MSP430F2247 ADC10 Internal Ref Voltage Settling time

Ning Wang10298

Other Parts Discussed in Thread: MSP430F2274

Hi, all

I am studying the MSP430F2274 chip which is on the ez430-RF2480 dev board. I found that in all sample codes(using internal reference REFON=1) & application notes (AN075 for cc2480) , the internal reference voltage needs at least 17ms to be settled down. But I don't find any description about this setting-up time in the datasheet & User Guide documents.

I only found that ADC12 need the external capacitors to charge. I wonder if we do need wait 17ms in LPM0 for the reference voltage setting-up when using ADC10.

Thanks and looking forward to hear from you.

Wang Ning

over 16 years ago

0 Harman over 16 years ago

TI__Expert 7845 points

Actually for the F2274 the reference settling time is only 30 us. Please see page 47 of the datasheet:
http://www.ti.com/lit/gpn/msp430f2274

and page 20-6 of the 2xx user's guide:
http://www.ti.com/litv/pdf/slau144e

The 17 ms settling time was required in older 1xx devices, but this is improved in the 2xx devices. Please note that this time is ONLY required if the reference is turned off and then ON again. If the reference is always kept ON, then this time is not required. For low power operation, it is recommended to turn the reference OFF when not needed.

0 Ning Wang10298 over 16 years ago in reply to Harman

Intellectual 395 points

Hi, Harman

Thanks a lot. for the answer. Yes we plan to use the ADC every 16ms and make the power consumption as low as possible. If the setup time of the reference is less than 30us, it will suite our application very well.

Wang Ning

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430F2247 ADC10 Internal Ref Voltage Settling time