TLV8544: PWR

MICHAEL SAGAYARAJ

Prodigy 130 points

Part Number: TLV8544

Is the quiescent current and supply current ( ie. the amplifier in the active mode ) same?

over 5 years ago

0 Chuck Sins over 5 years ago

TI__Mastermind 23415 points

Michael

Quiescent current and supply current are just different names for the same specification. The value in the EC table assumes a no load condition but you are correct in your assumption that the amplifier is on and active. The tlv8544 does not have a power down mode.

Chuck

0 MICHAEL SAGAYARAJ over 5 years ago in reply to Chuck Sins

Prodigy 130 points

Hi Chuck

Thanks for your quick reply.

So you are stating that at all times, the TLV8544 will consume 500nA current.

0 Chuck Sins over 5 years ago in reply to MICHAEL SAGAYARAJ

TI__Mastermind 23415 points

Yes but don’t overlook my comment about the load. 500na is just for the amplifier. If there is a load on the output, the current will increase to 500na + vout/rload.

0 MICHAEL SAGAYARAJ over 5 years ago in reply to Chuck Sins

Prodigy 130 points

Actually I am using the TLV8544 for capacitive load ( to ADC input ) so i have used Figure.31 circuit in the datasheet ( my Riso = 10k ).
Do i need to use the above formula for this circuit ?
If yes what is the value of Rload ?
If not let me know the another solution.

0 Chuck Sins over 5 years ago in reply to MICHAEL SAGAYARAJ

TI__Mastermind 23415 points

Sorry Michael
I missed that you had a follow up question. in the case of fig 31, once the capacitor reaches steady state, the capacitor looks like an open circuit and thus there is no load on the comparator to add to the quiescent current. however, if the input to amplifier is an AC waveform, you need to model the impedance of the capacitor as a load impedance and add that value to RISO. as the voltage at the input changes amplitude, you can calculate instantaneous quiescent current as VIN / (RISO + 1/(2xpixfreqxC)) + 500nA
Chuck