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AD7643:  18-Bit, 1.25 MSPS PulSAR® A/D Converter

Product Details

The AD7643 is an 18-bit, 1.25 MSPS, charge redistribution SAR, fully differential, analog-to-digital converter (ADC) that operates from a single 2.5 V power supply. The part contains a high speed, 18-bit sampling ADC, an internal conversion clock, an internal reference (and buffer), error correction circuits, and both serial and parallel system interface ports. The part has no latency and can be used in asynchronous rate applications. The AD7643 is hardware factory calibrated and tested to ensure ac parameters, such as signal-to-noise ratio (SNR), in addition to the more traditional dc parameters of gain, offset, and linearity. The AD7643 is available in Pb-free only packages with operation specified from −40°C to +85°C.

Product Highlights

  1. Fast Throughput. The AD7643 is a 1.25MSPS, charge redistribution, 18-bit SAR ADC.
  2. Superior Linearity. The AD7643 has no missing 18-bit code.
  3. Internal Reference. The AD7643 has a 2.048 V internal reference with a typical drift of ±10 ppm/°C and an on-chip TEMP sensor.
  4. Single-Supply Operation. The AD7643 operates from a 2.5 V single supply.
  5. Serial or Parallel Interface. Versatile parallel (18-, 16-, or 8-bit bus) or 2-wire serial interface arrangement compatible with 2.5 V, 3.3 V, or 5 V logic.

  • Medical instruments
  • High speed data acquisition/high dynamic data acquisition
  • Digital signal processing
  • Spectrum analysis
  • Instrumentation
  • Communications
  • ATE


  • Throughput: 1.25 MSPS
  • INL: ±2 LSB typical, ±3 LSB max; ±8 ppm of full scale
  • 18-bit resolution with no missing codes
  • Dynamic range: 95.5 dB
  • SNR: 93.5 dB typical @ 20 kHz (VREF = 2.5 V)
  • THD: −112 dB typical @ 20 kHz (VREF = 2.5 V)
  • No pipeline delay (SAR architecture)
  • 2.048 V internal reference: typ drift 10 ppm/°C; TEMP output
  • Differential input range: ±VREF
    (VREF up to 2.5 V)
  • Parallel (18-, 16-, or 8-bit bus) and serial 5 V/3.3 V/2.5 V interface
  • SPI®/QSPI™/MICROWIRE™/DSP compatible
  • Single 2.5 V supply operation

Functional Block Diagram for AD7643


Title Content Type File Type
AD7643: 18-Bit, 1.25 MSPS PulSAR™ ADC Data Sheet (Rev 0, 05/2006) (pdf, 676 kB) Data Sheets PDF
AN-931: Understanding PulSAR ADC Support Circuitry  (pdf, 299 kB)
This application note discusses in general the pitfalls that occur regularly when using SAR ADCs and, more importantly, how to easily prevent them.
Application Notes PDF
AN-932: Power Supply Sequencing  (pdf, 95 kB) Application Notes PDF
MS-2210: Designing Power Supplies for High Speed ADC  (pdf, 327 kB) Technical Articles PDF
High Speed, High Accuracy 14-Bit, 16-Bit, and 18-Bit PulSAR ADCs  (pdf, 3826 kB)
A PulSAR Family Brochure (6/2006)
Overview PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Evaluation Kits & Symbols & Footprints

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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.

Product Recommendations & Reference Designs

Companion Products

Suggested Companion Products

Recommended Driver Amplifiers for the AD7643

  • For low bias current, low frequency, we recommend the ADA4627.
  • For single-ended to differential driver applications, we recommend AD8139 or the ADA4930-1.
  • For a fully differential attenuating precision amplifier, we recommend the AD8475.
  • For low noise, low distortion, low power, we recommend the ADA4841-1.
Recommended External Voltage References for the AD7643
  • For low power, we suggest the ADR291.
  • For lowest cost, we suggest the AD1582.
  • For external reference buffer, we recommend the AD8031 or the AD8032.
Recommended Power Solutions

  • For selecting voltage regulator products, use ADIsimPower.

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Price, packaging, availability

AD7643 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
AD7643BCPZ Status: Production 48 ld LFCSP 7x7mm (5.25EP) 48 Ind Tray, 260 $21.57 $19.50 Y  Material Info Notify Me Purchase Sample
AD7643BCPZRL Status: Production 48 ld LFCSP 7x7mm (5.25EP) 48 Ind Reel, 2500 - $19.50 Y  Material Info Notify Me Purchase
AD7643BSTZ Status: Production 48 ld LQFP 48 Ind Tray, 250 $21.57 $19.50 Y  Material Info PCN Purchase Sample
AD7643BSTZRL Status: Production 48 ld LQFP 48 Ind Reel, 2000 - $19.50 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.

AD7643 Evaluation Kit
Model Description Price RoHS View PCN/ PDN Check Inventory/
EVAL-CED1Z Status: Production Evaluation Controller Board $249.00 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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