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Texas Instruments LM3S1R21-IQC80-C5 — Microcontrollers & Processors (MCU / MPU / DSP)

LM3S1R21-IQC80-C5 Stellaris ARM Cortex-M3 MCU, 80 MHz

MPNLM3S1R21-IQC80-C5
Obsolete

Texas Instruments Stellaris® ARM® Cortex®-M3S 1000 series, LM3S1R21-IQC80-C5, 32-Bit Single-Core MCU, 80MHz, 256KB Flash, 48K x 8 RAM, 67 I/O, 100-LQFP, -40°C~85°C.

Texas Instruments LM3S1R21-IQC80-C5 datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

LM3S1R21-IQC80-C5 specifications
ParameterValue
SeriesStellaris® ARM® Cortex®-M3S 1000
MountingSurface Mount
Oscillator typeInternal
Program memory typeFLASH
Voltage - supply (Vcc (Vdd))1.08V ~ 3.6V
Operating temperature-40°C~85°C(TA)
Speed80MHz
PackageTray
RAM size48K x 8
Core size32-Bit Single-Core
PeripheralsBrown-out Detect/Reset, DMA, POR, PWM, WDT
ConnectivityEBI/EMI, I²C, IrDA, LINbus, Microwire, SPI, SSI, UART/USART
Number of i (O)67
Core processorARM® Cortex®-M3
Case100-LQFP
Data convertersA/D 8x10b
Program memory size256KB (256K x 8)

Product details

80 MHz core and 256 KB Flash — sizing the firmware and the loop

The 80 MHz Cortex-M3 core delivers about 1.25 DMIPS/MHz, so you get roughly 100 DMIPS for control loops, sensor fusion, or protocol parsing. The 256 KB Flash is a comfortable fit for a bootloader plus a moderate application — think motor drive firmware with field-oriented control, or a multi-protocol gateway handling Modbus and CANopen. The 48 KB SRAM supports a few large buffers (e.g., two 1 KB Ethernet frames, a 4 KB display frame, and stack) without hitting swap.

The 8-channel 10-bit ADC handles analog feedback from sensors or potentiometers without an external converter.

No further factory orders are accepted; no last-time-buy window remains open. For production or repair, the part must be sourced through independent distribution — surplus inventory, broker channels, or open-market stock.

Package and mounting — 100-LQFP hand-solderable

It is a surface-mount device, so plan for a stencil if you are doing reflow in volume.

Frequently asked questions

Where can I buy LM3S1R21-IQC80-C5 and how do I get a price?

The LM3S1R21-IQC80-C5 is obsolete and no longer in factory production. We source it through independent distribution — surplus inventory and broker channels. Submit an RFQ for this part; we will confirm availability and current pricing at quote time. No stock or price figures are published here because the market moves daily for an obsolete part.

Is LM3S1R21-IQC80-C5 obsolete and can it be used in a new design?

Yes, the LM3S1R21-IQC80-C5 is obsolete per Texas Instruments. It should not be used in a new design — there is no factory support, no last-time-buy window, and no guarantee of long-term supply. For a new project, look at current-production Stellaris or TM4C Cortex-M4 parts from TI that are pin-compatible and offer better performance and longer lifecycle.

What is the replacement for LM3S1R21-IQC80-C5?

Texas Instruments has not published a direct pin-compatible replacement for the LM3S1R21-IQC80-C5. The Stellaris family evolved into the TM4C series (Cortex-M4F), which shares the same 100-LQFP footprint and peripheral set in many variants. For a specific cross-reference, compare the TM4C123 or TM4C129 parts against your firmware and peripheral requirements. We can help identify a suitable current-production alternate when you submit an RFQ.

What is LM3S1R21-IQC80-C5's listed speed and memory?

The core runs at 80 MHz. Program memory is 256 KB of Flash, and SRAM is 48 KB. That combination is typical for a mid-range Cortex-M3 MCU handling control loops, communication stacks, and moderate data buffering.