Microcontrollers
A microcontroller is a small, low-cost computer-on-a-chip that can be used to control electronic devices and systems. It consists of a central processing unit (CPU), memory, input/output (I/O) ports, and other peripherals integrated onto a single chip. Microcontrollers are commonly used in a wide range of applications, including automotive systems, home appliances, industrial automation, and consumer electronics. One of the key benefits of microcontrollers is their ability to interact with their environment through sensors and actuators, making them well-suited for use in embedded systems. These systems are often found in devices that require real-time control or data processing, such as medical equipment, aircraft, and factory automation systems. Flux.ai is home to the world's largest community-driven public library of microcontrollers, with footprints, symbols, datasheets, and simulation models for a wide range of devices. Whether you're a professional engineer looking for a specific microcontroller for your next project, or a hobbyist exploring the possibilities of microcontroller-based systems, Flux.ai has the resources you need to get started.
BALFHB-WL-06D3
50 Ω nominal input / conjugate match balun to QFN-2L STM32WL in low power mode, 862-928 MHz with integrated harmonic filter RF Balun 862MHz ~ 928MHz 8-WFBGA, CSPBGA Features • QFN STM32WL sub-GHz wireless microcontrollers impedance matched balun and Tx harmonics filter • Optimized for QFN STM32WL sub-GHz wireless microcontrollers in low power mode and dedicated to 2-layer PCB • 50 Ω nominal input / conjugate matched balun to QFN STM32WL • 50 Ω nominal impedance on antenna side Tx and Rx • Deep Tx rejection harmonic filter • Low insertion loss • Small footprint • Low profile ≤ 630 μm after reflow • High RF performance • RF BOM and area reduction • ECOPACK2 compliant component Applications • STM32WL sub-GHz wireless microcontrollers • LPWAN-compliant radio solution, enabling the following modulations: LoRa®, (G)FSK, (G)MSK, and BPSK
3 Uses0 StarsMAX44009EDT+T
Optical Sensor Ambient I2C 6-UDFN Exposed Pad ## Engineering Specification ## General Description The **MAX44009EDT+T** is an Analog Devices / Maxim Integrated digital ambient light sensor designed for portable electronics, display brightness control, industrial sensors, embedded systems, and low-power optical sensing applications. It integrates an ambient light photodiode, signal conditioning, analog-to-digital conversion, and an I²C digital output interface in a compact surface-mount package. The device is suitable for systems requiring automatic brightness adjustment, low current consumption, and light measurement behavior that closely follows human-eye response. ## Device Identification Manufacturer Part Number: **MAX44009EDT+T** Manufacturer: **Analog Devices / Maxim Integrated** Product Series: **MAX44009** Device Category: **Sensor Integrated Circuit** Device Type: **Digital Ambient Light Sensor** Sensor Interface: **I²C Digital Output** Mounting Type: **Surface Mount** Package Type: **UTDFN-Opto / UDFN** ## Functional Description The device functions as a digital ambient light sensor that measures surrounding light intensity and reports the measurement through an I²C interface. It is designed to help electronic systems adjust display brightness, conserve power, improve user visibility, and respond to changes in lighting conditions. The integrated optical sensing and digital conversion circuitry reduce the need for external analog signal-conditioning components. ## Optical Sensing Description The sensor includes an on-chip photodiode with spectral response optimized to approximate human-eye sensitivity. It also incorporates infrared and ultraviolet blocking capability to improve ambient light measurement accuracy. The adaptive gain function automatically selects the appropriate measurement range, allowing the device to operate across very low-light and bright-light conditions. ## Electrical Description The **MAX44009EDT+T** operates from a low-voltage supply range and is optimized for ultra-low power consumption. It supports digital communication through an I²C interface and is suitable for battery-powered and energy-sensitive systems. Proper supply decoupling, pull-up resistor selection, and bus voltage compatibility should be considered during circuit design. ## Package and Mechanical Description The component is supplied in a compact surface-mount optical package suitable for space-constrained printed circuit board designs. The package is intended for placement where the optical sensing window has access to ambient light while maintaining proper mechanical protection from contamination, shadowing, and enclosure obstruction. ## Interface and Control Description The device communicates with a host microcontroller or processor through an I²C digital interface. The host can read ambient light data and configure device behavior through register-based communication. The selectable I²C addressing feature supports flexible integration in systems that may include multiple I²C peripherals. ## Mounting and Assembly Description The **MAX44009EDT+T** is intended for surface-mount PCB assembly using standard reflow soldering processes. PCB layout should follow the manufacturer’s recommended footprint and assembly guidance. The optical sensing area should remain unobstructed, clean, and aligned with the product enclosure opening or light pipe when used. ## Application Suitability The device is suitable for smartphones, tablets, notebooks, wearable electronics, handheld devices, display brightness control, industrial light sensing, smart home devices, battery-powered equipment, sensor modules, and embedded systems requiring digital ambient light detection. ## Design Considerations The design should account for sensor placement, optical window design, enclosure transparency, light pipe geometry, I²C bus pull-up values, supply voltage compatibility, ambient interference, temperature conditions, and contamination protection. The sensor should not be blocked by opaque materials or placed where shadows, reflections, or nearby LEDs may distort the measured ambient light level. ## Hashtags #commonpartslibrary #integratedcircuit #sensor #ambientlightsensor #digitalsensor #opticalsensor #analogdevices #maximintegrated #max44009 #max44009edt #i2csensor #lightmeasurement #brightnesscontrol #lowpowersensor #portableelectronics #displaycontrol #embeddedhardware #embeddeddesign #smdcomponent #surfacemount #utdfnpackage #uDFNpackage #pcbdesign #hardwaredesign #electronicscomponents #electronicparts #componentlibrary #engineeringparts #electronicsengineering
9 Uses0 StarsLAN8770M-I/PRA
4/4 Transceiver Full MII, RMII 32-VQFN (5x5) ## Engineering Specification ## General Description The **LAN8770M-I/PRA** is a Microchip Technology single-port **100BASE-T1 Ethernet physical layer transceiver** designed for automotive, industrial, and embedded networking applications. It provides Ethernet communication over a single balanced twisted pair and is suitable for compact systems requiring reliable network connectivity, low-power operation, and standard MAC interface support. The device is commonly used in automotive electronic control units, infotainment systems, telematics modules, sensor nodes, industrial control systems, and embedded Ethernet hardware. ## Device Identification Manufacturer Part Number: **LAN8770M-I/PRA** Manufacturer: **Microchip Technology** Product Family: **LAN8770** Device Category: **Integrated Circuit** Device Type: **Ethernet PHY Transceiver** Ethernet Standard: **100BASE-T1** Interface Type: **MII and RMII** Mounting Type: **Surface Mount** Package Type: **VQFN** ## Functional Description The device functions as an Ethernet physical layer transceiver that connects a host controller or microcontroller MAC interface to a single-pair Ethernet physical medium. It handles the analog and digital PHY functions required for 100BASE-T1 communication, allowing embedded systems to transmit and receive Ethernet data over a single twisted pair cable. ## Network and Interface Description The **LAN8770M-I/PRA** supports 100 Mb/s single-pair Ethernet communication and provides MII and RMII host interface options. This allows integration with microcontrollers, processors, gateways, and network controllers that support standard Ethernet MAC interfaces. The device is intended for applications where compact Ethernet connectivity and reduced cabling complexity are required. ## Electrical Description The device is designed for low-voltage operation and supports multiple supply domains according to the manufacturer’s recommended operating conditions. Proper power sequencing, decoupling, reset handling, clocking, and reference layout should be implemented to maintain stable PHY operation and signal integrity. ## Package and Mechanical Description The component is supplied in a compact surface-mount **VQFN package**, suitable for dense printed circuit board assemblies. The package supports automated assembly and is appropriate for space-constrained automotive and industrial electronic designs. ## Control and Diagnostic Description The PHY supports management and configuration through standard control interfaces used in Ethernet designs. It provides status monitoring and configuration capability for link management, operating mode selection, and system-level diagnostics. These features allow the host controller to configure and monitor Ethernet link behavior during operation. ## Automotive and Industrial Suitability The **LAN8770M-I/PRA** is suitable for embedded systems requiring robust single-pair Ethernet communication. It is applicable to automotive networking, telematics, infotainment, advanced driver assistance systems, industrial Ethernet nodes, building automation, control modules, and other connected embedded platforms. ## Mounting and Assembly Description The component is intended for surface-mount PCB assembly using standard reflow soldering processes. PCB layout should follow Microchip’s hardware design guidance, including proper power supply decoupling, controlled impedance routing, short signal paths, grounding, and separation of sensitive analog and digital sections where applicable. ## Design Considerations The design should account for Ethernet signal integrity, single-pair cable interface requirements, common-mode noise control, EMC performance, supply filtering, oscillator or clock source requirements, reset timing, thermal performance, and package solderability. The device should not be operated beyond the manufacturer’s specified electrical, thermal, or mechanical limits. ## Application Suitability The device is suitable for automotive Ethernet nodes, electronic control units, telematics modules, infotainment systems, sensor interfaces, industrial controllers, embedded gateways, connected equipment, and compact network-enabled hardware requiring 100BASE-T1 Ethernet PHY functionality. ## Hashtags #commonpartslibrary #integratedcircuit #ethernetphy #microchip #microchiptechnology #lan8770 #lan8770mipra #singlepairethernet #100baset1 #automotiveethernet #ethernettransceiver #phytransceiver #embeddednetworking #mii #rmii #vqfnpackage #smdcomponent #surfacemount #automotiveelectronics #industrialethernet #telematics #infotainment #embeddedhardware #pcbdesign #hardwaredesign #electronicscomponents #electronicparts #componentlibrary #engineeringparts #electronicsengineering
3 Uses0 StarsS32K358GHT1MJBST
ARM® Cortex®-M7 S32K3 Microcontroller IC 32-Bit Tri-Core 240MHz 8MB (8M x 8) FLASH 289-LFBGA (14x14) ## Engineering Specification ## General Description The **S32K358GHT1MJBST** is an NXP Semiconductors **S32K3 series automotive microcontroller** designed for high-performance embedded control applications in automotive, industrial, and electrically harsh environments. It is built around an **Arm Cortex-M7 architecture** and provides high processing capability, large embedded flash memory, automotive-grade qualification, security support, and a broad set of communication interfaces. The device is suitable for body control, gateway systems, vehicle networking, motor control, domain control, safety-related embedded systems, and general-purpose automotive electronic control units. ## Device Identification Manufacturer Part Number: **S32K358GHT1MJBST** Manufacturer: **NXP Semiconductors** Product Family: **S32K3** Device Category: **Integrated Circuit** Device Type: **Automotive Microcontroller** Core Architecture: **Arm Cortex-M7** Processing Class: **Thirty-Two-Bit MCU** Qualification: **Automotive Grade, AEC-Q100** ## Functional Description The device functions as a high-performance automotive microcontroller for embedded control and communication systems. It provides processing resources for real-time control, communication management, diagnostics, security handling, and system-level application logic. The microcontroller is designed for scalable automotive platforms where software reuse, safety capability, and peripheral integration are important. ## Core and Processing Description The **S32K358GHT1MJBST** uses an Arm Cortex-M7 based processing architecture with tri-core capability and high-speed operation. The core architecture supports digital signal processing, floating-point operation, interrupt handling, and real-time embedded software execution. This makes the device suitable for control systems that require strong computing performance and deterministic response. ## Memory Description The device includes large embedded flash memory for application firmware storage and integrated RAM for runtime operation, data buffering, communication stacks, and control algorithms. The memory architecture is suitable for complex embedded applications requiring large program space, diagnostics, bootloader support, and over-the-air update capability. ## Security and Safety Description The microcontroller includes hardware security support through **HSE-B security** and is intended for automotive applications where secure boot, cryptographic services, protected firmware operation, and system integrity are important. The S32K3 family also supports automotive safety-oriented development through features such as error correction, monitoring, and diagnostic capability. ## Communication and Interface Description The device supports multiple embedded communication interfaces suitable for vehicle and industrial networks. Supported interface types include CAN, Ethernet, I²C, SPI, UART, LIN, QSPI, SAI, SENT, and FlexIO. These interfaces allow the device to communicate with sensors, actuators, transceivers, memory devices, network controllers, and other electronic control units. ## Analog and Peripheral Description The microcontroller includes analog-to-digital conversion capability, timers, watchdog functions, direct memory access, serial audio support, and general-purpose input and output resources. These peripherals support sensing, control, timing, supervision, communication, and system management functions in embedded hardware designs. ## Electrical Description The device is designed for automotive low-voltage operation and supports use across a wide supply voltage range. It is intended for applications requiring reliable operation in automotive and industrial temperature environments. Proper power supply design, decoupling, reset control, clock configuration, and grounding should follow the manufacturer’s hardware design recommendations. ## Package and Mechanical Description The **S32K358GHT1MJBST** is supplied in a **surface-mount LFBGA package** with a compact ball-grid-array footprint. The package is intended for dense printed circuit board layouts requiring careful routing, controlled assembly process, thermal management, and proper solder joint reliability. ## Mounting and Assembly Description The component is intended for automated surface-mount PCB assembly using BGA-compatible manufacturing processes. PCB layout should follow the recommended footprint, ball escape routing, power-plane design, decoupling capacitor placement, thermal design, and inspection requirements for high-density automotive microcontroller assemblies. ## Application Suitability The device is suitable for automotive electronic control units, body control modules, gateway controllers, vehicle networking systems, motor control platforms, battery-related control systems, industrial controllers, safety-oriented embedded systems, and high-performance general-purpose control applications. ## Design Considerations The design should account for supply voltage range, clocking requirements, flash and RAM usage, thermal limits, package routing density, communication interface requirements, EMC performance, boot configuration, security provisioning, debugging access, software safety requirements, and compliance with automotive design guidelines. The device should not be operated beyond the manufacturer’s specified electrical, thermal, or mechanical limits. ## Hashtags #commonpartslibrary #integratedcircuit #microcontroller #automotivemcu #nxp #nxpsemiconductors #s32k3 #s32k358 #s32k358ght1mjbst #armcortexm7 #cortexm7 #thirtytwobit #automotiveelectronics #aecq100 #hsesecurity #canfd #ethernet #vehicleelectronics #embeddedhardware #embeddeddesign #ecu #gatewaycontroller #bodycontrolmodule #pcbdesign #hardwaredesign #electronicscomponents #electronicparts #componentlibrary #engineeringparts #electronicsengineering
2 Uses0 StarsR7FA6E10F2CFM#AA0
ARM® Cortex®-M33 RA6E1 Microcontroller IC 32-Bit 200MHz 1MB (1M x 8) FLASH 64-LFQFP (10x10) ## Engineering Specification ## General Description The **R7FA6E10F2CFM#AA0** is a Renesas Electronics **RA6E1 series microcontroller** designed for embedded control, industrial electronics, IoT edge devices, automation systems, and general-purpose connected applications. It is built around an **Arm Cortex-M33 processor with TrustZone support**, providing high performance, secure execution capability, and flexible integration for modern embedded designs. ## Device Identification Manufacturer Part Number: **R7FA6E10F2CFM#AA0** Manufacturer: **Renesas Electronics** Product Family: **RA Family** Series: **RA6 Series** Group: **RA6E1 Group** Device Category: **Integrated Circuit** Device Type: **Microcontroller Unit** ## Core and Processing The device uses an **Arm Cortex-M33 core** and is intended for high-performance embedded processing. It supports secure application development through TrustZone technology and is suitable for systems requiring reliable control, fast response, and efficient software execution. ## Memory Configuration The microcontroller includes program flash memory, data flash memory, and SRAM resources suitable for embedded firmware, application code, configuration storage, and runtime processing requirements. ## Package and Mechanical Description The component is supplied in an **LQFP surface-mount package**, making it suitable for compact printed circuit board layouts and standard automated assembly processes. ## Electrical and Operating Description The device is designed for low-voltage embedded systems and supports operation across an industrial temperature range. It is suitable for products requiring stable performance in controlled, commercial, or industrial operating environments. ## Communication and Interface Support The device supports common embedded communication interfaces such as USB, UART, SPI, I²C, QSPI, and CAN, allowing integration with sensors, displays, external memory, communication modules, and other peripheral devices. ## Analog and Control Features The microcontroller includes analog conversion capability, timer functions, PWM support, watchdog protection, reset monitoring, and low-voltage detection features. These functions make it suitable for control systems, monitoring equipment, and mixed-signal embedded applications. ## Security and Debug Features The device supports embedded security functions including TrustZone, unique device identification, and true random number generation. Debug and development access is supported through standard JTAG and SWD interfaces. ## Application Suitability This device is suitable for embedded controllers, IoT devices, industrial automation, metering equipment, appliance control, USB-connected products, sensor-based systems, and general electronic control applications requiring a compact and secure microcontroller solution. ## Hashtags #commonpartslibrary #integratedcircuit #microcontroller #renesas #renesaselectronics #ra6e1 #ra6series #armcortexm33 #embeddedsystems #electronicscomponents #semiconductor #mcu #iotdevices #industrialautomation #pcbdesign #electronicparts #componentlibrary #engineeringparts #hardwaredesign #electronicsengineering
0 Uses0 Stars1085
ADS1115 series 16 Bit 860 Samples per Second Analog to Digital Converter (ADC) Evaluation Board Adafruit 1085 ADS1115 Adafruit 4-Channel ADC Breakout based on Texas Instruments ADS1115 (16-bit) or ADS1015 (12-bit) analog-to-digital converter, featuring I2C communication, four single-ended inputs or two differential inputs, programmable gain amplifier (PGA) up to x16, internal voltage reference, programmable comparator, and selectable I2C addresses (0x48–0x4B). Operates from 2.0V to 5.5V and supports interfacing analog sensors with 3.3V and 5V microcontrollers such as Arduino, ESP32, STM32, RP2040, and Raspberry Pi. Search Keywords: Adafruit 4-Channel ADC Breakout, ADS1115 Breakout, ADS1015 Breakout, Adafruit ADS1115, Adafruit ADS1015, I2C ADC Module, 16-bit ADC, 12-bit ADC, 4-channel ADC, differential ADC, programmable gain amplifier, PGA ADC, analog sensor interface, TI ADS1115, TI ADS1015, Raspberry Pi ADC, Arduino ADC module, ESP32 ADC expansion Hashtags: #Adafruit #ADS1115 #ADS1015 #ADCModule #I2CADC #16BitADC #12BitADC #AnalogToDigitalConverter #SensorInterface #DifferentialADC #PGA #Arduino #ESP32 #STM32 #RP2040 #RaspberryPi #DataAcquisition #EmbeddedSystems #AdafruitBreakout
27 Uses0 StarsMIMXRT1189XVM8C
ARM® Cortex®-M33F, ARM® Cortex®-M7F RT1180 Microcontroller IC 32-Bit Dual-Core 240MHz, 800MHz 160KB (160K x 8) ROM 289-LFBGA (14x14) The MIMXRT1189XVM8C is a high-performance crossover microcontroller from the NXP Semiconductors i.MX RT1180 family, designed for advanced industrial and real-time embedded applications. It combines the real-time performance of a microcontroller with the connectivity and security features typically found in application processors. The device integrates dual Arm® Cortex® cores, high-speed networking with Time-Sensitive Networking (TSN), and advanced EdgeLock® security technology, making it ideal for industrial automation, robotics, motor control, automotive gateways, and Industry 4.0 systems. Key Features Dual-core architecture: Arm® Cortex®-M7 core running up to 800 MHz Arm® Cortex®-M33 core running up to 300 MHz Integrated Gigabit TSN Ethernet switch for deterministic real-time networking Supports industrial Ethernet protocols including: EtherCAT PROFINET Ethernet/IP CC-Link IE Advanced EdgeLock® Secure Enclave for secure boot, cryptography, and tamper detection Up to 1.5 MB on-chip SRAM with ECC protection High-speed external memory interfaces Multiple communication peripherals: CAN-FD UART SPI I2C USB Ethernet High-resolution ADCs and advanced PWM/timer modules Supports MCUXpresso SDK and Zephyr RTOS Industrial temperature range operation from -40°C to +125°C BGA package optimized for compact industrial designs #Commonpartlibrary #Microcontroller #MIMXRT1189
15 Uses0 StarsRP2040
Raspberry Pi RP2040 dual-core Arm Cortex-M0+ microcontroller, running up to 133MHz, with 264KB on-chip SRAM, external QSPI flash support, USB 1.1 device/host controller, 30 GPIO pins, UART, SPI, I2C, PWM, ADC, timers and programmable I/O (PIO) blocks, 1.8V to 3.3V I/O support, low-cost MCU for embedded systems, development boards, IoT devices, USB peripherals, sensors and educational electronics. Search Keywords: RP2040, Raspberry Pi RP2040, RP2040 microcontroller, dual core Cortex-M0+ MCU, Raspberry Pi Pico MCU, RP2040 PIO, RP2040 USB microcontroller, RP2040 QSPI flash, RP2040 datasheet, RP2040 embedded MCU Hashtags: #RP2040 #RaspberryPiRP2040 #RaspberryPiPico #Microcontroller #CortexM0Plus RP2040 chip for Raspberry Pi Pico - ARM® Cortex®-M0+ MCU 32-Bit
2 Uses0 StarsSTM32WLE5JCI6
Multiprotocol LPWAN 32-bit Arm Cortex-M4 MCUs, LoRa, (G)FSK, (G)MSK, BPSK, up to 256KB flash, 64KB SRAM IC RF TxRx + MCU 802.15.4 LoRa™ 150MHz ~ 960MHz 73-UFBGA The STM32WLE5JCI6 is an ultra-low-power wireless System-on-Chip (SoC) from STMicroelectronics that combines a 32-bit Arm Cortex-M4 microcontroller with an integrated sub-GHz radio transceiver. It is designed for long-range, low-power IoT and LPWAN applications such as smart metering, smart cities, industrial sensors, and remote monitoring systems. It supports multiple modulation schemes including LoRa®, (G)FSK, (G)MSK, and BPSK, making it flexible for both proprietary and standardized wireless protocols like LoRaWAN®. The device integrates RF, analog, digital, and security features into a single chip to reduce external components and PCB size. Key Features Core & Performance 32-bit Arm® Cortex®-M4 core up to 48 MHz DSP instructions and MPU support Up to 256 KB Flash and 64 KB SRAM Wireless Radio Sub-GHz frequency range: 150 MHz – 960 MHz Supports LoRa®, (G)FSK, (G)MSK, BPSK High receiver sensitivity up to –148 dBm (LoRa mode) Output power up to +22 dBm Ultra-Low Power Operation Supply voltage: 1.8 V – 3.6 V Very low sleep currents (nA–µA range) Optimized for battery-powered and energy-harvesting devices Peripherals Up to 43 GPIOs ADC (12-bit), DAC, comparators Multiple timers (16-bit and 32-bit) Interfaces: SPI, I2C, UART/USART, LPUART, I2S Security Features Hardware AES-256 encryption True Random Number Generator (TRNG) Secure memory protection and unique device ID System Integration Integrated RF + MCU (highly reduced BOM) OTA firmware update capability Industrial temperature range (typically –40°C to +85°C / +105°C depending variant) Summary The STM32WLE5JCI6 is a highly integrated LoRa-capable MCU + RF transceiver SoC, optimized for long-range wireless communication with extremely low power consumption, making it ideal for IoT devices that must run for years on battery power. #CommonPartsLibrary #IntegratedCircuit #STM32WLE5JCI6 #STM32WL #LoRa #IoT #LowPowerMCU #ArmCortexM4 #SubGHzRF #WirelessMCU #LPWAN #STMicroelectronics
1 Uses0 StarsIRLML2502
MOSFET N-CH 20V 3.6A SOT-23 The IRLML2502 is a small-signal N-channel enhancement mode power MOSFET designed for low-voltage, high-efficiency switching applications. It is commonly used as a load switch or power control transistor in compact electronic systems such as battery-powered devices, LED drivers, and DC-DC converters. It features a low on-resistance (RDS(on)), which allows it to switch higher currents with minimal power loss and heat generation. The device is optimized for logic-level gate drive, meaning it can be driven directly from microcontrollers (like 3.3 V or 5 V systems). It is packaged in a compact SOT-23 (Micro3) surface-mount package, making it suitable for space-constrained PCB designs. Key Features N-channel enhancement mode MOSFET Drain-source voltage (VDS) up to 20 V Continuous drain current up to ~4.2 A (at 25°C) Very low RDS(on) ≈ 45 mΩ @ VGS = 4.5 V Logic-level gate drive capability (works with 2.5–4.5 V signals) Fast switching performance Compact SOT-23 (Micro3) surface-mount package Low gate charge for efficient switching Suitable for battery-powered and low-voltage applications RoHS compliant, lead-free design #IRLML2502 #MOSFET #NChannelMOSFET #PowerElectronics #SOT23 #LogicLevelMOSFET #PowerSwitch #ElectronicComponents #EmbeddedSystems #PCBDesign
413 Uses0 Stars