FSC-BW120 RTL8821CS Mini-Size Wi-Fi 5 + BT 5.3 Module


FSC-BW120 is an advanced Wi-Fi Bluetooth combo module designed for high-performance integrated wireless and Bluetooth connectivity. It supports 1-stream 802.11ac with Multi-user MIMO STA mode, incorporating a Bluetooth Smart Ready controller and versatile interfaces such as SDIO and HS-UART. The module integrates a WLAN MAC and 1T1R capable WLAN baseband with RF functionality in a single chip, ensuring seamless operation across IEEE 802.11b/g/a standards. It features robust signal processing capabilities, including adaptive frequency domain equalization and interference detection, enhancing reception reliability in diverse environments. The module’s MAC supports multimedia applications, security protocols like 802.11i and WAPI, and efficient packet aggregation techniques for enhanced protocol efficiency and power management. Compliant with Bluetooth v5.3, it facilitates dual-mode operation (BR/EDR + Low Energy) with support for simultaneous active links in various network topologies, ensuring versatile connectivity solutions.


  • General Features:
    • CMOS MAC, Baseband PHY and RF in a single chip for IEEE 802.11a/b/g/n/ac compatible WLAN
    • Support 802.11ac 1×1, Wave-2 compliant with MU-MIMO STA mode
    • Complete 802.11n MIMO solution for 2.4GHz and 5GHz band
  • Host Interface:
    • Complies with SDIO 1.1/2.0/3.0 for WLAN with clock rate up to 100 MHz (SDR50 and DDR50)
  • Standards Supported:
    • IEEE 802.11a/b/g/n/ac compatible WLAN
    • IEEE 802.11e QoS Enhancement (WMM)
    • IEEE 802.11i (WPA, WPA2). Open, shared key, and pair-wise key authentication services
    • IEEE 802.11h DFS, TPC, Spectrum Measurement
  • MAC Features:
    • Frame aggregation for increased MAC efficiency (A-MSDU, A-MPDU)
    • Low latency immediate Block Acknowledgement (BA)
    • Long NAV for media reservation with CF-End for NAV release
    • Maximum PHY data rate up to 86.7 Mbps using 20MHz bandwidth, 200 Mbps using 40MHz bandwidth, and 433.3 Mbps using 80MHz bandwidth
    • Backward compatible with 802.11a/b/g devices while operating at 802.11n data rates
    • Backward compatible with 802.11a/n devices while operating at 802.11ac data rates
    • G-SPI interface for configurable endian for WLAN
    • Complies with HS-UART with configurable baud rate for Bluetooth
    • IEEE 802.11k Radio Resource Measurement
    • WAPI (Wireless Authentication Privacy Infrastructure) certified
    • Cisco Compatible Extensions (CCX) for WLAN devices
    • PHY-level spoofing to enhance legacy compatibility
    • MIMO power saving mechanism
    • Channel management and co-existence
    • Multiple BSSID feature allows the FSC-BW120 to assume multiple MAC identities when used as a wireless bridge
    • Transmit Opportunity (TXOP) Short Inter-Frame Space (SIFS) bursting for higher multimedia bandwidth
    • WiFi Direct supports wireless peer to peer applications
  • Other Features:
    • Supports Wake-On-WLAN via Magic Packet and Wake-up frame
    • Transmit Beam forming
  • PHY Features:
    • IEEE 802.11ac OFDM
    • IEEE 802.11n OFDM
    • One Transmit and One Receive path
    • 5/10/20/40/80MHz bandwidth transmission
    • Support 2.4GHz and 5GHz band channels
    • Short Guard Interval (400 ns)
    • Sounding packet
    • DSSS with DBPSK and DQPSK, CCK modulation with long and short preamble
    • OFDM with BPSK, QPSK, 16QAM, 64QAM and 256QAM modulation. Convolutional Coding Rate: 1/2, 2/3, 3/4, and 5/6
    • WiFi NAN (Neighborhood Area Network) support
    • WiFi FTM (Fine Time Measurement) supported
    • WiFi TDLS (Tunneled Direct Link Setup) Supported
    • CCA on secondary through RTS/CTS handshake
    • Support TCP/UDP/IP checksum offload
    • Generates 40MHz clock for peripheral chip
    • Single external power source 3.3V only
    • Maximum data rate 54 Mbps in 802.11g, 150 Mbps in 802.11n and 433 Mbps in 802.11ac
    • Switch diversity used for DSSS/CCK
    • Support STBC receiving
    • Support LDPC transmitting
    • Hardware antenna diversity
    • Fast receiver Automatic Gain Control (AGC)
    • On-chip ADC and DAC
    • Build-in both 2.4GHz and 5GHz PA
    • Build-in both 2.4GHz and 5GHz LNA
  • Bluetooth Features:
    • Bluetooth 5.3, Support Simultaneous LE & BR/EDR, and High Duty Cycle Non-Connectable Advertising
    • HS-UART interface for Bluetooth data transmission compliant with H4 and H5 specification
    • PCM interface for audio data transmission via Bluetooth controller
    • Requires external MCU to execute Bluetooth protocol stack
    • Supports all packet types in basic rate and enhanced data rate
  • Bluetooth Transceiver:
    • Fast AGC control to improve receiving dynamic range
    • Integrated internal Class 1, Class 2, and Class 3 PA
    • Supports Enhanced Power Control
  • Peripheral Interfaces:
    • Supports SCO/eSCO link (allows one link for PCM interface and three links for HS-UART)
    • Supports Secure Simple Pairing
    • Enhanced BT/WLAN Coexistence Control to improve transmission quality in different profiles
    • Supports multiple Low Energy states
    • Supports Bluetooth Low Energy
    • Integrated 32K oscillator for power management


  • Internet-of-Things (IoT) Applications, including:
    • Home and Building Automation
    • Low-Power Video Cameras
    • Thermostats
    • Access Control and Electronic Locks (E-Locks)
    • Asset Tracking and Real Time Location System (RTLS) Tags
    • Cloud Connectivity
    • Internet Gateway
    • Appliances
    • Security Systems
    • Smart Energy
    • Industrial Control
    • Smart Plug and Metering
    • Wireless Audio
    • IP Network Sensor Nodes
    • Medical Devices
  • Car audio and video system


Categories Features Implementation
Bluetooth Standard Bluetooth V5.3 LE & BR/EDR
Frequency Band 2.402 ~ 2.480 GHz
Interfaces UART, PCM
Wi-Fi Standard 802.11 a/b/g/n/ac
Frequency Band 2.412 ~ 2.484 GHz / 4.900 ~ 5.925 GHz
Interface SDIO
Dimensions (mm) 12 × 12 × 2.4
Operating Temperature -40°C ~ +85°C
Storage Temperature -40°C ~ +85°C
VDD_3V3_WL 3.0V ~ 3.6V
VDD_IO 1.62V ~ 3.6V
Miscellaneous Lead Free Lead-free and RoHS compliant
Warranty One Year
Humidity 10% ~ 90% non-condensing
MSL grade: MSL 3
ESD grade: Human Body Model: Pass ±2000V, all pins
Charge device model: Pass ±400V, all pins
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