attaining lower power/faster wake times on the lcp55s69/lcp55s69

[PappaSmurf]

Hi all, 

we're looking into using either an lpc55s69 or lpc55s28 in several battery powered products to replace previous gen mcus.. one of the sales reps (3rd party) we talked to recommended the lpc series. 

I've been writing a couple demo applications using the xpresso devkit for the lpc55s69 and have been pretty happy with it but I just got around to looking at power consumption. the power modes and boot times I got from the datasheet are below:

* so there are 4 low power modes..
* sleep .5-4uS 700uA
* deepsleep 64uS 100-200uA *clock resets to 12m
* power down 346uS 4uA *clock resets+regs/reboot.
* deep power down not relevent

so looking at this, it seems obvious to me that these are not 'real'.. there must be a way to improve upon this, no? basically I'm looking back at other MCU's I've used and stunned that this uses so much.. I looked at AN13166 and it seems to verify these #'s but really doesent give a way to improve upon on them. 

I guess what I'm wondering is what I can shutdown to decrease both turn on and sleep numbers.. It does say that the PLL uses a lot, but I'm not using that, just the 12meg FRO at the moment.. Is most of this power being used by ram/flash?? 

I feel like there's some big power hog that I'm missing here.. 

for reference, I've used an atsam4l that could come out of wait mode(3ua) in 1.5us(realistically about 10) and the apollo3 which was similar. both of these retained full ram retention, which makes me skeptical that the ram on the lpc is taking that much power..

[PappaSmurf]

Thanks xiangjun, I hadn't seen this doc, but it seems to agree with the datasheet and that app note. Basically I found the 1st page where it talks about process technology most interesting. I guess a smaller node leaks a lot more, I hadn't really thought much about that but I suppose that has to be true. Anyways, I guess this cpu would become more favored at a higher duty cycle w more on time? 

funny I guess, all you ever hear about is smaller and smaller process technologies, when in a lot of cases that's not really favorable.. 

so what I might try is to make a little bootstrapper thing that copies our entire program into SRAM and shuts down the flash for the duration.. it looks like the flash draws a ton (80uA) all the time. I could try this.. or look for another mcu

Anyways, thx again 

[xiangjun_rong]

Hi,

I agree with you,  in sleep mode, only the core stops, all the flash, memory, peripherals are active, especially, the flash, SRAM consumes a lot of power.

I attach the low power modes doc, pls refer to it.

Hope it can help you

BR

XiangJun Rong