AD538BD

Overview

The AD538BD is a monolithic real-time analog computational unit providing precision multiplication, division, and exponentiation. It features a transfer function of VO = VY(VZ/VX)m with an exponent range of 0.2 to 5. The device operates within a wide dynamic range of 1000:1 (10 mV to 10 V) and supports a small signal bandwidth up to 400 kHz. Total error is specified at ±0.25% of reading plus offset over a 100:1 input range. It utilizes on-chip +2 V or +10 V scaling references and functions with supply voltages from ±4.5 V to ±18 V.

Feature Summary

• Monolithic construction enabling simultaneous analog multiplication, division, and exponentiation without external trimming.
• Resistor-programmable powers and roots allowing flexible configuration for complex mathematical operations.
• Integrated bandgap voltage reference providing selectable +2 V or +10 V scaling outputs.
• Low input offset voltage and high linearity ensuring accurate computation across a wide dynamic range.

Applications

• One- or two-quadrant multiply/divide operations
• Log ratio computation
• Squaring and square rooting
• Trigonometric function approximations
• Precision automatic gain control

Procurement Notes

Verify the specific BD suffix indicates the industrial grade accuracy variant (-25°C to +85°C). Confirm the package type matches the required 18-lead side-brazed ceramic DIP format. Ensure supply rails are compatible with the ±4.5 V to ±18 V operating range. Check for any recent product change notifications affecting pinout or electrical specifications before finalizing procurement.

Selection Notes

Select the AD538BD when industrial temperature operation is sufficient and lower cost is preferred over military grades. Choose this model if the application requires precise resistor-programmable exponentiation between 0.2 and 5. Verify that the required dynamic range fits within the 1000:1 specification. Consider the available internal references to minimize external component count for scaling requirements.

Part Context

The AD538 series serves as a versatile analog computational solution, replacing discrete multiplier circuits with a single monolithic IC. The BD variant specifically targets industrial applications requiring high accuracy and wide dynamic range. It integrates log-ratio and antilog sections to perform complex mathematical functions in real-time, offering a compact alternative to hybrid or modular computational units.

Replacement Considerations

The AD538AD offers similar functionality but with different accuracy specifications. The AD538SD provides extended military temperature range capabilities. Direct pin-compatible replacements should be verified against the specific accuracy and temperature requirements of the design.