The AD8330 is a wideband variable gain amplifier for applications requiring a fully differential signal path, low noise, well-defined gain, and moderately low distortion, from dc to 150 MHz. The input pins can also be driven from a single-ended source. The peak differential input is ±2 V, allowing sine wave operation at 1 V rms with generous headroom. The output pins can drive single-sided loads essentially rail-to-rail. The differential output resistance is 150 Ω. 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 ±2 V. 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 reposi-tioned 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 the linear-in-magnitude function. The exceptional stability of the HF response over the gain range is of particular value in those VGA applications where 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 5 Hz. 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 excep-tionally versatile VGA.
The AD8330 is available in 16-lead LFCSP and 16-lead QSOP packages and is specified for operation from −40°C to +85°C.
|Title||Content Type||File Type|
|AD8330: Low Cost DC-150MHz Variable Gain Amplifier Data Sheet (Rev F, 11/2012) (pdf, 1461 kB)||Data Sheets|
|Design and Operation of Automatic Gain Control Loops for Receivers in Modern Communication Systems (pdf, 129 kB)||Tutorials|
|UG-130: Differential Amplifier Evaluation Board for 8-lead SOIC and MSOP Packages (pdf, 493 kB)||User Guides|
|Variable Gain Amplifier Selection Table (pdf, 68 kB)||Product Selection Guide|
ADT7301: Accurate, SPI-Compatible Temperature Sensor in SOT Package
(analogZone September 1, 2003)
RF Source Booklet
(pdf, 815 kB)
RF IC Product Overview - Version O (11/2012)
|Leading Inside Advertorials: Solving Dynamic Range Problems in Analog Systems (pdf, 75 kB)||Overview|
|RAQs index||Rarely Asked Questions||HTML|
|What are Variable Gain Amplifiers (VGA's) and how are they used?||FAQs/RAQs||HTML|
|Glossary of EE Terms||Glossary||HTML|
|Title||Content Type||File Type|
|AD8330 SPICE Macro Model||SPICE Models||HTML|
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