The ADF7020-1 is a low power, highly integrated FSK/ GFSK/ ASK/ OOK/ GOOK transceiver designed for operation in the
low UHF and VHF bands. The ADF7020-1 uses an external
VCO inductor that allows users to set the operating frequency
anywhere between 135 MHz and 650 MHz. Using the divide-by-2
circuit allows users to operate the device as low as 80 MHz.
The typical range of the VCO is about 10% of the operating
frequency. A complete transceiver can be built using a small
number of external discrete components, making the ADF7020-1 very suitable for price-sensitive and area-sensitive
applications.
The transmit section contains a VCO and low noise
fractional-N PLL with output resolution of <1 ppm. This
frequency agile PLL allows the ADF7020-1 to be used in
frequency-hopping spread spectrum (FHSS) systems. The VCO
operates at twice the fundamental frequency to reduce spurious
emissions and frequency pulling problems.
The transmitter output power is programmable in 63 steps from
−20 dBm to +13 dBm. The transceiver RF frequency, channel
spacing, and modulation are programmable using a simple 3-wire interface. The device operates with a power supply range of
2.3 V to 3.6 V and can be powered down when not in use
A low IF architecture is used in the receiver (200 kHz),
minimizing power consumption and the external component
count and avoiding interference problems at low frequencies.
The ADF7020-1 supports a wide variety of programmable
features, including Rx linearity, sensitivity, and IF bandwidth,
allowing the user to trade off receiver sensitivity and selectivity
for current consumption, depending on the application. The
receiver also features a patent-pending automatic frequency
control (AFC) loop, allowing the PLL to compensate for
frequency error in the incoming signal.
An on-chip ADC provides readback of an integrated temperature
sensor, an external analog input, the battery voltage, or the
RSSI signal, which provides savings on an ADC in some
applications. The temperature sensor is accurate to ±10°C over
the full operating temperature range of −40°C to +85°C. This
accuracy can be improved by doing a 1-point calibration at
room temperature and storing the result in memory.
Applications
- Low cost wireless data transfer
- Wireless medical applications
- Remote control/security systems
- Wireless metering
- Keyless entry
- Home automation
- Process and building control
