Maxim Integrated Products has introduced the MAX1471, a dual-channel receiver that can receive both ASK and FSK data simultaneously, eliminating the switching lag time between modes.

Article Tools

• 

Designed for low-cost systems where both encoding schemes are present, the receiver also includes a discontinuous receive (DRX) feature for low-power duty-cycle operation. The DRX feature is user-configurable through a serial interface (SPI(TM)) bus. The DRX mode also allows self-polling, where the receiver can stay in sleep mode as long as eight minutes and can also be used to wake the system microprocessor, thus offering additional cost and power savings. The MAX1471 operates from 300 MHz to 450 MHz and includes an on-chip 45 dB (typical) image-rejection mixer, which eliminates the need for SAW filters in many applications. The device operates from either a 3.3 V or 5 V supply, down to 2.4 V.

The receiver features high sensitivities of -114 dBm (ASK) and -108 dBm (FSK). It has a low-noise amplifier (LNA), an image-reject (IR) mixer, a fully integrated phase-locked loop (PLL), local oscillator (LO), a 10.7 MHz IF-limiting amplifier with received-signal-strength indicator (RSSI), a low-noise FM demodulator, and a 3.0 V voltage regulator. Differential peak-detecting data demodulators are included for both FSK and ASK analog baseband data recovery.

The receiver is designed to operate in a wide variety of power-sensitive applications such as remote-keyless-entry systems, car alarms, tire-pressure monitoring systems, home-security systems, remote controls, and garage-door openers. The part draws less than 1.1 microamps in shutdown mode and only 7.0 mA in receive mode. Depending on the components selected, the MAX1471 can receive data rates up to 33 kbps (Manchester) or 66 kbps (NRZ), and transitions from shutdown to valid data out in less than 250 microseconds. In power-cycled applications, this quick transition minimizes how long the system needs to be in receive mode.

The MAX1471 comes in a 32-pin thin TQFN, and operates over the automotive temperature range (-40 degrees Celsius to +125 degrees Celsius). Prices start at $2.39 (10,000-up, FOB USA).