Raindrops on roses, as well as whiskers on kittens? They’re alright, I suppose. however when it comes down to it, I’d most likely rather have a lot of 4051, 4052, as well as 4053 analog multiplexers on the element shelf. Por quê? since the capability to switch analog signals around, routing them at will, under manage of a microcontroller is tremendously powerful.
Whether you want to checked out a capacitive-sensing keyboard or just switch among audio signals, nothing beats a mux! checked out on as well as see if you agree.
O básico
An perfect analog multiplexer routes a single typical pin on one side with several switches to several pins on the other. In the situation of the 4051 (an eight-way analog multiplexer) there are eight of these multiplexed switches. close any type of one of the eight switches, as well as you’ve selected where you’d like to send (or source) your signal.
In reality, these switches are made with transistors, as well as they have a non-zero on-resistance. Unlike wire-to-wire switches, the present ability of analog multiplexers is limited. however switches are opened as well as closed with digital logic voltages, which indicates that it’s a snap to put them under microcontroller control.
The fundamental trio of analog multiplexers stems from the venerable 4000-series CMOS logic chips: the 4051 is a single eight-way multiplexer, the 4052 has two four-way multiplexers, as well as the 4053 has three two-way switches. in spite of a large on resistance (around 200 Ω), these chips still have their location since they’re able to switch analog signals as much as twenty volts peak-to-peak, while only needing five volt logic inputs.
4051
4052
4053
The 74HC405x series chips trade off this large voltage variety for lower on-resistance as well as higher changing speed: passing ten-volt signals with something like 50 Ω resistance. Finally, there are low-voltage analog multiplexers indicated for battery-powered use: 74LV405x run on a single-ended two volt to five volt supply as well as pass signals of the exact same size with just somewhat lower on resistances.
While the different 405x series chips are a go-to of mine, you may likewise want to understand about the 3251, 3252, as well as 3253 series chips: CBT3251, FST3252, SN74CBT3253, etc. They are a high-speed, low-resistance handle the exact same theme. They have a changing speed normally under ten nanoseconds, as well as resistances under ten ohms. These are really quick sufficient that they can be utilized to make RF mixers that work as much as 30 MHz.
None of these chips are indicated to push considerable currents, however you can get ten to twenty milliamps with a lot of variants. They can pass signals as much as approximately ten megahertz, so they’re not beneficial for high-frequency applications however you might utilize them for routing lower speed digital data in a pinch.
All of these different chips are pin-compatible across varieties, as well as I tend to believe of them as the exact same thing, though you’ll want the low-voltage range for 3.3 V jobs as well as the old-fashioned kind for ground-referenced DC voltage signals, for instance.
Formulários
If an analog multiplexer isn’t on your listing of preferred things, perhaps the short listing of applications right here will influence you.
The a lot of evident utilize of an analog multiplexer is, um, multiplexing analog signals. A single 4052 (two four-way switches) makes a fantastic logic-controlled source selector for your house stereo, for instance. If you have eight sources, that’s a pair of 4051s. everybody grumbles about the ESP8266’s single ADC pin, however linking a $0.20 74LV4051 to that single pin provides you eight options for the ADC.
Speaking of ADCs, it’s typical to requirement to scale up or down an input voltage variety to match the ADC’s. This is frequently made with a pair of resistors configured as a voltage divider. utilizing an analog multiplexer as well as routing the input with as much as eight different resistors can put manage of the input variety under manage of the microcontroller in question. When the input signal is as well small, the multiplexer as well as resistors can be utilized to manage the get of an amplifier. You may be lured to utilize a digipot for either of these scenarios when you requirement a lot more resolution, however an analog mux can get the task performed in broad varieties for a great deal less money.
Switchable Voltage Divider
Switchable get Amp
You can make a quick-and-dirty 8×8 crosspoint switch with two 4051s by just tying the two “commons” together. now one of eight inputs on one side is routeable to one of eight outputs on the other. Make eight of these as well as you’ve got a totally versatile 8×8 routing matrix.
E entãoExistem os nichos que apenas um multiplexador analógico pode preencher. Por exemplo, você pode fazer um filtro básico com frequência de corte selecionável com um resistor da série, além de utilizar o multiplexador para escolher entre vários capacitores para o solo – você não pode obter um digicap. Da mesma forma, você pode utilizar uma mux analógica para escolher entre um conjunto de referências de tensão para muito mais precisão do que você pode obter com um digipot. Se você fez o check-out [Al Williams] a peça na lógica do relé, sem dúvida tem outros conceitos excêntricos sobre o que você pode fazer com um mux em mente.
É impossível listar todas as coisas incríveis que você pode fazer com essas fichas, por isso, se você tem uma coceira que é completamente arranhada por uma mux analógica, conte-nos nos comentários.