RENESAS ICL7650SCBA-1Z

The ICL7650S Super Chopper-Stabilized Amplifier offers exceptionally low input offset voltage and is extremely stable with respect to time and temperature. It is a direct replacement for the industry-standard ICL7650 offering improved input offset voltage, lower input offset voltage temperature coefficient, reduced input bias current, and wider common mode voltage range. Intersil’s unique CMOS chopper-stabilized amplifier circuitry is user-transparent, virtually eliminating the traditional chopper amplifier problems of intermodulation effects, chopping spikes, and overrange lockup. The chopper amplifier achieves its low offset by comparing the inverting and non-inverting input voltages in a nulling amplifier, nulled by alternate clock phases. Two external capacitors are required to store the correcting potentials on the two amplifier nulling inputs; these are the only external components necessary. The clock oscillator and all the other control circuitry is entirely self-contained. However the 14 lead version includes a provision for the use of an external clock, if required for a particular application. In addition, the ICL7650S is internally compensated for unity-gain operation. The functional diagram shows the major elements of the ICL7650S. There are two amplifiers, the main amplifier, and the nulling amplifier. Both have offset-null capability. The main amplifier is connected continuously from the input to the output, while the nulling amplifier, under the control of the chopping oscillator and clock circuit, alternately nulls itself and the main amplifier. The nulling connections, which are MOSFET gates, are inherently high impedance, and two external capacitors provide the required storage of the nulling potentials and the necessary nulling-loop time constants. The nulling arrangement operates over the full common-mode and power-supply ranges, and is also independent of the output level, thus giving exceptionally high CMRR, PSRR, and AVOL. Careful balancing of the input switches, and the inherent balance of the input circuit, minimizes chopper frequency charge injection at the input terminals, and also the feed forward-type injection into the compensation capacitor, which is the main cause of output spikes in this type of circuit.

• Guaranteed Max Input Offset Voltage for All Temperature Ranges
• Low Long-Term and Temperature Drifts of Input Offset Voltage
• Guaranteed Max Input Bias Current: 10pA
• Extremely Wide Common Mode Voltage Range: +3.5V to -5V
• Reduced Supply Current: 2mA
• Guaranteed Minimum Output Source/Sink Current
• Extremely High Gain: 150dB
• Extremely High CMRR and PSRR: 140dB
• High Slew Rate: 2.5V/μs
• Wide Bandwidth: 2MHz
• Unity-Gain Compensated
• Clamp Circuit to Avoid Overload Recovery Problems and Allow Comparator Use
• Extremely Low Chopping Spikes at Input and Output
• Improved, Direct Replacement for Industry-Standard ICL7650 and other Second-Source Parts
• Pb-Free Plus Anneal Available (RoHS Compliant)