MICRF002 Datasheet, PDF (1/13 Pages) Micrel Semiconductor – QwikRadiotm Low Power UHF Receiver Preliminary Information

MICRF002 / 022
QwikRadio^tm Low Power UHF Receiver
Preliminary Information
General Description
The MICRF002, an enhanced version of the MICRF001 and MICRF011,
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
MICRF002 is a true single-chip radio receiver, it is extremely easy to
apply, minimizing design and production costs, and improving time to
market.
The MICRF002 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 MICRF002 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 MICRF002 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 MICRF002 provides two feature enhancements over the
MICRF001/011, (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
MICRF002 ideal for low and ultra-low power applications, such as RKE
and RFID.
All post-detection (demodulator) data filtering is provided on the
MICRF002, so no external filters need to be designed. Any one of four
filter bandwidths may be selected externally by the user. Bandwidths
range in binary steps, from 0.625kHz to 5kHz (SWP mode) or 1.25kHz to
10kHz (FIXED mode). The user only needs to program the appropriate
filter selection based on data rate and code modulation format.
Features
• Complete UHF receiver on a monolithic chip
• Frequency range 300 to 440 MHz
• Typical range over 200 meters with monopole
antenna
• Data rates to 2.5kbps (SWP), 10kbps (FIXED)
• Automatic tuning, no manual adjustment
• No Filters or Inductors required
• Low Operating Supply Current—240 µA at 315MHz
(10:1 Duty Cycle)
• 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
• Long Range RFID
• Remote Fan/Light Control
• Garage Door/Gate Openers
Typical Operating Circuit
385.5 MHz, 1200 bps OOK RECEIVER
Micrel Inc. • 1849 Fortune Drive San Jose, Ca 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com