RF power detector stays accurate over temperature

April 26, 2007
The LMV221 RF power detector from National Semiconductor Corp., Santa Clara, Calif., targets mobile-phone power controls in current and emerging cellular standards, including GSM, CDMA, UMTS and TD-SCDMA.

RF power detector stays accurate over temperature

The detector gives precise, stable, and accurate control of power over a wide dynamic and temperature range. The LMV221 handles multiband frequencies from 50 MHz to 3.5 GHz with 40 dB of dynamic range, giving stable performance from –40 to 85°C with ±0.5-dB accuracy.

Real-time transmitter power adjustments simplify system calibration and cut accuracy requirements for connected power amplifiers and variable-gain amplifiers. The LMV221operates from a single 2.7 to 3.3-Vdc supply and gives an output voltage proportional to RF input power in dBm (power measurement relative to 1 mW). Output voltage goes from 0.3 to 2 Vdc and can scale to meet the input range of various analog-to-digital converters. The LMV221 detects RF power from –45 to –5 dBm and is well suited for direct use with a 30-dB directional coupler. The device remains in low-power shutdown mode until powered up through an enable pin.

The LMV22x RF power detectors extend the company's family of RF log-amp and mean-square detectors. They provide RF power data to its LM320x dc/dc converters, including the LM3208. The LM3208 dynamically controls supply voltage of WCDMA and CDMA RF power amplifiers to boost overall system efficiency. This combination of dc-dc converter plus power detector generates real-time optimum power supply voltage for a given RF transmit power, yielding significant efficiency gains throughout the entire transmit range, especially at low transmit power levels. The result: Longer battery life in portable RF applications.

MAKE CONTACT
National Semiconductor Corp.,
national.com/pf/LM/LMV221.html

Sponsored Recommendations

Pumps Push the Boundaries of Low Temperature Technology

June 14, 2024
As an integral part of cryotechnology, KNF pumps facilitate scientific advances in cryostats, allowing them to push temperature boundaries and approach absolute zero.

The entire spectrum of drive technology

June 5, 2024
Read exciting stories about all aspects of maxon drive technology in our magazine.

MONITORING RELAYS — TYPES AND APPLICATIONS

May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

Solenoid Valve Mechanics: Understanding Force Balance Equations

May 13, 2024
When evaluating a solenoid valve for a particular application, it is important to ensure that the valve can both remain in state and transition between its de-energized and fully...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!