ABSOLUTE MAXIMUM RATINGS

Hello kosta_tr,

Can you please answer the following questions:

1. Are the supply pins still connected to the equipment with no supply voltage (0V), or are they left floating?

2. What is the nature of the voltage that you will be applying? Is it AC or DC? Can you also provide the parameters of the voltage like the amplitude and frequency?

In relation to question number 1, if the supply pins are still connected to the equipment with no voltage (0 V), this would mean that both the supply pins are essentially connected to the GND. If this is the case, having input voltages of less than 0.6 V should be fine provided that the input current does not exceed 5 mA. If the input current exceeds 5 mA, it is recommended to uses a series resistor before the input pin to limit the input current and avoid damaging the device. See this section on the data sheet for more details:


Best regards,
Paul

Thanks for the answers.

1+2:

 It's like EV-ADF41020EB1Z:

a. Connect the 5.5 V power supply to the on-board banana connectors

b. Connect the 15 V power supply to the test points labeled +15V and AGND.

So, there is a time that the op-amp does NOT have dc supply, however it has voltage in pin 3 (and 2...)

Is it OK ? 

Thanks.

Hello kosta_tr ,

Please correct me if I'm wrong, so basically your circuit is like what is shown below, and the supply pins (pin 7 and 4) of the op amp are still connected to the power supply equipment via the connectors? The power supply equipment is just turned off right?


What is the nature of the voltage that is present on the input (pin 3 or pin 2) of the op amp? Is it AC or DC? Can you provide the parameters of the voltage like the amplitude and frequency (if AC) or the DC value (if DC)? Thank you.

Best regards,
Paul

Hi,

1. Yes. pin4 to gnd, pin 7 to the supply.

2. pins 3+2  - same as presentes here:

pin 3 is dc, vp/2 DC voltage, which is approximately 1.5V.

THE CP Output -  this provides ±ICP to the external loop filter, which in turn drives the external VCO. (ICPmax is 5mA)

The V- suppose to be ~1.5V DC when the PLL is locked.

Hello kosta_tr,

Having input voltages of 1.5 V when the supplies are turned off (Pin 7 and Pin 4 are essentially grounded) could potentially damage the device since the input current can quickly exceed 5 mA. I therefore recommend adding a series resistor on the inputs to limit the amount of current flowing on the inputs and avoid damaging the part. Please see the Input Overvoltage Protection section (page 14-15) on OP184's data sheet for more details.


Best regards,
Paul

Hello kosta_tr,

Having input voltages of 1.5 V when the supplies are turned off (Pin 7 and Pin 4 are essentially grounded) could potentially damage the device since the input current can quickly exceed 5 mA. I therefore recommend adding a series resistor on the inputs to limit the amount of current flowing on the inputs and avoid damaging the part. Please see the Input Overvoltage Protection section (page 14-15) on OP184's data sheet for more details.


Best regards,
Paul