Texas Instruments MSP430F67681AIPEU

Overview

MSP430F67681AIPEU from Texas Instruments is a polyphase metering SoC designed for 3-phase electronic watt-hour meters, integrating six 24-bit sigma-delta ADCs, a 25-MHz CPU with 32-bit multiplier, 512KB flash, 16KB RAM, LCD controller (320 segments), and dual eUSCI_A/B interfaces. It delivers <0.1% energy measurement accuracy over 2000:1 dynamic range and meets ANSI C12.20 and IEC 62053 standards.

For engineers reviewing the MSP430F67681AIPEU datasheet, MSP430F67681AIPEU pinout, MSP430F67681AIPEU application, or MSP430F67681AIPEU equivalent, key selection criteria include its 128-pin LQFP package with 90 GPIOs, RTC with tamper detection, ultra-low-power LPM3.5 mode (0.34 µA), and dedicated pulse outputs for active/reactive energy calibration in utility-grade metering designs.

Technical Context

The MSP430F67681AIPEU implements a metrology-optimized architecture with seven independent SD24_B modulators (six used) and one 10-bit SAR ADC for auxiliary sensing. Its analog front-end supports current transformers, Rogowski coils, and shunt resistors across three phases plus neutral, enabling 4-quadrant per-phase power calculation and exact phase-angle measurement.

Digital subsystems include three-channel DMA, 16-bit CRC, four 16-bit timers (nine capture/compare registers), and six eUSCIs-four UART/IrDA/SPI-capable (eUSCI_A0–A3) and two SPI/I2C-capable (eUSCI_B0–B1)-all operating under a flexible power management module supporting voltage scaling from 3.6 V to 1.8 V.

Key Specifications

Pinout & Package

Package: 128-pin LQFP (PEU), 20 mm × 14 mm body size, with 90 functional I/O terminals. Requires external connection between VDSYS1/VDSYS2 and VASYS1/VASYS2 pairs for proper operation; LCDCAP/R33 must be tied to DVSS if unused.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar polyphase metering SoC applications.

Compared with MSP430F67691AIPEU, the MSP430F67681AIPEU trades RAM capacity for lower cost while retaining identical metrology accuracy and peripheral set; versus MSP430F67671AIPEU, it doubles flash for complex firmware features like DLMS/COSEM stack support or advanced diagnostics.

Availability

MSP430F67681AIPEU is available at Aetrix Electronics and suitable for smart electricity meters, revenue-grade energy monitors, and anti-tamper utility metering systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MSP430F67681AIPEU 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, embedded processing, and connectivity technologies, with leadership in low-power microcontrollers and precision analog signal chains.

The MSP430F67681AIPEU belongs to TI's Metrology and Monitoring MCU portfolio, engineered specifically for high-accuracy energy measurement in smart grid infrastructure and building automation systems.

FAQ

What is the maximum number of simultaneous sigma-delta ADC channels supported by the MSP430F67681AIPEU?

The MSP430F67681AIPEU integrates six active 24-bit sigma-delta ADC channels (SD0–SD5) with differential inputs, confirmed in the device comparison table and functional description. A seventh channel (SD6) is physically present but disabled in this variant, distinguishing it from the MSP430F67691AIPEU which enables all seven. Each channel supports independent gain and data rate configuration for multi-sensor metrology.

Does the MSP430F67681AIPEU support IEC 62053-21 and ANSI C12.20 compliance out of the box?

Yes, the MSP430F67681AIPEU is explicitly stated to meet or exceed both IEC 62053-21 (class 0.2S active energy) and ANSI C12.20 (0.2 accuracy class) standards. This compliance is achieved through its <0.1% measurement accuracy over 2000:1 dynamic range, digital phase correction, temperature compensation, and 4-quadrant calculation engine-all verified in TI's metrology validation reports and referenced in the device overview.

What are the power supply requirements for the analog and digital domains of the MSP430F67681AIPEU?

The MSP430F67681AIPEU requires separate analog (AVCC, AVSS1/2, VASYS1/2) and digital (DVCC, DVSS1/2, VCORE, VDSYS1/2) supply domains. AVCC operates from 2.7 V to 3.6 V; DVCC from 1.8 V to 3.6 V; VCORE is internally regulated. Critical analog supplies (VASYS1/2, AVSS1/2) must be externally connected per the pinout diagram to ensure proper biasing of the SD24_B modulators and reference circuitry.

How does the RTC tamper detection function work on the MSP430F67681AIPEU?

The MSP430F67681AIPEU RTC includes dedicated tamper-detect pins (e.g., RTCCLK, RST/NMI) that trigger hardware interrupts and clear sensitive registers upon voltage, frequency, or pin-state anomalies. Tamper events are logged in dedicated TLV memory, and the RTC remains password-protected-even during LPM3.5 mode-preventing unauthorized clock manipulation or firmware access, satisfying IEC 62053-31 physical security requirements.

Can the MSP430F67681AIPEU drive a 320-segment LCD without external components?

Yes, the MSP430F67681AIPEU integrates a fully autonomous LCD_C controller supporting up to 320 segments (8 commons × 40 segments) with built-in charge pump, contrast control, and blinking logic. No external bias resistors or capacitors are required beyond the mandatory LCDCAP capacitor (connected to DVSS if unused), enabling direct drive of segmented displays in utility meters with minimal external BOM.