具有差分ADC的最小PIC是多少

UQFN-28中的1782为4x4mm。如果你能处理0.4毫米音高，没有比这更小的图片了。它是少数几个具有12bit ADC的小部件之一，但您没有指定是否需要12位。



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    The 1782 in UQFN-28 is 4x4mm. There aren't many PICs smaller than that, if you can handle 0.4mm pitch. It's one of the few smaller parts with a 12bit ADC, also, but you didn't specify if you need 12bits.

谢谢！有较小引脚数的选项吗？对于我的应用，14针装置就足够了。



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    Thanks! Any option with smaller pin count? For my application 14 pin device would be enough.

尝试使用单片机产品选择器为自己。苏珊



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    Try using the Microchip product selector for yourself.
Susan

部分选择器在微分对SE ADC上是无声的。但似乎只有16F17XX部分在28引脚或更大的差异的ADC。



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    Part selector is silent on diff vs se adc. But it seems that only 16f17xx parts in 28 pin or greater have diff adc.

有一些14引脚PIC24F部分与差分ADC输入。错！错了！错了！我很笨！对不起的。



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There are some 14-pin PIC24F parts with differential ADC inputs.
WRONG! WRONG! WRONG!
I am stupid!
Sorry.

是的，有趣的是，产品选择器在区分ADC/ADC之间产生了不同。谢谢你的夸夸其谈，你的猜想和我的一样。如果有人找到了一个确定的方法，让我知道！



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    Yes, would be interesting that the product selector makes a difference between diff ADC / regular ADC. Thanks mbrowning, your supposition is same than mine. If someone finds a way to know for sure, let me know!

谢谢DAN1138，哪个PIC24F部分？



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    Thanks dan1138, which PIC24F parts?

嘿，我把你需要看的零件的数量从几千个减少到十几个。使用部分选择器，开始读一些数据表。简短的回答：我在几周前偶然发现了它们，现在找不到我的笔记。甚至更短的答案：我是错的和愚蠢的。



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Hey, I reduced the number of parts you need to look through from several thousand to less than a dozen. Use the part selector and start read some data sheets.
 
Short answer: I stumbled across them a couple of week ago and cannot find my notes now.
 
Even shorter answer: I am wrong and stupid.

嗯，我显然得问一下才能节省时间！看看数据表，谢谢。



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    Well, I obviously had to ask in order to save time! Will have a look at the datasheets, thanks anyway.

只有三个14引脚PIC24F MCU-KA100，KL100，KL200。这些都没有一个差分ADC。



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    There are only three 14-pin PIC24F MCUs - KA100, KL100, KL200. None of these feature a differential ADC.

很难搜索这个。看起来像28引脚PIC16F1702是我所发明的最小的。PIC24FJ64 GC00 6附加了16位Sigma Delta ADC（2分频CH），附加到12位SAR AD。也许使用一个小的微控制器，但是带有一个差分输入的MCP3301 13位ADC。你在测量什么？如果我们对正在测量的东西有更好的了解，并且有时涉及到电压的话，OPAP前端可能会解决这个问题。其他时间，类似于PAC1710（电压和电流在一个意义上）电阻器很好地工作，因为它解决了许多问题与高侧传感。



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    Hard to search for this one.
Looks like 28 pin PIC16F1782 is the smallest I've found.
PIC24FJ64GC006 has a 16-bit Sigma-Delta ADC (2 diff. ch) in additional to 12bit SAR AD.
 
Maybe use a small micro, but with a MCP3301  13 bit ADC with differential input.
 
What are you measuring?   If we have a better idea of what is being measured, and voltages involved sometimes an opamp front end might solve it.  Other times something like the PAC1710 (voltage and current across a sense) resistor worked nicely as It solved a lot of issues with high side sensing.

只有三个14引脚PIC24F MCU-KA100，KL100，KL200。这些都没有一个差分ADC。你当然是正确的。我很尴尬。我能说的是，我并没有真正理解VIH和VIL进入一个看起来像一个差分放大器的框图。在仔细阅读数据表后，很明显ADC没有真正的差分输入模式。我真诚地为误导您而道歉。我很抱歉，将来会更加精确。



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    There are only three 14-pin PIC24F MCUs - KA100, KL100, KL200. None of these feature a differential ADC.
You are correct of course.
 
I am so embarrassed.
 
All I can say is that I did not really understand the block diagram where VINH and VINL go in to what looks like a differential amplifier. After a more careful reading of the data sheet it's clear that the ADC does not have a true differential input mode.
 
I sincerely apologize for misleading you. I am sorry and in future will try to be more precise.

丹--不必道歉。我们都会犯错，这也是我喜欢论坛的原因之一。我的FuBar几个星期后说：“什么，Microchip不能让CPLD的你在说什么？”当我意识到的时候，蛋在我的脸上。列出了FPGA和CPLD。22V10万岁！一旦我发现“我发现的最小的一个是28针”，我敢肯定它们是一个更小的。有趣的历史：我在1980年初在国家半导体公司开始了我的职业生涯。有一个DAC有一个差分输出，客户抱怨“通道A”（高端）一直工作，但“通道B”（低侧）大约有1%的失败。谢天谢地，他送回了失败的单位，产品工程说“他们都通过了”。奇怪的是，把它们放进一个面包板，发现它们确实失败了。哦，哦。更多的挖掘和测试夹具接地“通道B”。叹息。奇怪的是那部分已经装运了四年（？）他是第一个有问题的顾客。我学会了永远不要承担任何事情，所以不断张贴…很棒的学习工具。看看这个应用程序会有什么意思。



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    Dan -- no need to apologize. We all make mistakes, one reason I love the forum.
 
My FUBAR a few weeks back was "What, Microchip doesn't make CPLD's what are you talking about". Doh, egg on my face when I realized. FPGA's and CPLD's are listed. Long live the 22v10! 
 
As soon as I aid "smallest one I found is 28 pin" I'm sure their is a smaller one yet.
 
Funny History: I started my career in the early 1980's at National Semiconductor.  There was a DAC that had a differential output, and a customer complained "channel A" (high side) always worked, but "Channel B" (low side) had about 1% failure. Thankfully he sent back failed units, and Product Engineering said "they all passed". Odd, put them into a breadboard and found out the did they did indeed fail. Uh Oh.  More digging and the test fixture grounded "Channel B". Sigh. Odd part was that part had shipped for four years (??) and he was the first customer he had an issue.  I've learned never to assume anything.
 
So keep posting... great learning tool. 
 
It will be interesting to see what the application is.

这对我来说确实是个有趣的问题，奇怪的是没有更多的信息来选择零件。我以前使用16F17XX部分与差分ADCs，但使用ADC单端，并没有意识到它们是多么独特。这是一个非常好的特性，我想Microchip会想再多说一点。差分ADC会产生13位结果（由于添加了符号位）。参数搜索不提供一个13bit的搜索选项（只需在12bit选项中列出不同的部分），直到你到达PIC32，但是地图不。当你选择13bit ADC时，地图列出了几个部分（我不认为它们都是差异的，我发现地图是缓慢和不准确的），但不是1。6F17XX。列出的最小引脚数部分是DSIC33 EP32 GS502（和EP64）-28引脚。祝您的项目好运。



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    This is really an interesting question to me, and it's odd that there's not more information for selecting parts. I've used 16f17xx parts before with differential ADCs, but used the ADC single ended and didn't realize how unique they are. It's a very nice feature and I would think Microchip would want to crow about it a bit more.
 
The differential ADCs give 13bit results (due to the added sign bit). Parametric search doesn't offer a 13bit option for searching (just listing parts with diffADC in the 12bit option) until you get to PIC32 , but MAPS does.
 
MAPS lists several parts when you select 13bit ADC (I don't think all of them are diff, and I find MAPS to be slow and inaccurate), but not the 16f17xx. The smallest pin count parts listed are dspic33ep32gs502 (and ep64) - 28pins.
 
Good luck with your project.
 
 

找到一个14针装置。PIC24F04KA200。我在看框图，这是一个差分ADC转换器！很好地完成微芯片。10位50kHz的ADC。VIHMUX和VILMUX，这是一个差分前端。呸！反讽是PIC24F04KA200描述的页面现在显示它是一个5端***换机（KSZ设备）。叹息，是时候叫它一天了！



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    Found a 14 pin device.  PIC24F04KA200.
 
I was looking at the block diagram, and that is a differential ADC Convertor!  Nicely done Microchip.
10bit 50Khz ADC. VILH Mux and VILMux, that is a differential front end. DOH!
 
Irony is the page for the PIC24F04KA200 description now shows it is a 5 port switch (KSZ device). Sigh, time to call it a day!
 
 
   Attached Image(s)

正如我看到这个话题唤醒一些兴趣，我会解释一下…谢谢你的建议。这里有我的评论：PIC24FJ64 GC00 6有64针和3.48欧元@ 100，我正在寻找一个微控制器，大约1欧元的PIC24F04KA200有14针（好！）但是只有10位ADC（我们需要12位）MCP3301与一个简单的UC结合可以是一种选择，但是我们的第一个选择是尝试只用一个IC来解决这个问题。然而，这已经改变了…我们的小PCB必须做的是测量继电器接点上的电压降，以便知道电流是否超过某个阈值（但不需要精确的量），并且从哪个意义上讲。我们的第一个方法是使用差分ADC，因为电压的幅值很小。我们需要测量大约2MV的接触点上的掉落，所以我们需要一个12位ADC最小值，并且我们必须注意我们的样本没有噪声-GT；差分ADC。对于我们来说，它是一个相当高的生产产品，所以它对成本敏感。我们只有一个25x25mm的PCB空间，我们需要低的部分计数，因为很难找到一个便宜的和小的UC，具有12位差分ADC，在这一时刻，我们已经定向项目使用一个IA199集成电路来感知继电器触点上的小电压降，这是一个类似的S。我向PAC1710建议了什么。我们将做一个原创，看看它是否工作…谢谢你的所有贡献！



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    As I see this topic awoken some interest I will explain a little bit...

Thanks roundrocktom for your suggestions. Here are my comments:
PIC24FJ64GC006 has 64 pin and 3.48€@100, I am looking for a microcontroller around 1€
PIC24F04KA200 has 14 pin (good!) but only 10-bit ADC (we need 12-bit)
MCP3301 combined with a simple uC could be an option, but our first option was to try to solve the issue only with a single IC. However this now has changed...

What our little PCB has to do is to measure the voltage drop across the contact of a relay, in order to know if there is a certain pass of current exceeding a threshold (but not necessary the exact amount), and in which sense. Our first approach to the problem was to use a differential ADC because of the small magnitude of the voltage. We need to measure a drop across the contacts of around 2mV, so we need a 12-bit ADC minimum, and we have to take care our sample doesn't get noise -> differential ADC.
For us it is a quite high production product so it is sensitive to the cost. And we have only a PCB space of 25x25mm -> we need low part count.
Seeing that it was difficult to find a cheap and small uC with 12-bit differential ADC, at this moment we have oriented the project to use an INA199 IC to sense the small voltage drop across the relay contact, which is a similar solution to what suggested roundrocktom with the PAC1710. We will make a proto and see if it works....

Thanks for all your contributions!

你不需要差分ADC。只有2通道的ADC。如果继电器是在地面上，你可以使用较低的接触作为VREF -并测量与单通道的上接触。然而，即使采用最小的精度，ADC检测2MV也很困难。最好增加一些模拟前端放大和移位，这样你就可以得到一个单端信号给你的ADC。我会用比较器代替。



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    You don't need differential ADC. Just ADC with 2 channels. If relay is sitting at ground, you can use lower contact as VRef- and measure the upper contact with a single channel. However, detecting 2mV with ADC is hard even with minimum precision. It's best to add some sort of analog front end to amplify and shift it so that you get a single-ended signal to your ADC.
 
I would use a comparator instead.

继电器切换12V，所以如果我们用ADC直接读取电压，我们将需要除数（更多的噪声，更小的信号…）。IA199也解决了这一点，因为它能够测量其VCC上的张力。我们认为这将是一个很好的模拟前端。



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    The relay switches 12V, so if we read the voltage directly with ADC we would need divisors (more noise, smaller signal...). INA199 solves also this as it is capable of measuring tensions over its Vcc. We think it will be a good analog front end.

为什么不使用高电流测量中的许多IC？这样你就得到了一个比你试图测量的电压大得多的接地参考电压，所以你可以使用一个低比特数的ADC。例如，线性技术LTC6101，或者微芯片在它们的范围内都有类似的设备，因为它们获得了SuthTeX。模拟设备也有类似的芯片。



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    Why not use one of the many ICs available for high side current measurement? That way you get a ground referenced voltage that is much larger than the voltage you are attempting to measure, so you can use an ADC with lower number of bits.
 
Example devices include Linear Technology LTC6101, or Microchip have similar devices in thier range since they acquired Supertex. Analog Devices also have similar chips.