/tʃ/ and /dʒ/ are the only two affricate phonemes in English language. Exactly like in the case of plosives and most of the fricatives, the affricate phonemes /tʃ/ and /dʒ/ come in fortis/lenis pair. The voicing characteristics are the same as for other consonants.
/tʃ/ is slightly aspirated in the positions where p, t, and k are aspirated. However, personally I do not consider this a reason for learners of ESL to pay much attention to it. The place of articulation is plato-alveolar, exactly the same as for /ʃ/ and /ʒ/. In other words, the "t" part of /tʃ/ has a place of articulation further back in the mouth than the plosive "t" usually has.
As other fortis consonants, when /tʃ/ is final in the syllable, it is shortening the preceding vowel. Another important thing to mention is that /tʃ/ and /dʒ/ often have rounded lips.