post 7 by Marcos (MPY634_TB.TSC).

I have successfully used the attachment he has given for simulating MPY634.

Hi Marco,

Can you please create a PSPICE or MULTISIM model for MPY634?

I'm trying to simulate a Lorentz attractor using this chip for my project.

I have already built and tested the circuit. But I also need to simulate it for my report.

Regards,

Omair