Micrel Inc. • 1849 Fortune Drive San Jose, Ca 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

MICRF003 / 033

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

100:1

Microprocessors

microprocessor ICs

Applications

Typical Operating Circuit

915 MHz, 2400 bps OOK

ISM Band RECEIVER