Questions about a data-sheet for TC4420

On page 9 "APPLICATIONS INFORMATION", on the output pin they're showing ( CL = 2,500pf ) and a polarized capacitor symbol. I'm trying to understand what CL represents. Capacitive Load?

And, on page 2 "Functional Block Diagram", it shows a dashed line with ( C = 38pf ) for an un-polarized capacitor on the input . I have some of these but haven't so far had any success locating a 2,500pf polarized.

<Mod added:> https://ww1.microchip.com/downloads/en/DeviceDoc/21419D.pdf

A link to the "APPLICATIONS INFORMATION" would be helpful to save other members searching for it.

Les.

Second question first:


That capacitor is not something you add, nor is it something that will replace the two diodes. It simply represents the "effective" capacitance of that design.

Page 9:



1) That representation is probably just "laziness" to use the common American symbol. If you check EAGLE, you will see there is no non-polarized US symbol for a capacitor.
2) As in the above instance, that is not a component you add. That represents an estimated (maximum?) gate capacitance for a large power mosfet being driven by the IC.

EDIT: In other words, that gate driver can be considered as a device that takes an input from a device that cannot provide much current ,e.g., an microcontroller, to switch a small capacitance and gives an output that can provide much higher current to get the same switching time for a much higher capacitance.

That 2500 pf is the device's test-circuit load

It is much like a audio amplifier where some one drew a 4 ohm resistor on the output. (where a speaker goes)
The amp will work with 8 ohms or 16 ohm speakers, also. Will work with an open circuit.
Cl is max or typical load much like a audio amp has a typical load of 8 ohms.

To everybody that answered, very informative and helpful. Thank you all! I'm having boards made and left a footprint for the CL capacitor. As far as the rest of those capacitors I'm assuming they would be used? The 0.1uf being probably non-polarized metal film and the 4.7uf being polarized.

View attachment 110357

Les Jones said:

A link to the "APPLICATIONS INFORMATION" would be helpful to save other members searching for it.

Les.

Click to expand...

Thanks, I'll try to do better next time.