GENERAL DESCRIPTION
The ALD1721E is a monolithic rail-to-rail precision CMOS operational amplifier with integrated user programmable EPAD (Electrically Programmable Analog Device) based offset voltage adjustment. The ALD1721E operational amplifier is a direct replacement of the ALD1701 operational amplifier, with the added feature of user-programmable offset voltage trimming resulting in significantly enhanced total system performance and user flexibility. EPAD technology is an exclusive ALD design which has been refined for analog applications where precision voltage trimming is necessary to achieve a desired performance. It utilizes CMOS FETs as in circuit elements for trimming of offset voltage bias characteristics with the aid of a personal computer under software control. Once programmed, the set parameters are stored indefinitely within the device even after power down. EPAD offers the circuit designer a convenient and cost-effective trimming solution for achieving the very highest amplifier/system performance.
The ALD1721E operational amplifier features rail-to-rail input and output voltage ranges, tolerance to over-voltage input spikes of 300mV beyond supply rails, capacitive loading up to 50pF, extremely low input currents of 0.01pA typical, high open loop voltage gain, useful bandwidth of 700KHz, slew rate of 0.7V/µs, and low typical supply current of 120µA.

KEY FEATURES
• EPAD (Electrically Programmable Analog Device)
• User programmable VOS trimmer
• Computer-assisted trimming
• Rail-to-rail input/output
• Compatible with standard EPAD Programmer
• High precision through in-system circuit precision trimming
• Reduces or eliminates VOS, PSRR, CMRR and TCVOS errors
• System level “calibration” capability
• Application Specific Programming mode
• In-System Programming mode
• Electrically programmable to compensate for external
   component tolerances
• Achieves 0.01pA input bias current and 35µV input offset
   voltage simultaneously
• Compatible with industry standard pinout

BENEFITS
• Eliminates manual and elaborate
   system trimming procedures
• Remote controlled automated trimming
• In-System Programming capability
• No external components
• No internal chopper clocking noise
• No chopper dynamic power dissipation
• Simple and cost effective
• Small package size
• Extremely small total functional
   volume size
• Low system implementation cost
• Micropower and Low Voltage

APPLICATIONS
• Sensor interface circuits
• Transducer biasing circuits
• Capacitive and charge integration circuits
• Biochemical probe interface
• Signal conditioning
• Portable instruments
• High source impedance electrode
   amplifiers
• Precision Sample and Hold amplifiers
• Precision current to voltage converter
• Error correction circuits
• Sensor compensation circuits
• Precision gain amplifiers
• Periodic In-system calibration
• System output level shifter