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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →The Freescale Kinetis KL03 is a compact, ultra-low-power 32-bit microcontroller designed for small battery-powered devices. Its top documented configuration runs at up to 48 MHz and includes 32 KB of flash, 2 KB of SRAM and 8 KB of ROM. NXP now hosts the KL03 documentation; the cited specifications come from Freescale’s 2014 product brief and NXP’s 2017 data sheet.
What is the Kinetis KL03?
The KL03 is a member of Freescale’s Kinetis microcontroller family, built around an Arm Cortex-M0+ core. It is intended to handle embedded control tasks such as reading sensors, managing low-power operation and communicating with other components. NXP’s August 2017 data sheet describes it as suited to Internet of Things edge nodes, while Freescale’s July 2014 product brief positions it for cost-sensitive portable devices that need long battery life.
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It is a microcontroller, not a complete wireless IoT module. The documented peripherals include wired serial interfaces and analog functions, but the KL03 documents do not list integrated Wi-Fi, Bluetooth or 802.15.4 radio hardware. A product needing wireless connectivity therefore needs a separate radio or connectivity device.
How small is the KL03, and what are its main specifications?
The smallest documented package is a 20-pin wafer-level chip-scale package (WLCSP) measuring approximately 1.6 × 2.0 mm, according to NXP’s August 2017 data sheet. The family also offers 16-pin and 24-pin QFN package options. Package choice affects the available pins and board layout, so check the data sheet’s package and pin assignments before selecting a part.
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| Specification | Documented value | Source qualification |
|---|---|---|
| CPU | Arm Cortex-M0+, up to 48 MHz | Freescale 2014 product brief; NXP data sheet revision 2017 |
| Flash | Up to 32 KB | Freescale 2014 product brief |
| SRAM | Up to 2 KB | Freescale 2014 product brief |
| ROM | Up to 8 KB | Freescale 2014 product brief |
| Smallest listed package | 20-pin WLCSP, approximately 1.6 × 2.0 mm | Freescale/NXP 2014 fact sheet and NXP 2017 data sheet |
| Other listed package choices | 16-pin and 24-pin QFN | KL03 product documentation |
Freescale and NXP historically promoted the WLCSP as exceptionally small. That is a vendor positioning claim, not evidence that it remains the smallest MCU package available today.
What power figures does the data sheet report?
NXP’s 2017 data sheet gives several power figures that help explain the KL03’s intended battery-powered use. They are document specifications, not a guarantee of a particular device’s runtime: actual consumption depends on operating conditions, clocking, peripherals and the application circuit.
- Run current: 50 µA/MHz.
- Static current: 2.2 µA with full retention and a stated 7.5 µs wakeup.
- Deep-sleep current: 77 nA.
These figures describe different operating states and should not be treated as interchangeable. A design that frequently wakes, uses analog blocks or drives external components will have a different average current from one spending most of its time in deep sleep.
What peripherals and functions are built in?
The KL03 combines basic digital control, analog input and serial communication features, reducing the number of external parts needed in a simple sensing or control design. The documented set includes:
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- Boot ROM.
- ADC, comparator and DAC-related functions.
- UART/LPUART, SPI and I2C serial interfaces.
- Timers and GPIO.
- Voltage reference and low-power operating modes.
These integrated blocks make the KL03 suitable for coordinating sensors, switches, indicators or a separate communications component. The small memory capacity is a practical constraint: applications with large protocol stacks, extensive logging or complex user interfaces may need a larger MCU.
Why did Freescale target the KL03 at IoT edge nodes?
An edge node often needs to sample a sensor, make a local decision and report or pass along a small amount of data without consuming much battery or board area. The KL03’s combination of a small package, low-power modes, modest 32-bit processing capability, analog inputs and serial interfaces maps to that role.
Its significance is not that it independently supplies an entire IoT connection. Rather, it can serve as the compact control layer in a larger device, alongside whatever sensor, power-management and radio hardware the design requires. Freescale announced the product’s full market launch on July 25, 2014, according to a 2015 DigiKey technical article reporting the launch.
What tools and development options are documented?
The KL03 ecosystem documented by Freescale includes a Freedom development platform and support for Kinetis Design Studio, IAR Embedded Workbench, ARM Keil MDK, and Atollic/GCC toolchains. These names describe documented development options; they do not establish that every package, board or software download remains available today.
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Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →For evaluation, look for a KL03 Freedom board in NXP or distributor documentation, then confirm its exact board identifier, supported silicon and software downloads before buying or building around it. The available information does not establish a current board SKU or live marketplace stock.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Is MKL03Z32CAF4R still available?
MKL03Z32CAF4R is an orderable KL03 part number listed in NXP’s documentation. That listing identifies a device variant; it does not confirm present-day stock, price, lifecycle status or delivery region. Check NXP’s current product page and authorized distributors for live availability before committing a design, especially if long-term supply is important.
What should designers check before choosing it?
Compare the KL03 against alternatives using the requirements that affect the whole product, not clock speed alone:
- Package dimensions, pin count and the signals exposed in the chosen package.
- Flash, SRAM and ROM capacity against firmware and data needs.
- Active and sleep current under the conditions your application will actually use, plus wakeup behavior.
- ADC and analog requirements, serial interfaces and timer/GPIO count.
- Supply-voltage and temperature limits in the applicable data sheet.
- Toolchain, debugging and development-board support for your team.
- Current lifecycle and supply status for the exact orderable part.
The KL03 is most compelling when a design can fit within its small memory and peripheral set and benefits from compact packaging and low-power operation. A project that needs integrated wireless, substantially more memory or more processing headroom should account for those needs elsewhere in the system or evaluate a different MCU.
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