Texas Instruments LM3S308-IQN25

Overview

LM3S308-IQN25 from Texas Instruments is a 32-bit ARM Cortex-M3 microcontroller with 256 KB flash, 32 KB SRAM, integrated ADC (10-bit, 1 MSPS), dual UARTs, I²C, SSI, and PWM-capable timers. It operates at up to 50 MHz and targets motor control, industrial sensing, and embedded HMI applications.

For engineers reviewing the LM3S308-IQN25 datasheet, LM3S308-IQN25 pinout, LM3S308-IQN25 application, or LM3S308-IQN25 equivalent, key selection criteria include its 50 MHz CPU clock, 10-bit 1 MSPS ADC resolution/speed, QFP-100 package footprint, and support for real-time motor control peripherals including PWM timing and watchdog supervision.

Technical Context

The LM3S308-IQN25 implements the ARM Cortex-M3 core with nested vectored interrupt controller (NVIC), memory protection unit (MPU), and SysTick timer. It integrates dedicated motor control peripherals including 6-channel PWM generator with dead-band control and quadrature encoder interface.

Its analog subsystem includes a 10-bit, 1 MSPS ADC with four sample sequencers and hardware averaging, plus an internal temperature sensor and two analog comparators with programmable reference. System-level features include on-chip LDO regulator, power gating for sleep modes, and JTAG debug interface compliant with IEEE 1149.1.

Key Specifications

Pinout & Package

LM3S308-IQN25 is housed in a 100-pin Low-Profile Quad Flat Package (LQFP) with 0.5 mm pitch, thermal pad, and standard JEDEC MO-137AC footprint. Pin assignments are defined per TI SPMS068I datasheet Section 15 (Pin Diagram) and Section 16 (Signal Tables).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TM4C123GH6PM and STM32F103VCT6, the LM3S308-IQN25 delivers purpose-built motor control peripherals and on-chip power regulation in a mature, production-proven platform-ideal for cost-optimized, volume industrial designs where feature parity matters more than raw clock speed.

Availability

LM3S308-IQN25 is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, human-machine interfaces, and PLC I/O modules requiring stable component supply across long-life production cycles.

Supply support for LM3S308-IQN25 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 specializing in analog, embedded processing, and connectivity technologies, with decades of experience in industrial and automotive markets.

The Stellaris LM3S series was engineered specifically for real-time embedded control applications-emphasizing deterministic interrupt latency, integrated analog/motor peripherals, and robust debug infrastructure for industrial firmware development.

FAQ

What is the maximum operating frequency of the LM3S308-IQN25?

The LM3S308-IQN25 operates at a maximum CPU clock frequency of 50 MHz, as specified in the TI SPMS068I datasheet Section 17 (Operating Characteristics). This frequency is achieved using the internal PLL with crystal or external clock input, and supports deterministic real-time execution for motor control loops and sensor acquisition tasks. The LM3S308-IQN25 maintains full peripheral functionality-including ADC sampling, PWM generation, and UART communication-at this rated speed.

Does the LM3S308-IQN25 include an integrated voltage regulator?

Yes, the LM3S308-IQN25 integrates an on-chip low-dropout (LDO) regulator that generates the core voltage (VDDC) from the main supply (VDD). As documented in Section 18.1.3 of the SPMS068I datasheet, this LDO supports input voltages from 2.25 V to 3.63 V and provides stable core power without requiring external regulation-reducing BOM count and PCB area in space-constrained industrial designs using the LM3S308-IQN25.

How many ADC channels does the LM3S308-IQN25 support, and what is its resolution?

The LM3S308-IQN25 features a single 10-bit successive-approximation register (SAR) ADC with eight input channels (PA0–PA7), supporting both single-ended and differential configurations. Its maximum sampling rate is 1 MSPS, and it includes four independent sample sequencers with hardware averaging-enabling concurrent acquisition of multiple analog signals such as motor phase currents and DC bus voltage. This ADC architecture is fully documented in Section 10 of the SPMS068I datasheet for the LM3S308-IQN25.

What debug interface does the LM3S308-IQN25 provide?

The LM3S308-IQN25 provides a standard IEEE 1149.1-compliant JTAG interface for boundary scan testing, flash programming, and real-time debugging. It supports full SWD (Serial Wire Debug) compatibility via the same physical pins and includes integrated debug features such as breakpoints, watchpoints, and memory access tracing. This interface is detailed in Section 4 of the SPMS068I datasheet and is used by TI's Code Composer Studio and third-party tools to develop and validate firmware for the LM3S308-IQN25.

Is the LM3S308-IQN25 pin-compatible with other Stellaris devices?

The LM3S308-IQN25 uses a 100-pin LQFP (IQN) package with a specific pinout defined in Section 15 of the SPMS068I datasheet. While several Stellaris LM3S devices share the same IQN package, pin compatibility is not guaranteed across the family-peripheral mappings, power pin locations, and reset configuration differ between variants. For example, LM3S811-IQN25 has different GPIO alternate function assignments and lacks the dedicated motor control PWM block present in the LM3S308-IQN25.