MAXIM MAX7032ATJ+T

The MAX7032 is a crystal-based fractional-N transceiver designed to transmit and receive ASK/OOK or FSK data in the 300MHz to 450MHz frequency range, with data rates up to 33kbps (Manchester coding) or 66kbps (NRZ coding). The device delivers a typical output power of +10dBm into a 50Ω load, with typical receive sensitivity of -114dBm (ASK data) and -110dBm (FSK data). The MAX7032 features separate transmit and receive pins (PAOUT and LNAIN), with an internal RF switch that connects the transmit and receive pins to a shared antenna.

The MAX7032 transmit frequency is generated by a 16-bit fractional-N PLL, while the receiver local oscillator (LO) is generated by an integer-N PLL. Because the fractional-N PLL can tune the transmit frequency to within 2kHz of the receive frequency, this hybrid architecture eliminates the need for separate transmit and receive crystal oscillators. The 12-bit resolution fractional-N PLL allows the crystal frequency to be multiplied in steps of fxTAL/4096. The receiver employs a fixed integer-N PLL, eliminating the higher current consumption of the fractional-N PLL to minimize receiver current draw.

The fractional-N architecture of the MAX7032 transmitter PLL enables precise FSK deviation setting, completely resolving issues associated with oscillator-pulling FSK signals. All frequency generation components are integrated on-chip, requiring only a single crystal, a 10.7MHz IF filter, and a few simple discrete components for a complete antenna-to-digital-data solution.

The MAX7032 is available in a compact 5mm×5mm, 32-pin thin QFN package, operating over the -40°C to +125°C automotive temperature range.

• Single supply: +2.1V to +3.6V or +4.5V to +5.5V
• Single crystal transceiver
• User-adjustable carrier frequency from 300MHz to 450MHz
• ASK/OOK and FSK modulation
• User-adjustable FSK frequency deviation via fractional-N PLL registers
• Flexible transmit frequency synthesizer with fXTAL/4096 carrier frequency spacing
• +10dBm output power into 50Ω load
• Integrated TX/RX switch
• Integrated TX/RX PLL, VCO, and loop filter

• 45dB image rejection

• Typical RF sensitivity: ASK: -114dBm, FSK: -110dBm
• IF bandwidth selectable by external filter
• RSSI output with high dynamic range
• Automatic low-power management mode
• TX mode current <12.5mA
• RX mode current <6.7mA
• Polling mode current <23.5μA
• Shutdown current <800nA
• Fast power-up enable, <250μs
• Compact 32-pin thin QFN package

• Two-way remote keyless entry
• Security systems
• Home automation
• Remote control
• Remote sensing
• Smoke detectors
• Garage door openers
• Local automated metering systems