The real world problem
The ISM band is extensively for wireless solutions used across a number of market segments including:
- Body Area Networking / Biomedical telemetry
- Wireless sensor networks
- RFID network communication
- Wireless alarm and security systems
- Keyless entry
- Environmental control
- Domestic and industrial remote control systems
- Remote metering
In many of these applications the ability to operate using a single alkaline or even a zinc-air battery or using energy savaging techniques e.g. solar cells, piezo electric push buttons, can make otherwise unrealizable applications possible.
The solution
To meet this market demand, AnSem developed an ultra low-power RF ISM FSK transceiver in 0.25µm CMOS with a operational voltage range 0.9 V to 1.6 V and a power consumption of 2.6mW for transmission / 1.2mW for reception. The device is highly flexible including:
- Programmable frequency channels with 60 Hz accuracy
- Programmable FSK data rate from 0.9 to 200 kbps (tx) and 2.4 to 19.2 kbps (rx)
- Programmable frequency deviation from 60 Hz to 125 kHz
- Programmable power supply for the transmitter PA.
The RF ISM FSK transceiver also features built in filtering of FSK modulation for low adjacent channel power, quick crystal startup plus a fast PLL for use of frequency hopping spread spectrum. The receiver has a high sensitivity considering its low power consumption, which makes it suitable for watchdog applications. Both short and mid range (~100m) communication are supported.
Key technical statistics
- Ultra low receiver power consumption: 1.2 mW
- Ultra low transmitter energy consumption: 1.9 mA or 10 nJ/bit @ -10 dBm output power
- Frequencies 315 MHz, 418 MHz, 426 MHz, 433 MHz
- On-chip XTAL trimming without need for TCXO
- On-chip automatic VCO trimming
- 14 bit analog-to-digital converter consuming only 48 µA
