IL300 www.vishay.com Vishay Semiconductors The same procedure can be used to design isolation 2 45 amplifiers that accept bipolar signals referenced to ground. dB These amplifiers circuit configurations are shown in Phase 0 0 figure 17. In order for the amplifier to respond to a signal that swings above and below ground, the LED must be pre - 2 - 45 biased from a separate source by using a voltage reference source (Vref1). In these designs, R3 can be determined by the following equation. - 4 - 90 V V ref1 ref1 Phase Response (°) = ------ = -------- - 6 R3 - 135 I K1I Amplitude Response (dB) P1 Fq - 8 - 180 103 104 105 106 iil300_21 F - Frequency (Hz) Fig. 16 - Amplitude and Phase Power Supply Control Non-inverting input Non-inverting output + Vref2 R5 V - V in cc 3 7 + Vcc 1 IL 300 8 R6 6 100 Ω 2 7 R1 2 7 – R2 Vcc 2 - V V – cc +V 6 cc cc 3 6 4 Vo 20 pF 3 + - V 4 5 cc 4 R3 R4 - Vref1 Inverting input Inverting output Vin 3 7 + Vcc + V 100 Ω ref2 R1 6 1 IL 300 8 R2 + V 2 V cc cc 3 7 – 2 7 + 4 Vcc 20 pF Vcc 6 3 6 Vout 2 R3 4 5 – - Vcc - Vcc 4 + Vref1 R4 iil300_22 Fig. 17 - Non-inverting and Inverting Amplifiers TABLE 2 - OPTOLINEAR AMPLIEFIERSAMPLIFIERINPUTOUTPUTGAINOFFSET VOUT K3 x R4 x R2 V x R4 x K3 ref1 Inverting Inverting ------- = --------------------- V = --------------------- V R3 x R1 x R2 ref2 IN R3 Non-inverting V OUT K3 x R4 x R2 x R5 + R6 - V x R4 x R5 + R6 x K3 Non-inverting Non-inverting ------- = ------------------------------------- V ref1 = ----------------------------------------- V R3 x R5 x R1 x R2 ref2 IN R3 x R6 V OUT - K3 x R4 x R2 x R5 + R6 V x R4 x R5 + R6 x K3 ref1 Inverting Non-inverting ------- = --------------------------------------- V = --------------------------------------- V R3 x R1 x R2 ref2 IN R3 x R6 Inverting VOUT - K3 x R4 x R2 - V x R4 x K3 ref1 Non-inverting Inverting ------- = --------------------- V = ----------------------- V R3 x R1 x R2 ref2 IN R3 Rev. 1.8, 02-Jun-14 9 Document Number: 83622 For technical questions, contact: optocoupleranswers@vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000