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QwikRadio Transmitter-Receiver Pair Handle 115 kbits/s Data-Rate at 800MHz-1GHz
Highly Integrated Ideal for Cost Sensitive Applications
| The manufacturer says . . . | ChipCenter's Paul O'Shea says . . . |
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Aimed at low-cost short-range wireless applications, an ASK (Amplitude Shift Keyed) transmitter-receiver pair providing up to 115 kbits/s data-rate at 800MHz-1GHz operating frequency is now available from Micrel Semiconductor. The MICRF005 receiver and MICRF103 transmitter are the latest additions to Micrel's family of QwikRadio RF products. The transmitter-receiver pair provides a unique combination of data-rate, low cost, low power and ease of use. The devices are more highly integrated and easier to use than earlier RF ICs. Only hybrid modules provide similar levels of integration; but at a much higher cost. "Micrel's earlier MICRF003 receiver supports up to 20 kbits/s in the same 800MHz-1GHz frequency band. Many designers came to us asking for the same low cost and ease of use but at higher data-rates," said Scott Brown, Linear and RF Business Unit Manager. ýThe MICRF005 is our response to those requests." The MICRF005, like all other QwikRadio receivers, requires just three external components -- two capacitors and a reference oscillator -- to implement a complete RF receiver. One of the capacitors sets the attack/decay time of the on-board the AGC (automatic gain control); the second capacitor sets the data demodulator slicing threshold; and the reference oscillator determines the receive frequency. Target applications include wireless keyboards, video game controllers, home security, HVAC systems, and home automation. Both devices operate off a 5V supply. The MICRF005 consumes 10mA supply current; the MICRF103 consumes 16mA. |
This transmitter-receiver pair used for wireless applications offers some significant improvements from previous versions of the product. For example, the 115 kbits/s is a significant improvement from previous iterations of this type of product in the 800 MHz ý 1 GHz ISM bands. Customers who used to be satisfied with the 20 ý 25 kbits/s rates will look closely at this offering. The MICRF103 transmitter uses a novel architecture where the external antenna is tuned by an internal UHF synthesizer that has I and Q outputs. The in phase signal drives the power amplifier while the quadrature signal compares signals for the antenna tuning control by varying the capacitance across the antenna feed with an on-chip varactor. The incoming Amplitude Shift Key (ASK) modulation switches the bias to the power amplifier. The control for the RF output varies from approximately -15 dBm to -3 dBm. The MICRF103 transmitter is a 5-V part and the quiescent current is typically 20 mA, with 0.10 micro amp standby current. The MICRF005 receiver requires just three external components including a reference crystal and two capacitors. The company says that an external timing signal can be used, if needed. The capacitors are needed for automatic gain control and for setting the threshold. All the filters are on-chip with nominal bandwidths of 300 kHz. The part has -84 dBm sensitivity from a 5 V supply and typically draws 8 mA to 13 mA over the 800 MHz to 1 GHz range. The maximum RF input signal is limited to -10 dBm while the IF used is at 2.496 MHz and has a 3 dB bandwidth of 1.2 MHz. The receiver is divided into three sections: the UHF downconverter, the demodulator, and the reference and control section. Automatic gain control from the detector output is applied to both IF amplifiers and the mixer. Expectations for these parts are high. They could be an alternative for users who donýt need the speeds, or the expense, of an 802.11 device for their security systems or even home automation systems. The MICRF005 is provided in SOIC-14 packaging and priced at $2.33 in 1k quantities. The MICRF103 comes in a SOIC-8 package and is priced at $1.61 in 1k quantities. Samples of both devices are available immediately, and production quantities are available in 8 weeks ARO.
103 Transmitter Data Sheet
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