Texas Instruments LM3S308-EGZ25-C2

Overview

LM3S308-EGZ25-C2 from Texas Instruments is a 32-bit ARM Cortex-M3 microcontroller with 25 MHz maximum CPU frequency, 32 KB flash memory, 8 KB SRAM, integrated ADC (10-bit, 8-channel), two UARTs, I²C, SSI, and GPIOs. It targets industrial control, motor drive monitoring, and embedded sensor interface applications requiring deterministic real-time response.

For engineers reviewing the LM3S308-EGZ25-C2 datasheet, LM3S308-EGZ25-C2 pinout, LM3S308-EGZ25-C2 application, or LM3S308-EGZ25-C2 equivalent, key selection criteria include its 25 MHz operation limit, QFP-48 package, lack of USB or Ethernet peripherals, and support for single-cycle multiply and hardware divide instructions in the Cortex-M3 core.

Technical Context

The LM3S308-EGZ25-C2 implements the ARMv7-M architecture with NVIC-based interrupt handling, SysTick timer, and Memory Protection Unit (MPU). It executes Thumb-2 instructions and supports up to 32 priority levels across 24 system and peripheral interrupts.

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 controller, one SSI port, and 39 GPIO pins with programmable slew rate and pull-up/down control.

Key Specifications

Pinout & Package

LM3S308-EGZ25-C2 uses a 48-pin LQFP (Low-Profile Quad Flat Package) with 0.5 mm pitch, exposed thermal pad, and JEDEC-standard footprint. Pin numbering follows counter-clockwise sequence starting from top-left corner (Pin 1 marked).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3S308-EGZ25-C2, LM3S310-EGZ25-C2 offers expanded memory without layout change, while TM4C123GH6PM delivers architectural upgrades including FPU and USB-but requires PCB redesign and toolchain migration.

Availability

LM3S308-EGZ25-C2 is available at Aetrix Electronics and suitable for industrial motor monitoring, embedded sensor nodes, PLC I/O modules, and smart actuator controllers requiring stable component supply and long-term production continuity.

Supply support for LM3S308-EGZ25-C2 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and consumer markets.

The Stellaris LM3S series was designed as TI's first ARM-based microcontroller line targeting cost-sensitive, real-time industrial and automation applications with integrated analog and communication peripherals.

FAQ

What is the maximum operating frequency of the LM3S308-EGZ25-C2?

The LM3S308-EGZ25-C2 operates at a maximum CPU frequency of 25 MHz, as specified in its electrical characteristics table. This limit applies across the full industrial temperature range (–40°C to +85°C) and 3.3 V supply. The part does not support overclocking or higher-frequency variants-its PLL and clock tree are configured to deliver stable 25 MHz from internal or external sources. LM3S308-EGZ25-C2 timing margins assume this rated speed for all peripheral synchronization.

Does the LM3S308-EGZ25-C2 include a hardware floating-point unit (FPU)?

No, the LM3S308-EGZ25-C2 does not include a hardware FPU. It implements the ARM Cortex-M3 core, which supports only integer and fixed-point arithmetic. Floating-point operations must be performed in software using compiler-provided libraries. For applications requiring hardware-accelerated floating-point math, TI's later TM4C123x series (Cortex-M4F) is the direct upgrade path. LM3S308-EGZ25-C2 remains optimized for deterministic integer-based control tasks.

How many ADC channels does the LM3S308-EGZ25-C2 support, and what is their resolution?

The LM3S308-EGZ25-C2 integrates a single 10-bit successive-approximation ADC with eight input channels (ADC0–ADC7), all mapped to GPIO pins PC0–PC7. It supports hardware sample averaging (up to 64 samples) and includes an internal temperature sensor channel. No external reference is required-the ADC uses the internal 3.3 V supply as reference. LM3S308-EGZ25-C2 ADC performance is characterized for 1 MSPS sampling rate under specified conditions.

Is the LM3S308-EGZ25-C2 pin-compatible with other Stellaris LM3S devices?

The LM3S308-EGZ25-C2 is pin-compatible with other LM3S3xx-series devices in the same 48-pin LQFP package (e.g., LM3S310-EGZ25-C2), sharing identical pin assignments for power, ground, JTAG, reset, and peripheral signals. However, it is not pin-compatible with LM3S1xx or LM3S2xx families due to differing peripheral mappings and register layouts. LM3S308-EGZ25-C2 users should verify signal routing against the specific variant's datasheet before substitution.

What debug interfaces are supported by the LM3S308-EGZ25-C2?

The LM3S308-EGZ25-C2 supports both JTAG and SWD (Serial Wire Debug) protocols via its dedicated debug pins (TCK, TMS, TDI, TDO, nTRST). TI's Stellaris ICDI and third-party CMSIS-DAP debug probes are fully compatible. Debug access enables full breakpoint, watchpoint, and memory inspection capabilities without requiring code instrumentation. LM3S308-EGZ25-C2 retains debug functionality even when running from internal flash or ROM-based bootloader.