Putting a display on MAX038

Good day! I'm making a project (waveform generator) and will be using a MAX038 on it.
And i think my project will look good if a display or 7-segment will be attached on MAX038. so everytime the frequency is varied it can be seen on the display the actual frequency of the generator.

is it possible putting a display on MAX038? What can you recommend guys? :slight_smile:


I recommend you not post the same thing in multiple places. Other post will deleted.

Browse MAX038, there was a post with MAX038 and a display yesterday or the day before. Maybe by liudr.

MAX038 is an analog waveform generator chip. You won't be putting a display on it.
You might build a waveform generator project (CIRCUIT) arround the MAX038.
You'll need to buffer the outputs with wideband amps to avoid loading the MAX038.
You can use digital signals, from an arduino, to control the type of wave generated.
you might be able to use digi-pots, controlled by anarduino to set frequency, offset, duty cycle...
you can tap the sync output of the circuit with a frequency meter based upon another arduino (or a PIC) to drive a display to show the output frequency of the circuit.

It gets to be a very complicated set of sub-projects. Do-able, but intense.....
You might not yet have the expertise/experience to accomplish it all. But, if you stay with it, do a lot of research, you can get there.

This is the post I was thinking about

With respect Crossroads, that post has nothing to do with a MAX038 (what the OP is asking about).

However, having given up on the grandeos MAX038 based 'variable frequency microcontroller controlled waveform generator, with frequency read out' project several times, I whole-heartedly agree the the instructable project with arduino controlled DSS would be much more suitable for the OP.

A similar concept could be put together tho.
Board with MAX038, some pots for controlling frequency, four 8-bit counters, and a '328P to control count collection.

MAX038 output goes into the counter, the '328P allows counting for 1/4 or 1/2 or even a full second, captures the number of pulses, does the math and displays on an LCD.
MAX038 seems to be obsolete tho, so seems like a poor starting point for a project.

I have four MAX038 chips that I’d lost, er, saved years ago. You can control the frequency with a voltage. I am thinking of building something using the Arduino as frequency counter and control using a combination of digipots and control voltage. Tough to get as clean a signal by digital as you can with analog.

And I have the chips… Otherwise, the only source is eBay, until all those are gone.

I’d not design a project around it if I were building more than a few.

Whoa! Back that off.... I see the MAX038 is rated at 2% THD at 1kHz, although it seems to me it was possible to tweak it to much better than that.

But the AD9850 is rated at much better, but at higher frequencies. So for an audio signal generator, the MAX038 may be better. I'll have to do some more looking. Otherwise, a Teensy 3.1 or some other variant with an actual DAC may be better.

hello. we did this project and our supply V- = -5v and
V+ = +5v. but why does the input voltage in pin1 is in negative??:frowning: Vref= -3.5v)

pls help us. this is for our project study.. thank you!! :slight_smile:

I don't know. Vref should be +2.5V. Where are you putting your meter's negative lead?

Is it working?

Check your wiring.

The XR2206 doesn't cover as wide a range, only up to 1MHz, but has a cleaner sine wave output at about 0.5% distortion versus the MAX038's 2%.

I already checked my wirings but then vref is in the negative range. Maybe the max038 is damaged? When i was assemblying my circuitry and checking the voltages, the max038 is overheating. Because of the fact that i haven’t put any heatsink on my regulators(in the power supply). Do you think the max038 is damaged?

:frowning: i only have two max038. :frowning:

Yes, it may be damaged. Have you checked your power supply voltages?

No heatsinks in the regulators? What regulators? What package? How much current is your circuit drawing? How much voltage is going into the regulators?

You never said. Is it working?

I put heatsink on my regulators it doesn't cause any overheating to the max038. But then the voltage in vref is -3.5V.

My regulator for +5V is 7805 and produces +5.02V when it is loaded/unloaded.
And for the -5V is 7905 and produces -5.02V when it is loaded/unloaded.

Also i put a ceramic 100nF capacitor on the vref. But then the voltage is in the negative range. Datasheet said that it must produce stable voltage of 2.5V. I don't know how to troubleshoot on this. Help me sir polymorph. Thanks in advance :slight_smile:

Sir polymorph have you tried already making a function generator using max038. You said you have 4pieces of it.

I must ask again....

Is it working?

It is not working since the reference voltage is in the negative range. But then when i tried to put on the oscilloscope there is a waveform produced. But the IIN PIN cannot be varied. (Where there is an op amp attached on it.)

I bought my max038 in ebay. (huaji hongkong store)

Check and doublecheck your wiring. Remove the MAX038 from the socket and measure voltage on that pin. What is it?

Can you post a schematic of what you have built?

If the wiring checks out and voltages are as expected with the chip removed, then I'd say you have a bad chip.