In terms of relative position of the particle in relation to the verb, we distinguish three types of transitive phrasal verbs:
1. separable optional
It means the object of the verb can come between the verb and the particle or it can come after them. However, if the object is a pronoun, it always has to come between them.
Put your coat on. :tick:
Put on your coat. :tick:
Put it on. :tick:
Put on it. :cross:
2. separable obligatory
Separation is always mandatory.
Definition from Cambridge Dictionary Online: Free English Dictionary and Thesaurus
The particle and the verb are inseparable. Nothing can come between them.
I came across this vase. :tick:
I came across it. :tick:
I came this vase across. :cross:
I came it across. :cross:
Can I say "Put down these"?
Strange. It does not sound bad to my ears; still I can't comes up with an explanation as to why it should be okay.
Put it down. :tick:
Put down the receiver. :tick:
It means the pv is separable optional. Separable optional pv's have their pronoun objects obligatorily
surrounded by the verb and its particle.
Put down it. :cross:
Put down these. :cross:
Put down these tools. :tick: