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Texas Instruments LM3S5B91-IQC80-C3T — Microcontrollers & Processors (MCU / MPU / DSP)

LM3S5B91-IQC80-C3T Stellaris ARM Cortex-M3 MCU, 80MHz, 256KB Flash

MPNLM3S5B91-IQC80-C3T
Obsolete

Texas Instruments Stellaris ARM Cortex-M3S 5000 series MCU, LM3S5B91-IQC80-C3T, 32-bit single-core at 80MHz, 256KB Flash, 96K x 8 RAM, 72 I/O, CAN/USB OTG/SPI/I²C, 100-LQFP (14x14 mm), -40°C to 85°C.

Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

LM3S5B91-IQC80-C3T specifications
ParameterValue
SeriesStellaris® ARM® Cortex®-M3S 5000
MountingSurface Mount
Oscillator typeInternal
Program memory typeFLASH
Voltage - supply (Vcc (Vdd))1.08V ~ 1.32V
Operating temperature-40°C~85°C(TA)
Speed80MHz
PackageTape & Reel (TR)
RAM size96K x 8
Core size32-Bit Single-Core
PeripheralsBrown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
ConnectivityCANbus, EBI/EMI, I²C, IrDA, LINbus, Microwire, QEI, SPI, SSI, UART/USART, USB OTG
Number of i (O)72
Core processorARM® Cortex®-M3
Case100-LQFP
Data convertersA/D 16x10b
Program memory size256KB (256K x 8)

Product details

What this Stellaris MCU actually does

The operating temperature range spans -40°C to 85°C. Supply voltage is 1.08 V to 1.32 V.

80 MHz Cortex-M3 — what the speed buys you

At 80 MHz, this core executes a single-cycle multiply and a two-cycle hardware divide. The DMA controller can move ADC results or UART data without stealing cycles from the CPU.

The LM3S5B91-IQC80-C3T is officially obsolete (EOL). Texas Instruments has ended production; no last-time-buy window remains open. New units are available only through independent distribution and surplus channels. If your BOM line needs a production-run alternative, the Stellaris family includes pin-compatible siblings with similar memory and peripheral maps; we can help identify the closest fit for a redesign.

Peripheral set for industrial control

The 16-channel 10-bit ADC samples analog inputs from sensors or potentiometers without an external converter. The quadrature encoder interface (QEI) reads incremental encoder pulses directly — useful for motor position feedback. The PWM module with dead-band insertion drives a half-bridge or H-bridge with minimal software overhead. Brown-out detect and power-on reset are built in, so the MCU starts predictably on power-up and resets cleanly on a supply dip.

Frequently asked questions

Is LM3S5B91-IQC80-C3T obsolete?

Yes, the LM3S5B91-IQC80-C3T is obsolete and no longer in production by Texas Instruments. It is available through surplus and independent distributor channels, sourced to order against an RFQ.

What is the replacement for LM3S5B91-IQC80-C3T?

Texas Instruments has not published a direct pin-compatible replacement for this specific Stellaris 5000-series MCU. For a new design, consider a current-production ARM Cortex-M4 or M7 part from TI's TM4C series, which offers similar peripheral integration and a migration path. We can review your requirements and suggest a cross-reference for a BOM redesign.

What is LM3S5B91-IQC80-C3T's listed speed?

The core runs at 80 MHz, which is the maximum clock for this Stellaris ARM Cortex-M3 device.

What is the datasheet for LM3S5B91-IQC80-C3T?

The datasheet is available from Texas Instruments' archive for the Stellaris LM3S5B91. It covers the full electrical specifications, pinout, and application notes for this MCU.