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AD602:  Dual, Low Noise, Wideband Variable Gain Amplifier, -10 dB To +30 dB Gain

Product Details

The AD600/AD602 dual channel, low noise, variable gain amplifiers are optimized for use in ultrasound imaging systems, but are applicable to any application requiring precise gain, low noise and distortion, and wide bandwidth. Each independent channel provides a gain of 0 dB to +40 dB in the AD600 and -10 dB to +30 dB in the AD602. The lower gain of the AD602 results in an improved signal-to-noise ratio (SNR) at the output. However, both products have the same 1.4 nV/√Hz input noise spectral density. The decibel gain is directly proportional to the control voltage, accurately calibrated, and supply and temperature-stable.

To achieve the difficult performance objectives, a proprietary circuit form, the X-AMP®, was developed. Each channel of the X-AMP comprises a variable attenuator of 0 dB to -42.14 dB followed by a high speed fixed gain amplifier. In this way, the amplifier never has to cope with large inputs, and can benefit from the use of negative feedback to precisely define the gain and dynamics. The attenuator is realized as a 7-stage R-2R ladder network having an input resistance of 100 W, laser trimmed to ±2%. The attenuation between tap points is 6.02 dB; the gain-control circuit provides continuous interpolation between these taps. The resulting control function is linear in dB.

The gain-control interfaces are fully differential, providing an input resistance of ~15 M W and a scale factor of 32 dB/V (that is, 31.25 mV/dB) defined by an internal voltage reference. The response time of this interface is less than 1 µs. Each channel also has an independent gating facility that optionally blocks signal transmission and sets the dc output level to within a few millivolts of the output ground. The gating control input is TTL- and CMOS-compatible.

The maximum gain of the AD600 is 41.07 dB, and the maximum gain of the AD602 is 31.07 dB; the -3 dB bandwidth of both models is nominally 35 MHz, essentially independent of the gain. The SNR for a 1 V rms output and a 1 MHz noise bandwidth is typically 76 dB for the AD600 and 86 dB for the AD602. The amplitude response is flat within ±0.5 dB from 100 kHz to 10 MHz; over this frequency range, the group delay varies by less than ±2 ns at all gain settings.

Each amplifier channel can drive 100 W load impedances with low distortion. For example, the peak specified output is ±2.5 V minimum into a 500 W load, or ±1 V into a 100 W load. For a 200 W load in shunt with 5 pF, the total harmonic distortion for a ±1 V sinusoidal output at 10 MHz is typically -60 dBc.

The AD600J/AD602J are specified for operation from 0°C to 70°C and are available in 16-lead PDIP (N) and 16-lead SOIC packages. The AD600A/AD602A are specified for operation from -40°C to +85°C and are available in 16-lead CERDIP (Q) and 16-lead SOIC packages. The AD600S/AD602S are specified for operation from -55°C to +125°C, are available in a 16-lead CERDIP (Q) package, and are MIL-STD-883 compliant. The AD600S/AD602S are also available under DESC SMD 5962-94572.

AD600 - Gain Range: 0 dB to 40 dB

AD602 - Gain Range: -10 dB to + 30 dB


  • 2 channels with independent gain control
    Linear in dB gain response
  • 2 gain ranges
    AD600: 0 dB to 40 dB
    AD602: -10 dB to +30 dB
  • Accurate absolute gain: ±0.3 dB
  • Low input noise: 1.4 nV/√Hz
  • Low distortion: -60 dBc THD at ±1 V output
  • High bandwidth: dc to 35 MHz (-3 dB)
  • Stable group delay: ±2 ns
  • Low power: 125 mW (maximum) per amplifier
  • Signal gating function for each amplifier
  • Drives high speed ADCs
  • MIL-STD-883-compliant and DESC versions available

Functional Block Diagram for AD602


Title Content Type File Type
AD600/AD602: Dual channel, Low Noise Variable Gain Amplifiers Data Sheet  (Rev F, 10/2008) (pdf, 612 kB) Data Sheets PDF
AD602: Military Data Sheet (Rev A, 01/2002) (pdf) Data Sheets PDF
Design and Operation of Automatic Gain Control Loops for Receivers in Modern Communication Systems  (pdf, 129 kB) Tutorials PDF
X-amp, A New 45-dB, 500-MHz Variable-Gain Amplifier (VGA) Simplifies Adaptive Receiver Designs
(Analog Dialogue, Vol. 36, No. 1, January-February, 2002)
Analog Dialogue HTML
Choosing High-Speed Signal Processing Components for Ultrasound Systems
(Analog Dialogue, Vol. 29, No. 2, 1995)
Analog Dialogue HTML
ADI Warns Against Misuse of COTS Integrated Circuits  (pdf, 13 kB)
(Revised 1/03)
Invites Customer Participation in Creative Mil/Aero System Solutions
Recommended Reading PDF
Space Qualified Parts List  (pdf, 93 kB)
This document lists 67 (240+) space level products that are available from Analog Devices. Many of the products listed are state-of-the-art data conversion and signal processing products that were previously only available as commercial or military Class B products. Through our Space Products Group and MIL-PRF-38535 certified Level V (Class S) facility, we are pleased to offer these products to the space marketplace.
Aerospace Information PDF
Variable Gain Amplifier Selection Table  (pdf, 68 kB) Product Selection Guide PDF
Leading Inside Advertorials: Solving Dynamic Range Problems in Analog Systems  (pdf, 75 kB) Overview PDF
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

Design Tools,Models,Drivers & Software

Title Content Type File Type
AD602 SPICE Macro-Model SPICE Models HTML

Evaluation Kits & Symbols & Footprints

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

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Price, packaging, availability

AD602 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
AD602AR Status: Last Time Buy 16 ld SOIC - Wide 16 Ind Tube, 47 $27.53 $24.89 N  Material Info PCN/PDN Purchase
AD602AR-REEL Status: Production 16 ld SOIC - Wide 16 Ind Reel, 1000 - $24.89 N  Material Info PCN Purchase
AD602AR-REEL7 Status: Last Time Buy 16 ld SOIC - Wide 16 Ind Reel, 250 - $24.89 N  Material Info PCN/PDN Purchase
AD602ARZ Status: Production 16 ld SOIC - Wide 16 Ind Tube, 47 $24.36 $22.02 Y  Material Info PCN Purchase
AD602ARZ-R7 Status: Production 16 ld SOIC - Wide 16 Ind Reel, 250 - $22.02 Y  Material Info PCN Purchase
AD602ARZ-RL Status: Production 16 ld SOIC - Wide 16 Ind Reel, 1000 - $22.02 Y  Material Info PCN Purchase
AD602JNZ Status: Production 16 ld PDIP 16 Comm. Tube, 25 $18.74 $16.94 Y  Material Info PCN Purchase
AD602JR Status: Last Time Buy 16 ld SOIC - Wide 16 Comm. Tube, 47 $21.18 $19.15 N  Material Info PCN/PDN Purchase
AD602JR-REEL7 Status: Last Time Buy 16 ld SOIC - Wide 16 Comm. Reel, 400 $21.18 $19.15 N  Material Info PCN/PDN Purchase
AD602JRZ Status: Production 16 ld SOIC - Wide 16 Comm. Tube, 47 $18.74 $16.94 Y  Material Info PCN Purchase
AD602JRZ-R7 Status: Production 16 ld SOIC - Wide 16 Comm. Reel, 400 - $16.94 Y  Material Info PCN Purchase
AD602JRZ-RL Status: Production 16 ld SOIC - Wide 16 Comm. Reel, 1000 - $16.94 Y  Material Info PCN Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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