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AD538:  Real-Time Analog Computational Unit (ACU)

Product Details

The AD538 is a monolithic real-time computational circuit which provides precision analog multiplication, division, and exponentiation. The combination of low input and output offset voltages and excellent linearity results in accurate computation over an unusually wide input dynamic range. Laser wafer trimming makes multiplication and division with errors as low as 0.25% of reading possible, while typical output offsets of 100 microV or less add to the overall off-the-shelf performance level. Real-time analog signal processing is further enhanced by the device's 400 kHz bandwidth.

The AD538's overall transfer function is Vo=Vy(Vz/Vx)m. Programming a particular function is via pin strapping. No external components are required for one-quadrant (positive input) multiplication and division. Two-quadrant (bipolar numerator) division is possible with the use of external level shifting and scaling resistors. The desired scale factor for both multiplication and division can be set using the on-chip +2 V or +10 V references, or controlled externally to provide simultaneous multiplication and division. Exponentiation with an M value from 0.2 to 5 can be implemented with the addition of one or two external resistors.

Direct log ratio computation is possible by utilizing only the log ratio and output sections of the chip. Access to the multiple summing junctions adds further to the AD538's flexibility. Finally, a wide power-supply range of ±4.5 V to ±18 V allows operation from standard ±5 V, ± 12 V and ± 15 V supplies.

The AD538 is available in two accuracy grades (A and B) over the industrial (-25°C to +85°C) temperature range and one grade (S) over the military (-55°C to +125°C) temperature range. The device is packaged in an 18-pin TO-118 hermetic size-brazed ceramic DIP. A-grade chips are also available.


  • VOUT = VY (VZ divided by VX)m Transfer Function
  • Wide Dynamic Range (Denominator) -1000:1
  • Simultaneous Multiplication and Division
  • Resistor-Programmable Powers and Roots
  • No External Trims Required
  • Low Input Offsets <100 µV
  • Low Error ±0.25% of Reading (100:1 Range)
  • +2 V and +10 V On-Chip References
  • Monolithic Construction

Functional Block Diagram for AD538

AD538 Diagram
Functional Block Diagram for AD538


Title Content Type File Type
AD538: Real-Time Analog Computational Unit Data Sheet  (Rev E, 06/2011) (pdf, 167 kB) Data Sheets PDF
AN-213: Low Cost, Two-Chip, Voltage -Controlled Amplifier and Video Switch  (pdf, 391 kB) Application Notes PDF
AN-304: 04: One Chip "Slide-Rule" Works With Logs, Antilogs for Real Time Processing  (pdf, 563 kB)
The AD538 Analog Computer IC Multiplies and Divides Signals, Computes Powers and Roots. A Log-Antilog Section Increases Dynamic Range During Division.
Application Notes PDF
Ask The Applications Engineer-1
(Analog Dialogue, 30th Anniversary Reader Bonus)
Analog Dialogue HTML
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
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary 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

AD538 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
AD538ACHIPS Status: Production CHIPS OR DIE 0 Ind Tray, 49 - - Y  Material Info Notify Me Contact ADI
AD538AD Status: Production 18 ld CerDip 18 Ind Tube, 20 $43.45 $39.28 N  Material Info PCN Purchase
AD538ADZ Status: Production 18 ld CerDip 18 Ind Tube, 20 $38.18 $34.52 Y  Material Info PCN Purchase
AD538BD Status: Production 18 ld CerDip 18 Ind Tube, 20 $52.53 $47.50 N  Material Info PCN Purchase
AD538BDZ Status: Production 18 ld CerDip 18 Ind Tube, 20 $46.16 $41.73 Y  Material Info PCN Purchase
AD538SD Status: Production 18 ld Side-Brazed CerDIP 18 Mil Tube, 20 $85.76 $85.76 N  Material Info PCN Purchase
AD538SD/883B Status: Production 18 ld Side-Brazed CerDIP 18 Mil Tube, 20 $90.77 $82.05 N  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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