TI中文支持网Other Parts Discussed in Thread:THS4303
I downloaded the THS4303spice model, and connected the components in ADS to simulate the schematic diagram.
However, the voltage and current cannot match the simulation results during the actual machining test.
For example, the simulated output voltage is 121mV, but the output voltage will become -0.71V during testing.
I follow the power supply method recommended in the manual to power the op amp.
I don’t know where the problem is, or the model itself is not accurate enough.
Thank you for help!
Amy Luo：
Hi,
Could you share your circuit ? What is the signal you input? Please provide more detailed application information to help you solve your problems more effectively
,
user6531562：
The schematic diagram in ADS is shown in the figure below,
The simulated voltage of the input pin and output pin of the op amp is different from the actual test value.
the simulate voltage of the pin——— vout, +vin and -vin all are 1.56V.
but the test voltage was different——- vout/-vin: -1.72V, +vin: when I first tested, it was -1.72V, but after connecting the voltmeter for a while, it becomes -0.03V.
Moreover, the test current of the positive and negative power supply ports of the op amp is also different from the simulation.
The simulation current is 36.8mA, but the test voltage is 18mA.
I just simulate the DC of the circuit, so there is no input voltage.
Thank you for your help!
,
Amy Luo：
I haven't used ADS. I can't understand the THS4303 model in ADS. what's your actual circuit like? Can you share it
If there is no input signal, are you grounded for in + pin and in – pin？
,
user6531562：
The actual circuit is to connect the output terminal of the op amp to the positive input terminal through a 176 ohm resistor, the negative input terminal is suspended, the pd pin is grounded, and the power port is connected to ±2.5V. The following picture is the circuit structure diagram.
,
Amy Luo：
Idon't know what parameters of the THS4303 you want to test, but the input end of the op amp is not recommended to be suspended. It is easy to pick up electromagnetic interference and cause undesirable output
,
user6531562：
Electromagnetic interference will affect AC, but it should not affect DC. Now the simulation results and test results of DC voltage are completely incompatible.
,
Amy Luo：
The suspended pin has no fixed level, which will cause potential input, so the input pin of op amp can not be suspended.
Can you tell me what you are testing
,
user6531562：
This is a proportional operational amplifier circuit used to amplify voltage.It is indeed caused by the negative pin being left floating. I am correct after correcting it according to what you said.
,
Amy Luo：
Has your problem been solved?
The THS4303 device is a fixed-gain amplifier, which integrates Rf and Rg, so I don't know your purpose of connecting 176 Ω resistor externally.
,
user6531562：
This a non-foster circuit, it can produce a negtive impedance, After connecting the circuit, I want to check the DC of the circuit. But the simulation voltage of the +vin&-vin&vout was totally different from the actual measurement results. I don't know why this happens, it really caused by the negative pin hanging?
,
Amy Luo：
Under what state do you want to check the DC of the circuit? If the input pin is suspended, the circuit will not have a stable static working point, and it is meaningless to measure all its parameters
,
user6531562：
It is connected according to the previous circuit, the negative pin is left floating, and the DC condition of the circuit is measured. I want to ask how much power the op amp is suitable for, I am giving ±2.5V.
,
user6531562：
The simulated power supply current is 36.8mA, but the power supply current is only about 10mA during the test
,
user6531562：
What should I do to make this circuit work properly?
,
Amy Luo：
Is the previous circuit working properly? Maybe you can test the parameters you need on the previous circuit board
What is your test circuit and what are the component parameters? The current consumed by THS4303 is related to your specific circuit connection
What is the output phenomenon of your circuit to realize the function you need
