Low end Cortex-M MCU: ST vs. NXP
Now that we have broken down the ARM Cortex M portfolios of ST and NXP, let’s dive into the low end of the spectrum, where the power, price and features are low, i.e. the LPC11xx, LPC11U, LPC11C, LPC12xx and STM32L.
By looking at the Flash memory – one of the main silicon cost drivers – we clearly see ST focused on applications that require at least 64kB while NXP’s portfolio stretches from 8 kB to 128kB. One could easily conclude that NXP is clearly undercutting ST on price, but, after a few clicks, we discover we have to take into account the absence of USB ports on all NXP parts on the low end while ST has equipped each and every STM32L part with a USB FS port (no PHY though). NXP does provide the LPC11U family with USB, but it isn’t publicly available at press time.
If the end application is less sensitive to power consumption, ST offers the STM32F100 family that covers much of the gap left by the low-power STM32L.
Now, looking deeper, we can compare ST and NXP devices at 64kB of Flash memory – a middle ground.
- LPC1225FBD64/301 and -FBD48/301 with respectively 64-pin and 48-pin LQFP packages
- STM32L151C8T6 and -C8U6 with respectively 48-pin UFQFPN and LQFP packages
Each pair is likely to carry the same die.
Given the same price for the 2 ST parts, we will use for the purpose of the comparison the generic part STM32L151C8 and for NXP, the 48 pin version which happen to have the same package as one of the ST parts.
So, how much do your get for your money?
It is obvious from the color coding that ST has the upper hand on a majority of features. But, are you willing to pay an additional $0.54, a mere 28% for the extra features?
As usual, it all depends on the application’s requirements. If we set aside power consumption, with a somewhat more limited core and analog peripherals and no USB, the LPC1225 will save some, if the end product is in need of some additional margin. But as soon as your application requires a bit more interfaces and USB, the STM32L151C8 will save headaches down the road.
If we look back at this limited comparison, aren’t you left wondering if an additional $0.54 is worth the value it brings?
Over the next couple of months, we will look at feature pricing before coming back to our current NXP vs. ST theme.
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