Texas Instruments LM3S1968-IQC50-A2T

Overview

LM3S1968-IQC50-A2T from Texas Instruments is a 32-bit ARM Cortex-M3 microcontroller with 256 KB flash, 64 KB SRAM, integrated ADC (12-bit, 1 MSPS), dual UARTs, I²C, SSI, PWM, and hibernation module. It operates at 50 MHz and supports industrial motor control, sensor interface, and embedded automation systems.

For engineers reviewing the LM3S1968-IQC50-A2T datasheet, LM3S1968-IQC50-A2T pinout, LM3S1968-IQC50-A2T application, or LM3S1968-IQC50-A2T equivalent, key selection criteria include its 50 MHz CPU clock, hibernation mode with RTC and battery-backed memory, 12-bit ADC sampling rate, GPIO interrupt capability, and QFP-100 package compatibility for space-constrained industrial PCB layouts.

Technical Context

The LM3S1968-IQC50-A2T implements the ARM Cortex-M3 core with NVIC, SysTick, and MPU, enabling deterministic real-time interrupt handling and memory protection. It integrates a hibernation module with RTC, battery-backed RAM, and wake-up sources including external pins and RTC match events.

Peripherals include two UARTs supporting IrDA/SIR, one I²C master/slave interface, two SSI modules, eight PWM outputs, and an analog comparator pair. The ADC features four sample sequencers, hardware averaging, and internal temperature sensor support - all directly accessible via APB bus without DMA dependency.

Key Specifications

Pinout & Package

LM3S1968-IQC50-A2T is housed in a 100-pin Low-Profile Quad Flat Package (LQFP) with exposed thermal pad, rated for industrial temperature range (–40°C to +85°C) and RoHS compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3S811-IQN50-A2 and TM4C123GH6PM, the LM3S1968-IQC50-A2T uniquely balances legacy industrial firmware compatibility, integrated hibernation, and full peripheral set in a mature 100-pin LQFP footprint - making it optimal for sustaining existing designs requiring long-term supply stability.

Availability

LM3S1968-IQC50-A2T is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, PLC I/O modules, and embedded HMI applications requiring stable component supply across extended production lifecycles.

Supply support for LM3S1968-IQC50-A2T 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 the first ARM Cortex-M3-based microcontroller family for cost-sensitive, real-time industrial applications - emphasizing integration, low-power hibernation, and peripheral flexibility without external support chips.

FAQ

What is the maximum operating frequency of the LM3S1968-IQC50-A2T?

The LM3S1968-IQC50-A2T operates at a maximum CPU clock frequency of 50 MHz, as specified in the production data sheet (SPMS037I, Rev I). This speed is achieved using the internal PLL with an external crystal or oscillator input. The 50 MHz rating applies across the full industrial temperature range (–40°C to +85°C) and is validated under worst-case voltage and process corners. LM3S1968-IQC50-A2T maintains deterministic interrupt latency and instruction throughput at this frequency without throttling.

Does the LM3S1968-IQC50-A2T support USB device functionality?

Yes, the LM3S1968-IQC50-A2T includes a USB 2.0 Full-Speed device controller compliant with USB Specification Revision 2.0. It supports control, interrupt, bulk, and isochronous transfer types. The USB interface requires external termination resistors and a 12 MHz crystal; VBUS detection and ID pin support enable limited OTG awareness. LM3S1968-IQC50-A2T does not support USB host mode or high-speed operation.

What are the hibernation current and wake-up sources for the LM3S1968-IQC50-A2T?

The LM3S1968-IQC50-A2T achieves 1.7 µA typical hibernation current with RTC running and 2 KB of SRAM retained. Wake-up sources include RTC match events, external GPIO pins (HIBWAKE), and the hibernate enable signal (HIB). The hibernation module retains register context and supports fast wake-up (<10 µs) to active mode. LM3S1968-IQC50-A2T does not support deep-sleep wake-up from ADC or comparator events without exiting hibernation first.

How many UART interfaces does the LM3S1968-IQC50-A2T integrate?

The LM3S1968-IQC50-A2T integrates two independent UART modules (UART0 and UART1), each supporting full-duplex asynchronous communication, programmable baud rates, 16-byte FIFOs, modem control signals, and IrDA/SIR infrared encoding. Both UARTs can operate simultaneously with separate GPIO mappings. LM3S1968-IQC50-A2T does not share UART resources with other peripherals - each has dedicated APB bus access and interrupt vectors.

Is the LM3S1968-IQC50-A2T pin-compatible with other LM3S devices?

No, the LM3S1968-IQC50-A2T is not universally pin-compatible with other LM3S microcontrollers. While it shares the 100-pin LQFP package with some variants (e.g., LM3S8962), pin functions differ significantly across the family due to varying peripheral sets and routing constraints. For example, USB signals appear on different pins than in LM3S811, and hibernation module pins (HIB, RTCCLK) are absent in non-hibernation variants. LM3S1968-IQC50-A2T requires its own layout and cannot be substituted without schematic and PCB revision.