MICRF505 Datasheet, PDF (1/27 Pages) Micrel Semiconductor – 868MHz and 915MHz ISM Band Transceiver

MICRF505
Micrel
MICRF505
868MHz and 915MHz ISM Band Transceiver
General Description
The MICRF505 is a true single chip, frequency shift keying
(FSK) transceiver intended for use in half-duplex, bidirec-
tional RF links. The multi-channeled FSK transceiver is
intended for UHF radio equipment in compliance with the
North American Federal Communications Commission (FCC)
part 15.247 and 249, as well as the European Telecommuni-
cation Standard Institute (ETSI) specification, EN300 220.
The transmitter consists of a PLL frequency synthesizer and
a power amplifier. The frequency synthesizer consists of a
voltage-controlled oscillator (VCO), a crystal oscillator, dual
modulus prescaler, programmable frequency dividers, and a
phase-detector. The loop-filter is external for flexibility and
can be a simple passive circuit. The output power of the
power amplifier can be programmed to seven levels. A lock-
detect circuit detects when the PLL is in lock. In receive mode,
the PLL synthesizer generates the local oscillator (LO) signal.
The N, M , and A values that give the LO frequency are stored
in the N0, M0, and A0 registers.
The receiver is a zero intermediate frequency (IF) type which
makes channel filtering possible with low-power, integrated
low-pass filters. The receiver consists of a low noise amplifier
(LNA) that drives a quadrature mixer pair. The mixer outputs
feed two identical signal channels in phase quadrature. Each
channel includes a pre-amplifier, a third order Sallen-Key RC
low-pass filter that protects the following switched-capacitor
filter from strong adjacent channel signals, and a limiter. The
main channel filter is a switched-capacitor implementation of
a six-pole elliptic low pass filter. The cut-off frequency of the
Sallen-Key RC filter can be programmed to four different
frequencies: 100kHz, 150kHz, 230kHz, and 340kHz. The I
and Q channel outputs are demodulated and produce a
digital data output. The demodulator detects the relative
phase of the I and the Q channel signal. If the I channel signal
lags behind the Q channel, the FSK tone frequency is above
the LO frequency (data ‘1’). If the I channel leads the Q
channel, the FSK tone is below the LO frequency (data ‘0’).
The output of the receiver is available on the DataIXO pin. A
receive signal strength indicator (RSSI) circuit indicates the
received signal level. All support documentation can be
found on Micrel’s web site at www.micrel.com.
Features
• True single chip transceiver
• Digital bit synchronizer
• Received signal strength indicator (RSSI)
• RX and TX power management
• Power down function
• Reference crystal tuning capabilities
• Baseband shaping
• Three-wire programmable serial interface
• Register read back function
Applications
• Telemetry
• Remote metering
• Wireless controller
• Remote data repeater
• Remote control systems
• Wireless modem
• Wireless security system
Ordering Information
Part Number Junction Temp. Range
MICRF505BML
–40∞C to +85∞C
Package
32-Pin MLF™
MicroLeadFrame and MLF are trademarks of Amkor Technology, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
May 13, 2004
1
M9999-051304