AS3940 2.4GHz Star Network Transceiver
Low Power Multi-Channel 2.4GHz FSK Transceiver with protocol for star network
The AS3940 is a highly integrated low power FSK transceiver for wireless communication in the worldwide 2.4 GHz ISM band. It supports data transfer in burst mode and streaming mode at data rates up to 2 Mbit/s.
All communication with a MCU and all configuration of the transceiver can be done using a bidirectional 4 pin serial data interface (SDI). The integrated timers and link manager enable very low average current consumption in operation and standby and help to reduce overall system cost by eliminating the need for a complex microcontroller (MCU). Optimum MCU clock frequency can be obtained from a programmable glitch-free clock output derived from the 16 MHz reference crystal oscillator.
The integrated link manager controls all power management modes, like power-down, standby, sleep, wakeup, and data mode, which enable to save power. The link manager handles all data and frame management in a star network (one master and up to 8 clients) using four separate 256-bit data buffers; two for RX and two for TX. This decreases MCU workload and ensures a smooth data transfer and correct protocol handling. All low level transmission codec and CRC generation is done internally. Microcontroller controlled data transfer (MCDT) mode enables support of proprietary protocols.
Excellent blocking and sensitivity, pseudorandom allocation of communication time slots and the adaptive channel switching enable reliable data transmission and high resistance to interferers like WLAN or Bluetooth.
The high level of integration eliminates the need for external components like battery monitoring circuitry, additional high frequency crystal, and power-on-reset circuitry.
The product is available in a QFN 32 pin (5mm x 5mm) package.
- Link manager for reliable control of star network (up to 8 clients)
- Device ID recognition and 16-bit CRC computation
- Pairing and automatic (re-)synchronization
- Power-optimized wakeup modes
- Programmable auto-acknowledgement and re-transmit
- Adaptive channel switching / support of frequency hopping
- Programmable timers to define time slots for communication
- Pseudo-random allocation of time slots
- Package synchronized digital RSSI
- Integrated RTC, 32 kHz XTAL oscillator / calibrated 6.25 kHz derived from a RCO
- Glitch-free CMOS compatible reference clock output 8/4/2/1 MHz or 6.25 kHz
- Output power programmable in 3dB steps (-24 dBm to 0 dBm)
- Integrated Gaussian filter, PLL and loop filter
- 4 separate 256-bit user data buffers (2x Rx, 2x Tx)
- Power on reset (POR, NPOR) for reliable system start
- Battery voltage detection
- Fully integrated FSK transceiver
- Operating frequency 2405 to 2480 MHz
- Minimum channel spacing 1MHz
- Data rates in burst mode 250, 1000, 2000 kbps
- Net data rate in streaming mode up to 1000 kbps
- Sensitivity of -100dBm@250kbps, -95.5dBm@1000kbps and -92.5dBm@2000kbps
- Excellent adjacent channel rejection and blocking performance
- Low-power short range devices
- Body area networks (health, fitness)
- Simple control networks (industry, home)
- Interactive remote controls