Linear Technology Offers 40MHz to 3.8GHz Log RF Power Detector

Linear Technology has released its monolithic broadband, high performance logarithmic RF power detector that provides accurate RF power measurement over a frequency range covering the 800-900MHz and the 1.7GHz to 2.2GHz cellular bands, as well as the 2.6GHz and 3.5GHz WiMAX bands. The LT5538 RF power detector provides a DC output voltage that is log-linearly proportional to its input power level. Within its measurement dynamic range, the detector exhibits best-in-class accuracy and linearity of +/- 0.8dB over its rated operating temperature range of -40°C to +85°C. The LT5538 has outstanding sensitivity, capable of detecting signals as small as -75dBm to as large as +10dBm at 2.14GHz. The device operates with a single-ended RF input. It requires no external RF transformer, thus simplifying design while reducing costs. The LT5538 operates over a wide supply voltage range of 3V to 5.25V, drawing a low quiescent supply current of 29mA compared to other similar class detectors. A shutdown feature is provided. When the chip is disabled with a logic LOW applied to its ENABLE input pin, the chip draws a typical shutdown current of 1uA, and a maximum of 100uA. The device comes in a tiny 8-lead, 3mm x 3mm DFN surface mount package. Pricing starts at $4.50 each in 1,000-piece quantities. The LT5538 is available immediately from stock.