PIC32MX274F256B-I/MM - 32-bit 72MHz MCU 256KB Flash USB 28-QFN | Microchip
MPN: PIC32MX274F256B-I/MM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.83 | $5.83 |
| 10 | $5.2 | $52.00 |
| 100 | $4.62 | $462.00 |
| 500 | $4.1 | $2,050.00 |
| 1,000 | $3.66 | $3,660.00 |
PIC32MX274F256B-I/MM Overview
A 32-bit microcontroller (MCU) is a programmable processor with a 32-bit data path, on-chip Flash program memory, SRAM data memory, and a rich set of digital and analog peripherals. Within the embedded hierarchy, the PIC32MX family sits in Microchip's mid-range 32-bit tier between 8-bit PIC MCUs and 32-bit Cortex-M parts from other vendors, offering deterministic MIPS performance with low power consumption. The PIC32MX27x sub-family specifically targets XLP (eXtreme Low Power) applications with deep sleep currents in the microamp range while running the core up to 72 MHz.
Key specifications include 256 KB single-voltage Flash with live update capability, 64 KB SRAM, full-speed USB 2.0 device/host/OTG, 21-channel 10-bit ADC at 1 Msps, three analog comparators, a CTMU for capacitive touch and precise time measurement, and an RTCC module with calendar alarm. The device supports 3.3V single-supply operation, integrates a 4-channel DMA controller, and offers PMP/EPMP for graphics interfaces, plus multiple UART, SPI, and I2C peripherals. The 28-QFN-S 6x6 package footprint is compact yet provides a thermal pad for moderate power dissipation.
The PIC32MX274F256B-I/MM is suitable for industrial USB peripherals, consumer devices with capacitive touch, low-power sensor hubs, and battery-powered embedded applications where the XLP run/sleep/deep-sleep currents extend operating life. Typical end products include USB barcode scanners, smart sensors, portable medical peripherals, HMI control panels, and audio playback modules. Designers using MPLAB Harmony v3 and MPLAB XC32 can leverage integrated middleware and software stacks to accelerate time-to-market.
When designing with this part, plan PCB layout around the exposed thermal pad for proper heat spreading, and place decoupling capacitors close to each VDD/VSS pair. Note that code that worked on PIC32MX1xx/2xx 28-pin variants is generally portable, but USB stack and PMP usage should follow Microchip's Harmony 3 application notes for reliable operation. The Flash endurance is rated for typical embedded use and is well documented in the device family reference manual.
Drop-in alternatives for PIC32MX274F256B-I/MM — 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 PIC32MX274F256B-I/MM (same form factor and footprint) — differing in Package, Operating Temperature, USB, ADC, Comparators.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC32MX274F256BT-I/MM
✅ Drop-In✓ In Stock
$3.16 / Unit
View Datasheet →PIC32MX274F128B-I/MM
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PIC32MX274F256B-I/SP
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PIC32MX274F256B-V/MM
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PIC32MX274F256D-I/PT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC32MX270F256B-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC32MX274F256B-I/MM Maximum Ratings & Electrical Characteristics
| Core | MIPS32 M4K 32-bit |
| Family | PIC32MX27x (XLP) |
| Maximum CPU Frequency | 72 MHz |
| Program Flash Memory | 256 KB (256K x 8) |
| SRAM | 64 KB |
| Operating Voltage | 2.3V to 3.6V |
| USB | USB 2.0 Full-Speed Device/Host/OTG |
| ADC | 10-bit, 1 Msps, up to 13 channels |
| Comparators | 3 Analog Comparators |
| CTMU | Yes (Charge Time Measurement Unit) |
| RTCC | Yes (Real-Time Clock Calendar) |
| DMA Channels | 4 |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 28-pin QFN-S (6x6x0.9 mm) with exposed pad |
| Mounting Type | Surface Mount |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC32MX274F256B-I/MM Pin Configuration
| Pin 1 | SDA2/RPG7/PMD7/RB7 — I2C2 SDA / GPIO / Parallel Master Data |
| Pin 2 | SCL2/RPG8/PMD8/RB8 — I2C2 SCL / GPIO / Parallel Master Data |
| Pin 3 | VSS — Ground |
| Pin 4 | VBUS — USB VBUS sense (3.3V tolerant) |
| Pin 5 | VDD — Power supply (2.3V-3.6V) |
| Pin 6 | D-/RG2 — USB D- / GPIO |
| Pin 7 | D+/RG3 — USB D+ / GPIO |
| Pin 8 | RPG6/PMD6/SCK2/RB6 — SPI2 clock / GPIO / Parallel Master Data |
| Pin 9 | VSS — Ground |
| Pin 10 | OSC1/CLKI/RA3 — Crystal oscillator input or external clock / GPIO |
| Pin 11 | OSC2/CLKO/RA2 — Crystal oscillator output / GPIO |
| Pin 12 | MCLR — Master clear reset (active low) |
| Pin 13 | PGED2/TDI/RA1 — ICSP data / JTAG TDI / GPIO |
| Pin 14 | PGEC2/TCK/RA0 — ICSP clock / JTAG TCK / GPIO |
| Pin 15 | AN1/C1IN+/CVREF+/RPA1/RB1 — Analog input / Comparator input / CVREF / GPIO |
| Pin 16 | AN0/C1IN-/CVREF-/RPB0/RB0 — Analog input / Comparator input / CVREF / GPIO |
| Pin 17 | AN2/C2IN-/C1IN+/SS1/RPB2/RB2 — Analog input / Comparator / SPI1 slave select / GPIO |
| Pin 18 | AN3/C2IN+/RPA2/RB3 — Analog input / Comparator / GPIO |
| Pin 19 | VREF-/CVREF-/RA9 — Voltage reference / GPIO |
| Pin 20 | VREF+/CVREF+/RA10 — Voltage reference / GPIO |
| Pin 21 | AN4/C3IN+/SS1/RPB5/RB5 — Analog input / Comparator / SPI1 / GPIO |
| Pin 22 | AN5/C1IN+/CTED2/RPB6/RB6 — Analog input / Comparator / CTMU / GPIO |
| Pin 23 | AN6/CTED1/RPB7/RB7 — Analog input / CTMU / GPIO |
| Pin 24 | AN7/RPB8/RB8 — Analog input / GPIO |
| Pin 25 | VDD — Power supply (2.3V-3.6V) |
| Pin 26 | RTCC/RPC1/RC1 — Real-Time Clock Calendar output / GPIO |
| Pin 27 | SDA1/SDI1/RPC4/RC4 — I2C1 data / SPI1 data in / GPIO |
| Pin 28 | SCL1/SCK1/RPC3/RC3 — I2C1 clock / SPI1 clock / GPIO |
Typical Applications
PIC32MX274F256B-I/MM is suitable for 6 applications: USB Barcode Scanner, Capacitive Touch Control Panel, Battery-Powered Sensor Hub, Portable Medical Peripheral, Industrial USB-to-UART Bridge, Audio Playback Module with USB Update.
USB Barcode Scanner
The PIC32MX274F256B-I/MM is well suited for handheld USB barcode scanners because its integrated full-speed USB 2.0 controller with on-chip transceiver eliminates the need for an external PHY, and the 72 MHz MIPS M4K core processes image decoding within typical 1D/2D scan-to-read latency budgets. With 256 KB Flash it can host full USB HID or vendor-class stacks plus image-decode firmware, while 64 KB SRAM buffers scan-line data without flow control. The XLP deep-sleep current extends battery life between scans to weeks. Decoupling capacitors and the exposed thermal pad on the 28-QFN-S footprint keep the part stable across thermal swings. Designers typically pair it with a CMOS image sensor over PMP and use the CTMU for trigger-button capacitive touch.
Recommended
Capacitive Touch Control Panel
The PIC32MX274F256B-I/MM integrates a CTMU (Charge Time Measurement Unit) that delivers precise timing measurement for capacitive touch electrodes, making the part a strong fit for industrial and consumer control panels with 8 to 16 touch keys. The 10-bit 1 Msps ADC and three comparators handle mixed signal input from slider/wheel electrodes alongside the touch channels. 256 KB Flash hosts a Harmony 3-based touch library plus main application code, while 64 KB SRAM buffers touch scan results. The -40C to +85C industrial temperature range is appropriate for factory-floor HMI. The exposed pad on the 28-QFN-S package enables reliable operation under the thermal stress of sealed front-panel designs.
Recommended
Battery-Powered Sensor Hub
The PIC32MX274F256B-I/MM's XLP deep-sleep currents below 1 uA and RTCC with calendar alarm enable multi-year battery operation for wireless sensor hubs that wake periodically to read sensors over I2C or SPI. The 72 MHz core handles on-wake data aggregation, filtering, and wireless packet preparation, while 64 KB SRAM buffers sensor history without losing data on next sleep. The 28-QFN-S 6x6 mm footprint fits compact sensor modules, and the 2.3V-3.6V supply range works with common Li-ion or coin-cell chemistries. Designers use the DMA to offload sensor reads and rely on the RTCC for precise wake timing.
Recommended
Portable Medical Peripheral
The PIC32MX274F256B-I/MM is well matched to portable medical peripherals such as USB-connected pulse oximeters, handheld spirometers, and Bluetooth bridges where the integrated full-speed USB 2.0 simplifies data upload to a host PC. Its 256 KB Flash supports FDA-style firmware traceability with version tagging, and the 64 KB SRAM buffers waveform samples before transmission. The -40C to +85C industrial grade meets the temperature profile of clinical and home-use environments. The three analog comparators and 10-bit ADC handle front-end analog signal conditioning for optical or flow sensors, while the RTCC timestamps each measurement for clinical records. The compact 28-QFN-S footprint enables small, ergonomic enclosures.
Recommended
Industrial USB-to-UART Bridge
The PIC32MX274F256B-I/MM makes an excellent USB-to-UART/SPI/I2C bridge for industrial control and debug applications because the on-chip USB and multiple UART instances replace external bridge ICs like the FTDI FT232. The 72 MHz MIPS core handles USB CDC or vendor-class enumeration and protocol translation at line speeds up to 1 Mbaud. The 256 KB Flash hosts the USB stack plus optional command-line shells for industrial configuration. The exposed thermal pad on the 28-QFN-S keeps the part within temperature limits when housed in DIN-rail enclosures. Design engineers typically expose the PGECx/PGEDx pins to a header for in-field firmware updates.
Recommended
Audio Playback Module with USB Update
The PIC32MX274F256B-I/MM is suitable for low-cost USB-updatable audio playback modules where its full-speed USB enables drag-and-drop firmware or audio file updates from a PC, and its 256 KB Flash holds both the audio decoder and a small library of wav or ADPCM samples. The DMA channels offload audio sample transfer to a DAC or PWM output, freeing the 72 MHz core for housekeeping. 64 KB SRAM holds audio buffers and decoded frames without dropouts. The exposed pad and 28-QFN-S footprint suit compact module designs. Designers using the I2S peripheral or PWM with low-pass filter can reach acceptable audio quality for toys, kiosks, and doorbells.
Recommended
Recommended Products Summary
Engineering reference data for PIC32MX274F256B-I/MM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC32MX274F256BT-I/MM | PIC32MX274F128B-I/MM | PIC32MX274F256B-I/SP | PIC32MX274F256B-V/MM | PIC32MX270F256B-I/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-QFN-S (6x6 mm) | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same | 28-QFN (6x6 mm) - same footprint |
| Maximum CPU Frequency | 72 MHz | 72 MHz | 72 MHz | 72 MHz | 72 MHz | 40 MHz |
| Flash Memory | 256 KB | 256 KB | 128 KB | 256 KB | 256 KB | 256 KB |
| SRAM | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB |
| USB | USB 2.0 Full-Speed Device/Host/OTG | USB 2.0 Full-Speed Device/Host/OTG | USB 2.0 Full-Speed Device/Host/OTG | USB 2.0 Full-Speed Device/Host/OTG | USB 2.0 Full-Speed Device/Host/OTG | USB 2.0 Full-Speed Device/Host/OTG |
Key Differentiators
- Higher core speed within the same XLP family (vs PIC32MX270F256B-I/ML)
- Larger program memory than the 128 KB cousin (vs PIC32MX274F128B-I/MM)
- Wider operating temperature option via V-grade variant (vs PIC32MX274F256B-I/MM (Industrial))
Design Notes
Place a 10 uF plus 0.1 uF ceramic decoupling capacitor pair within 5 mm of each VDD/VSS pin pair on the 28-QFN-S package. The exposed thermal pad must be soldered to a continuous ground plane with at least 4 thermal vias (0.3 mm drill) connecting to a bottom-layer ground pour to keep junction temperature within the -40C to +85C industrial rating during sustained 72 MHz operation. Avoid routing high-speed USB D+/D- traces near the switching power section; keep D+/D- matched within 2 mm and 90 ohm differential impedance. Add a 500 mA polyfuse on VBUS if the design is bus-powered, to comply with USB inrush-current limits.
The PIC32MX274F256B-I/MM operates from 2.3V to 3.6V, with the upper end required for USB. For USB applications use a 3.3V LDO rated at 200 mA or higher (Microchip MCP1700 or equivalent) upstream of VDD. Add a ferrite bead in series with VBUS to isolate USB bus noise from the 3.3V rail. Decouple VBUS itself with a 4.7 uF capacitor as required by USB 2.0 spec. When sourcing from a Li-ion cell, ensure the LDO has at least 200 mV dropout margin at full 72 MHz core current to avoid regulation loss.
Do not leave unused comparator or ADC inputs floating; configure them as digital outputs low or tie them to VSS through a 10 kohm resistor to minimize deep-sleep leakage that would defeat the XLP low-power profile. The RTCC requires a 32.768 kHz crystal on SOSC1/SOSC2 (or a 50 Hz/60 Hz input on RTCC pin) for timekeeping during deep sleep - omitting it eliminates the RTCC wake source. The PGECx/PGEDx programming/debug pins must not be repurposed without considering that they are required for ICSP, even in production firmware. Configuration bits must be set explicitly in code to avoid the default debugger-disabled state locking out ICSP.
Compliance Information
RoHS and REACH compliance per Microchip product page. Lead-free packaging confirmed. AEC-Q100 is not applicable to standard PIC32MX parts; the automotive grade is the PIC32MX274F256B-V/MM (extended temperature grade only).
