LMH1208: IN0+/- Input Voltage

user6360548

Prodigy 70 points

Part Number: LMH1208

Hi Team,

IN0+/- are required external 4.7uF, AC-coupling capacitors.
So IN0+ and IN0- swing centered around 0V.

On the other hand, input common voltage(VIN0_CM) is 2.06V(typ).

I guess IN0+/- have internal pull-up and pull-down resistance.

Ex.)5k_Ohm Pull-up and 8k_Ohm Pull-down for 2.03V

Is this guess correct?
Then, would you pls tell me internal resistance value?

Best regards,
Hasegawa

over 4 years ago

0 Nasser Mohammadi over 4 years ago

TI__Guru* 93670 points

Greetings,

Your understanding is correct. There is internal weak bias that centers typical common mode voltage to be at about 2.06V. Weak bias is due to high value resistor divider. Resistor values are in order of 5K and 8K ohm you noted.

Regards,, Nasser

0 user6360548 over 4 years ago in reply to Nasser Mohammadi

Prodigy 70 points

Hi Nasser-san,

Could you tell me concrete values of internal resistor?

Best regards,

Hasegawa

0 Nasser Mohammadi over 4 years ago in reply to user6360548

TI__Guru* 93670 points

Hi Hasegawa-San,

I checked and these resistor values have not been characterized. Ratio of these two resistors across different lots provide a typical 2.06V DC common mode voltage.

Regards,, Nasser

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LMH1208: IN0+/- Input Voltage