Semiconductor device

A semiconductor device, comprising:

• a first filter circuit to sub-divide and output a signal received from a first input terminal into a relatively low frequency first signal and a relatively high frequency second signal;
• a second filter circuit to sub-divide and output a signal received from a second input terminal into a relatively low frequency third signal and a relatively high frequency fourth signal;
• a first channel including a first photocoupler to convey the first signal output from the first filter circuit;
• a second channel including a first isolator, the first isolator conveying the second signal output from the first filter circuit;
• a third channel including a second photocoupler to convey a third signal output from the second filter circuit;
• a fourth channel including a second isolator to convey a fourth signal output from the second filter circuit;
• a first signal synthesis circuit to sum and output the first signal conveyed by way of the first channel and the second signal conveyed by way of the second channel;
• a second signal synthesis circuit to sum and output the third signal conveyed by way of the third channel and the fourth signal conveyed by way of the fourth channel,
• wherein the first photocoupler mounted in the first channel includes a first light emitting diode to emit light according to the first signal, and a first photodiode to receive the light from the first light emitting diode,
• wherein the first isolator mounted in the second channel includes a first capacitor,
• wherein the third photocoupler mounted in the third channel includes a second light emitting diode to emit light according to the third signal, and a second photodiode to receive the light of the second light emitting diode, and
• wherein the second isolator mounted in the fourth channel includes a second capacitor;
• a first semiconductor chip including the first filter circuit, the second signal synthesis circuit, the second photodiode, and the second capacitor;
• a second semiconductor chip including the first light emitting diode;
• a third semiconductor chip including the second filter circuit, the first signal synthesis circuit, the first photodiode, and the first capacitor;
• and
• a fourth semiconductor chip including the second light emitting diode,
• wherein the second photodiode and the second capacitor are formed over a single substrate in the first semiconductor chip, and
• wherein the first photodiode and the first capacitor are formed over a single substrate in the third semiconductor chip.