What is rail-to-rail supply voltage?

[Syukri]

Is it the voltage swing of the device?

 

[IanP]

One picture can be worth more that one million words ..

Regards,
IanP

 

[VSMVDD]

ye very good pic

i think an ac supply to an opamp is a bad example to set

and an open ended opamp has infinite gain so its not i/o levels shown




rail to rail is simple


this is called a floating ground setup

and rail to rail is

the voltage between ( (+rail and gnd) + (-rail to gnd)) = volts = rail to rail level

a good example in ac systems is a split secondary tap

where you have one coil {transformer}

split in the middle this 'tap' is then used as a common rail
each end is a rail so rail to rail is the voltage between each end and the tap added together to give rms voltage split rail

 

[Kral]

Syukri,
Rail to rail supply voltage is the voltage between the + and - supply voltages of a device. When authors refer to "rail-to-rail output" capability, they mean that the devices is capable of providing outputs that are equal to the positive and negative supply (rail) voltages. When they refer to "rail-to-rail input" capability, they mean that the device is capable of operating with inputs that are equal to the positive and negative supply voltages.
Regards,
Kral

 

[Davood Amerion]

Rail to rail voltage is |V+| + |V-| value.

 

[mohazaga]

Hello ,

rail-to-rail supply voltage is the voltge from most +V of the circuit to the most -V of the circuit. As example , from Vdd to ground (when it's the max. supply voltage to the circuit).
Thanx

 

[pillar_chen]

The input range is vdd to ged or -vdd