ALD1721ESAL

Overview

The ALD1721ESAL is a monolithic rail-to-rail precision CMOS operational amplifier featuring integrated user-programmable EPAD-based offset voltage adjustment. It operates on supply voltages from 2V to 10V single supply or ±1V to ±5V dual supply, with a typical supply current of 120µA. The device offers a bandwidth of up to 1 MHz and a slew rate of 1 V/µs at ±5V. Input bias current is typically 0.01 pA, and the initial input offset voltage is 35 µV. The SAL package supports an operating temperature range of 0°C to +70°C.

Feature Summary

• Integrates Electrically Programmable Analog Device (EPAD) technology for computer-assisted, in-system trimming of offset voltage without external components.
• Features rail-to-rail input and output voltage ranges with tolerance to over-voltage input spikes beyond supply rails.
• Provides extremely low input bias currents and high open-loop gain suitable for high source impedance applications.
• Eliminates manual system trimming procedures and reduces errors associated with PSRR, CMRR, and temperature drift.

Applications

• Sensor interface circuits
• Biochemical probe interfaces
• Precision sample and hold amplifiers
• High source impedance electrode amplifiers

Procurement Notes

Verify that the specific ordering suffix 'SAL' corresponds to the 8-pin Small Outline Plastic DIP (SOIC) package and the commercial temperature range of 0°C to +70°C. Confirm RoHS compliance status as indicated by the 'L' suffix in the part number. Ensure compatibility with standard EPAD programmers for the required offset voltage programming functionality before finalizing procurement.

Selection Notes

Select this component when application requirements demand precise offset voltage calibration under specific operating conditions without adding external trimmer potentiometers. It is suitable for low-voltage, micropower designs requiring rail-to-rail signal handling. Consider the SOIC package constraints regarding thermal dissipation and board space compared to PDIP alternatives if higher temperature ratings are needed.

Part Context

The ALD1721E series belongs to the EPAD family of micropower CMOS operational amplifiers manufactured by Advanced Linear Devices. This series replaces the ALD1701 model, offering enhanced flexibility through programmable trimming capabilities. The ALD1721ESAL specifically denotes the surface-mount variant within this lineup, designed for automated assembly processes while maintaining the precision characteristics of the broader product family.

Replacement Considerations

The datasheet identifies the ALD1721E as a direct replacement for the ALD1701 operational amplifier. Verify pinout compatibility and ensure that the target circuit can accommodate the EPAD programming pulses during any in-system calibration phases.

FAQ

How does the EPAD technology function for offset voltage adjustment?

EPAD technology utilizes internal CMOS FETs as in-circuit elements. Users can program the VE1 and VE2 pins using software control to permanently store charge, adjusting the offset voltage in either direction. These settings remain stored even after power-down.

What is the maximum load capacitance the ALD1721ESAL can drive?

The device is internally compensated for unity gain stability and can typically drive up to 50pF of external load capacitance without oscillation.