MICRF506
410MHz and 450MHz ISM Band
Transceiver
General Description
The MICRF506 is a true single-chip, frequency shift keying
(FSK) transceiver intended for use in half-duplex,
bidirectional RF links. The multi-channeled FSK transceiver
is intended for UHF radio equipment in compliance with the
European Telecommunication Standard Institute (ETSI)
specification, EN300 220.
The transmitter consists of a PLL frequency synthesizer
and 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 mix 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.
RadioWire®
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
•
Frequency error estimator
•
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
July 2006
1
M9999-092904
+1 408-944-0800
