Use BJT transistor as a switch without inverting the signal

Absolutely.

enter image description here

This circuit takes advantages of the properties of a MOSFET to bidirectionally switch a signal between two different voltage levels.


This circuit tends to be used quite often: -

enter image description here


The input is digital at 3.3V and should output 5V TTL levels.

For this situation you very likely do not need any conversion circuit at all.

Both 3.3 V and 5 V TTL logic switch with a threshold of about 0.8 V. Therefore no conversion circuit is needed to drive a 5 V TTL input with a 3.3 V logic signal. To be absolutely sure, check the minimum Vih of your 5 V TTL device and make sure this number is less than the minimum Voh of your 3.3 V device.

This figure, from the TI app note, "Selecting the Right Level-Translation Solution", shows that the specified input, output, and threshold levels are the same for 5 V and 3.3 V TTL circuits:

enter image description here

If your devices are actually not TTL but CMOS, you may still be able to connect them without a conversion circuit, but noise margin will be reduced because the CMOS switching threshold is Vcc/2 rather than a fixed voltage level.

As you see from the chart, you cannot reliably use a 3.3 V TTL signal (or even 5 V TTL) signal to switch a 5 V CMOS input, so for either of those situations you would need a converter circuit as outlined by the other answers here.