AD7845JR

Overview

The AD7845JR is a 12-bit CMOS multiplying digital-to-analog converter (MDAC) featuring an integrated output amplifier. Fabricated on the LC2MOS process, it supports full 4-quadrant multiplication and guarantees monotonicity across its operating temperature range of 0°C to +70°C. The device utilizes a parallel interface with TTL and 5V CMOS compatible inputs. Key electrical specifications include a maximum settling time of 5 µs to 0.01% of full-scale range, a typical slew rate of 1 V/µs, and a unity gain small-signal bandwidth of 600 kHz. It operates with dual power supplies ranging from ±14.25 V to ±15.75 V and consumes a maximum supply current of 6 mA for VDD and 4 mA for VSS.

Feature Summary

• Integrated Output Amplifier: Includes an on-chip amplifier capable of sourcing –10 V into a 2 kΩ load, reducing component count.
• On-Chip Application Resistors: Features three internal resistors (RA, RB, RC) matched to RFB for simplified gain ranging and offset adjustment.
• High Speed Performance: Achieves a settling time of 5 µs max and a full power bandwidth of 175 kHz.
• Monotonic Operation: Guaranteed monotonic over the entire specified temperature range (TMIN to TMAX).

Applications

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

Procurement Notes

Verify the specific suffix 'JR' corresponds to the commercial temperature grade (0°C to +70°C) and the 24-lead SOIC package. Confirm that the required accuracy meets the J version specification of –1 LSB relative accuracy at +25°C. Ensure power supply decoupling is implemented near the VDD and VSS pins to maintain performance given the high-speed switching characteristics.

Selection Notes

Select the AD7845JR when a compact surface-mount solution is required for 12-bit multiplying DAC applications. This model is suitable for systems needing a single-supply or dual-supply operation within the commercial temperature range. Consider the internal application resistors if gain scaling or offset adjustments are needed without external components. Verify that the parallel interface timing requirements align with the host microprocessor system.

Part Context

The AD7845 series represents Analog Devices' first 4-quadrant multiplying DAC with an on-chip amplifier. The 'J' suffix denotes the commercial temperature range (0°C to +70°C), while 'R' indicates the 24-lead Small Outline Integrated Circuit (SOIC) package. Other variants in the family include ceramic DIP, PLCC, and LCC packages with industrial and extended temperature options.

Replacement Considerations

Direct pin-compatible replacements within the same package and temperature grade include the AD7845KR, which offers improved relative accuracy of –1/2 LSB at +25°C. For broader temperature ranges, the AD7845AR (Industrial, –40°C to +85°C) is available in the same SOIC package.