Maxim transmitter delivers over 10dBm output

Maxim Integrated Products has presented what it claims as the world's smallest VHF/UHF PLL-based ASK/FSK transmitter to deliver more than 10dBm output. Additionally, the device can transmit at date rates up to 100kbps in ASK and 20kbps in FSK (both Manchester encoded).

Designed for low-cost, high-volume applications where space is critical, the MAX1479 transmitter can run directly off a lithium cell and will operate down to 2.1V, consuming 0.2nA of current in standby mode. It has a simple data interface and a divider-programmable clock-out feature that eliminates the need for an MCU resonator. The output power of the MAX1479 can be adjusted from -10dBm to 10dBm into a 50-ohm load by using an external resistor. And at the 10dBm power level, the MAX1479 consumes 6.7mA of current at 315MHz when using a 50 percent duty-cycle encoding scheme. Current consumption is 4.5mA at 0dBm output.

Once the enable pin of the MAX1479 is activated, it takes 200?s for the PLL and crystal to settle and be available to transmit. Since the device is targeted at small, portable applications, the MAX1479 accepts crystal frequencies from 9MHz to 15MHz, widely available in inexpensive, surface-mount packages. Since the MAX1479 uses a crystal-based PLL, most of the problems of an LC or SAW-based transmitter are eliminated. The inherent accuracy of the crystal frequency allows a narrower IF bandwidth in the receiver to improve system sensitivity.

Housed in a 3-by-3mm, 16-pin thin QFN package, the MAX1479 operates over the automotive temperature range of -40°C to 125°C and is priced at 99 cents (10,000-up, FOB USA). Evaluation kits are also available to help speed designs.