LM27762: LM27762 with lower consumption

John Chou62

Intellectual 2070 points

Part Number: LM27762
Other Parts Discussed in Thread: ADS1291, , TPS60401, TPS62743, TPS62802

hi Team,

customer is using positive and negative voltage output for ADS1291 for ECG device

it was evaluated with the LM27762, but the consumption during operation mode is considered too high.

can we check any compatible parts with lower working consumption?

or if we separate in to two device one positive and the other negative output (-2V), will it be less consumption?

Thanks

over 6 years ago

0 Chris Glaser over 6 years ago

TI__Guru**** 150950 points

Hi John,

To best answer your question, please provide the Vin and the required +/- Vout and load currents. As well, what current consumption did they measure? What were the conditions of Vin, +/-Vout, load current for this measurement?

0 John Chou62 over 6 years ago in reply to Chris Glaser

TI__Intellectual 2070 points

Thanks for your reply

the design requirement

LDO Vin = 3~4.3V

Vout = +3V, -2V or +2V, -2V

load current < 10mA, actual <2mA

Thanks

0 Chris Glaser over 6 years ago in reply to John Chou62

TI__Guru**** 150950 points

Thanks for confirming. What input current did they measure? What level do they want to reduce this to?

There are numerous discrete LDOs with Iq below 10uA. As well, the TPS60401 inverter has much lower Iq than LM27762. These devices would help reduce the Iq which would reduce the overall input current if this is the main goal.

0 John Chou62 over 6 years ago in reply to Chris Glaser

TI__Intellectual 2070 points

Thanks for the help, will evaluate the TPS60401

the LM277 consumes 340uA within the spec

however, for wearable device, they want to elongate the battery life as long as possible.

thanks for the recommendations

0 Chris Glaser over 6 years ago in reply to John Chou62

TI__Guru**** 150950 points

Thanks for confirming.

For a wearable, using a DC/DC for the positive rail will save much current. The TPS62743 and TPS62802 are very small DC/DCs with much lower Iq and commonly used in this EE.

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LM27762: LM27762 with lower consumption