Features
| • | Typical operation at 110 MHz |
| • | RF sensitivity to -75 dBm; RSSI sensitivity to -82 dBm |
| • | High gain (70 dB) limiting amplifier |
| • | Average current consumption: 480 µA for DECT handset (burst mode) |
| • | +3V operation |
| • | Power down mode for increased current savings |
| • | Part of a complete receiver solution with the LMX2216 LNA/Mixer, the LMX2315/20 Phase-locked Loop, and the LMX2411 Baseband Processor |
| • | Compliant to ARi1™ specification |
Description The LMX2240 is a monolithic, integrated intermediate frequency receiver suitable for use in Digital European Cordless Telecommunications (DECT) systems as well as other mobile telephony and wireless communications applications. It is fabricated using National's ABiC™ IV BiCMOS process (fT = 15 GHz).
The LMX2240 consists of a high gain limiting amplifier, a frequency discriminator, and a received signal strength indicator (RSSI). The high gain limiting amplifier and discriminator operate in the 40 MHz to 150 MHz frequency range, and the limiter has approximately 70 dB of gain. The use of the limiter and the discriminator provides a low cost, high performance demodulator for communications systems. The RSSI output can be used for channel quality monitoring.
The LMX2240 is intended to support single conversion receivers. This device saves power, size, and cost by eliminating the second local oscillator (LO), second converter (mixer), and additional filters. The LMX2240 is recommended for systems with channel bandwidths of 300 kHz to 2.5 MHz.
The LMX2240 is available in a 16-pin JEDEC surface mount plastic package.
Applications
| • | Digital European Cordless Telecommunications (DECT) |
| • | Portable wireless communications (PCS/PCN, cordless) |
| • | Wireless local area networks (WLANs) |
| • | Digital cellular telephone systems |
| • | Other wireless communications systems |
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