Stellaris® LM4F230H5QR Microcontroller power consumption by clock source and speed

John Osen

I am looking to reduce the power consumption of an LM4F chip. I will be running off of a few AAAs on what we call a handheld or HH. I began development at 80MHz. The HH does not do much other than check keys, display some information on a LCD and transmit a wireless message. The power consumption data in the data sheet for run mode is for an 80MHz system clock. Is there power consumption data for other clock speeds for an LM4F chip? I want a ballpark estimate on what I can save in power by going to a lower clock speed. This will give me an idea on where to focus first - wireless amps, LCD backlight or CPU system clock.

over 13 years ago

0 Lela Garofolo over 13 years ago

TI__Mastermind 18905 points

Hi John,

We will be updating the Data Sheet with numbers across frequency and clock options when the final version of silicon, B0, is released to production.

In the interim, below are some informal numbers I took from bench testing. It should give you a better idea of frequency and clock option effect on power consumption values:

Parameter	All Peripherials	Current (mA)
Idd_run_80MHz_FLASH, PLL ON, MOSC ON	ON	41
Idd_run_80MHz_FLASH, PLL ON, MOSC ON	OFF	25
Idd_run_40MHz_FLASH, PLL ON, MOSC ON	ON	27
Idd_run_40MHz_FLASH, PLL ON, MOSC ON	OFF	19
Idd_run_16MHz_FLASH, PIOSC only	ON	15
Idd_run_16MHz_FLASH, PIOSC only	OFF	10
Idd_run_12MHz_FLASH, MOSC only	ON	16
Idd_run_12MHz_FLASH, MOSC only	OFF	11
Idd_run_1MHz_FLASH, PIOSC/16	ON	10
Idd_run_1MHz_FLASH, PIOSC/16	OFF	7

You can estimate that the PLL will consume ~1.5-2mA when enabled, and the MOSC ~2.5-3mA when enabled. The lowest power clock option is the PIOSC, but accuracy over the MOSC should be rationalized for your application.

Lela

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Stellaris® LM4F230H5QR Microcontroller power consumption by clock source and speed