We are planing to drive a Head phone as per specification attached with the above circuit. Could you please suggest is the values are mentioned in the schematic able to drive the Head phone.
please suggest what are the changes required to drive the Headphone.the input to INA1620 is from audio signal driven by Laptop audio output signal.
Hello Rohith,
The INA1620 is more than capable of driving heavy loads such as 160ohms. I have successfully driven 3 ohms. We have an application note as well if you need even more current at the heavy loads where you can put two amps in parallel using the INA1620 as shown here:
I did notice in your schematic that you are setting the device up to operate on a single supply voltage. I have added a mid DC operating point as shown in the application circuit in the product datasheet to bias everything around mid supply. I have put this into simulation and attached the simulation at the bottom of this post. We offer Tina Ti as a free download, and this application can open my attached simulation. If you don't currently have Tina Ti, it can be downloaded here:
https://www.ti.com/tool/TINA-TI
You can see below with the DC simulation, that the INA1620 is biased with a single supply of 5V and a mid point bias on the inputs of 2.5V or mid-supply. I added DC blocking capacitors on the outputs as well in order to block the DC voltage from being applied to the headphones. The input and output capacitors are chosen such that the bandwidth requirement on the low end is achieved.
The Gain vs Frequency plot shows the bandwidth requirement is met. There is a slight -1.7dB attenuation at 15Hz. This frequency is inaudible. Throughout the audible frequencies the gain of 1 is achieved.
Simulating the transient response and driving the output to clipping we can calculate an approximate power capability drive to the headphones. I calculate that the amp can drive roughly 9.2mW when we hit clipping. This can be backed off such that we don't clip but this illustrates that we are well above 1mW at 1kHz.
Best Regards,
Chris Featherstone
