Texas Instruments MSP430FR5731IRHAR

Overview

MSP430FR5731IRHAR from Texas Instruments is a 16-bit ultra-low-power mixed-signal microcontroller featuring 4KB FRAM, 1KB RAM, 24-MHz CPU, 12-channel 10-bit ADC, 16-channel analog comparator, and dual eUSCI modules (UART/IrDA/SPI/I²C) in a 40-pin VQFN package. It targets battery-powered sensor nodes and data acquisition systems requiring nonvolatile memory endurance and sub-µA RTC operation.

For engineers reviewing the MSP430FR5731IRHAR datasheet, MSP430FR5731IRHAR pinout, MSP430FR5731IRHAR application, or MSP430FR5731IRHAR equivalent, key selection criteria include FRAM write endurance (10¹⁵ cycles), LPM3.5 RTC current (1.5 µA), ADC sampling rate (200 ksps), I/O count (32), and RHA-package thermal pad layout compatibility.

Technical Context

The MSP430FR5731IRHAR implements the MSP430xV2 CPU core with hardware multiplier and three-channel DMA for efficient signal processing. Its FRAM memory architecture enables simultaneous read/write without erase cycles, supporting real-time logging and firmware updates in low-power modes.

Power management integrates an on-chip LDO, supply voltage supervisor with reset, and zero-power brownout detection. Clock system includes DCO (up to 24 MHz), VLO, LFXT (32 kHz crystal), and HFXT support - enabling precise RTC operation and flexible peripheral timing.

Key Specifications

Pinout & Package

40-pin VQFN (RHA) package with 6 mm × 6 mm body size and exposed thermal pad (to be connected to DVSS).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-power microcontroller applications.

Compared with MSP430FR5735IRHAR, the MSP430FR5731IRHAR offers identical low-power performance and peripheral set at lower FRAM density; versus MSP430FR5969IPM, it provides pin-compatible upgrade path within RHA footprint but lacks advanced security and higher-speed peripherals.

Availability

MSP430FR5731IRHAR is available at Aetrix Electronics and suitable for smart metering, wireless sensor networks, home automation hubs, and portable data loggers requiring stable component supply and long-term industrial availability.

Supply support for MSP430FR5731IRHAR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company delivering analog and embedded processing solutions for industrial, automotive, and consumer markets.

The MSP430FR573x product line was designed for ultra-low-power sensing and system management in building automation, smart grid, and industrial monitoring applications - emphasizing FRAM endurance, sub-µA RTC, and integrated analog front-ends.

FAQ

What is the maximum operating frequency of the MSP430FR5731IRHAR?

The MSP430FR5731IRHAR supports a maximum system clock frequency of 24 MHz via its digitally controlled oscillator (DCO). This frequency is factory-trimmed across six selectable settings and can be further calibrated using the built-in hardware multiplier and reference clock sources. The 24-MHz capability enables real-time signal processing and high-speed ADC sampling up to 200 ksps, making the MSP430FR5731IRHAR suitable for time-critical sensor applications where deterministic execution is required.

Does the MSP430FR5731IRHAR support real-time clock operation with external 32-kHz crystal?

Yes, the MSP430FR5731IRHAR supports real-time clock (RTC) operation using an external 32-kHz crystal connected to PJ.4/XIN and PJ.5/XOUT pins. In LPM3.5 mode with crystal enabled, the device achieves 1.5 µA typical current consumption while maintaining full calendar functionality including alarms and time-of-day tracking. This configuration is validated for long-term battery operation in applications such as utility meters and environmental monitors where accurate timekeeping over years is essential.

How much FRAM memory does the MSP430FR5731IRHAR have, and what is its endurance rating?

The MSP430FR5731IRHAR integrates 4 KB of embedded ferroelectric RAM (FRAM) with a write endurance rating of 10¹⁵ cycles - orders of magnitude higher than flash memory. This enables reliable, wear-free data logging, firmware updates, and parameter storage even under frequent write conditions. Unlike flash, FRAM supports byte-level writes without erase overhead, allowing atomic updates and power-loss resilience - critical for applications like smart meters and industrial controllers where data integrity is non-negotiable.

Which communication interfaces are available on the MSP430FR5731IRHAR?

The MSP430FR5731IRHAR features two enhanced universal serial communication interfaces: eUSCI_A0 supporting UART, IrDA, and SPI; and eUSCI_B0 supporting I²C and SPI. These peripherals operate independently and can be configured simultaneously - for example, using eUSCI_B0 for sensor I²C polling while eUSCI_A0 handles UART-based host communication or bootloader functions. Both modules support automatic baud-rate detection and hardware flow control, reducing firmware overhead in robust communication stacks.

What is the supply voltage range and temperature grade for the MSP430FR5731IRHAR?

The MSP430FR5731IRHAR operates across a supply voltage range of 2.0 V to 3.6 V and is rated for industrial temperature operation from –40°C to +85°C. This voltage range supports direct connection to common battery chemistries including Li-SOCl₂, Li-ion, and alkaline cells without external regulation. The specified temperature grade ensures reliable performance in uncontrolled environments such as outdoor utility enclosures, HVAC ducts, and factory floor instrumentation - aligning with design requirements for long-lifecycle industrial deployments.