Loading effect on L293D

Hello, I'm trying to supply a 4.5 V dc motor with L293D IC ,i connect 5 volts to pin 8 . My problem is that the output voltage decrease to 2.6 volts when i connect the motor,if the motor is not connected i get an output voltage equals to 5 V. Hope someone could help me. Thanks

As the L293D data sheet states, the output transistors consume 2-4 volts, depending on the output current. Your motor power supply has to supply enough voltage to compensate. You would be better off using a modern motor driver with MOSFET transistors.

Yes, H-bridges with darlington(*) output stages (such as L298 and L293) are not good
at low voltage, you lose so much of the power as heat in the driver chip.

For low voltages MOSFET H-bridge is always going to be superior and run far cooler.

(*) Darlington pairs lose 1 to 1.5V per output driver, so 2 to 3V overall, due to the design
of the circuit.