General Description
The MAX7032 crystal-based, fractional-N transceiver is
designed to transmit and receive ASK/OOK or FSK
data in the 300MHz to 450MHz frequency range with
data rates up to 33kbps (Manchester encoded) or
66kbps (NRZ encoded). This device generates a typi-
cal output power of +10dBm into a 50Ω load, and
exhibits typical sensitivities of -114dBm for ASK data
and -110dBm for FSK data. The MAX7032 features sep-
arate 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 MAX7032 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 inte-
ger-N PLL. This hybrid architecture eliminates the need
for separate transmit and receive crystal reference
oscillators because the fractional-N PLL allows the
transmit frequency to be set within 2kHz of the receive
frequency. The 12-bit resolution of the fractional-N PLL
allows frequency multiplication of the crystal frequency
in steps of f
XTAL
/4096. 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 MAX7032 transmit
PLL allows the transmit FSK signal to be programmed for
exact frequency deviations, and completely eliminates
the problems associated with oscillator-pulling FSK sig-
nal 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 imple-
ment a complete antenna/digital data solution.
The MAX7032 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.
Applications
2-Way Remote Keyless Entry
Security Systems
Home Automation
Remote Controls
Remote Sensing
Smoke Alarms
Garage Door Openers
Local Telemetry Systems
Features
♦ +2.1V to +3.6V or +4.5V to +5.5V Single-Supply
Operation
♦ Single Crystal Transceiver
♦ User-Adjustable 300MHz to 450MHz Carrier
Frequency
♦ ASK/OOK and FSK Modulation
♦ User-Adjustable FSK Frequency Deviation
Through Fractional-N PLL Register
♦ Agile Transmitter Frequency Synthesizer with
f
XTAL
/4096 Carrier-Frequency Spacing
♦ +10dBm Output Power into 50Ω Load
♦ Integrated TX/RX Switch
♦ Integrated Transmit and Receive PLL, VCO, and
Loop Filter
♦ > 45dB Image Rejection
♦ Typical RF Sensitivity*
ASK: -114dBm
FSK: -110dBm
♦ Selectable IF Bandwidth with External Filter
♦ RSSI Output with High Dynamic Range
♦ Autopolling Low-Power Management
♦ < 12.5mA Transmit-Mode Current
♦ < 6.7mA Receive-Mode Current
♦ < 23.5µA Polling-Mode Current
♦ < 800nA Shutdown Current
♦ Fast-On Startup Feature, < 250µs
♦ Small 32-Pin, Thin QFN Package
MAX7032
Low-Cost, Crystal-Based, Programmable,
ASK/FSK Transceiver with Fractional-N PLL
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-3685; Rev 2; 11/10
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
