Sunnyvale, Calif.Maxim Integrated Products has introduced the MAX7058 crystal-referenced, PLL VHF/UHF transmitter for transmitting OOK/ASK/FSK data at 315MHz or 390MHz.
The MAX7058 supports 315MHz/390MHz switched operation with a single 15MHz crystal, and can operate at any two frequencies in the 300MHz to 450MHz range with the use of different crystal frequencies. To enable this flexibility, the MAX7058 integrates a wideband VCO with internal tuning capacitors that can be programmed for matching the impedance of the power amplifier (PA) to the antenna. This topology ensures highly efficient transmission at multiple operating frequencies, making the MAX7058 well-suited for power-sensitive applications such as home security systems, remote controls, and garage door openers.
To further improve performance, the MAX7058 integrates an envelope-shaping resistor between the output of the PA and the power supply. This resistor slows the turn-on/off time of the PA in ASK mode, reducing the spectral width of the PA's modulated output signal. Additionally, the MAX7058 features a toggle pin that allows the device to switch automatically between two frequencies, thus eliminating the need for a microprocessor or switch.
According to Maxim, the MAX7058's crystal-based architecture eliminates many common SAW transmitter problems by providing greater modulation depth, faster frequency settling, tighter transmit-frequency tolerance, and reduced temperature dependence. This device thus provides better overall receiver performance when using a superheterodyne receiver with a narrow IF (i.e., lower noise) bandwidth.
The MAX5078 operates from a single, 2.1V to 3.6V supply, and draws less than 1 microamp in standby mode and less than 8mA in transmit mode (50% duty cycle OOK). Available in a small, 4mm x 4mm, 24-pin TQFN package, this device is fully specified over the -40°C to +125°C automotive temperature range.
Pricing: Starts at $1.32 (1000-up, FOB USA).
Datasheet: Click here.
Maxim Integrated Products, www.maxim-ic.com