Hi,

Is Mosfet analog component or digital component???

I need to seperate the gnds for the circuits based on components(like AGND and DGND)

I am attaching the circuit in with some circuit and controller and joystick,push bottons dataflash,current sensor is there


In these components which are analog and which are digital???

Regards,
Vivek

 

Hi,


I am using AGND and DGND in my circuit

So, For microcontroller I have both AGND and DGND in datasheet.

But for MOSFET it is not given in datasheet as AGND or DGND.

Can anyone suggest me something about this???


Regards
Vivek

 

Must have schematic. A MOSFET is not, by its nature, digital or analog. The circuit it is used in is analog or digital.

 

Hi,

Thanks for your reply

In my circuit Mosfet receives the input from micro controller and is used for ON/OFF(SWITCHING)

so, I must use AGND or DGND for grounding the Mosfet

I am adding schematic for the circuit here

 

The top, left circuit is where I found MOSFETs. That is an analog circuit, except for the switching power supply, but the power supply doesn't have a MOSFET that I could see.

 

Hi,

Thanks for your reply

Exactly the MOSFETS are in top left

they are used for alternative switching of current from the LC circuit.

Yes,exactly it is analog circuit

So, can I use AGND for the Mosfets

 

All components in the analog section go to the analog ground, and all the components in the digital section use the digital ground. This includes MOSFETs.

 

Now you have three threads on the same subject. What gives?

 

The more I look, the more I think I might be wrong. It depends on the inputs to the op-amps. If they are used for fast switchers, the MOSFETs are in a digital circuit.

 

Hi,

Then what about gate drivers connected to Mosfets.

I think obviously they are also digital ground.

I have used a switch for converting 24V supply to 5V .

what about that circuit. Is it AGND or DGND

 

Digital circuits use the digital ground. Analog circuits use the analog ground.

 

Hi,

what about LDO(LINEAR REGULATOR)?

which converts the voltage ?

Is it a digital circuit or analog circuit?

 

Analog is separated out for a time varying signal you wish to process. It is kept in a separate section for amplification/filtering prior to ADC or other operation to reduce digital switching noise being added onto the signal.

Digital is separated out for clocks, it tends to need a higher current power supply, sometimes at a different voltage than the analog side.

All of these are dependent on the power supply, which can be linear (analog, poor efficiency), or Switching (pwm on/off control, very efficient). The power supply needs to be filtered very well by caps for both the analog and digital portions of the circuit, and is connected to both Analog Ground and Digital Ground (unless an isolator is used, then they can be entirely separate).

All of the DSP/Logiic/Controller ICs use the digital ground for supply, and Analog Ground for signal input (Signal must be referenced to something). All of the analog amplifier and filtering components are connected to the Analog ground.

You cannot look at a component and decide "Is this analog or digital"? While some, like certain logic ICs are obviously digital, other ICs in the "digital family" are actually analog. Same for MOSFETs. The context of the circuit in which it is used determines which ground to use for each sub-circuit.

 

Is an ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) analog or digital? Where do you connect the GND, to analog ground or digital ground?

 

Is an ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) analog or digital? Where do you connect the GND, to analog ground or digital ground?

Both ADC and DACs and other Mixed Signal ICs usually have VDD/VSS and AVDD/AVSS (or similar names) So the "wall" between digital functions and analog output is still isolated.

The distinction between analog and digital is more important when dealing with millivolt analog signals going into a DSP, interference at that level becomes a problem after amplification. If the incoming analog signal is already at the level required, the signal/noise ratio lowers, and is less of a concern, but still a strong enough concern to warrant separate supplies in a critical application.