AD7845BQ

Overview

The AD7845BQ is a complete 12-bit multiplying digital-to-analog converter (DAC) with an integrated output amplifier, fabricated on the LC2MOS process. It features full 4-quadrant multiplication capability and includes three on-chip application resistors for gain ranging and offset adjustment. The device operates within a temperature range of -40°C to +85°C and accepts TTL and 5 V CMOS compatible digital inputs. Key electrical specifications include a maximum relative accuracy of -1/2 LSB at +25°C, a settling time of 5 µs to 0.01% of full-scale range, and power supply ranges of ±14.25 V to ±15.75 V. It is housed in a Q-24 Cerdip package.

Feature Summary

• Integrated 12-bit CMOS Multiplying DAC with on-chip unity-gain output amplifier
• Full 4-quadrant multiplication capability with low multiplying feedthrough error
• Three internal application resistors (RA, RB, RC) for flexible gain and offset scaling
• Guaranteed monotonic operation across the specified industrial temperature range

Applications

• Automatic Test Equipment
• Programmable Gain Amplifiers
• Digital Attenuators
• Programmable Power Supplies
• Digital-to-4–20 mA Converters

Procurement Notes

Verify the specific ordering suffix 'BQ' corresponds to the Industrial temperature grade (-40°C to +85°C) and the Q-24 Cerdip package configuration as defined in the manufacturer's ordering guide. Confirm that the required performance metrics, such as the -1/2 LSB relative accuracy, align with the B version specifications in the datasheet before finalizing procurement.

Selection Notes

Select the AD7845BQ when a 12-bit resolution with integrated buffering and 4-quadrant multiplying functionality is required for industrial environments. Ensure the system design accommodates the recommended dual power supply rails of ±15 V and provides adequate decoupling for the digital and analog ground pins to minimize noise injection into the analog output.

Part Context

The AD7845 series represents Analog Devices' first 4-quadrant multiplying DAC with an on-chip amplifier. The 'B' designation indicates the industrial temperature grade variant, while the 'Q' suffix specifies the ceramic DIP (Cerdip) package option. This component is part of a broader family including commercial (J/K), extended (S/T), and hermetic military variants.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.