The ADF7025 is a low power， highly integrated FSK transceiver. It is designed for operation in the license–free ISM bands of 433 MHz， 863 MHz to 870 MHz， and 902 MHz to 928 MHz. The ADF7025 can be used for applications operating under the European ETSI EN300-220 or the North American FCC （Part 15） regulatory standards. The ADF7025 is intended for wideband， high data rate applications with deviation frequencies from 100 kHz to 750 kHz and data rates from 9.6 kbps to 384 kbps. A complete transceiver can be built using a small number of external discrete components， making the ADF7025 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. The VCO operates at twice the fundamental frequency to reduce spurious emissions and frequency pulling problems. The transmitter output power is programmable in 0.3 dB steps from ?16 dBm to +13 dBm. The transceiver RF frequency 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 zero-IF architecture is used in the receiver， minimizing power consumption and the external component count， while avoiding the need for image rejection. The baseband filter （low-pass） has programmable bandwidths of ±300 kHz， ±450 kHz， and ±600 kHz. A high-pass pole at ~60 kHz eliminates the problem of dc offsets that is characteristic of zero-IF architecture. The ADF7025 supports a wide variety of programmable features， including Rx linearity， sensitivity， and filter bandwidth， allowing the user to trade off receiver sensitivity and selectivity against current consumption， depending on the application. 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.