Apart from the precautions mentioned in the data sheet, is there any other electrical precautions we need to take care. Since, I have problems in some of the SP4T's individual switches getting damaged. I am using MEMS switches for making a switched capacitor network and the switches undergo hot switching (i.e. voltage between Drain & Source exists when the switch turn on or turn-off). The worst-case voltages between Drain & Source during such hot-switching is ~ 3 V.
Particularly I would like to know, if there are any thing I can follow, so as to avoid such damages to the beams. Apart from this, should we enable/disable the IC using sleep pin only when all INx pins are low.
You are having failures due to hot switching. 3V RMS is around 23dBm which is quite lot of power for hot switching. You need to add 10M ohm resistors to GND on all the RF pins of ADGM1304 to avoid any floating nodes and also to provide discharge path to avoid any hot switching due to charging and discharging of the cap. Can you please make sure not to do any hot switching also can you please tell me what is the size of the cap you are using in your design.
yes, you can use sleep pin to enable and disable the ADGM1304 but please make sure to allow 1.2ms to wake up when you are enabling the ADGM1304 again.
Thanks for your prompt reply. The size of the cap is not fixed and is ~ > 20 pF. It is not possible to completely avoid hot switching in my case, but can reduce the voltage levels. If I connect the 10 Mohm resistor at RF nodes, it affects my switched capacitor network due to loading of the capacitor. By the way, Vds=3V during hot switching is the worst case value.
In case of hot switching, what is the life time of MEMS switches?. (This question was asked earlier in the forum, https://ez.analog.com/switches_multiplexers/f/q-a/76708/adgm1304-hot-switching-performance, but quantitative answer was not provided)
In my previous question last part, my clarification was: should we "only" disable the switch when all INx pins are low.
For optimum operation of ADGM1304 it's recommended to add 10M ohm resistors on all RF nodes to avoid any floating which may cause unreliable actuation and also we don't recommend to connect cap directly to the ADGM1304 as cap holds the charge which causes hot switching and damages the device. For more information on floating nodes please refer to application section of ADGM1304.
Below is the hot switching plot indicating different power levels. T50 refers to the number of cycles for 50% of the population to fail.
To enable sleep mode, it's recommended to connect all the INx pins to low before you place the ADGM1304 to sleep mode for optimum operation.
I want to ask more about the floating node issue.
I'm using MEMS to direct continuous DC generated from a "floating ground" power supply. Two ends of the power supply is connected to the In and the RF1 nodes, for example. I'm wondering if it is true that 10M ohms resistor does not work as protection at all because there is an infinite impedance between the power supply and the MEMS ground, as the power supply being completely "floating ground".
In my case, how can I properly reference the DC voltage at the nodes? Do you have any suggestions?
Thank you very much for your help.
Can you please tell me you VDD and GND voltage levels and also can you share your schematic?
Please note the IN1 to IN4 pins are the digital logic pins to control RF pins.