NXP Semiconductors MK21DX256AVLK5

Overview

MK21DX256AVLK5 from NXP Semiconductors (formerly Freescale) is a 32-bit ARM Cortex-M4 microcontroller with DSP extensions, operating at up to 50 MHz, featuring 256 KB program flash with FlexMemory, 64 KB RAM, and integrated USB OTG, ADC, timers, and cryptographic accelerators. It targets industrial control, smart sensors, and low-power HMI applications requiring secure firmware updates and real-time signal processing.

For engineers reviewing the MK21DX256AVLK5 datasheet, MK21DX256AVLK5 pinout, MK21DX256AVLK5 application, or MK21DX256AVLK5 equivalent, key selection criteria include its -40°C to 105°C extended temperature grade, 80-pin LQFP package, FlexNVM-based field-upgradable storage, hardware AES/SHA-256 acceleration, and support for multiple low-power stop modes down to 0.36 µA in VLLS0 (POR disabled).

Technical Context

The MK21DX256AVLK5 implements an ARM Cortex-M4 core with single-cycle DSP instructions and no FPU, paired with a multi-purpose clock generator supporting crystal oscillators (3–32 MHz and 32 kHz), internal reference, and PLL-based frequency synthesis. Its memory subsystem integrates 256 KB flash with FlexNVM partitioning (64 KB FlexNVM + 4 KB FlexRAM), enabling EEPROM-like wear leveling and over-the-air update resilience.

Peripherals include a 16-bit SAR ADC with configurable resolution and sampling rate, two analog comparators with integrated 6-bit DACs, eight-channel PWM timer with motor control features, quadrature decoder, RTC with battery backup, and full-speed USB OTG with on-chip transceiver and charger detection - all operating within the 1.71–3.6 V supply range and qualified for extended temperature operation.

Key Specifications

Pinout & Package

Package: 80-pin LQFP (12 mm × 12 mm), RoHS-compliant, moisture sensitivity level 3, rated for reflow up to 260°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MK21DX256AVLK5, MK22FN512VLH12 offers higher compute throughput and networking capability at the cost of larger footprint and no FlexNVM, while STM32L476RG provides superior power efficiency and display support but requires external USB PHY and software-based cryptography.

Availability

MK21DX256AVLK5 is available at Aetrix Electronics and suitable for industrial motor control, smart energy metering, medical wearable sensor hubs, and building automation controllers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MK21DX256AVLK5 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 AI processing.

The MK21DX256AVLK5 belongs to the Kinetis K21 sub-family - designed specifically for cost-sensitive, low-power industrial and consumer applications demanding robust security, flexible memory architecture, and rich analog/motor control peripherals.

FAQ

What is the maximum operating frequency of the MK21DX256AVLK5?

The MK21DX256AVLK5 operates at a maximum system and core clock frequency of 50 MHz. This is achieved using the internal PLL driven by the primary crystal oscillator (3–32 MHz) or internal reference. The 50 MHz rating applies across the full -40°C to +105°C temperature range and 1.71–3.6 V supply voltage, as verified in the K21 Sub-Family Data Sheet Rev. 4.1.

Does the MK21DX256AVLK5 include hardware cryptographic acceleration?

Yes, the MK21DX256AVLK5 includes dedicated hardware modules supporting DES, 3DES, AES (128/192/256-bit), MD5, SHA-1, and SHA-256 algorithms. These accelerators operate independently of the CPU core, enabling fast firmware signature verification, secure boot, and TLS handshake offload - confirmed in Section 5.5 "Security and integrity modules" of the K21P80M50SF4 datasheet.

What package type and pin count does the MK21DX256AVLK5 use?

The MK21DX256AVLK5 uses an 80-pin LQFP package (12 mm × 12 mm), identified by the "LK" suffix in its part number per the K21 naming convention. This package is RoHS-compliant, rated for moisture sensitivity level 3, and supports standard reflow profiles up to 260°C, as documented in Section 7 "Dimensions" and Section 8 "Pinout" of the K21 Sub-Family Data Sheet.

How much FlexNVM and FlexRAM does the MK21DX256AVLK5 provide?

The MK21DX256AVLK5 provides 64 KB of FlexNVM and 4 KB of FlexRAM, as specified in the "Memories and memory interfaces" section of the K21P80M50SF4 datasheet. This configuration enables EEPROM-emulation functionality, allowing byte-level writes and wear leveling - distinct from standard flash and essential for reliable parameter storage and OTA update staging in the MK21DX256AVLK5.

What is the operating temperature range supported by the MK21DX256AVLK5?

The MK21DX256AVLK5 is rated for operation from -40°C to +105°C ambient temperature, indicated by the "V" suffix in its part number per the K21 family naming convention. This extended temperature grade is validated across all electrical specifications including flash programming, USB operation, and low-power modes, making it suitable for under-hood automotive, industrial control, and outdoor IoT applications.