Designed for remote control, remote keyless entry and home automation, the MICRF007 is a low power, fully integrated 300-440MHz QwikRadio receiver in SOIC-8 packaging. The maker of the MICRF007, Micrel Semiconductor, is an industry leader in analog and power management integrated circuits.

The MICRF007 is the latest addition to Micrelıs family of single-chip QwikRadio receivers. This version shares many of the features of earlier devices but achieves lower power consumption -- just 1.7mA supply current during full operation at 315MHz, and 3mA at 433MHz. To further reduce power consumption, the MICRF007 has a shutdown pin to enable power cycling.

As with all QwikRadio products, the MICRF007 achieves much higher integration than conventional RF receivers. Just two capacitors and one reference oscillator are required to take RF in and provide digital data out. This compares with 20 or more external components typically required by competing solutions. Whatıs more, unlike many existing RF receivers, QwikRadio devices do not require manual tuning of active components in production.

The baseband demodulator bandwidth is fixed at 2.1kHz (typical) enabling the MICRF007 to comfortably handle most remote actuation applications that typically have a transfer rate of 1.2kbps or less. For applications requiring higher data-rate, the MICRF002 covers the same frequency band at data-rates up to 10kbps.

"Micrel has been in the RF receiver business now for almost 3 years, and weıve closely studied usersı needs during that time. Weıve applied all we learned to the MICRF007. Itıs the direct result of many requests," said Scott Brown, Linear and RF Business Unit Manager. "In coming months more highly-targeted application-specific QwikRadio devices will be introduced to address specific needs."

It is interesting to follow product cycles as a manufacturer hones in step-by-step to what is thought to be the perfect product. Sometimes product families are simply nice accidents but the QwikRadio receivers from Micrel have been developing very nicely for the 300-440 MHz family. The first was the totally innovative MICRF001, which showed that RF reception did not have to be an arena where magicians only were permitted; so, the designers of the data chains following the receiver could play in that area as well. But the quiescent current in the 001 was a fairly high 6.3 mA (at low 300 MHz frequencies.) The MICRF011 reduced the quiescent to 2.4 mA -- mostly related, I think, to a reduction in the sweep-mode data rate from 4.8 kbit/s to 2.5 kbit/s -- but the part was still in 14-pin packages (SOP and DIP.) The MICRF002 added power-cycle modes but increased the pin count to 16 (SOP and DIP.) The MICRF022 then got the part into an SOP-8. This latest version, the MICRF007 reduces the sweep-mode data rate a little more -- to 2.1 kbit/s -- and reduces the quiescent (at 315 MHz) to 1.7 mA, but retains the power-saving mode and the SOP-8 package.

Why the need for low quiescent? In RKE applications it is useful but most locations involve a supply derived from a vehicle battery or a line supply. However, in RFID (radio frequency identification) applications the receiver is often going to be battery-powered. Unlike applications where an RFID tag is very close to the remaining equipment -- and sometimes powered by it -- the MICRF series allows quite long range reception (Micrel has often quoted it as about 200 m with a monopole antenna.) With a 170 uA load in a 10:1 polled mode and a 0.5 uA load in full shutdown the MICRF007 fits the bill. At 440 MHz the quiescent goes up to 3.0 mA, the polled operation goes to 300 uA, and the shutdown drain stays at 0.5 uA. The part retains the need for just a crystal and two capacitors for basic operation, with no external filters or inductors required, and provides a data output that is CMOS-level compatible. The receiver sensitivity is a typical -96 dBm with a maximum input of -20 dBm. The receive duty cycle can be from 20 to 80%. The data sheet is an updated version of the MICRF002 and several times refers to that part number.