The LMH6518 is a digitally controlled variable gain amplifier with a total gain that varies from –1.16dB to 38.8dB for a 40dB range in 2dB steps. The −3dB bandwidth is 900MHz at all gains. Gain accuracy at each setting is typically 0.1dB. When used in conjunction with TI’s gigasamples per second (GSPS) ADC with adjustable full-scale range, the LMH6518 gain adjustment accommodates full scale input signals from 6.8mVPP to 920mVPP to get 700mVPP nominal at the ADC input. The auxiliary output (+OUT AUX and −OUT AUX) follows the main output and is intended for use in oscilloscope trigger function circuitry, but can have other uses in other applications.

The LMH6518 gain is programmed through a SPI-compatible serial bus. A signal path combined gain resolution of 8.5mdB is achieved when the device gain and the GSPS ADC FS input are both manipulated. Inputs and outputs are dc-coupled. The outputs are differential with individual common-mode voltage control (for main and auxiliary outputs), and have selectable bandwidth limiting circuitry (common to both main and auxiliary) of 20MHz, 100MHz, 200MHz, 350MHz, 650MHz, 750MHz, or full BW.

The LMH6518 is a digitally controlled variable gain amplifier with a total gain that varies from –1.16dB to 38.8dB for a 40dB range in 2dB steps. The −3dB bandwidth is 900MHz at all gains. Gain accuracy at each setting is typically 0.1dB. When used in conjunction with TI’s gigasamples per second (GSPS) ADC with adjustable full-scale range, the LMH6518 gain adjustment accommodates full scale input signals from 6.8mVPP to 920mVPP to get 700mVPP nominal at the ADC input. The auxiliary output (+OUT AUX and −OUT AUX) follows the main output and is intended for use in oscilloscope trigger function circuitry, but can have other uses in other applications.Read more