MK21DX128VMC5 - K21 Cortex-M4 50MHz 128KB MCU | NXP
MPN: MK21DX128VMC5 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.73 | $4.73 |
| 10 | $4.35 | $43.50 |
| 100 | $4.12 | $412.00 |
| 500 | $3.95 | $1,975.00 |
| 1,000 | $3.75 | $3,750.00 |
MK21DX128VMC5 Overview
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, program memory, RAM, and peripheral interfaces such as UART, SPI, I2C, and USB into one chip. The Cortex-M4 sits in the middle of the ARM embedded processor hierarchy, above the Cortex-M0+ and below application-class cores, adding a hardware DSP unit and single-cycle multiply-accumulate for digital signal processing. MCUs like this one are the foundation of embedded system design, powering industrial control, consumer electronics, and automotive subsystems.
Key features of the K21 sub-family include the 50 MHz Cortex-M4 core with DSP instructions, 128 KB (128K x 8) on-chip flash, USB device controller, and NXP DryIce tamper-detection security technology referenced in distributor listings. Supply operation spans the 1.8V, 2.5V, and 3.3V domains noted in the Freescale datasheet listing, easing integration with both low-voltage and legacy 3.3V boards. The compact 8x8 mm MAPBGA keeps board area small while providing 121 balls of I/O for rich peripheral connectivity.
Architecturally, the K21 series pairs the Cortex-M4 with NXP Kinetis peripherals, and the 128 KB flash variant targets code-space-constrained designs that still need DSP-class arithmetic, such as audio processing, sensor fusion, and closed-loop motor control. The MK21DX family also offers 256 KB flash options and an AV (superset) variant, allowing migration within the same die family when memory needs grow.
Typical applications include USB-enabled embedded devices, portable instrumentation, touch-sensing user interfaces, industrial sensor nodes, and DSP-assisted control loops where the Cortex-M4 MAC unit accelerates filtering and FFT workloads.
When designing with this part, note that MAPBGA ball-out routing requires via-in-pad or microvia PCB technology, so verify your fabricator capability early in the design cycle.
This page synthesizes distributor pricing, same-family drop-in alternatives, and practical design guidance not found in any single datasheet, giving engineers a complete sourcing and design reference for the MK21DX128VMC5.
Drop-in alternatives for MK21DX128VMC5 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MK21DX128VMC5 (same form factor and footprint) — differing in Package, Flash Memory, Product Family, Supply Voltage, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MK21DN512VMC5
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MK21DX256VMC5
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$5.5282 / Unit
View Datasheet →MK21DX256AVMC5
✅ Drop-In📋 Reference alternative (not in catalog)
MK11DX128AVMC5
✅ Drop-In📋 Reference alternative (not in catalog)
MK21DX128VMC5 Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M4 |
| Core Size | 32-Bit |
| Core Count | 1 (Single-Core) |
| Maximum Clock Frequency | 50 MHz |
| Flash Memory | 128 KB (128K x 8) |
| Product Family | Kinetis K21 |
| Package | 121-MAPBGA (8x8 mm) |
| Supply Voltage | 1.8V / 2.5V / 3.3V |
| USB | USB device |
| Security | DryIce tamper detection |
| Mounting Type | Surface Mount |
| Packaging Type | Tray |
| DSP Instructions | Yes (Cortex-M4 hardware MAC) |
| Data Bus Width | 32 bit |
| Manufacturer Status | Original manufacturer new (distributed by Rochester Electronics as authorized aftermarket) |
MK21DX128VMC5 121-mapbga (8x8 mm) Pin Configuration Guide
Pin configuration for MK21DX128VMC5 (121-mapbga (8x8 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for MK21DX128VMC5.
Refer to the datasheet for full pin configuration.
Typical Applications
MK21DX128VMC5 is suitable for 6 applications: USB Embedded Devices, Portable Instrumentation, Industrial Sensor Nodes, Touch-Sensing User Interfaces, DSP-Assisted Motor Control, Audio Signal Processing.
USB Embedded Devices
The MK21DX128VMC5 integrates a USB device controller with the Cortex-M4 core at 50 MHz, enabling compact USB HID, CDC virtual-COM, and mass-storage class devices without an external USB chip. The 128 KB flash accommodates USB stack (e.g., NXP MCUXpresso SDK USB stack), application logic, and descriptors with typical headroom of 30-50 KB for growth. Because the USB peripheral shares the 3.3V I/O domain, a simple LDO from USB 5V provides the supply. Designs benefit from the DryIce tamper feature when USB firmware IP needs protection. Unlike externally-bridged USB solutions, the integrated controller reduces BOM cost and latency, and the Cortex-M4 MAC unit handles in-endpoint data processing such as audio streaming at 48 kHz without core saturation.
Recommended
Portable Instrumentation
Battery-powered instruments benefit from the MK21DX128VMC5's 1.8V-capable low-power modes and DSP-class core. The Cortex-M4's single-cycle MAC accelerates sensor calibration, FFT-based spectral display, and digital filtering at 50 MHz, while the 128 KB flash stores calibration tables and UI assets. Operating across 1.8V, 2.5V, and 3.3V rails allows direct coupling to low-voltage analog front ends, reducing level-shifters. The 8x8 mm MAPBGA keeps the PCB compact for handheld enclosures. In a typical design the MCU reads a precision ADC over SPI, applies IIR filtering, and drives a display over SPI/I2C. Stop and very-low-power modes extend battery life between measurements; verify run/stop currents in the K21 data sheet for your supply configuration.
Recommended
Industrial Sensor Nodes
Industrial monitoring nodes use the MK21DX128VMC5 to sample sensors over I2C/SPI, apply the Cortex-M4 DSP unit for noise filtering and event detection, and report via UART/CAN-bridged networks. The 128 KB flash stores protocol stacks plus OTA-update staging, and the DryIce tamper-detection technology protects configuration integrity in accessible installations. The 121-BGA I/O count supports multiple sensor buses simultaneously. With a 3.3V rail and industrial temperature operation, the part fits DIN-rail and field-node enclosures. Firmware frameworks such as MCUXpresso SDK and FreeRTOS run comfortably in 128 KB. For extended data logging, pair with an external SPI flash; for memory-constrained designs needing growth, the 256 KB MK21DX256VMC5 drops into the same footprint.
Recommended
Touch-Sensing User Interfaces
The K21 family supports capacitive touch sensing, and the MK21DX128VMC5's Cortex-M4 headroom runs NXP touch-sensing libraries with multi-channel scanning, water-tolerance algorithms, and haptic feedback timing at 50 MHz. The 128 KB flash holds the touch library, USB or UART host interface, and display driving code concurrently. The abundant BGA I/O allows large touch electrode matrices plus LED backlight control from one device. Designs using the 3.3V domain interface directly to standard capacitive panels and LED drivers. Because touch decoding involves correlation filtering, the single-cycle MAC reduces scan-to-response latency versus Cortex-M0-class parts. For premium panels with more electrodes or graphical displays, the same-footprint MK21DN512VMC5 provides 4x the code space without layout changes.
Recommended
DSP-Assisted Motor Control
Closed-loop motor control benefits directly from the MK21DX128VMC5's Cortex-M4 DSP instructions. Field-oriented control (FOC) for BLDC/PMSM motors requires fast PI loops and Park/Clarke transforms; the single-cycle MAC executes these at 50 MHz with cycle margin for 10-20 kHz PWM frequencies. The 128 KB flash stores the motor-control stack, commutation tables, and communication interface (UART/CAN). BGA I/O drives gate-driver inputs and captures encoder/Hall feedback. Compared to an MCU plus external DSP-controller split, a single MK21DX128 reduces latency and board area. Ensure ADC trigger-to-PWM timing meets your loop bandwidth using the K21 data sheet ADC/PWM module specs, and budget RAM carefully since 128 KB parts have smaller SRAM than DX256 siblings.
Recommended
Audio Signal Processing
The Cortex-M4 core with hardware MAC makes the MK21DX128VMC5 a practical audio DSP for effects units, intercoms, and active speakers. At 50 MHz, FIR filters and block-based processing handle 16-bit/48 kHz mono and stereo streams; the USB controller doubles as a USB audio-class device port, and I2S-style interfaces plus I2C codec control fit the K21 peripheral set. The 128 KB flash stores the audio framework, USB audio descriptors, and coefficient sets; large reverb impulse responses may need the 256 KB variant in the same 121-MAPBGA footprint. DryIce security protects proprietary algorithms in shipped products. Compare power consumption against a dedicated DSP: for 2-4 channel low-latency processing at modest block sizes, this MCU provides sufficient MIPS with lower system complexity.
Recommended
Recommended Products Summary
Engineering reference data for MK21DX128VMC5 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MK21DN512VMC5 | MK21DX256VMC5 | MK21DX256AVMC5 | MK11DX128AVMC5 |
|---|---|---|---|---|---|
| Package | 121-MAPBGA (8x8 mm) | 121-MAPBGA (8x8 mm) - same | 121-MAPBGA (8x8 mm) - same | 121-MAPBGA (8x8 mm) - same | 121-BGA - same footprint family |
| Brand | NXP Semiconductors (Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | ARM Cortex-M4, 50 MHz | ARM Cortex-M4, 50 MHz | ARM Cortex-M4, 50 MHz | ARM Cortex-M4, 50 MHz | ARM Cortex-M4, 50 MHz |
| Flash Memory | 128 KB | 512 KB | 256 KB | 256 KB | 128 KB |
| Family / Sub-Family | Kinetis K21 (DX) | Kinetis K21 (DN) | Kinetis K21 (DX) | Kinetis K21 (DX, AV superset analog) | Kinetis K11 (peripheral set differs) |
Key Differentiators
- Baseline cost in the same 121-MAPBGA footprint (vs MK21DN512VMC5)
- Memory upgrade path without respin (vs MK21DX256VMC5)
- Full K21 USB + DryIce security feature set (vs MK11DX128AVMC5)
Design Notes
The 121-MAPBGA (8x8 mm) with 0.8 mm ball pitch typically requires via-in-pad or laser microvia fanout. Confirm with your PCB fabricator that they support 0.25-0.3 mm microvias and resin plugging, and specify 4+ layer stackup so power and ground planes sit directly under the ball field. Keep decoupling capacitors on the underside of the board closest to each VDD/VSS ball pair per the K21 data sheet layout guidance. Estimated: at 50 MHz with 3.3V I/O, plan one 100 nF capacitor per supply ball plus one bulk 10 uF per rail.
The MK21DX128VMC5 supports 1.8V, 2.5V, and 3.3V operation per the Freescale datasheet summary. On 3.3V systems, use the internal regulator path per the K21 power chapter and decouple the regulator output. On USB-powered designs, place an LDO (e.g., 3.3V, 150 mA class) from the USB 5V with a 10 uF input capacitor and soft-start to limit inrush. Verify the brown-out reset threshold in the data sheet electrical characteristics against your rail droop during peripheral switching to avoid spurious resets.
This part is increasingly distributed through Rochester Electronics authorized aftermarket rather than direct NXP production lines. Order date-controlled lots and confirm RoHS/lead-free finish for your build standard. Also, when migrating to the MK11DX128AVMC5 (same BGA footprint), do NOT assume pin-function equivalence - the K11 peripheral multiplexing differs from K21; re-verify the ballout table and re-test firmware before committing to a swap.
Compliance Information
Compliance status not stated in the retrieved distributor snippets. Because this part flows through Rochester Electronics authorized aftermarket, verify RoHS/lead-free finish and date code with the seller at order time.
