ULN3003A

Bob Rongo

Other Parts Discussed in Thread: ULN2003A

It appears that then maximum input voltage for any given input is 24VDC, What is the maximum input current ? is a series resistor required ?

over 11 years ago

0 Ron Michallick over 11 years ago

TI__Guru**** 165016 points

Bob,

Input voltages up to 30V are allowed. However high input voltage causes more internal power dispassion (heating). Pd=VIN*IIN. A series resistor is helpful to reduce power dissipation.

0 Bob Rongo over 11 years ago

Prodigy 20 points

Hi Ron, Thanks for your input. Understand that the chip in question is actually a ULN2003A... not ULN3003

Can you provide a recommendation in regard to a series resistor when operating at 24V logic levels ?

0 Ron Michallick over 11 years ago in reply to Bob Rongo

TI__Guru**** 165016 points

Bob,

The nominal input impedance is 2.7k ohms terminated at 1.4V.
To drop 24V to 5V. RIN=2.7k*(24V-5V)/(5V-1.4V) = 14.3k

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ULN3003A