LM3900 Quadruple Norton Operational Amplifier IC

The LM2900 series designed with four independent, dual input, internally compensated amplifiers. These op-amp designed explicitly to operate from a single power supply voltage over a wide range of voltages. And also the operation via split supply is possible. Meanwhile, these amplifiers make use of a current mirror to achieve the non-inverting input function.  This LM2900 offers low supply current drain that is essentially independent of the magnitude of the supply voltage. As a result, these devices provide wide bandwidth and large output voltage swing. The LM2900 designed specifically for operation in the temperature range from –40°C to 85°C.

Norton, also known as the current-differencing amplifiers used widely in standard general-purpose operational amplifier applications. In short, the performance as a dc amplifier via a single-power-supply mode is not as accurate as a standard integrated-circuit operational amplifier operating from dual supplies.The noise immunity of a Norton amplifier is quite less than that of standard bipolar amplifiers. Whereas the Circuit layout is more critical since coupling from the output to the noninverting input generate oscillations.

In this LM2900 series, the input currents differenced at the inverting input terminal and fed through the external feedback resistor to produce the output voltage. Common-mode current biasing is generally useful to allow operating with signal levels near (or even below) ground. And also the Internal transistors clamp negative input voltages at a range of approximately –0.3 V. But the magnitude of current flow limited by the external input network. For operation at high temperatures, this limit should be approximately 100 µA.

NOTE:

• Highly recommended to place a limiting resistor  in series with the input lead to limit the peak input current.

Application:

• AC amplifiers
• RC active filters
• low-frequency triangle
• square-wave and pulse waveform generation circuits
• Tachometers and low speed, high voltage digital logic gate