Chipsets for 900 MHz Spread Spectrum, WLAN Released
900 MHz chipset
The ML2721 low IF digital cordless transceiver is a complete RF solution for standard range 900 MHz spread spectrum radios. It fully integrates the mixers, IF filtering, FM discriminator, data filtering, data slicer, voltage controlled oscillator (VCO) resonator, a 12-channel frequency PLL, and DC voltage regulation, allowing frequency generation for both receive and transmit functions supporting data rates up to 1.536 Mbps.
New functions include transmit/receive calibration that functions as a channel frequency tuner to ensure maximum power transmission and optimum sensitivity to meet FCC guidelines, and modulation compensation that stabilizes modulation deviation over VCO tuning range, thus effectively improving transmission range while minimizing out-of-band emissions. All IF filters and data filter are fully integrated. The only circuits that are not integrated into the chip are bypass capacitors, resistors and two capacitors for the PLL filter.
A single ML2721 chip replaces previous designs that required two to five integrated circuits plus an additional 10 to 30 discrete components. As a standalone solution, the ML2721 is the only RF chip needed for a spread spectrum 900 MHz digital cordless phone. It outputs RF-to-digital data for easy system integration with various baseband processors and provides a flexible baseband interface that includes frequency selection via PLL programming, PLL lock indication and received signal strength indication (RSSI).
By adding the ML2751 to the ML2721, manufacturers can offer extended range applications at a low cost. The ML2751 integrates a power amplifier (PA), a low noise amplifier (LNA), and PIN diode drivers for an external transmit/receiver switch and control.
The ML2721 and the ML2751 contain all of the necessary components for a 900 MHz ISM band radio front-end intended for use in half-duplex radio applications and FCC Part 15-compliant devices or general purpose DSSS or FSK/FM systems. While designed to work together, and primarily targeted at the cordless phone market, the chipset can be used separately in other applications.
2.4 GHz chipset
The ML2712 RF transceiver and the ML2713 IF transceiver provides a complete radio transceiver requiring minimal external components for products using FHSS transmissions in the 2.4 GHz ISM frequency band. It is highly integrated, incorporating many filters on-chip and minimizing external chip count, thus reducing the customer's time to market requirements as well as manufacturing costs. The architecture has been optimized to significantly reduce the time required by the radio to switch between transmit and receive modes, allowing much higher data throughput than competitive solutions.
The architecture implemented in the ML2712 and ML2713 provides a number of performance advantages for WLAN applications including high sensitivity to maximize operating range and data throughput. The transmitter implements a final frequency voltage controlled oscillator (VCO) to achieve high modulation accuracy and reduced filtering requirements. The receiver implements traditional dual superhetrodyne architecture to achieve high sensitivity levels.
The ML2712 and ML2713 provide a flexible interface to a baseband processor, allowing the radio to be configured in many different applications. Mode control, PLL frequency selection and lock condition, and received signal strength indicator are some of the programmable functions.
Pricing
The ML2712EH is available in a 48-pin TQFP package and priced at $6.05 in quantities of 10,000. The ML2713EH is available in a 48-pin TQFP package and priced at $3.80 in quantities of 10,000. The ML2721DH is available in a 32-pin TQFP package and priced at $5.75 in quantities of 10,000. The ML2751DT is available in a 32-pin TSSOP and is priced at $3.55 in quantities of 10, 000. For more information, call 408-433-5200.