hf/rf ZONE Products for the week of August 30, 2004
Micrel Says . . .
MICRF009: Enhanced QwikRadio Low-Power UHF Receiver
Chip Offers Increased Performance, Highest Level of Intergration
Micrel Inc., an industry leader in Power, Connect and Protect IC solutions, today launched the MICRF009, a QwikRadio Low-Power UHF Receiver aimed at the automotive, industrial and consumer markets. The IC offers enhanced performance over other QwikRadio receivers by providing higher sensitivity and faster recovery from shutdown..
"In the five years since Micrel released its first QwikRadio receiver, the product line has enjoyed rapid and enduring customer acceptance," said Scott Brown, director of Mixed-Signal and RF Products, Micrel. "We continue to work closely with customers and the MICRF009 is a direct result of this effort. The product addresses our customers' need for improved sensitivity and reduced start-up time -- among many other performance enhancements."
The IC features sensitivity typically 6dB higher than previous MICRF00x series chips. It also offers quicker recovery from shutdown, characteristically 1ms. The IC has a frequency range of 300 to 440 MHz, and a data rate up to 2.0kbps (Manchester encoding). The MICRF009 also provides designers with low power consumption (2.9mA fully operational).
"Our mission for Micrel's line of RF ICs is to provide drop-in RF
solutions with the highest possible integration, for virtually any manufacturer
that wants to add this technology to a product," said Bob Whelton,
executive vice president of Operations, Micrel. "Micrel's comprehensive
suite of RF products, including the new MICRF009, enables designers to quickly
and painlessly add this capability to a wide range of applications including
automotive remote keyless entry, garage door and gate openers, and remote
fan and light control."
analogZONE Says . . .
The MICRF009 follows on from the MICRF002 and MICRF022, which themselves were upgrades of the original MICRF001. With the MICRF002 sensitivity was improved by about 6 dB, the IF bandwidth was nearly halved to 500 kHz, a shutdown pin was added, as was a wake-up output flag, and power consumption was reduced. MICRF022 was a limited operating version, in a smaller package, offering different operatiing choices from the MICRF002. The MICRF002 was launched in February 1999 with a 1000-piece price of $3.80. It is now available in 48-piece lots through distribution for $3.55.
With the launch of the MICRF009 (thank you, Micrel, for not calling it a 0022 or something!) the wake-up output flag has gone away again, the data rates are reduced, bandwidths are reduced, one more external component is removed, and the fundamental oscillator frequency is doubled. It is very important to note that the new part is not pin-compatible with the MICRF002.
Taking those one at a time: the data rates are reduced from 10 kbit/s to 2.0 kbit/s (fixed-mode with Manchester coding). That reduces the needs of the IF bandwidth and it has been reduced to 430 kHz (from 680 kHz) which is exactly half of the center frequency, which remains at 860 kHz. Demodulator bandwidth has, likewise, been reduced with options over 2500 Hz gone away. The external component that has been removed is a series 68 nH inductor on the antenna input. The series capacitor and RF blocking inductor (to ground) have also small changes in value.
The other change is that the resonator frequency being used has doubled (to 9.794 MHz from 4.897 MHz for a 315 MHz receiver, for example) and the resonator is connected across two component pins instead of having one end connected to ground. Whatever change has been made in the maintaining amplifier it has removed the restriction on the series resistance of the resonator which was, for example, that it had to be less than 100 ohm for a crystal. The higher frequency and restriction removal will reduce the cost of the resonator.
Power consumption has gone up a little (to 2.9 mA from 2.2 mA at 315 MHz, for example) but the standby current has reduced to 150 nA from 900 nA. Receiver sensitivity has increased a healthy 5 dB to -102 dBm at 315 MHz, and by a very nice 9 dB to -104 dBm at 434 MHz -- giving a more uniform band sensitivity as well. The output rise and fall times have been improved from 10 µs to 4 µs.
The two remaining demodulator filter bandwidths are 1000 Hz and 500 Hz in sweep mode, and 2000 Hz and 1000 Hz in fixed mode (the changes selected by a mode pin status and a select pin status -- both using the rail and ground for the logic changes). Sweep mode is the logical operating condition when the system uses a low-cost transmitter whose frequency is not that stable. In sweep the receiver captures signals in a band of about 1.5% around the nominal frequency, which is a major advantage over standard superhet receivers.
It is nice to see a vendor track the needs of its customers in such a way and the MICRF009 will continue Micrel's sterling performance in the remote market, particularly in RKE. The part has also been more sensibly priced from the get-go.
The MICRF009 is in production in SOIC-16 priced at $1.88 in 1000-piece lots.