Integrated Circuit Pins

[Atomic_Sheep]

Hello,

I'm trying to learn some basics about IC pins. I'm using at this IPS (Integrated Pressure Sensor) as an example:

https://electronic-engineering.ch/microchip/datasheets/sensors/MPX4100A.pdf

What is:

V1 -

V2 -

VCC -

VEX -

VOUT - how is this different to VCC?

I'm also quite stumped as to the meaning of the decoupling diagram on page 3. Is this related to the pins at all? I started reading about decoupling capacitance but it's a bit over my head at the moment, is there a logical step that I should be reading prior to looking into decoupling capacitors? I'm guessing this has something to do with transistors and the change of signal from 0 to Voltage High and back from Voltage high to 0?

 

[ronsimpson]

I searched the .PDF you pointed to and did not fine "VEX" or "V2" etc.

VCC usually means power. +12V or +5V or +3.3Volts. Something like that.
Usually something a name starting out with a "V" is voltage.
V1=voltage one, V2=voltage two. VEX if probably external voltage.
These names could mean something different.
r
Page 3: decoupling capacitors:
Electricity is much like water in a pipe. If it must travel a distance it will take time to get there.
A capacitor is a storage tank.
When the IC needs power right now it can not wait for it. So it gets power from the very small 0.01uF capacitor that is very close. Before that energy can be used up the larger 1uF cap, that is farther away, gets power to the IC. While the IC is living on this stored power there is time go get power from the power supply.

The best "water pipe" story about decoupling capacitors is a toilet. In the bathroom the toilet needs a very large amount of water for 1 second only. Then for hours it needs no water. There is a very small pipe going to the toilet. Water is stored in the tank in the toilet. It might take 2 minutes to refill the tank.

 

[ramuna]

Hi,
In the order that they appear in your question, and with reference to the datasheet, the voltage (?) symbols mean:
V1 - Not in datasheet
V2 - Not in datasheet
Vcc - Not in datasheet. However Vs is in datasheet, and means Supply voltage
VEX - Not in datasheet
VOUT - The output voltage from the sensor

The Pin numbers for the small outline package and for the unibody package are given at the bottom of page 1. You need to cross-reference these to the pin numbers as they appear in the package outline drawings on pages 7 to 9.

Decoupling capacitors are to shortcircuit (or in more formal language: to offer a low impedance to) high frequency voltage spikes in the power supply (between Vcc and ground), as well as in the output voltage. If not decoupled, such spikes would produce erroneous results from the sensor. Such spikes are more commonly called noise; such erroneous results are more commonly called glitches.

 

[Reloadron]

Looking at the data sheet these devices only use 3 connections. Vout (the signal out proportional to the applied pressure) Vsupply which is 5.0 Volts and Ground which is ground or common. The data sheet also shows the pin out in
Figure 3. Recommended power supply decoupling
and output filtering.

Ron

 

[KeepItSimpleStupid]

Since your looking at pressure sensors V1 and V2 are like the bridge voltages that need to amplified differential. e.g. V1-V2. Vex is the excitation potential to the bridge. In this app note Vcc is Vex https://www.maximintegrated.com/en/app-notes/index.mvp/id/683.

Bridges can use a voltage or current source for excitation.

 

[Atomic_Sheep]

The voltages are all on page 7 under Style 1.