cc1101 for dc/dc switching regulator

ram krishnan

Other Parts Discussed in Thread: CC1101, TPS62840

We are looking for a high efficiency dc/dc switching power supply for a CC1101/MSP430 based sensor node operating in the 868 MHz band.

Input supply is two 3V batteries in series. Since the input is 6V, we can't use the bypass option on a DC/DC regulator.

Required output is 3V (with max current of 100 mA).

Deep sleep current consumption of the radio/micro/sensors on our node is around 2 uA. We are looking for a regulator which will increase the sleep mode current consumption by at most 2 uA.

over 6 years ago

0 Bjoern Goerner over 6 years ago

TI__Intellectual 1525 points

Hi Ram,

Is the 3V rating of the batteries the nominal voltage or the actual voltage of a fully charged cell? The actual voltage is usually higher than the nominal value.

If a switching regulator with an absolute maximum input voltage of 7V is sufficient for your application, you should have a look at our newest ultra low IQ part:

http://www.ti.com/product/TPS62840

It provides enough current while consuming only 60nA when switching and supports a 100% duty mode which allows to drain the battery down to 3V.

If you need a higher input voltage range, this part should fit your requirements:

http://www.ti.com/product/TPS62745

Both devices offer a ultra low quiescent current well below your required maximum. Also they are a good choice for low power RF applications.

0 ram krishnan over 6 years ago in reply to Bjoern Goerner

Intellectual 820 points

Hi Bjoern ,

The node is powered by two 3V non-rechargeable batteries in series and we have a component which needs a minimum of 2.8 V.

This TPS62840 looks like a great fit. We will evaluate this regulator.

Thx

Kris

0 Ashok R41 over 6 years ago in reply to Bjoern Goerner

Intellectual 360 points

Hi Bjoern,

How about batteries connected in parallel and use a boost convertor of 3V? Is there any booster which is good choice for low power RF applications?

0 Bjoern Goerner over 6 years ago in reply to Ashok R41

TI__Intellectual 1525 points

Hi Ram,

you can also use a boost converter, but typically the efficiency would be lower and currently there are no other devices on the market, which offer a quiescent current as low as our TPS62840.
Therefore I would recommend connecting both batteries in series and using a buck converter.

If the boost solution fits your application better, you should have a look at those devices:

http://www.ti.com/lit/ds/symlink/tps61099.pdf

http://www.ti.com/lit/ds/symlink/tps610985.pdf

If you decide to go with the TPS61098x, please check if the minimum switch current limit of 350mA is sufficient for your application.

0 Ashok R41 over 6 years ago in reply to Bjoern Goerner

Intellectual 360 points

Hi Bjoern,

Just to clarify, As the batteries are in series

Supply voltage to TPS62840 is 6V. Output Voltage required is 3V. If the batteries voltages reach 3V TPS62840 will operate in 100% duty cycle mode. If battery voltages fall below 3V, let's say 2.8V. will it still operate at 100 % duty cycle to give 2.8V or shuts down?

0 Bjoern Goerner over 6 years ago in reply to Ashok R41

TI__Intellectual 1525 points

Hi Ram,

the TPS62840 can operate down to 1.8V.

For more details, you can have a look at section 8.4.3 of the datasheet.

0 Bjoern Goerner over 6 years ago in reply to Bjoern Goerner

TI__Intellectual 1525 points

Hi Ram,

as there are no other questions, I'll close this thread. Of course you can reopen it again if you have more questions!

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cc1101 for dc/dc switching regulator