how can I wire a DS1809 digital pot to a AN7510 stereo amp ?

How can I wire a DS1809 digital pot to a AN7510 stereo amp ?  I am trying to boost a left and a right audio signal to produce fairly significant sound through 2x 8ohm speakers.  i currently have it running off of 2x LM386's and a wheel potentiometer with 5 pins.  as you know, LM386's dont have the best sound. and who likes wheel pots and trimmers when you can use tact switches. so heres where I am.(Datasheets can be accessed by clicking on the IC's)
This is to run sound directly from an N64 game console being converted to a portable, to a pair of 8 ohm speakers approx 1".
o I want to be able to have a P.B. volume up and down, and mute if possible.
o Power is 14.8 VDC, or 5VDC
o Was going to follow this schematic and use a TDA7053A Stereo Amp(By Phillips), with a DS1669 Digital Pot (By Dallas), but the IC's are hard
    to get and pricey.
o Want use a AN7510 Stereo Amp w/ Volume control (By Panasonic) and a DS1809 Digital Pot w/ Storage(By Dallas)
Whilst designing the circuit i couldn't figure out where to connect PIN 6 on the Dallastat to on the amp. it claims it has volume control.???
o I also dont know how to use the MUTE PIN feature or the STANDBY PIN feature. Are the Tact Switches???

I am still just a begginner at low voltage electronics. I have done a lot of reading and tinkering.  I do understand the basic principles of electricity, ohms law, working with resistors, LEDS, and the basic functionality of capacitors, transistors, and the like.  I am a quick study so if anyone can help me to make this work and understand why it will work, that would be great.  I have attached some pictures to help my cause and will supply whatever other information may be needed to accomplish this.  The first picture is the schematic that gave me the idea, the second is a perfboard layout i was working on for this idea.  Thankyou all in advance for your time and help

 So Im going to go with a AN7510 from panasonic and a MAX5456 from maxim. and i have added a new diagrahm. can anyone tell me if it will or if it wont work.  If it wont, can you advise me on what to fix.
o Not worried about the mute button, or the standbye, Balance or shutdown features
the cluster at the top of the circuit would be a 12-pin header for a connection containing the
audio left and right in, +5v, grd, speaker left +/- and right +/-, and tact switches leads for vol up +/-, and vol dn +/-

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There's a great application circuit in the Maxim datasheet for you.

Note that the low end of the "pot" is biased to Vdd/2 - so adding an opamp to feed that would be a good plan, and if you do THAT, you may as well use a quad pack and put the buffers in.......
supramp (author)  steveastrouk5 years ago
I may seem like an idiot for asking, but what does that mean "biased to VDD/2" i thought the low end just connected to ground. is their something i should change on my last diagrahm
Try a potential divider of say 2, 150 ohm resistors across your supply., the centre point is Vdd/2. You need to use low value resistors.

A better approach is to make a "voltage follower" with an op-amp, and connect a 1k x 2 resistor divider as the input to it - the output is Vdd/2, and the source impedance is very low.

supramp (author)  steveastrouk5 years ago
you just spoke a foreign langauge, could you provide some kind of picture or diagrahm to show me what you mean
Try this. The two resistors should be around a 1k each.

rail splitter.jpg
supramp (author)  steveastrouk5 years ago
would i use this inplace of something, or add it in, if so why, and where would i add it. because all i want to do is build a audio aplifier that can output stereo sound using a push button volume up and down. to run 2 8ohm speakers directly off the motherboard of a n64.
This is the component you need to put Vdd/2 on the chip, as per the application note.
supramp (author)  steveastrouk5 years ago
everytime i come back to this page I feel less and less inteligent. If its not to much to ask, can you answer the following questions.
1. What pin on the lm741 connects to L1 (pin 11) and L0 (pin 6). amd do i need two lm741's.
2. Pin 7 is the power supply. can it run off of 5V . You have 9V on your diagrahm, and the datasheet only says +/- 22V. whats the Min V+
3. Pin 6 and 2 are connnected on the lm741, is pin 3 connected as well or is it jumped in your diagrahm.
4. Are their any other connections ive missed, and what exactly does this do. i thought the lm741 was an op-amp, so what does connecting the L0 and L1 to this as opposed to connecting it directly to ground do.
1.) You only need one 741.
Connect pin 6 on the 741 to pins 6 and 11 on the Maxim chip.

2) 5V will work.

3) Pin 3 is JUMPED. Lines crossing like that are taken to NOT be connected in professional practice.

This circuit forms a "virtual earth" The output at pin 6 will be Vdd / 2. The key is that, for the loads you put on it, that Vdd/2 won't change, it will stay fixed.

supramp (author)  steveastrouk5 years ago
Ok, so how does this look, am i missing anything, capacitors, resistors, grounds, anything. or am i way off here.

I cant figure out how to attach the photo so that its larger, but ill put it up top too, so you can click the "i" and like to its orginal size.
Its looking OK, but always put a 100uF electrolytic and a 0.1uF ceramic across the power rails.

Especially in audio circuits, its a VERY good idea to run the grounds to a SINGLE common ground point, rather than chain them from chip to chip.

supramp (author)  steveastrouk5 years ago
when you say "accross the power rails", do you mean from power to ground?
and when you say i should run the grounds to a single point, do you just mean that a ground from one chip should Not run to the ground of another chip so not to risk having voltage back feeding into on of the chips?
Yes, from power to ground.

In audio circuits, and precision analogue in general, you avoid "ground loops" by using a single "star" ground, wired, as you say.
supramp (author)  steveastrouk5 years ago
im my circuit layout, do you see a way that i can do that, a "star ground"
Yes, pretty close. You need to cut some tracks OUT and add one I think.
supramp (author)  steveastrouk5 years ago
how does this look
Here's my quick hack.
supramp (author)  steveastrouk5 years ago
cool, the ground "star" makes sense now, but why did you add +5v tp pin 15 the V logic pin? also, why did you remove the .1uf cermaic cap from pin 13 VSS to ground? why dont i want to bypass that, im not sure what it does.
Because it needs power on that pin.
Vss IS ground on this design, so there is no point putting a capacitor on it.

supramp (author)  steveastrouk5 years ago
AWESOME, I think im ready to buy the components and start printing the circuit in my pcb program. I hope this works. thanks for all the help. Its nice when someone actually takes the time to help and "INSTRUCT", not just belittle and degrade those of us who are trying to learn. ill post how it turns out and maybe you can assist me in the future, Im sure ill need it.
I'd belittle and denigrate you if you'd whined at me and said "fix it for me", but you didn't whine and you delivered a plausible design with a little bit of guidance.

Well done.

Hope it works now !!!


supramp (author)  steveastrouk5 years ago
OK, one last post. i relized after all of this that the max5456 is an smd chip and would have to be soldered to the back of the board directly on the traces as opposed to the throuogh hole chips, so I woould have to reconfigure the schematic and flip the traces to work with that. (instead of left to right, top to bottom,16 ->9 and 1->8, it would be 9->16 and 8->1) and i also sized everything to scale. Steve, can you take a look and tell me what you think. the image on the right has the componants in place to scale, to include caps, resistors, chips, and the header i plan to use. thanks again.
real to scale audio circuit final.JPG
Looks OK to me.
supramp (author)  steveastrouk5 years ago
so i just got the components in today, and didnt realize how small the 5456 is. im ok with SOIC smd's but not sure if i will be able to etch and solder my board with a QSOP.  I didnt realize how small and close together the pins were. i geuss im alittle worried about my ability to do this successfully. so ive been trying to come up with a back up plan. do you have any recomendations on a substitute DIP pot. I was looking at the DS1802.  not that I want to spend $8 each.  or possibly a technique that might help.  currently, im using an "iron on" technique for making my pcb's. using ferric chloride to etch with them.  You have been such a help so far that i hate to ask anything more from you, but i have a hard time finding parts. It gets overwhelming reading all that data, and very confusing.
Try and use the UV sensitive board instead - its really the only way to get to QSOP feature sizes. You can still use laser printed masters - all you need is a cheap UV source.
Stupid datasheet. It DOESN'T have a "volume control". It can mute, which I suppose is a binary volume adjustment.....

The 1809 has a LINEAR taper - which means it won't work for you as a volume control. YOu want an "audio" or "log" taper pot.

Did you want stereo ?
supramp (author)  steveastrouk5 years ago
the DS1809 can be used for volume up and down, but your saying the an7510 doesnt have volume control even though the datasheet says on page 1:

• 1-W output (8 Ω) with supply voltage of 5 V
• On-chip standby function
• On-chip volume function <----- (is this an typo)

??????????? I am so confused. these are the things that make learning and understanding electronics so hard
Yes, being charitable, its a typo, otherwise its just outright deceptive.

No, you cannot use an 1809 because the response curve is not right for a volume control- try it by all means, then come back and tell me what it does.

HINT: human hearing follows a logarithmic response.
supramp (author)  steveastrouk5 years ago
do you have any recomendations on what pair of stereo amp and digital pot might work for me
The amp's fine. Try a MAX5456 for the digital pot.
supramp (author)  steveastrouk5 years ago
that would still raise the question of how to hook the digital pot to the amp. your saying that the AN7510 Amp doesnt actually have a volume control pin, even though it says it does on the datasheet. therefor, wouldnt i need a different amp as well or am i missing something. i wouldnt begin to know how to build that circuit, and the datasheet doesnt have a typical setup or anything.
No, just pass through the pot wiper to the input pins on the amp.
supramp (author)  steveastrouk5 years ago
ok so left audio to pin 5 on the 5456, and right audio to pin 12. then out of the wipers pins 7 and 10 to pins 3 and 6 (ch.1 and 2 inputs) on the 7510. right?? if so, now i just have to figure out how to build the circuit
Yep. Looks about right.
supramp (author)  steveastrouk5 years ago
is their a DIP equivelant to the max5456??
No, but its failry straightforward to mount SMT devices.
supramp (author)  steveastrouk5 years ago
i have updated the main discussion / question. any help?
supramp (author)  steveastrouk5 years ago
And yes, I am trying to get stereo sound ( that is what left and right audio are called when you have a left audio signal and a right audio signal???) not trying to be a smart a$$, honestly not sure anymore.
gmoon5 years ago
IF you already have ordered the digital pots, you can convert linear pots to audio taper easily. (PDF)

However, you'll lose a fair amount of the maximum resistance, because it requires fixed resistor(s) in parallel to the pot. This technique yields an "average" audio taper pot that's about 20% of the original linear value, so 100K linear = 20K audio.

The taper (and maximum resistance) can be adjusted to taste, though. So that 5:1 ratio (20%) isn't set in stone.