IR2104, Clarification needed.

Thread Starter

MaxHeadRoom

Joined Jul 18, 2013
30,656
I have used the IR2110 ever since IR offered the initial issue & development board.
I have been looking at going to the smaller FP , IR2104.
The thing I am not clear on is the wording, there is just VCC on the IR2104, not like the IR2110 that has VCC & VDD.
So if I am using Mosfets that require 10v - 12v for the gate, I assume the VCC requires this voltage, but it also seems to says that the inputs can driven by 5v logic.
Does this mean that it accepts both values for input when VCC is 12v?
Or am I reading it wrong? :(
 

Thread Starter

MaxHeadRoom

Joined Jul 18, 2013
30,656
IMO that would an insane chip design if it didn't.
Unfortunately, it does not specifically claim that, IOW, does the single supply replace the need as used on the IR2110 of using the correct voltage for both the input logic and the VCC boost, where 10v VCC is used on the IR2104 and the input can be 5v to 10v?
 

nsaspook

Joined Aug 27, 2009
16,321
Unfortunately, it does not specifically claim that, IOW, does the single supply replace the need as used on the IR2110 of using the correct voltage for both the input logic and the VCC boost, where 10v VCC is used on the IR2104 and the input can be 5v to 10v?
I would need to find a more complete design with the chip to analyze.

1708318626774.png
1708318736851.png
This seems to give the value of logic low and logic high vs VCC.
 

Alec_t

Joined Sep 17, 2013
15,118
If I'm reading the datasheet correctly, the minimum Vin(high) is 3V. So 3.3V logic would have to drive its logic 1 output right up to the +ve rail. Seems a bit marginal?
 

Ian0

Joined Aug 7, 2020
13,131
If I'm reading the datasheet correctly, the minimum Vin(high) is 3V. So 3.3V logic would have to drive its logic 1 output right up to the +ve rail. Seems a bit marginal?
I would interpret it as the minimum (I.e. lowest) voltage that will be interpreted as logic high, so all voltages above that will be logic 1. (74LS00 is specified the same way). It’s not the minimum value of the logic threshold, but the maximum value of the threshold!
Certainly, not much noise margin on a logic 1 for 3.3V logic. I think I’d like to drive it with 5V.
 

sarahMCML

Joined May 11, 2019
697
I would interpret it as the minimum (I.e. lowest) voltage that will be interpreted as logic high, so all voltages above that will be logic 1. (74LS00 is specified the same way). It’s not the minimum value of the logic threshold, but the maximum value of the threshold!
Certainly, not much noise margin on a logic 1 for 3.3V logic. I think I’d like to drive it with 5V.
The Diodes Inc datasheet specs their version as 2.3V minimum for Vin (High)!
 
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