LMH6518 900 MHz, Digitally Controlled, Variable Gain Amplifier | TI.com


900 MHz, Digitally Controlled, Variable Gain Amplifier



The LMH6518 device is a digitally controlled variable gain amplifier whose total gain is varied from −1.16 dB to 38.8 dB for a 40 dB range in 2-dB steps. The −3-dB bandwidth is 900 MHz at all gains. Gain accuracy at each setting is typically 0.1 dB. When used in conjunction with TI's Gsample/second (Gsps) ADC with adjustable full-scale (FS) range, the LMH6518 gain adjustment accommodates full scale input signals from 6.8 mVPP to 920 mVPP to get 700 mVPP 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 may have other uses in other applications.

The LMH6518 gain is programmed through a SPI-1 compatible serial bus. A signal path combined gain resolution of 8.5 mdB is achieved when the device's gain and the Gsps ADC’s FS input are both manipulated. Inputs and outputs are DC-coupled. The outputs are differential with individual common mode (CM) voltage control (for main and auxiliary outputs), and have a selectable bandwidth limiting circuitry (common to both main and auxiliary) of 20, 100, 200, 350, 650, 750 MHz or full bandwidth.


  • Gain Range: 40 dB
  • Gain Step Size: 2 dB
  • Combined Gain Resolution With Gsps ADCs:
    8.5 mdB
  • Minimum Gain: −1.16 dB
  • Maximum Gain: 38.8 dB
  • −3 dB BW: 900 MHz
  • Rise and Fall Time: <500 ps
  • Recovery Time: <5 ns
  • Propagation Delay Variation: 100 ps
  • HD2 at 100 MHz: −50 dBc
  • HD3 at 100 MHz: −53 dBc
  • Input-Referred Noise (Maximum Gain): 0.98 nV/√Hz
  • Overvoltage Clamps for Fast Recovery
  • Power Consumption: Auxiliary Turned Off 1.1 W to 0.75 W

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Parametrics Compare all products in Programmable & variable gain amplifiers (PGA/VGA)

Number of channels (#)
Vs (Min) (V)
Vs (Max) (V)
BW @ Acl (MHz)
Acl, min spec gain (V/V)
Gain (Max) (dB)
Slew Rate (Typ) (V/us)
Operating temperature range (C)
Package Group
Package size: mm2:W x L (PKG)
-40 to 85    
WQFN | 16    
16WQFN: 16 mm2: 4 x 4 (WQFN | 16)