AD8330评估板

白小白_3003415

AD8330评估板是一个带宽可变的增益放大器，其应用程序的运行环境为：一个不同的信号通道、低噪声、定义良好的增益、适度低失真，直流--150Hz。The input pins can also be driven from a single-ended source. The peak differential input is ±2 V, allowing sine wave operation at 1V rms with generous headroom. The output pins can drive single-sided loads essentially rail-to-rail. The differential output resistance is 150Ω. The output swing is a linear function of the voltage applied to the VMAG pin that internally defaults to 0.5 V,providing a peak output of ±2V.This can be raised to 10 V p-p, limited by the supply voltage.The basic gain function is linear-in-dB, controlled by the voltage applied to Pin VDBS. The gain ranges from 0 dB to 50 dB for control voltages between 0 V and 1.5 V—a slope of 30 mV/dB.The gain linearity is typically within ±0.1 dB. By changing the logic level on Pin MODE, the gain decreases over the same range, with an opposite slope. A second gain control port is provided at the VMAG pin and allows the user to vary the numeric gain from a factor of 0.03 to 10. All the parameters of the AD8330 have low sensitivities to temperature and supply voltages.Using VMAG, the basic 0 dB to 50 dB range can be repositioned to any value from 20 dB higher (that is, 20 dB to 70 dB) to at least 30 dB lower (that is, –30 dB to +20 dB) to suit the application, thereby providing an unprecedented gain range of over 100 dB. A unique aspect of the AD8330 is that its bandwidth and pulse response are essentially constant for all gains, over both the basic 50 dB linear-in-dB range, but also when using thelinear-in-magnitude function. The exceptional stability of the HF response over the gain range is of particular value in those VGA applicationswhere it is essential to maintain accurate gain law-conformance at high frequencies.An external capacitor at Pin OFST sets the high-pass corner of an offset reduction loop, whose frequency can be as low as 5Hz. When this pin is grounded, the signal path becomes dc-coupled. When used to drive an ADC, an external common-mode control voltage at Pin CNTR can be driven to within 0.5 V of either ground or VS to accommodate a wide variety of requirements. By default, the two outputs are positioned at the midpoint of the supply, VS/2.Other features, such as two levels of power-down (fully off and a hibernate mode), further extend the practical value of this exceptionally versatile VGA.产品图片产品特性

       

• Fully differential signal path,also used with single-sided signals       
  
• Inputs from 0.3 mV to 1 V rms, rail-to-rail outputs       
  
• Differential RIN = 1 kΩ; ROUT (each output) 75 Ω       
  
• Automatic offset compensation (optional)       
  
• Linear-in-dB and linear-in-magnitude gain modes       
  
• 0 dB to 50 dB, for 0 V < VDBS< 1.5 V (30 mV/dB)       
  
• Inverted gain mode: 50 dB to 0 dB at −30 mV/dB       
  
• ×0.03 to ×10 nominal gain for 15 mV < VMAG < 5 V       
  
• Constant bandwidth: 150 MHz at all gains       
  
• Low noise: 5 nV/√Hz typical at maximum gain       
  
• Low distortion: ≤−62 dBc typical       
  
• Low power: 20 mA typical at VS of 2.7 V to 6 V       
  
• Available in a space-saving, 3 mm × 3 mm LFCSP package
  

典型应用

       

• Pre-ADC signal conditioning       
  
• 75 Ω cable driving adjust       
  
• AGC amplifiers