Why do application schematics involving op amps seldom show supply connections?
Power supply connections are often omitted to simplify the application schematic. This was done historically when op amps were first being used, and the tradition is perpetuated itself, mainly to keep the application schematic from looking overly complicated. Drawing the supply connections to all op amps can be especially confusing with multiple (e.g. dual or quad) amplifiers in one package. In such cases, only one supply pin per package needs to be connected, and the supply is routed internally to all the op amps in the package. Even if there is no supply connection shown on the application schematic, a power supply must be connect to the amplifier for it to operate. Consult the device datasheet for appropriate power supply voltages. When developing circuits using Amplifiers WEBENCH, the choice of supply voltage is incorporated into the design requirements.
