Texas Instruments LM3S811-IQN50

Overview

LM3S811-IQN50 from Texas Instruments is a 32-bit ARM Cortex-M3 microcontroller with 64 KB flash, 8 KB SRAM, integrated ADC (10-bit, 8-channel), UART, I²C, SSI, PWM, and analog comparator. It operates at up to 50 MHz and supports industrial temperature range (–40°C to +85°C) in a 48-pin LQFP package. It targets embedded control applications requiring real-time responsiveness and mixed-signal integration.

For engineers reviewing the LM3S811-IQN50 datasheet, LM3S811-IQN50 pinout, LM3S811-IQN50 application, or LM3S811-IQN50 equivalent, key selection criteria include its 50 MHz CPU clock, on-chip flash/SRAM memory map, peripheral set (UART/I²C/SSI/PWM/ADC), industrial-grade thermal rating, and LQFP-48 mechanical compatibility.

Technical Context

The LM3S811-IQN50 integrates an ARM Cortex-M3 core with NVIC, SysTick, and MPU for deterministic real-time execution. Its system-level peripherals include clock gating, reset control, and power management supporting sleep modes (sleep/deep-sleep) with wake-up via GPIO, timer, or UART.

It features a single 10-bit ADC with hardware averaging and internal temperature sensor, three general-purpose timers (two 16/32-bit, one watchdog), and dual communication interfaces: UART (with FIFO and modem control) and I²C (master/slave, 100/400 kbps). The SSI supports SPI, Microwire, and TI synchronous serial protocols.

Key Specifications

Pinout & Package

LQFP-48 package with exposed thermal pad (EP); 0.5 mm lead pitch; JEDEC MO-220 compliant; RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3S1968-IQN50 and TM4C123GH6PM, the LM3S811-IQN50 delivers optimal cost-performance balance for non-networked, resource-constrained industrial controllers where flash >64 KB or USB/CAN are unnecessary-reducing both component cost and layout complexity.

Availability

LM3S811-IQN50 is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, PLC I/O modules, and industrial HMI panels requiring stable component supply and long-lifecycle assurance.

Supply support for LM3S811-IQN50 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 Stellaris LM3S series was designed as TI's first ARM-based microcontroller line targeting cost-sensitive, real-time industrial control applications-emphasizing peripheral integration, low-power operation, and ease of migration from 8/16-bit MCUs.

FAQ

What is the maximum operating frequency of the LM3S811-IQN50?

The LM3S811-IQN50 operates at a maximum system clock frequency of 50 MHz. This is achieved using the internal PLL driven by the precision 6 MHz internal oscillator or an external crystal. At this speed, the ARM Cortex-M3 core executes instructions with deterministic timing critical for real-time control tasks. The LM3S811-IQN50 maintains full peripheral functionality-including ADC sampling, UART transmission, and PWM generation-at 50 MHz without throttling or feature disablement.

Does the LM3S811-IQN50 support in-circuit debugging?

Yes, the LM3S811-IQN50 supports in-circuit debugging via ARM Serial Wire Debug (SWD) using two dedicated pins: SWCLK and SWDIO. It does not require full JTAG; SWD reduces pin count and simplifies debug header design. The LM3S811-IQN50 is fully compatible with TI's ICDI-based debuggers (e.g., Tiva C Series LaunchPad) and third-party tools supporting SWD, enabling breakpoints, register inspection, and real-time variable monitoring during development and field validation of the LM3S811-IQN50.

What analog peripherals are integrated into the LM3S811-IQN50?

The LM3S811-IQN50 integrates a 10-bit, 8-channel successive-approximation ADC with hardware averaging (2x–64x), an internal temperature sensor calibrated across –40°C to +85°C, and two independent analog comparators with programmable hysteresis and interrupt output. These analog resources are directly accessible via shared GPIO pins (e.g., ADC0_IN0–ADC0_IN7 mapped to GPIOA[7:0]), allowing flexible signal routing without external signal conditioning for basic sensing applications using the LM3S811-IQN50.

Is the LM3S811-IQN50 pin-compatible with other Stellaris devices?

No, the LM3S811-IQN50 is not pin-compatible with other Stellaris microcontrollers-even within the LM3S family. Its LQFP-48 pinout is unique to the LM3S811 variant. For example, the LM3S1968-IQN50 uses the same package but assigns different functions to several pins (e.g., Ethernet PHY interface pins absent on LM3S811-IQN50). Migration between LM3S devices requires PCB redesign. The LM3S811-IQN50 pinout is fixed and documented in Section 16 (Pin Diagram) of its official datasheet.

What is the flash endurance and data retention specification for the LM3S811-IQN50?

The LM3S811-IQN50 specifies 100,000 erase/write cycles for its 64 KB on-chip flash memory, with data retention guaranteed for 20 years at 85°C or indefinitely at lower temperatures. Flash sectors can be erased independently (1 KB or 4 KB), enabling robust firmware update schemes. These specifications are validated under TI's production test flow and apply to the LM3S811-IQN50 across its full industrial temperature range without derating.