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MAX7031 Datasheet, PDF (1/19 Pages) Maxim Integrated Products – Low-Cost, 308MHz, 315MHz, and 433.92MHz FSK Transceiver with Fractional-N PLL | |||
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19-3707; Rev 0; 5/05
Low-Cost, 308MHz, 315MHz, and 433.92MHz
FSK Transceiver with Fractional-N PLL
General Description
The MAX7031 crystal-based, fractional-N transceiver is
designed to transmit and receive FSK data at factory-
preset carrier frequencies of 308MHzâ , 315MHz, or
433.92MHz with data rates up to 33kbps (Manchester
encoded) or 66kbps (NRZ encoded). This device gen-
erates a typical output power of +10dBm into a 50â¦
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
receiverâs 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 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 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
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.
â Consult factory for availability.
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
⦠Factory-Preset Frequency (No Serial Interface
Required)
⦠FSK Modulation
⦠Factory-Preset FSK Frequency Deviation
⦠+10dBm Output Power into 50⦠Load
⦠Integrated TX/RX Switch
⦠Integrated Transmit and Receive PLL, VCO, and
Loop Filter
⦠> 45dB Image Rejection
⦠Typical RF Sensitivity*: -110dBm
⦠Selectable IF Bandwidth with External Filter
⦠RSSI Output with High Dynamic Range
⦠< 12.5mA Transmit-Mode Current
⦠< 6.7mA Receive-Mode Current
⦠< 800nA Shutdown Current
⦠Fast-On Startup Feature, < 250µs
⦠Small, 32-Pin, Thin QFN Package
*0.2% BER, 4kbps Manchester-encoded data, 280kHz IF BW
Ordering Information
PART
TEMP
RANGE
PIN-PACKAGE
PKG
CODE
MAX7031_ATJ__
-40°C to
+125°C
32 Thin QFN-EP** T3255-3
**EP = Exposed paddle.
Note: The MAX7031 is available with factory-preset operating
frequencies. See the Selector Guide for complete part num-
bers.
Pin Configuration, Selector Guide, Typical Application
Circuit, and Functional Diagram appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maximâs website at www.maxim-ic.com.
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