# Had a trouble understanding the input voltage range of datasheet of OPAMP TLV2442AQPWR.

#### ashokraj

Joined Feb 1, 2018
96
I would like to know the following:
1. what is the input voltage range of power supply i could give to this opamp.
2. lets say if i give -3.3V what is the VDD+ i will have to give ?
I have a trouble understanding this. Below is from the datasheet of TLV2442aqpwr.
For example if i consider Q suffix, does it mean if i give -2.7 to negative power supply of opamp , max i can give to positive power supply of opamp is =2.7-1.3 --->=1.4!!!?

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#### Papabravo

Joined Feb 24, 2006
14,872
1. The power supply range is given as ± 12 VDC. So for example if I use +4.5 VDC and -0.8 VDC as my supply rails the input range would be [-0.8 VDC, 3.5 VDC] for the C suffix part
2. If Vi = -3.3 V then Vdd- must be -3.3 VDC or less. Vdd+ can be anything between say 2.7 VDC and +12 VDC
No, the positive supply must be in the range [2.7, 10] as a recommended operating condition. The negative supply is not similarly restricted. Whatever it is, that will be the minimum input voltage. Also the input mist be some amount , depending on the suffix below the positive rail, whatever that is.

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#### Audioguru again

Joined Oct 21, 2019
2,410
The OP asked, "What is the input voltage range of the power supply?". The datasheet recommends a total power supply of 10V max. A negative supply is not needed, it works fine with 0V and +2.7V to +10V.
He is confusing the power supply voltage range with the input voltage range.

For the Q version, if the negative power supply is -2.7V then the max positive supply is 10V - 2.7V= +7.3V.
The recommended input voltage range is +2V above the negative supply voltage to -1.3V below the positive supply voltage.

#### ashokraj

Joined Feb 1, 2018
96
The OP asked, "What is the input voltage range of the power supply?". The datasheet recommends a total power supply of 10V max. A negative supply is not needed, it works fine with 0V and +2.7V to +10V.
He is confusing the power supply voltage range with the input voltage range.

For the Q version, if the negative power supply is -2.7V then the max positive supply is 10V - 2.7V= +7.3V.
The recommended input voltage range is +2V above the negative supply voltage to -1.3V below the positive supply voltage.
For a power supply voltage is it recommended to give -3.3v and +4.7V??

#### crutschow

Joined Mar 14, 2008
26,053
The data sheet is somewhat confusing.
My take is that the input can go between the negative rail and within 1V of the positive rail.

For example, below is the range for Vdd=5V.

#### Audioguru again

Joined Oct 21, 2019
2,410
I do not see why they recommend that the input should not go within 2V from the negative supply voltage.

#### MisterBill2

Joined Jan 23, 2018
7,739
Certainly there must be a lot more to the data sheet, such as typical operating conditions. The rest of the data sheet is where to find the answer.