PIC32MX250F128B-I/ML - 32-bit MCU 128KB Flash 40MHz | Microchip
MPN: PIC32MX250F128B-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.3 | $4.30 |
| 10 | $3.86 | $38.60 |
| 100 | $3.28 | $328.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.62 | $2,620.00 |
PIC32MX250F128B-I/ML Overview
A 32-bit microcontroller (MCU) is an integrated processor core with on-chip memory, peripherals, and I/O that executes instructions on 32-bit-wide data paths. Within the broader taxonomy, PIC32MX sits at: 32-bit MCU -> MIPS M4K architecture -> Microchip PIC32 family -> embedded microcontroller -> semiconductor IC. The "MX" suffix indicates the mainstream PIC32 line, balancing peripherals, performance, and cost for general-purpose applications including audio, graphics, USB, and advanced analog interfaces.
The PIC32MX250F128B integrates two I2S/SPI modules for codec/serial comms, a Parallel Master Port (PMP) for graphics, Peripheral Pin Select (PPS) for flexible I/O mapping, mTouch capacitive touch support, and 1 ns high-resolution time measurement. The on-chip 10-bit ADC reaches 500 ksps with a 16-channel input mux, and an on-die temperature diode supports internal thermal monitoring without an external sensor.
Architecturally, the device uses a 5-stage pipeline Harvard MIPS core with hardware multiply/divide and a single-cycle MAC. Code execution is from Flash through a 16-entry instruction cache, accelerating loops common in DSP-style signal chains. USB 2.0 full-speed device/host/OTG and CAN 2.0B peripherals are available in sibling variants of the PIC32MX2xx family, while this "B" pinout exposes 21 general-purpose I/O pins.
Typical applications include USB HID peripherals (audio interfaces, HID controllers), mTouch capacitive-button front panels, low-cost graphics HMI with PMP-driven LCDs, sensor-hub data acquisition with on-chip temperature, and industrial control with CAN-style comms. The wide 2.3-3.6 V supply range and 40 MHz operation also suit battery-powered IoT nodes.
For layout, place a 10 uF + 0.1 uF decoupling pair within 5 mm of VDD/AVDD pins and keep the analog reference trace short. Note that the USB-equipped "50I" sibling at 50 MHz has a different supply budget, so verify firmware timing constraints when migrating between speed grades.
This page consolidates distributor pricing, same-family pin-compatible alternatives, and practical design notes that go beyond the manufacturer datasheet to help engineers select and source this MCU efficiently.
Drop-in alternatives for PIC32MX250F128B-I/ML — 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 PIC32MX250F128B-I/ML (same form factor and footprint) — differing in Package, ADC, Operating Temperature, Timers, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC32MX250F128B-50I/ML
✅ Drop-In✓ In Stock
$3.16 / Unit
View Datasheet →PIC32MX230F256B-I/ML
✅ Drop-In✓ In Stock
$2.69 / Unit
View Datasheet →PIC32MX150F128B-I/ML
✅ Drop-In✓ In Stock
$3.3 / Unit
View Datasheet →PIC32MX170F256B-I/ML
✅ Drop-In✓ In Stock
$3.25 / Unit
View Datasheet →PIC32MX130F128B-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC32MX130F256B-I/ML
✅ Drop-In✓ In Stock
$4.12 / Unit
View Datasheet →PIC32MX250F128B-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | MIPS32 M4K 32-bit RISC |
| Maximum CPU Speed | 40 MHz |
| Performance | 1.56 DMIPS/MHz (up to 83 DMIPS) |
| Flash Program Memory | 128 KB |
| SRAM | 32 KB |
| Supply Voltage (VDD) | 2.3 V to 3.6 V |
| Active Current | 0.5 mA/MHz |
| Operating Temperature | -40 C to +85 C (Industrial, I-temp) |
| I/O Pins | 21 general-purpose |
| Package | 28-QFN 6x6 mm (ML) |
| Mounting Type | Surface Mount |
| ADC | 10-bit, 500 ksps, 16-channel |
| Timers | Five 16-bit and two 32-bit (capture/compare) |
| Communication | 2x I2S/SPI, I2C, UART, PMP |
| Special Features | Peripheral Pin Select (PPS), mTouch, 1 ns time measurement, on-chip temperature sensor |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant |
PIC32MX250F128B-I/ML Pin Configuration
| Pin 1 | RB5/PMD5 — I/O port B bit 5 / Parallel Master Port data 5 (PPS-mappable) |
| Pin 2 | RB4/PMD4 — I/O port B bit 4 / PMP data 4 (PPS-mappable) |
| Pin 3 | RB3/PMD3 — I/O port B bit 3 / PMP data 3 (PPS-mappable) |
| Pin 4 | RB2/PMD2 — I/O port B bit 2 / PMP data 2 (PPS-mappable) |
| Pin 5 | RB1/PMD1 — I/O port B bit 1 / PMP data 1 (PPS-mappable) |
| Pin 6 | RB0/PMD0 — I/O port B bit 0 / PMP data 0 (PPS-mappable) |
| Pin 7 | RB6/PGC — I/O port B bit 6 / Programming clock (ICD/debug) |
| Pin 8 | RB7/PGD — I/O port B bit 7 / Programming data (ICD/debug) |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Digital supply voltage (2.3 V - 3.6 V) |
| Pin 11 | RA0 — I/O port A bit 0 (PPS-mappable) |
| Pin 12 | RA1 — I/O port A bit 1 (PPS-mappable) |
| Pin 13 | RA2 — I/O port A bit 2 (PPS-mappable) |
| Pin 14 | RA3 — I/O port A bit 3 (PPS-mappable) |
| Pin 15 | RA4 — I/O port A bit 4 (PPS-mappable) |
| Pin 16 | RA5 — I/O port A bit 5 (PPS-mappable) |
| Pin 17 | RA6 — I/O port A bit 6 (PPS-mappable) |
| Pin 18 | RA7 — I/O port A bit 7 (PPS-mappable) |
| Pin 19 | VSS — Ground reference |
| Pin 20 | AVDD — Analog supply voltage |
| Pin 21 | AVSS — Analog ground |
| Pin 22 | RB8 — I/O port B bit 8 (PPS-mappable) |
| Pin 23 | RB9 — I/O port B bit 9 (PPS-mappable) |
| Pin 24 | RB10 — I/O port B bit 10 (PPS-mappable) |
| Pin 25 | RB11 — I/O port B bit 11 (PPS-mappable) |
| Pin 26 | RB12 — I/O port B bit 12 (PPS-mappable) |
| Pin 27 | RB13 — I/O port B bit 13 (PPS-mappable) |
| Pin 28 | RB14 — I/O port B bit 14 (PPS-mappable) |
Typical Applications
PIC32MX250F128B-I/ML is suitable for 6 applications: USB Audio Class (UAC) Device Interface, mTouch Capacitive Touch Front Panel, Low-Cost Graphics HMI with PMP, Industrial Control Sensor Acquisition Hub, IoT Edge Node with On-Chip Temperature, Hobbyist / Maker Arduino-style Board.
USB Audio Class (UAC) Device Interface
The PIC32MX250F128B-I/ML's USB 2.0 full-speed peripheral and two I2S modules enable direct USB audio streaming at 48 kHz / 16-bit without an external codec controller. Its 32 KB SRAM comfortably holds stereo 48 kHz RX + TX ping-pong buffers (~6 KB total), leaving headroom for the USB stack and HID control. At 40 MHz the MIPS32 M4K core sustains ~83 DMIPS, sufficient for software volume/mute DSP while maintaining a glitch-free USB isochronous endpoint. Place a 27 %-tolerance crystal on the dedicated USB clock pins and use the on-chip 3.3 V regulator to power VUSB, which simplifies BOM for low-cost USB headsets and USB DAC dongles.
Recommended
mTouch Capacitive Touch Front Panel
The PIC32MX250F128B-I/ML's mTouch peripheral provides up to 16 channels of charge-time-measurement (CTMU) touch acquisition with no external IC, making it ideal for sealed-key front panels on appliances, medical pumps, and industrial controllers. At 40 MHz the core completes a 16-button scan plus debounce/filter in well under 1 ms, enabling sub-30 ms response times that meet IEC 60335 household-appliance safety response budgets. The 128 KB Flash stores UI state machines and self-test routines without external EEPROM. Use the on-chip temperature diode to compensate touch thresholds against ambient drift, eliminating the external NTC needed by older microcontrollers.
Recommended
Low-Cost Graphics HMI with PMP
The PIC32MX250F128B-I/ML's Parallel Master Port (PMP) can drive a small 320x240 QVGA TFT directly in 8-bit intel-8080 mode, eliminating an external graphics controller IC and saving both BOM cost and PCB area. With 32 KB SRAM the firmware can host a 16-bit framebuffer for a partial-screen QVGA at 8 bpp (~150 KB) using partial-refresh strategies. The MIPS32 M4K's hardware multiply makes antialiased text rendering practical on bare metal. The 28-QFN ML package exposes enough I/O for SPI-touch + PMP data + backlight PWM, making this MCU a fit for small industrial HMI modules, thermostat UI panels, and laboratory instrument readouts.
Recommended
Industrial Control Sensor Acquisition Hub
The PIC32MX250F128B-I/ML's 16-channel 10-bit ADC at 500 ksps combined with 1 ns timer resolution makes it a strong fit for industrial sensor hubs that need to sample multiple analog inputs with precise timestamping. At 0.5 mA/MHz active current, the device consumes roughly 20 mA at full 40 MHz operation, well within the thermal envelope of the 28-QFN without a heatsink. The PPS remapping lets designers route UART/CAN-style comms to convenient pins, simplifying board layout when adding RS-485 transceivers. The 2.3-3.6 V supply also supports 3.3 V-powered industrial sensor chains without level shifters, reducing BOM in 4-20 mA loop interfaces.
Recommended
IoT Edge Node with On-Chip Temperature
The PIC32MX250F128B-I/ML integrates an on-die temperature diode that can be read via the ADC, eliminating an external temperature sensor in IoT edge nodes that need cold/hot ambient telemetry alongside primary sensing. At 0.5 mA/MHz active and deep-sleep currents below typical 1 uA (per family datasheet), battery life on a 2x AA pack can stretch to years in duty-cycled wireless sensor applications. The 128 KB Flash stores TLS libraries, sensor fusion state, and OTA staging slots, while 32 KB SRAM covers TLS record buffers. The industrial -40 C to +85 C temperature range supports outdoor deployments in IoT agriculture, asset tracking, and HVAC monitor nodes.
Recommended
Hobbyist / Maker Arduino-style Board
The PIC32MX250F128B-I/ML is the chip used by open-source designs like the *uino-mx250, where its 3.3 V native supply, 83 DMIPS performance, and Arduino-Uno shield pinout compatibility make it a strong step-up from 8-bit AVR designs. With 128 KB Flash and 32 KB SRAM, hobbyists can run MicroPython or full Arduino cores with significant headroom over an ATmega328P. The chip's USB device peripheral replaces the ATmega16U2/CH340 USB bridge, removing a bill-of-materials component. Designers must observe that the PIC32MX250F128B has 21 usable I/Os versus the ATmega328P's 23, and that the 3.3 V logic requires level shifting for 5 V shields.
Recommended
Recommended Products Summary
Engineering reference data for PIC32MX250F128B-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC32MX250F128B-50I/ML | PIC32MX230F256B-I/ML | PIC32MX150F128B-I/ML | PIC32MX170F256B-I/ML | PIC32MX130F128B-I/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-QFN (ML) 6x6 mm | 28-QFN (ML) 6x6 mm - same | 28-QFN (ML) 6x6 mm - same | 28-QFN (ML) 6x6 mm - same | 28-QFN (ML) 6x6 mm - same | 28-QFN (ML) 6x6 mm - same |
| Max CPU Speed | 40 MHz | 50 MHz (+25%) | 40 MHz (same) | 40 MHz (same) | 40 MHz (same) | 40 MHz (same) |
| Flash Memory | 128 KB | 128 KB (same) | 256 KB (+100%) | 128 KB (same) | 256 KB (+100%) | 128 KB (same) |
| SRAM | 32 KB | 32 KB (same) | 16 KB (-50%) | 32 KB (same) | 64 KB (+100%) | 32 KB (same) |
| I/O Pins | 21 GPIO | 21 GPIO (same) | 21 GPIO (same) | 21 GPIO (same) | 21 GPIO (same) | 21 GPIO (same) |
| I2S Module | Yes (2x) | Yes (2x) | Yes (2x) | Yes (1x) | No | No |
| 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 | 2.3 V to 3.6 V | 2.3 V to 3.6 V |
| Operating Temperature | -40 C to +85 C (I-temp) | -40 C to +85 C (I-temp) | -40 C to +85 C (I-temp) | -40 C to +85 C (I-temp) | -40 C to +85 C (I-temp) | -40 C to +85 C (I-temp) |
Key Differentiators
- 2x I2S modules + USB 2.0 in same 28-QFN (vs PIC32MX150F128B-I/ML)
- 32 KB SRAM for stereo audio + USB stack (vs PIC32MX230F256B-I/ML)
- Same memory map as 50 MHz upgrade enables seamless speed migration (vs PIC32MX250F128B-50I/ML)
Design Notes
Decoupling: place a 10 uF bulk + 0.1 uF ceramic pair within 5 mm of each VDD/AVDD pin, and a 10 uF + 0.1 uF pair on the VCAP pin for the internal 1.2 V core regulator. The VCAP capacitor must be low-ESR ceramic; do not substitute electrolytic. For USB applications, also bypass VUSB with a 0.1 uF capacitor and route DP/DM as a 90 ohm differential pair per USB 2.0 layout guidelines. Estimated input-current budget at 40 MHz full peripheral activity is ~20 mA, so a regulator with at least 100 mA headroom is recommended.
QFN thermal pad: the exposed pad (EP) on the 28-QFN ML package is the primary thermal path and MUST be soldered to a continuous ground plane with thermal vias (typically a 3x3 via array, 0.3 mm drill, 0.5 mm pitch) to keep the junction temperature inside the -40 C to +85 C range. Use NSMD pads with a slightly oversized solder mask opening for reliable QFN reflow. A non-connected EP can raise junction temperature by 15-20 C above the rated limit at 40 MHz full load.
Analog isolation: keep analog input traces (AN0-AN15) short and away from switching signals like PWM outputs and the 48 MHz USB clock trace. Route the analog reference voltage (AVDD/VREF+) through a ferrite bead from VDD, and dedicate one ground pour to the analog section stitched to the digital ground at a single point near the IC. The 10-bit ADC achieves 500 ksps only when these analog layout practices are followed; otherwise effective resolution degrades to ~8 bits in electrically noisy environments.
Clock configuration: the PIC32MX250F128B-I/ML cannot self-start from an internal RC at 40 MHz USB-accurate timing; a crystal or external oscillator on the OSCI/OSCO pins is required for USB, PMP graphics, and I2S-bus baud-rate stability. A common pitfall is leaving the on-chip 8 MHz FRC enabled after switching to a PLL, causing the bus clock to drift out of spec and triggering USB enumeration failures. Always set the OSCCON.SOSCEN, SPLL bits and CFGMULT bits in the unlock sequence described in the family reference manual section 6.
Compliance Information
RoHS/lead-free per Microchip product page. Not AEC-Q100 qualified - choose a -V automotive variant for vehicle applications. Halogen-free per Microchip Material Composition disclosure.
