STR731FV2T6 - ARM7TDMI 32-bit MCU 256KB Flash | STMicroelectronics
MPN: STR731FV2T6 ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $14.05 | $1,405.00 |
| 500 | $12.4 | $6,200.00 |
| 1,000 | $10.95 | $10,950.00 |
STR731FV2T6 Overview
A microcontroller (MCU) is an integrated circuit that combines a processor core, program and data memory, timers, communication peripherals, and analog/digital interfaces on a single die. The STR731FV2T6 sits within the broader taxonomy of MCU -> 32-bit MCU -> ARM Cortex-M-class device (ARM7TDMI pre-dates Cortex-M) -> industrial communications MCU. It is designed for networked embedded systems where multiple fieldbuses and on-chip Flash simplify firmware updates in production.
Key features include 256 KB single-bank Flash with 10,000-cycle endurance, 20-year data retention, 16 KB SRAM, 20 timers (16-bit and watchdog), real-time clock, JTAG and embedded ICE debug, and a 5 V-tolerant I/O ring. The 10-bit ADC offers 12 input channels and conversion speeds up to 1 us. The 100-pin LQFP package provides a 0.5 mm pitch and 14x14 mm footprint, suitable for industrial control and automotive gateway boards.
Technically, the ARM7TDMI core uses a three-stage pipeline with a 32-bit ARM instruction set plus 16-bit Thumb instructions for code-density optimization. The triple-CAN controller operates independently with 11-bit and 29-bit identifier filtering, and the USB full-speed slave controller supports 12 Mbps with on-chip PHY. Industrial-grade EMC, ESD protection, and wide supply tolerance (4.5 V to 5.5 V) suit harsh environments requiring extended reliability.
Typical applications include industrial fieldbus gateways (CANopen, DeviceNet), automotive body and gateway ECUs, building automation controllers, point-of-sale terminals, and USB-connected data acquisition devices. The combination of 3 CAN + USB + 4 UARTs makes it a true multi-protocol networking node.
Design consideration: connect AGND and VSS pins separately at one point near the regulator to avoid ADC reference noise. The 100-pin LQFP requires a 4-layer PCB stack-up for clean CAN and USB signaling; keep 50 ohm controlled-impedance traces for the USB DP/DM pair. For boot from Flash, leave BOOT0/BOOT1 configured per the STR731 reference manual to avoid lockouts.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for STR731FV2T6 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STR732FV2T6
✅ Drop-In📋 Reference alternative (not in catalog)
STR735FV2T6
✅ Drop-In📋 Reference alternative (not in catalog)
STR731FV1T6
✅ Drop-In📋 Reference alternative (not in catalog)
STR736FV1T7
✅ Drop-In📋 Reference alternative (not in catalog)
LPC2106FBD100
✅ Drop-In📋 Reference alternative (not in catalog)
AT91SAM7A3-AU
✅ Drop-In📋 Reference alternative (not in catalog)
STR731FV2T6 Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM7TDMI 32-bit RISC |
| CPU Speed | 36 MHz (32 MIPS) |
| Maximum Internal Clock | 72 MHz |
| Flash Program Memory | 256 KB (256K x 8) |
| SRAM | 16 KB |
| CAN Interfaces | 3 (CAN 2.0B) |
| UART | 4 |
| SPI | 2 |
| I2C | 2 |
| USB | 1 (Full-Speed slave) |
| ADC | 10-bit, 12 channels |
| Timers | 20 (16-bit and watchdog) |
| Supply Voltage | 4.5 V to 5.5 V |
| Operating Temperature | -40 C to +85 C |
| Package | 100-pin LQFP (14x14 mm) |
| Mounting Type | Surface Mount |
STR731FV2T6 Pin Configuration
| Pin 1 | PB10/INT0 — GPIOB bit 10 / External interrupt 0 |
| Pin 2 | PB11/INT1 — GPIOB bit 11 / External interrupt 1 |
| Pin 3 | PB12/INT2 — GPIOB bit 12 / External interrupt 2 |
| Pin 4 | PB13/INT3 — GPIOB bit 13 / External interrupt 3 |
| Pin 5 | VSS — Digital ground |
| Pin 6 | VDD — Digital supply 5 V |
| Pin 7 | VDDA — Analog supply 5 V |
| Pin 8 | VSSA — Analog ground |
| Pin 9 | VREF+ — ADC positive reference |
| Pin 10 | VREF- — ADC negative reference |
| Pin 11 | OSC_IN — Main oscillator input |
| Pin 12 | OSC_OUT — Main oscillator output |
| Pin 13 | NRST — Reset input, active low |
| Pin 14 | BOOT0 — Boot mode selection 0 |
| Pin 15 | BOOT1 — Boot mode selection 1 |
| Pin 16 | TCK — JTAG test clock |
| Pin 17 | TMS — JTAG test mode select |
| Pin 18 | TDI — JTAG test data input |
| Pin 19 | TDO — JTAG test data output |
| Pin 20 | TRST — JTAG test reset |
Typical Applications
STR731FV2T6 is suitable for 6 applications: Industrial CAN Fieldbus Gateway, Automotive Gateway ECU, Building Automation Controller, USB Industrial Data Acquisition Module, Point-of-Sale Terminal Controller, Multi-Protocol Sensor Hub.
Industrial CAN Fieldbus Gateway
The STR731FV2T6's three independent CAN 2.0B controllers with 11/29-bit identifier filtering make it ideal for industrial gateway nodes bridging multiple CANopen or DeviceNet segments to a host controller. The 36 MHz ARM7TDMI core executes stack protocol layers with deterministic latency, while the 256 KB Flash hosts complete CANopen CiA 401/402/404 device profiles alongside application logic. With 4 UARTs and 2 SPI buses, the MCU can simultaneously manage Modbus RTU slaves, RS-485 sensor networks, and an SPI-connected display. The 100-LQFP package and 5 V tolerant I/O simplify integration with industrial 24 V isolator front-ends using standard 5 V CAN transceivers such as the TJA1050.
Recommended
Automotive Gateway ECU
Although not AEC-Q100 qualified, the STR731FV2T6 has been used in prototype and pre-production automotive body and gateway ECUs where its multi-CAN architecture consolidates powertrain, body, and chassis buses into a single routing node. The 12-channel 10-bit ADC reads analog sensor inputs such as coolant temperature, throttle position, and battery voltage. With 256 KB Flash and 16 KB SRAM, the device can host OBD-II diagnostic handlers and UDS (Unified Diagnostic Services) stacks. Industrial -40 C to +85 C operation accommodates under-hood environments when paired with proper thermal management, though production automotive designs should migrate to AEC-Q100 qualified parts such as SPC56 or STM32.
Recommended
Building Automation Controller
Building automation systems require multi-protocol connectivity to KNX, BACnet, Modbus, and proprietary sensor networks. The STR731FV2T6 exposes 4 UARTs for RS-485 multi-drop sensor buses, 2 I2C for HVAC sensor arrays, and 2 SPI for RF transceiver modules such as sub-GHz radios for wireless sensor mesh nodes. The 32 MIPS ARM7TDMI core processes control loops for HVAC, lighting, and access-control subsystems with sufficient headroom for the BACnet MS-TP stack. Operating temperature -40 C to +85 C and 5 V supply tolerance suit unconditioned mechanical rooms where temperatures swing with seasonal loads.
Recommended
USB Industrial Data Acquisition Module
The STR731FV2T6's USB full-speed slave controller with on-chip PHY enables direct connection to a PC host running LabVIEW or custom DAQ software, eliminating external bridge chips. The 12-channel 10-bit ADC at 1 us conversion rate samples analog signals up to 500 kSps aggregate, suitable for multi-channel vibration, strain gauge, and process variable logging. The 256 KB Flash stores calibration tables and lookup curves, while the 20 timers generate sample-rate clocks and PWM outputs for actuator control. Industrial -40 C to +85 C operation and the 100-LQFP package with 0.5 mm pitch allow assembly on standard 4-layer FR-4 PCBs using reflow profiles.
Recommended
Point-of-Sale Terminal Controller
Point-of-sale (POS) terminals require multiple peripheral interfaces - magnetic-stripe readers, thermal printers, barcode scanners, and cash-drawer solenoids - alongside secure transaction processing. The STR731FV2T6 provides 4 UARTs to drive these peripherals, while its USB controller connects to a PC-based POS host or links to a payment terminal via a tethered cable. The 256 KB Flash stores firmware update images with rollback support, and the JTAG interface permits secure in-field firmware verification. Hardware cryptographic acceleration is absent, so payment data must be encrypted in software with appropriate HSM offload considerations per PCI PTS requirements.
Recommended
Multi-Protocol Sensor Hub
Sensor hubs aggregating wireless, wired, and analog inputs benefit from the STR731FV2T6's mix of 2 SPI (for RF transceiver ICs like CC1101 or nRF24L01), 2 I2C (for low-speed digital sensors), 4 UART (for GPS modules and legacy instruments), 3 CAN, and 12 ADC channels. The 36 MHz ARM7TDMI core aggregates sensor readings into a unified data frame for upstream transmission. With 256 KB Flash the device can host multiple sensor drivers and a TinyOS or Contiki RTOS kernel. Industrial temperature rating and wide 4.5-5.5 V supply tolerance suit solar-powered outdoor sensor installations with battery voltage variation.
Recommended
Recommended Products Summary
Engineering reference data for STR731FV2T6 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STR732FV2T6 | STR735FV2T6 | STR736FV1T7 | LPC2106FBD100 | AT91SAM7A3-AU |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors | Microchip Technology |
| Package | 100-LQFP (14x14) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same |
| Core | ARM7TDMI 32-bit | ARM7TDMI 32-bit | ARM7TDMI 32-bit | ARM7TDMI 32-bit | ARM7TDMI 32-bit | ARM7TDMI 32-bit |
| CPU Speed | 36 MHz | 55 MHz | 36 MHz | 36 MHz | 60 MHz | 60 MHz |
| Flash Memory | 256 KB | 256 KB | 256 KB | 512 KB | 128 KB | 256 KB |
| CAN Interfaces | 3 | 3 | 3 | 3 | 1 | 1 |
| USB | 1 Full-Speed Slave | 1 Full-Speed Slave | 1 USB OTG | 1 USB OTG | None | 1 Full-Speed |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 3.0 V to 3.6 V | 3.0 V to 3.6 V |
Key Differentiators
- Three CAN 2.0B controllers with independent filtering (vs LPC2106FBD100)
- USB full-speed integrated with on-chip PHY (vs LPC2106FBD100)
- STR7 family pin compatibility (vs AT91SAM7A3-AU)
Design Notes
Use a low-noise 5 V LDO such as the LM7805 or a switching regulator followed by an LC filter for VDD and a separate filtered 5 V rail for VDDA. Decouple each VDD/VSS pair with 100 nF X7R ceramic plus 10 uF bulk tantalum per the STR731 hardware design guide. Sharing VDD and VDDA via ferrite beads improves ADC noise performance by isolating digital switching transients from analog reference voltage. Estimated decoupling: 11 VDD/VSS pairs require 22 capacitors total on a dense 100-LQFP layout.
Route the USB DP/DM pair as 90 ohm differential with continuous ground reference and length matching within 2 mm. Place the 27 ohm series termination resistors within 5 mm of the MCU pins and keep the trace away from oscillator and switching nodes. The 100-LQFP requires 4-layer stack-up with dedicated VSS plane for clean 36 MHz ARM7 operation; ground plane stitching vias spaced every 50 mm along high-speed signal edges maintain return-path integrity.
BOOT0 and BOOT1 pins must be pulled correctly before NRST release or the device may enter bootloader or fail to start - configure per the STR731 reference manual boot mode table. Do not enable JTAG pins (PB5-PB7) as GPIO without disabling JTAG in firmware or external debuggers will halt the core. The CAN sample-point configuration must be tuned per network baud rate and propagation delay; ST recommends 75-80% sample point for 1 Mbps CAN with short stubs.
Compliance Information
RoHS and REACH compliant per STMicroelectronics product declaration. Not AEC-Q100 qualified - automotive designs should use SPC56 or STM32 automotive variants. Halogen-free per ST eco-compliance program.
