MICRF003 Datasheet, PDF (1/16 Pages) Micrel Semiconductor – QwikRadiotm 900 MHz UHF Receiver Preliminary Information

MICRF003 / 033
QwikRadio^tm 900 MHz UHF Receiver
Preliminary Information
General Description
The MICRF003 is a single chip OOK (ON-OFF Keyed) Receiver IC for
remote wireless applications, employing Micrel’s latest QwikRadio^tm
technology. This device is a true “antenna-in, data-out” monolithic device. All
RF and IF tuning is accomplished automatically within the IC, which
eliminates manual tuning, and reduces production costs. Receiver functions
are completely integrated. The result is a highly reliable yet extremely low
cost solution for high volume wireless applications. Because the MICRF003
is a true single-chip radio receiver, it is extremely easy to apply, minimizing
design and production costs, and improving time to market.
The MICRF003 provides two fundamental modes of operation, FIXED and
SWP. In FIXED mode, the device functions like a conventional
Superheterodyne receiver, with an (internal) local oscillator fixed at a single
frequency based on an external reference crystal or clock. As with any
conventional superheterodyne receiver, the transmit frequency must be
accurately controlled, generally with a crystal or SAW (Surface Acoustic
Wave) resonator.
In SWP mode, the MICRF003 sweeps the (internal) local oscillator at rates
greater than the baseband data rate. This effectively “broadens” the RF
bandwidth of the receiver to a value equivalent to conventional super-
regenerative receivers. Thus the MICRF003 can operate with less
expensive LC transmitters without additional components or tuning, even
though the receiver topology is still superheterodyne. In this mode the
reference crystal can be replaced with a less expensive ± 0.5% ceramic
resonator.
The MICRF003 provides two additional key features: (1) a Shutdown Mode,
which may be used for duty-cycle operation, and (2) a “Wakeup” function,
which provides a logical indication of an incoming RF signal. These features
make the MICRF003 ideal for low and ultra-low power applications, such as
RKE and RFID.
All post-detection (demodulator) data filtering is provided on the MICRF003,
so no external filters need to be designed. Any one of four filter bandwidths
may be selected externally by the user. Nominal filter bandwidths range in
binary steps, from 0.75kHz to 6kHz (SWP mode) or 2.8kHz to 22.4kHz
(FIXED mode). The user only needs to program the appropriate filter
selection based on data rate and code modulation format.
Features
• Complete 900 MHz Band receiver on a monolithic IC
• UHF Frequency range 800 to 1000 MHz
• Typical range over 170 meters with monopole antenna
• Data rates to 5kbps (SWP), 20kbps (FIXED)
• Automatic tuning, no manual adjustment
• No Filters or Inductors required
• Low Operating Supply Current--4mA @ 868MHz
• Shutdown Mode for Duty-Cycle Operation in excess of
100:1
• Wakeup Function to Enable External Decoders and
Microprocessors
• Very low RF re-radiation at the antenna
• CMOS logic interface to standard decoder and
microprocessor ICs
• Extremely low external part count
Applications
• Automotive Remote Keyless Entry
• Security Systems
• Low Rate Data Modems
• Remote Meter Data Collection
Typical Operating Circuit
915 MHz, 2400 bps OOK
ISM Band RECEIVER
Micrel Inc. • 1849 Fortune Drive San Jose, Ca 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com