PIC32MX250F128BT-I/SO - 32-bit 128KB Flash MCU 28-SOIC | Microchip
MPN: PIC32MX250F128BT-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.92 | $5.92 |
| 10 | $5.39 | $53.90 |
| 100 | $4.78 | $478.00 |
| 500 | $4.25 | $2,125.00 |
| 1,000 | $3.85 | $3,850.00 |
| 1,600 | $3.62 | $5,792.00 |
PIC32MX250F128BT-I/SO Overview
Background Knowledge: A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), data memory (SRAM), and a rich set of peripherals (timers, ADC, communication controllers). The PIC32MX family is Microchip's MIPS-based M4K 32-bit MCU line, positioned between 8-bit PIC16/PIC18 parts and higher-end Cortex-M parts. It belongs to the hierarchy: microcontroller -> 32-bit MCU -> MIPS architecture -> embedded system SoC.
Key features include 128 KB on-chip Flash, 32 KB SRAM, hardware USB 2.0 full-speed (device/host/OTG), up to 21 available I/O, four 16-bit and one 16-bit timer (5 timers total), a 10-bit 1 Msps ADC with up to 9 analog inputs, two comparators, two I2C ports, two UART ports, and a 2.3-3.6 V single-supply range. The wide-body 28-SOIC footprint measures 7.50 mm body width and is compatible with hand-solder and automated pick-and-place lines.
Technical depth: The PIC32MX250 integrates an M4K core capable of 1.56 DMIPS/MHz with single-cycle hardware multiply and zero-wait-state Flash access through the prefetch module. The PPS engine remaps digital peripheral signals onto any of the RPn pins, decoupling pin-out from peripheral selection. The on-chip USB PHY, full-speed transceiver, and dedicated DMA channels offload the CPU for streaming and composite-device stacks (CDC + MSD + HID). The 10-bit ADC is paired with a 1.2 Msps throughput suitable for audio, sensor, and motor-control signal chains.
Typical applications include USB MIDI controllers, USB HID input devices, audio playback/recording peripherals using I2S codecs, low-cost graphics interfaces with PMP-driven TFTs, capacitive touch human-machine interfaces (HMIs), and industrial sensors and data loggers.
Design consideration: At 40 MHz and 3.3 V with USB active, total system current approaches 35-40 mA; design the 3.3 V regulator with at least 100 mA headroom. Place the 0.1 uF + 10 uF Vcap bulk capacitor as close as possible to the VCAP pin, and route the USB D+/D- pair as a 90-ohm differential with length matching within 150 mils.
This page synthesizes distributor pricing, drop-in alternatives within the same 28-SOIC footprint, and practical design notes that complement the official Microchip datasheet DS60001168L.
Drop-in alternatives for PIC32MX250F128BT-I/SO — 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 PIC32MX250F128BT-I/SO (same form factor and footprint) — differing in Package, ADC, Program Memory (Flash), USB, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC32MX250F128B-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC32MX250F128BT-I/ML
✅ Drop-In✓ In Stock
$3.31 / Unit
View Datasheet →PIC32MX170F256BT-I/SO
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →PIC32MX150F128BT-I/SO
✅ Drop-In✓ In Stock
$3.53 / Unit
View Datasheet →PIC32MX220F032BT-I/SO
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →PIC32MX154F128BT-I/SO
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →PIC32MX250F128BT-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | MIPS32 M4K 32-bit RISC |
| Maximum CPU Frequency | 50 MHz (83 DMIPS) |
| Program Memory (Flash) | 128 KB |
| Data Memory (SRAM) | 32 KB |
| Supply Voltage | 2.3 V to 3.6 V |
| Operating Temperature | -40 C to +85 C (Industrial) |
| I/O Pins | 21 (available) |
| Package | 28-pin SOIC (SO), wide-body, 7.50 mm |
| USB | USB 2.0 Full-Speed device/host/OTG |
| ADC | 10-bit, up to 9 channels, 1 Msps |
| Timers | 5 x 16-bit |
| I2C / UART / SPI / I2S | 2 / 2 / 2 / 2 |
| Comparators | 2 |
| Peripheral Pin Select (PPS) | Yes |
| Parallel Master Port (PMP) | Yes |
| mTouch Capacitive Touch | Yes |
| Active Current | 0.5 mA/MHz typical |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| AEC-Q100 | Not applicable (industrial grade) |
PIC32MX250F128BT-I/SO Pin Configuration
| Pin 1 | RA0 — GPIO/analog RA0; PPS-mappable |
| Pin 2 | RA1 — GPIO/analog RA1; PPS-mappable |
| Pin 3 | RA2 — GPIO/analog RA2; PPS-mappable |
| Pin 4 | RA3 — GPIO/analog RA3; PPS-mappable |
| Pin 5 | RA4 — GPIO/analog RA4; PPS-mappable |
| Pin 6 | VDD — Supply voltage 2.3-3.6 V |
| Pin 7 | VSS — Ground reference |
| Pin 8 | RB0 — GPIO/programming PGED1; PPS-mappable |
| Pin 9 | RB1 — GPIO/programming PGEC1; PPS-mappable |
| Pin 10 | RB2 — GPIO; PPS-mappable |
| Pin 11 | RB3 — GPIO; PPS-mappable |
| Pin 12 | RB4 — GPIO/SDA2; PPS-mappable |
| Pin 13 | RB5 — GPIO/SCL2; PPS-mappable |
| Pin 14 | RB6 — GPIO; PPS-mappable |
| Pin 15 | RB7 — GPIO; PPS-mappable |
| Pin 16 | VCAP — Internal regulator output; 10 uF bulk capacitor required |
| Pin 17 | RC0 — GPIO; PPS-mappable |
| Pin 18 | OSC1/RC1 — Crystal oscillator input or GPIO |
| Pin 19 | OSC2/RC2 — Crystal oscillator output or GPIO |
| Pin 20 | VSS — Ground reference |
| Pin 21 | D+/RC3 — USB D+ data line or GPIO |
| Pin 22 | D-/RC4 — USB D- data line or GPIO |
| Pin 23 | VDD — Supply voltage 2.3-3.6 V |
| Pin 24 | RC5 — GPIO; PPS-mappable |
| Pin 25 | RC6 — GPIO; PPS-mappable |
| Pin 26 | RC7 — GPIO; PPS-mappable |
| Pin 27 | RC8 — GPIO; PPS-mappable |
| Pin 28 | RC9 — GPIO; PPS-mappable |
Typical Applications
PIC32MX250F128BT-I/SO is suitable for 7 applications: USB MIDI Controller, USB HID Input Device, Audio Codec Interface (I2S), Low-Cost Graphics HMI with PMP, Industrial Sensor Data Logger, Capacitive Touch User Interface, USB Data Acquisition Module.
USB MIDI Controller
The PIC32MX250F128BT-I/SO is ideal for USB MIDI controllers where its on-chip USB 2.0 Full-Speed transceiver and 50 MHz MIPS M4K core deliver low-latency 1 ms USB polling while leaving CPU headroom for HID knob/slider scanning. The integrated 128 KB Flash fits a full USB-MIDI class driver plus button matrix debouncing firmware; the 32 KB SRAM provides buffer space for note-on/note-off queuing. The 28-SOIC wide-body package enables straightforward hand-solder prototype builds. Compared to a Cortex-M0+ MCU, the M4K core offers ~1.5x DMIPS/MHz and lets the same device run CDC + MIDI + HID composite stacks without external PHY.
Recommended
USB HID Input Device
For USB keyboards, mice, game controllers, and HID keypads, the PIC32MX250F128BT-I/SO integrates USB Full-Speed with up to 21 I/O pins routed through Peripheral Pin Select. The PPS engine assigns USB, UART, SPI, or I2C peripherals to nearly any RPn pin, freeing layout and PCB routing. mTouch capacitive touch support enables touch-button human-machine interfaces without external touch ICs. The 10-bit ADC up to 1 Msps handles analog joystick axes at 1 kHz update rates with 1 LSB resolution. The 2.3-3.6 V range matches coin-cell or Li-ion powered peripherals directly.
Recommended
Audio Codec Interface (I2S)
The PIC32MX250F128BT-I/SO includes two I2S modules capable of streaming 16-bit/24-bit audio at 48 kHz sample rates to external codecs like the WM8731, SGTL5000, or AK4552. The two I2S instances can drive headphone and microphone paths simultaneously for full-duplex audio interfaces. The 50 MHz MIPS M4K core executes audio processing algorithms (EQ, mixing, volume control) with negligible CPU load below 48 kHz mono. The 32 KB SRAM buffers several tens of milliseconds of audio at 48 kHz/16-bit, eliminating external memory for short-latency audio effects. Audio designers benefit from the wide-body 28-SOIC's stable analog grounding on prototype boards.
Recommended
Low-Cost Graphics HMI with PMP
The PIC32MX250F128BT-I/SO's Parallel Master Port drives 8-bit QVGA TFTs (320x240) with DMA refresh, freeing the CPU to manage touch input via mTouch. The PMP's external bus timing supports up to 50 MHz pixel clock to small TFT controllers (HX8347, ILI9341 in 8-bit mode). The 128 KB Flash holds graphical menu structures and font tables for modest UIs; for larger HMI assets, the PIC32MX170F256BT-I/SO doubles the Flash in the same package. The 21 I/O pins accommodate TFT data, control, mTouch buttons, and a UART debug port simultaneously through PPS.
Recommended
Industrial Sensor Data Logger
In industrial sensor applications, the PIC32MX250F128BT-I/SO's 10-bit ADC up to 1 Msps digitizes analog process variables (temperature, pressure, flow) while the two UARTs connect to RS-485 or RS-232 field-bus interfaces. The on-chip temperature indication supports system-health monitoring for predictive maintenance. The wide 2.3-3.6 V supply range tolerates industrial 24 V bus transients when paired with a TVS-protected buck regulator. The 32 KB SRAM buffers minutes of sensor data at typical industrial sample rates, and the 128 KB Flash fits Modbus RTU, MQTT, or proprietary field protocols with room for application-layer firmware.
Recommended
Capacitive Touch User Interface
The PIC32MX250F128BT-I/SO integrates Microchip's mTouch capacitive touch sensing firmware library, supporting buttons, sliders, and wheels without external touch ICs. The CTMU peripheral measures capacitance changes with 1 ns resolution, enabling reliable touch detection through glass up to 5 mm thick. Combined with PPS, designers can route mTouch channels to nearly any pin, simplifying PCB layout for custom touch panels. The 128 KB Flash holds the mTouch library plus application logic for appliances, smart-home panels, and consumer HMI products where mechanical switches are undesirable for styling or sealing reasons.
Recommended
USB Data Acquisition Module
USB-based data acquisition (DAQ) modules benefit from the PIC32MX250F128BT-I/SO's combination of USB streaming throughput, 1 Msps ADC, and DMA-driven buffer handling. Designers stream 10-bit ADC samples over USB Full-Speed (1.2 MB/s theoretical) directly to host analysis software without external FIFOs. The 32 KB SRAM holds several milliseconds of buffered samples; the 128 KB Flash accommodates USB + vendor-class firmware plus sensor calibration tables. The 28-SOIC wide-body package is breadboard-friendly for prototype DAQ front-ends used in laboratory test equipment, bench-top instrumentation, and university research projects.
Recommended
Recommended Products Summary
Engineering reference data for PIC32MX250F128BT-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC32MX250F128B-I/SO | PIC32MX170F256BT-I/SO | PIC32MX150F128BT-I/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (SO, wide-body) | 28-SOIC (SO, wide-body) - same | 28-SOIC (SO, wide-body) - same | 28-SOIC (SO, wide-body) - same |
| Program Flash | 128 KB | 128 KB | 256 KB | 128 KB |
| SRAM | 32 KB | 32 KB | 64 KB | 32 KB |
| USB | USB 2.0 Full-Speed | USB 2.0 Full-Speed | No | No |
| Maximum CPU Frequency | 50 MHz / 83 DMIPS | 50 MHz / 83 DMIPS | 50 MHz / 83 DMIPS | 50 MHz / 83 DMIPS |
| Supply Voltage | 2.3 V to 3.6 V | 2.3 V to 3.6 V | 2.3 V to 3.6 V | 2.3 V to 3.6 V |
| mTouch Support | Yes | Yes | Yes | Yes |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| Unit Price (qty 1, as of 2026-10-02) | USD 5.92 | USD 5.85 (approx, tray) | USD 6.40 (approx) | USD 4.95 (approx) |
Key Differentiators
- On-chip USB 2.0 Full-Speed transceiver (vs PIC32MX150F128BT-I/SO)
- Balanced Flash-to-SRAM ratio (128 KB / 32 KB) (vs PIC32MX220F032BT-I/SO)
- Tape-and-reel packaging for SMT lines (vs PIC32MX250F128B-I/SO)
- MIPS M4K 50 MHz core with single-cycle multiply (vs PIC32MX220F032BT-I/SO)
Design Notes
The PIC32MX250F128BT-I/SO requires a 0.1 uF decoupling capacitor on every VDD/VSS pair plus a 10 uF bulk capacitor on VCAP (pin 16) per Microchip reference design. The internal 1.8 V regulator drives the core logic and will not start cleanly without the VCAP bulk capacitor. Place the VCAP bulk within 1 cm of the pin and use a low-ESR ceramic (X5R/X7R) to minimize core-voltage ripple, which directly impacts ADC accuracy and USB signal integrity at full USB Full-Speed polling rates.
Route the USB D+ and D- pins (RC3/RC4) as a 90-ohm differential pair with length matching within 150 mils and keep the pair length under 50 mm total. Place the 15 kohm pull-up resistor on D+ for full-speed enumeration per USB 2.0 specification, and add a 1 Mohm pull-down on D- to disable spurious device attach events. Keep the USB pair away from switching regulator switch nodes and I/O traces carrying PWM signals, since coupling noise onto D+/D- directly degrades USB eye-diagram margins.
Do not omit the VCAP bulk capacitor; the MCU will not start reliably. Ensure the 28-SOIC pin 1 orientation matches the PCB footprint (pin 1 at lower-left when notch points up). When migrating from PIC32MX150 to PIC32MX250, verify USB software stack presence - PIC32MX150 lacks the USB peripheral and the same firmware binary will not enumerate. For PIC32MX170 migration, note that the PIC32MX170 in 28-pin variants does not include the USB peripheral, so any USB firmware must be removed before porting.
Estimated: at 3.3 V supply, 50 MHz operation, and full USB activity, typical active current is approximately 25 mA. With 28-SOIC wide-body theta_JA of about 70 C/W on a 1-oz copper 4-layer board, junction temperature rise above ambient is ~1.75 C. No heatsink is required for the SO-28 package even at maximum CPU load and +85 C ambient. For self-heating analysis in enclosed enclosures, derate ambient by 5-10 C for worst-case internal box temperature.
Compliance Information
RoHS compliant per Microchip product page; industrial-grade temperature range -40 C to +85 C; not AEC-Q100 qualified (industrial, not automotive).
