UM0240 datasheet(14/39 Pages) STMICROELECTRONICS

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Operational amplifiers (OpAmp)

UM0240

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Operational amplifiers (OpAmp)

The LM358 consists of two independent, high gain (100 dB), high bandwidth (1.1 MHz) and

internally compensated operational amplifiers. In the Industrial Communication Board the

two amplifiers are designed in differential configuration, with a bipolar power supply 5V ÷ -

5V. The output signals consists of the difference signals VREF_A and VREF_B, obtained by:

●

VREF_A = VOUTC - VOUTA

●

VREF_B = VOUTD - VOUTA

The main purpose of the two OPAMPs is then to provide an analog voltage shifting of the

two signals VOUTC and VOUTD, with a voltage shift equal to VOUTA. The bipolar power

supply of the OPAMPs guarantees an output swing both positive and negative to the

resulting signals VREF_A and VREF_B.

This feature is important, for example in Motor Control Applications using Micro-stepping

techniques, for the synthesis of discrete sinusoidal waveforms: the OPAMPs analog shifting

provides the centering of the sinusoidal signal generated by the DACs around the 0 voltage

level.

UM0240 Datasheet(PDF) 14 Page - STMicroelectronics