Texas Instruments LM3S308-EQN25-C2T

Overview

LM3S308-EQN25-C2T from Texas Instruments is a 32-bit ARM Cortex-M3 microcontroller with 64 KB flash, 24 KB SRAM, integrated ADC (10-bit, 8-channel), dual UARTs, I²C, SSI, and PWM-capable timers. It operates at up to 50 MHz and targets real-time motor control and industrial sensor interfaces.

For engineers reviewing the LM3S308-EQN25-C2T datasheet, LM3S308-EQN25-C2T pinout, LM3S308-EQN25-C2T application, or LM3S308-EQN25-C2T equivalent, key selection criteria include its QFN-25 package, 50 MHz CPU clock, on-chip LDO regulator, GPIO alternate function mapping, and lack of Ethernet or USB peripherals.

Technical Context

The LM3S308-EQN25-C2T implements the ARMv7-M architecture with NVIC-based interrupt handling, SysTick timer, and memory protection unit (MPU). It supports Thumb-2 instruction set and executes from internal flash with zero-wait-state access up to 25 MHz.

Its analog subsystem includes an 8-channel, 10-bit ADC with hardware averaging and internal temperature sensor; digital peripherals include two UARTs with FIFOs, one I²C master/slave, one SSI interface, and four 16/32-bit general-purpose timers with PWM and RTC modes.

Key Specifications

Pinout & Package

LM3S308-EQN25-C2T uses a 25-pin QFN package with exposed thermal pad. Pin numbering follows TI's standard QFN layout (pin 1 marked by dot); all power and ground pins are distributed across corners and edges for low-noise operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3S318-IQN25-C2 and TM4C123GH6PM, the LM3S308-EQN25-C2T provides optimal balance of real-time performance, analog integration, and minimal footprint for fixed-function embedded controllers where CAN or USB are unnecessary.

Availability

LM3S308-EQN25-C2T is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, PLC I/O modules, and power supply monitoring units requiring stable component supply and long-term obsolescence management.

Supply support for LM3S308-EQN25-C2T 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 microcontrollers.

The Stellaris LM3S series was designed specifically for cost-sensitive, real-time embedded applications requiring high analog integration, deterministic interrupt response, and compact packaging - exemplified by the LM3S308-EQN25-C2T.

FAQ

What is the maximum operating frequency of the LM3S308-EQN25-C2T?

The LM3S308-EQN25-C2T operates at a maximum system clock frequency of 50 MHz. This is achieved using the internal PLL with a 4–25 MHz crystal or external clock source. The ARM Cortex-M3 core executes instructions at this rate with zero wait states for flash accesses below 25 MHz, ensuring deterministic real-time behavior critical for motor control loops and sensor sampling timing in the LM3S308-EQN25-C2T.

Does the LM3S308-EQN25-C2T support USB or CAN interfaces?

No, the LM3S308-EQN25-C2T does not include USB or CAN peripherals. Its peripheral set includes two UARTs, one I²C, one SSI, and analog features like ADC and comparator, but lacks dedicated USB PHY or CAN controller logic. For USB or CAN capability, engineers should consider the pin-compatible LM3S318-IQN25-C2 or newer TM4C123GH6PM - both of which retain QFN-25 packaging while adding those interfaces.

What power supply requirements does the LM3S308-EQN25-C2T have?

The LM3S308-EQN25-C2T requires a single 3.3 V ±5% supply applied to VDD and VDDA pins, with separate ground connections for digital (GND) and analog (VSSA) domains. An internal LDO generates the 1.25 V core voltage, eliminating need for external core regulators. Decoupling capacitors (100 nF ceramic per VDD/VDDA pin) and proper PCB layout separating analog/digital grounds are mandatory to meet specified noise immunity and ADC accuracy in the LM3S308-EQN25-C2T.

How many ADC channels does the LM3S308-EQN25-C2T support, and what is their resolution?

The LM3S308-EQN25-C2T integrates a single 10-bit successive approximation register (SAR) ADC with eight input channels (AIN0–AIN7). Channel AIN7 is internally connected to the on-die temperature sensor. The ADC supports hardware sample averaging (up to 64 samples per conversion) and programmable trigger sources including timer match, software, and GPIO events - enabling precise, low-overhead analog acquisition in the LM3S308-EQN25-C2T.

Is the LM3S308-EQN25-C2T still in production, and what is its lifecycle status?

Texas Instruments discontinued the LM3S308-EQN25-C2T in 2015 as part of the broader Stellaris product line transition to the TM4C series. However, Aetrix Electronics maintains active inventory and provides extended lifecycle support, including obsolescence forecasting, last-time-buy coordination, and verified second-source alternatives for ongoing production programs relying on the LM3S308-EQN25-C2T.