Hi,
I'm looking for a solution to monitoring three analog voltages from an acce=
lerometer.=A0 I need to be able to set two threshold levels for each voltag=
e.=A0 The total power budget for the voltage monitor is about 1mA @ 3.3V.=
=A0 I need to set the threshold levels through SPI or I2C.=A0 I need to be =
able to read the voltage levels once a threshold level is tripped.=A0 The m=
easurements are outside of the 1mA power budget since they're only for whil=
e the system is in motion.

I'm building a position tracking system.=A0 I have a sensor which reports a=
 very accurate position delta, but it has two failings:=A0 it's power hungr=
y and it's got nasty latency waking up from sleep (as bad as 2 seconds) aft=
er waking up from sleep mode.=A0 This will be a battery powered sensor pack=
age, so power consumption when idle is an issue.

My current solution is to use a MAX1363, which will do both the monitoring =
and the level reading.=A0 I'm limited to 400kbps I2C, which means I have a =
maximum of 33ksps, divided over 3 channels, not including I2C overhead, whi=
ch leaves me with about 10ksps per axis.

I think that 10ksps should more than do the job since the tracking system s=
hould see movement not exceeding 5Hz, with peak acceleration of no more tha=
n 5g (peak should usually be around 2.5g) , RMS acceleration closer to 0.5g=
.=A0 The sensor I've picked has four selectable G levels from +/-2.5G to +/=
-10G which should make that range easy to work with: MMA7261QT. To get posi=
tion delta, I plan to do a discrete double integral of the acceleration and=
 set a zero point every time that my other sensor reports no motion.

So, is there a better solution for my application than the MAX1363 + MMA726=
1QT?=A0 Together they take 1mA @ 3.3V, which is within my power budget.

Thanks,
Brendan

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