NXP Semiconductors MKL27Z256VFM4

Overview

MKL27Z256VFM4 from NXP Semiconductors (formerly Freescale) is a 48 MHz ARM® Cortex®-M0+ microcontroller with 256 KB flash, 32 KB SRAM, and integrated USB FS 2.0 device controller supporting crystal-less operation. It delivers 54 µA/MHz in very low power run mode and 1.96 µA in VLLS3 deep sleep (RAM + RTC retained), targeting battery-powered sensor nodes and portable medical devices requiring secure, low-power USB connectivity.

For engineers reviewing the MKL27Z256VFM4 datasheet, MKL27Z256VFM4 pinout, MKL27Z256VFM4 application, or MKL27Z256VFM4 equivalent, key selection criteria include its 32-pin 5×5 mm QFN package, internal 48 MHz ±0.5% reference clock, FlexIO peripheral for custom serial emulation, and support for ISO7816 UART and 16-channel 12-bit ADC with internal Vref.

Technical Context

The MKL27Z256VFM4 implements an ARM Cortex-M0+ core with Micro Trace Buffer and Bit Manipulation Engine, paired with a multi-mode clock system featuring factory-trimmed 48 MHz HIRC (±0.5%), 8/2 MHz LIRC (±3%), and 1 kHz low-power reference active across all sleep states except VLLS0. Its memory subsystem includes 256 KB flash with erase/write protection, 32 KB SRAM, and 16 KB ROM containing a boot loader for field firmware updates.

Peripheral integration centers on ultra-low-power operation: USB FS 2.0 operates without external crystal; two low-power UARTs retain asynchronous functionality in VLPS/VLLS modes; FlexIO enables runtime reconfiguration to emulate UART, SPI, I²C, I²S, or PWM; and the 16-bit ADC achieves 818 ksps with programmable high-accuracy internal voltage reference (1.2 V ±1.5%).

Key Specifications

Pinout & Package

Package: 32-pin QFN (5×5 mm, 0.5 mm pitch), thermally enhanced with exposed pad for improved heat dissipation and ground integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with MKL27Z256VFM4, MKL26Z128VLH4 offers more I/O but sacrifices crystal-less USB and compact QFN packaging, while STM32L072KBU6 provides competitive power efficiency but lacks the FlexIO flexibility and integrated smart-card interface critical for secure portable devices.

Availability

MKL27Z256VFM4 is available at Aetrix Electronics and suitable for wearable health monitors, industrial sensor nodes, USB-C medical devices, and secure access terminals requiring stable component supply across long product lifecycles.

Supply support for MKL27Z256VFM4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT markets, with deep expertise in ARM-based microcontrollers and edge processing.

The Kinetis KL27 series was designed specifically for cost-sensitive, battery-powered USB devices requiring robust low-power operation, integrated security, and flexible peripheral emulation - addressing design constraints in portable diagnostics and smart sensing.

FAQ

Does MKL27Z256VFM4 support USB device operation without an external crystal?

Yes, MKL27Z256VFM4 integrates a factory-trimmed 48 MHz internal reference clock with ±0.25% accuracy over temperature and voltage, enabling full USB FS 2.0 device compliance without any external crystal or matching components. This is confirmed in Section 3.8.1 of the Rev. 5 datasheet and validated in Freescale's AN5013 application note.

What is the maximum ADC sampling rate and resolution supported by MKL27Z256VFM4?

MKL27Z256VFM4 features a 16-bit SAR ADC capable of 818 ksps with configurable resolution (8–16 bits). It supports up to 16 input channels in differential or single-ended mode and includes a high-accuracy internal 1.2 V reference (±1.5%) - eliminating need for external voltage references in most precision sensing applications.

How many GPIO pins does MKL27Z256VFM4 provide in its 32-pin QFN package?

MKL27Z256VFM4 in the 32-pin QFN (VFM4) package provides 23 general-purpose I/O pins, including 6 high-drive pads rated for 18 mA output. Pin assignments are fully documented in Table 5-1 ("KL27 Family Pinouts") of the Rev. 5 datasheet, with multiplexing controlled via PORTx_PCRn registers.

What low-power modes are available on MKL27Z256VFM4, and what is the lowest achievable current draw?

MKL27Z256VFM4 supports six static low-power modes, including VLLS0 (0.18 µA typ at 3.0 V), VLLS1 (0.66 µA), VLLS3 (1.96 µA with RTC + RAM retained), and VLPS (3.31 µA). All modes maintain SRAM and RTC state, with wake-up sources including GPIO, LPTMR, and USB activity - verified in Table 9 of the Rev. 5 datasheet.

Is there a built-in bootloader in MKL27Z256VFM4, and how is it accessed?

Yes, MKL27Z256VFM4 includes a 16 KB ROM-based bootloader accessible via UART or USB HID interface. It supports secure firmware updates without consuming user flash space and is activated by asserting the RESET pin while holding a specific GPIO low - detailed in Chapter 4 ("Bootloader") of the KL27P64M48SF6RM1 reference manual.