Texas Instruments MSP430F6731AIPZ

Overview

MSP430F6731AIPZ from Texas Instruments is an ultra-low-power mixed-signal microcontroller designed for single-phase electronic watt-hour metering. It integrates three 24-bit sigma-delta ADCs, a 10-bit 200-ksps ADC, LCD driver supporting up to 320 segments, and a real-time clock with crystal offset calibration - all in a 100-pin LQFP package operating from 1.8 V to 3.6 V.

For engineers reviewing the MSP430F6731AIPZ datasheet, MSP430F6731AIPZ pinout, MSP430F6731AIPZ application, or MSP430F6731AIPZ equivalent, key selection criteria include its 32 KB flash/2 KB RAM configuration, triple SD24_B ADC support for current/voltage sensing, low-power RTC operation down to 1.24 µA (LPM3.5), and compatibility with utility metering reference designs like EVM430-F6736.

Technical Context

The MSP430F6731AIPZ implements a 16-bit RISC CPU with 25-MHz system clock capability, unified clock system featuring FLL stabilization, VLO/REFO internal sources, and 32-kHz XT1 crystal support. Its power architecture includes an integrated LDO with programmable core voltage, dual auxiliary supply rails (AUXVCC1–3), and dedicated backup subsystem for RTC and 4×16-bit backup memory.

Peripherals are optimized for metrology: three independent SD24_B modules accept differential PGA inputs for high-precision energy measurement; eUSCI_A0/A1/A2 support UART with auto-baud detection and IrDA; eUSCI_B0 provides I²C with multi-slave addressing; and four 16-bit timers (one with three capture/compare registers, three with two each) enable precise waveform timing and pulse accumulation.

Key Specifications

Pinout & Package

Package: 100-pin LQFP (PZ), 14 mm × 14 mm body size, 0.5-mm pitch, exposed thermal pad (not electrically connected). Compatible with standard reflow profiles and automated optical inspection.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar metrology microcontroller applications.

Compared with MSP430F6733AIPZ, the MSP430F6731AIPZ trades flash capacity for lower cost and power in fixed-function meters; compared with MSP430F6721AIPZ, it adds a third SD24_B channel essential for IEC 62053-23-compliant neutral current monitoring in TN-C-S systems.

Availability

MSP430F6731AIPZ is available at Aetrix Electronics and suitable for single-phase electronic watt-hour meters, utility prepayment systems, and smart grid sensor nodes requiring stable component supply, long-term lifecycle support, and TI-qualified metrology performance.

Supply support for MSP430F6731AIPZ 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 specializing in analog and embedded processing technologies, with leadership in low-power microcontrollers and precision analog signal chains.

The MSP430F673xA family is engineered specifically for utility metering applications, integrating metrology-grade ADCs, LCD drivers, and ultra-low-power RTC functionality to meet IEC 62053 and ANSI C12 standards without external support ICs.

FAQ

What is the maximum system clock frequency supported by the MSP430F6731AIPZ?

The MSP430F6731AIPZ supports a maximum system clock frequency of 25 MHz, enabled by its integrated FLL control loop and DCO oscillator. This speed allows real-time execution of metrology algorithms such as RMS, fundamental power, and harmonic analysis while maintaining ultra-low active-mode current of 265 µA/MHz at 3.0 V. The MSP430F6731AIPZ achieves this performance without external clock components beyond the required 32.768-kHz crystal for RTC.

Does the MSP430F6731AIPZ include hardware support for cryptographic operations?

The MSP430F6731AIPZ does not include dedicated cryptographic accelerators (e.g., AES, SHA, or RSA engines). It relies on software-based implementations for security functions such as token validation or firmware signature checking. However, its hardware multiplier (MPY32) and three-channel DMA can accelerate CRC, checksum, and modular arithmetic routines. For production-grade security, external secure elements or newer TI devices like MSP430FR5994 are recommended alongside the MSP430F6731AIPZ.

How many LCD segments can the MSP430F6731AIPZ drive, and what multiplexing configurations are supported?

The MSP430F6731AIPZ integrates the LCD_C module supporting up to 320 segments in 8-mux mode. It provides eight COM lines (COM0–COM7) and up to 40 SEG lines (via P1–P8 ports), enabling flexible display layouts for meter readouts, tariff indicators, and status icons. Contrast is adjustable via internal charge pump and software-controlled voltage division, eliminating need for external potentiometers or DACs. The LCDCAP pin requires a 2.2-µF ceramic capacitor for stable operation.

What are the key differences between the MSP430F6731AIPZ and MSP430F6731AIPN packages?

The MSP430F6731AIPZ uses a 100-pin LQFP (PZ) package with 72 GPIOs and full peripheral access, including all three SD24_B differential inputs (SD2P0/SD2N0) and eight LCD COM lines. The MSP430F6731AIPN is an 80-pin LQFP (PN) variant offering 52 GPIOs and omitting SD2P0/SD2N0 and two COM lines - reducing metrology channel count and display capacity. Both share identical core specifications (32 KB flash, 2 KB RAM), but the PZ package is required for full IEC 62053-23 neutral current compliance and large LCD interfaces.

Can the MSP430F6731AIPZ operate from a single 3.3-V supply without external regulators?

Yes, the MSP430F6731AIPZ operates from a single 3.3-V supply across its full 1.8-V to 3.6-V range. Its integrated LDO generates the regulated VCORE voltage, and AVCC/DVCC rails are internally connected when VASYS = DVCC. External decoupling (100 nF ceramic + 10 µF tantalum per rail) is mandatory. However, the auxiliary supply pins (AUXVCC1–3) must be tied to DVCC for RTC backup operation, and VASYS must be externally connected to DVCC to enable analog subsystem functionality - no external regulator is needed for core operation.