Vishay34840 IR Rcvr Vout Fail +5v transition to 2.5v s/b 0v

[Dale(294engr]]

Has anyone experienced IR Rcvr 4840 failures?
(i.e. output pin gnd level faill to go to 0v)

We've experienced 2 failures in two days.
Logically (code perspective), fault appears as a rcvr that never sees IR beacon, i.e. always high

Using oscilloscope to view Vout:
observe +5v = no IR, 0V pulse = normal 40 kHz detected (1 or 2 mS long)
Failed mode = low voltage transition falls short of 0v by ~2.5v.
Waveshape is sharp, just voltage level failure.
Fault appears equivalent to 30K resistance inside the 4840,
in series with collector. prior to Vout pin (voltage divider to gnd)

May have happened during scope probing,
either brief short to adjacent pin(s) or maybe ESD (static?)

[ControlsTeam]

Dale,

Yes and other will too. it only has a 5 ma output max without holding to ground. U must drive the controller by using a high impedance sink to the rcvr. Not gate or a 2N7000 mosfet.

Good luck!

[Dale(294engr]]

Originally Posted by ControlsTeam

Dale,

Yes and other will too. it only has a 5 ma output max without holding to ground. U must drive the controller by using a high impedance sink to the rcvr. Not gate or a 2N7000 mosfet.

Good luck!

Team 16 controls:
I'm not sure I understand your reply
or perhaps my problem is unclear.

and other too ??

high impedance sink to the rcvr ??
4840 output per data sheet
is an open collector NPN (sink)
w/ 30k (source) internal pullup.

Our 4840's go direct to Dig inpits 1,2,4,5 via 3 conductor cable as FRC suggests for +5v power, gnd & OUT.

5 mA is more than adequate for sinking the Hi R DIG input.
(BTW what is the DIG input resistance (load) ?)

What kind of sink are you using to the DIG inputs if not direct from 4840??

Our problem is sudden and catastrophic failure due to the gnd level offset
raising a few volts above gnd after a period of working fine !!

Have you encountered any unexplained IR rcvr (4840) failures ?

Thanks....