Texas Instruments MSP430AFE221IPW

Overview

MSP430AFE221IPW from Texas Instruments is an ultra-low-power 16-bit mixed-signal microcontroller featuring one 24-bit sigma-delta ADC, 4 KB flash, 256 B RAM, and 11 I/O pins in a 24-pin TSSOP package. It operates from 1.8 V to 3.6 V, draws 220 µA at 1 MHz/2.2 V active mode, and supports single-phase electricity metering with differential PGA inputs and programmable voltage reference.

For engineers reviewing the MSP430AFE221IPW datasheet, MSP430AFE221IPW pinout, MSP430AFE221IPW application, or MSP430AFE221IPW equivalent, this page delivers verified technical context, exact pin functions, real-world metering use cases, and two validated alternative parts for design continuity and supply resilience.

Technical Context

The MSP430AFE221IPW integrates a 16-bit RISC CPU with constant generators and digitally controlled oscillator (DCO), enabling sub-1 µs wake-up from standby mode. Its SD24_A module provides 24-bit resolution with differential input pairs, internal reference buffering, and temperature sensor support - all optimized for high-accuracy analog front-end acquisition in energy measurement systems.

It features a single USART supporting UART or SPI, Timer_A3 with three capture/compare registers, hardware multiplier, brownout detector, and supply voltage supervisor with programmable level detection. All peripherals operate under five low-power modes, with LPM4 consuming only 0.1 µA at 2.2 V.

Key Specifications

Pinout & Package

Package: 24-pin TSSOP (PW), body size 7.8 mm × 4.4 mm, JEDEC MS-013AC compliant. Pinout reflects MSP430AFE2x1 variant with NC pins at positions 3, 4, 8, and 9 - all must be connected to AVSS per TI recommendation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar mixed-signal microcontroller applications.

Compared with MSP430AFE222IPW, the MSP430AFE221IPW reduces ADC channel count to lower cost and power while retaining identical timing, memory, and I/O - ideal for single-channel metering. Versus MSP430F2274IPW, it trades general-purpose flexibility for metrology-optimized analog integration, delivering 14+ ENOB versus 6.5 ENOB in real-world conditions.

Availability

MSP430AFE221IPW is available at Aetrix Electronics and suitable for single-phase electricity meters, digital power monitors, and portable energy loggers requiring stable component supply and long-term industrial lifecycle support.

Supply support for MSP430AFE221IPW 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 leader focused on analog, embedded processing, and connectivity technologies, serving industrial, automotive, and consumer markets with high-reliability silicon solutions.

The MSP430AFE2xx product line is designed specifically for ultra-low-power, high-precision analog acquisition in utility metering and energy monitoring applications - integrating metrology-grade ADCs, reference buffers, and low-power timing in a single chip.

FAQ

What is the maximum system clock frequency supported by the MSP430AFE221IPW?

The MSP430AFE221IPW supports a maximum MCLK frequency of 12 MHz when VCC ≥ 3.3 V and duty cycle is 50% ±10%. At 2.7 V, max frequency is 9 MHz; at 1.8 V, it is 4.15 MHz. These limits are defined by the DCO and internal clock distribution - exceeding them may cause timing violations or increased current draw. The MSP430AFE221IPW datasheet specifies these values in Section 5.3 Recommended Operating Conditions.

Does the MSP430AFE221IPW include an internal voltage reference for the ADC?

Yes, the MSP430AFE221IPW includes an internal voltage reference that can be output on the VREF pin as a mid-supply voltage (VCC/2). It also supports external reference inputs from 2.5 V to 3.6 V. The SD24_A module uses this reference for full-scale calibration, and the internal reference is buffered to drive external circuitry. This capability is documented in Sections 5.25–5.31 of the MSP430AFE221IPW datasheet.

How many I/O pins does the MSP430AFE221IPW have, and what are their key functions?

The MSP430AFE221IPW provides 11 configurable I/O pins: P1.0–P1.7 (8 pins), P2.0, P2.6, and P2.7. Key functions include XT2 crystal interface (P2.6/P2.7), USART0 (UART/SPI on P1.3–P1.7), Timer_A3 capture/compare (P1.0–P1.2, P1.6–P1.7, P2.0), and SD24_A bitstream signals (P1.1–P1.4). Unused analog input pins (A1.0±, A2.0±) are NC on this variant and must be tied to AVSS. This mapping is confirmed in Figure 4-3 and Table 4-1 of the MSP430AFE221IPW datasheet.

What power-saving modes are available on the MSP430AFE221IPW, and what is the lowest current consumption?

The MSP430AFE221IPW offers five low-power modes (LPM0–LPM4). LPM4 achieves the lowest current: 0.1 µA typical at 2.2 V and 25°C, with RAM retention enabled. This mode disables all clocks including the VLO, making it ideal for extended sleep periods in battery-powered meters. LPM3 draws 0.5 µA (VLO active), while active mode consumes 220 µA at 1 MHz/2.2 V. All values are specified in Section 5.7 of the MSP430AFE221IPW datasheet.

Is the MSP430AFE221IPW pin-compatible with other devices in the MSP430AFE2xx family?

Yes, the MSP430AFE221IPW shares the same 24-pin TSSOP (PW) package and pinout with all MSP430AFE2xx variants, including MSP430AFE222IPW and MSP430AFE223IPW. Pin functions are identical across the family; differences lie only in internal peripheral count (e.g., one vs. two vs. three SD24_A converters). NC pins are consistent across variants, and all require connection to AVSS. This compatibility is explicitly confirmed in Figures 4-1 through 4-3 of the MSP430AFE221IPW datasheet.