Hey, by providing a DAC input, I'm using the LM358 as a voltage amplifier to produce a 0-10 V signal. The image is included below.
V_Supply_Filter is a 24V
I want to ask if I can remove the SS34 diode. How do I add reverse polarity protection to the output.
Hey Dheeraj,
Correct, the LM324N does not have internal ESD protection, the LM324B offers internal ESD protection cells.Here is a snippet from the datasheet. 
I recommend leveraging Design Guidelines for Devices with LM324/LM358 Cores (Rev. A) along with the respective datasheets when implementing your design changes.
All the best,
Carolina
Hi Dheeraj,
1. It's unusual to use the "SS34" which is a big 3A Schottky diode for ESD protection. The "BAT54S" may be better suited.
2. The "LM358B" withstands 2kV HBM ESD. But when the customer can touch the output of "LM358B" the CE standards demand to withstand 8kV HBM ESD. Because of that, the add of an external ESD protection clamp at the output can make sense. The "BAT54S" is often used for this purpose.
3. The "SS34" being a big 3A Schottky diode shows a huge junction capacitance of 200pF...1000pF (depending on the reverse voltage) which can make the OPAmp circuit instable.The developer of your circuit has used the "dual feedback method" which is often used when a big load capacitance has to be handled but the circuit is still instable. See the following phase stability analysis:
With the "BAT54S" offering a way smaller junction capacitance the phase margin is better and the circuit is stable:
(The aim is to establish a phase margin of > 45°, better 60°. Then there are no stability issues.)
But when you connect a cable to the output the additional cable capacitance will ruin the phase margin again. A 2m long cable with 200pF will give a phase margin of only 30°.
Reducing your C53 can help to restore the phase margin again and even allow the connection of cables:
4. There's a nice TI's training video series on stability, also discussing the dual feedback method:
https://training.ti.com/node/1138805
5. For best ESD protection move the BAT54S (but only the BAT54S) a bit away from the LM358B, best close to the connector where the signal leaves the board. Have a 100nF decoupling cap there for the 24V supply voltage and connect the upper BAT54 to this decoupling cap.The lower BAT54 connects to the ground terminal of this decoupling cap which sits in a solid ground plane. Connect from this ground point a 1...10nF Y-cap to the metall chassis. By this ESD is very effectively hindered from entering the whole board. The ground point of said decoupling cap, and the connector of course, should sit closest to the edge of board and the metall chassis.
Use a solid ground plane for the circuit and have the decoupling cap of the LM358B closest to the supply voltage pins.
Have all connectors sitting on one side of the board. This also hinders ESD from travelling over the whole board, from one connector to the other.
Kai
