Texas Instruments LM3S818-IQN50-C2

Overview

LM3S818-IQN50-C2 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, SSI, PWM, QEI, and analog comparator. It operates at up to 50 MHz and supports industrial temperature range (–40°C to +85°C) in a 100-pin LQFP package. Used in motor control, industrial automation, and embedded HMI systems.

For engineers reviewing the LM3S818-IQN50-C2 datasheet, LM3S818-IQN50-C2 pinout, LM3S818-IQN50-C2 application, or LM3S818-IQN50-C2 equivalent, key selection criteria include its 50 MHz CPU clock, integrated motor-control peripherals (QEI, PWM with dead-band), on-chip analog front-end (ADC + comparator), and industrial-grade thermal rating.

Technical Context

The LM3S818-IQN50-C2 implements the ARM Cortex-M3 core with Thumb-2 instruction set, NVIC for priority-based interrupt handling, and SysTick timer. It integrates a hardware memory protection unit (MPU) and supports sleep modes with wake-up via GPIO, timer, or peripheral interrupt.

Its system-level design includes an on-chip LDO regulator supplying core voltage (1.2 V) from 3.3 V input, configurable GPIO with slew-rate control and weak pull-ups/pull-downs, and clock tree with PLL-based 50 MHz system clock derived from internal oscillator or external crystal.

Key Specifications

Pinout & Package

LM3S818-IQN50-C2 is housed in a 100-pin LQFP package (JEDEC MO-152AC) with exposed thermal pad. Pin assignments support full peripheral multiplexing including dual UARTs (TX/RX/RTS/CTS), two SSI ports, six PWM outputs, eight ADC inputs, four QEI signals (PhA/PhB/Index/Enable), and 68 GPIOs with configurable alternate functions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TMS320F28027PTT and STM32F103VCT6, the LM3S818-IQN50-C2 offers balanced integration of motor-control peripherals (QEI + PWM + ADC) in a compact 100-pin LQFP, making it optimal for cost-sensitive, space-constrained industrial controllers where mixed-signal integration reduces bill-of-materials complexity.

Availability

LM3S818-IQN50-C2 is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controllers, and embedded human-machine interfaces requiring stable component supply across extended product lifecycles.

Supply support for LM3S818-IQN50-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 wireless technologies with over 90 years of innovation in industrial and automotive electronics.

The Stellaris LM3S series was designed specifically for cost-sensitive, real-time industrial control applications-emphasizing integrated analog/motor peripherals, deterministic interrupt response, and robust operation across wide temperature ranges.

FAQ

What is the maximum operating frequency of the LM3S818-IQN50-C2?

The LM3S818-IQN50-C2 operates at a maximum system clock frequency of 50 MHz, achieved using its internal PLL locked to either the internal 6 MHz oscillator or an external crystal. This frequency is specified under industrial temperature conditions (–40°C to +85°C) and 3.3 V supply, delivering 38.1 DMIPS of performance. The LM3S818-IQN50-C2 does not support overclocking beyond this rated speed.

Does the LM3S818-IQN50-C2 include a hardware quadrature encoder interface?

Yes, the LM3S818-IQN50-C2 includes a dedicated Quadrature Encoder Interface (QEI) peripheral with 16-bit position counter, velocity capture, and index pulse detection. It accepts PhA, PhB, Index, and Enable signals directly on GPIO pins mapped to QEI0, supporting encoder input frequencies up to 500 kHz. This hardware block offloads position tracking from the CPU, and is fully functional in the LM3S818-IQN50-C2 without external components.

What are the memory resources available on the LM3S818-IQN50-C2?

The LM3S818-IQN50-C2 integrates 64 KB of on-chip flash memory for program storage and 24 KB of SRAM for runtime data and stack. Flash supports in-application programming (IAP) and has write-protection bits; SRAM is zero-wait-state at maximum clock speed. These memory sizes are fixed for the LM3S818-IQN50-C2 and do not vary by temperature grade or package variant.

Is the LM3S818-IQN50-C2 pin-compatible with other LM3S8xx devices?

No, the LM3S818-IQN50-C2 is not pin-compatible with other LM3S8xx variants such as LM3S811 or LM3S815. While sharing the same 100-pin LQFP package outline, pin functions differ significantly across the family - for example, QEI and PWM signal assignments are unique to the LM3S818-IQN50-C2's peripheral configuration. Board layout must be designed specifically for the LM3S818-IQN50-C2.

What debug interface does the LM3S818-IQN50-C2 support?

The LM3S818-IQN50-C2 supports both JTAG and Serial Wire Debug (SWD) interfaces via dedicated pins (TCK, TMS, TDI, TDO, nTRST, SWDIO, SWCLK). It includes full ARM CoreSight debug infrastructure - including breakpoints, watchpoints, and real-time memory access - compatible with TI's Code Composer Studio and third-party tools like Segger J-Link. This capability is inherent to the LM3S818-IQN50-C2 silicon and requires no external debug probe firmware modification.