for phase cutting control we would like use either BTA16 (T0-220AB) or T1635 (D2PAK) on ouer PCB.the controlsignal is a 3,3 VDC pwm. ( see attachment ) A T1635H-6T is placed instead the T1635 in the boom list by a mistake .

[bmose.1]

now we have following situation.

1. the circuit works fine at using the BTA16
2. at using the T1635H-6T the hase cutting doesn't works ( full wave is engaged over the PWM range )

Questions:

a. what is the difference between T1635 and T1635H-6T ?

b.how can we solved this problem ?