Logarithmic amplifiers simplify control-loop design of power and transimpedance amplifiers

Sunnyvale, Calif. — Maxim Integrated Products has introduced a series of low-power logarithmic amplifiers that control RF power amplifiers and transimpedance amplifiers (TIAs), and detect RF power levels. The MAX9930-MAX9933 devices provide a choice of three different input-voltage ranges, which eliminate the need for external attenuators and, therefore, simplify amplifier control-loop design.

The MAX9930-MAX9933 log amps are designed to operate in the 2 MHz to 1.6 GHz frequency range and have a typical dynamic range of 45 dB with an accuracy of &plusmn1 dB, making them suitable for a variety of wireless and GPON fiber video applications such as transmitter power measurement and RSSI for terminal devices.

Logarithmic amplifiers are said to provide a much wider, and more accurate measurement range than controllers based on diode detectors. Each of these amplifiers measure voltage in a distinct, typical signal range: -58 dBV to -13 dBV (MAX9930/MAX9933), -48 dBV to -3 dBV (MAX9931), and -43 dBV to +2 dBV (MAX9932).

The MAX9930-MAX9933 devices consume 5.9 mA with a 5-V supply, and the typical shutdown current is 13 microamps. These devices feature a glitch-free output by asserting a power-on delay when coming out of shutdown. The MAX9930-MAX9933 devices are available in an 8-pin microMAX package that offers high temperature stability over the extended operating range of -40° to +85°.

Pricing: Starts at $1.29 (1000-up, FOB USA).
Datasheet: MAX9930

Maxim Integrated Products , 1-800-998-8800,

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