THS4521 Datasheet, PDF (33/65 Pages) Texas Instruments – VERY LOW POWER, NEGATIVE RAIL INPUT, RAIL-TO-RAIL OUTPUT, FULLY DIFFERENTIAL AMPLIFIER

www.ti.com
THS4521, THS4522, THS4524
SBOS458H – DECEMBER 2008 – REVISED JUNE 2015
8.3.12 Audio On/Off Pop Performance
The THS4521 was tested to show on and off pop performance by connecting a speaker between the differential
outputs and switching the power supply on and off, and also by using the PD function of the THS4521. Testing
was done with and without tones. During these tests, no audible pop could be heard.
With no tone input, Figure 70 shows the pop performance when switching power on to the THS4521 and
Figure 71 shows the device performance when turning the power off. The transients during power on and off
illustrate that no audible pop should be heard
POWER-SUPPLY TURN-ON POP PERFORMANCE
5.0
4.5
4.0
3.5
Power
Supply
3.0
Outputs
2.5
2.0
1.5
1.0
0.5
0
0
50
100
150
200
Time (ms)
Figure 70. THS4521 Power-Supply Turn-On Pop
Performance
POWER-SUPPLY TURN-OFF POP PERFORMANCE
5.0
4.5
4.0
3.5
Outputs
3.0
Power
Supply
2.5
2.0
1.5
1.0
0.5
0
0
50
100
150
200
Time (ms)
Figure 71. THS4521 Power-Supply Turn-Off Pop
Performance
With no tone input, Figure 72 shows the pop performance using the PD pin to enable the THS4521, and
Figure 73 shows performance using the PD pin to disable the device. Again, the transients during power on and
off show that no audible pop should be heard. It should also be noted that the turn on/off times are faster using
the PD pin technique.
PD ENABLE POP PERFORMANCE
5.0
4.5
4.0
PD
3.5
Outputs
3.0
2.5
2.0
1.5
1.0
0.5
0
0
50
100
150
200
Time (ms)
Figure 72. THS4521 PD Pin Enable Pop Performance
PD DISABLE POP PERFORMANCE
5.0
4.5
PD
4.0
3.5
Outputs
3.0
2.5
2.0
1.5
1.0
0.5
0
0
50
100
150
200
Time (ms)
Figure 73. THS4521 PD Pin Disable Pop Performance
The power on/off pop performance of the THS4521, whether by switching the power supply or when using the
power-down function built into the chip, shows that no special design should be required to prevent an audible
pop.
Copyright © 2008–2015, Texas Instruments Incorporated
Submit Documentation Feedback
33
Product Folder Links: THS4521 THS4522 THS4524