The MAX7031 crystal-based, fractional-N transceiver is designed to transmit and receive FSK data at factory-preset carrier frequencies of 308MHz, 315MHz, or
433.92MHz with data rates up to 33kbps (Manchester encoded) or 66kbps (NRZ encoded). This device generates a typical output power of +10dBm into a 50Ω
load, and exhibits typical sensitivity of -110dBm. The MAX7031 features separate transmit and receive pins (PAOUT and LNAIN) and provides an internal RF switch that can be used to connect the transmit and receive pins to a common antenna.
The MAX7031 transmit frequency is generated by a 16-bit, fractional-N, phase-locked loop (PLL), while the receiver's local oscillator (LO) is generated by an integer-N PLL. This hybrid architecture eliminates the need for separate transmit and receive crystal reference oscillators because the fractional-N PLL is preset to be 10.7MHz above the receive LO. Retaining the fixed-N PLL for the receiver avoids the higher current-drain requirements of a fractional-N PLL and keeps the receiver current drain as low as possible.
The fractional-N architecture of the MAX7031 transmit PLL allows the transmit FSK signal to be preset for exact frequency deviations, and completely eliminates the problems associated with oscillator-pulling FSK signal generation. All frequency-generation components are integrated on-chip, and only a crystal, a 10.7MHz IF filter, and a few discrete components are required to implement a complete antenna/digital data solution.
The MAX7031 is available in a small, 5mm x 5mm, 32-pin, thin QFN package, and is specified to operate in the automotive -40°C to +125°C temperature range.
Key Features
Applications/Uses
+2.1V to +3.6V or +4.5V to +5.5V Single-Supply Operation
Single-Crystal Transceiver
Factory-Preset Frequency (No Serial Interface Required)
FSK Modulation
Factory-Preset FSK Frequency Deviation
+10dBm Output Power into 50Ω Load
Integrated TX/RX Switch
Integrated Transmit and Receive PLL, VCO, and Loop Filter
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
*0.2% BER, 4kbps Manchester-encoded data, 280kHz IF BW
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