DRV632 Datasheet, PDF (11/23 Pages) Texas Instruments – DirectPath™, 2-VRMS Audio Line Driver With Adjustable Gain

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VSUP_MO
R1
R3
R2
DRV632
SLOS681B – JANUARY 2011 – REVISED AUGUST 2015
UVP
Figure 7. UVP Resistor Divider
9.4 Device Functional Modes
9.4.1 Using the DRV632 as a Second-Order Filter
Several audio DACs used today require an external low-pass filter to remove out-of-band noise. This is possible
with the DRV632, as it can be used like a standard operational amplifier. Several filter topologies can be
implemented, both single-ended and differential. In Figure 8, multi-feedback (MFB) with differential input and
single-ended input are shown.
An ac-coupling capacitor to remove dc content from the source is shown; it serves to block any dc content from
the source and lowers the dc gain to 1, helping to reduce the output dc offset to a minimum.
To calculate the component values, use the TI WEBENCH^® Filter Designer (www.ti.com/filterdesigner).
Differential Input
R2
Inverting Input
R2
C3 _R1
R3
–IN
C2
+IN
C3 ^R1
R3
C1
–
DRV632
+
C1
C3 _R1
R3
–IN
C2
C1
–
DRV632
+
R2
Figure 8. Second-Order Active Low-Pass Filter
The resistor values should have a low value for obtaining low noise, but should also have a high enough value to
get a small-size ac-coupling capacitor. With the proposed values of R1 = 15 kΩ, R2 = 30 kΩ, and R3 = 43 kΩ, a
dynamic range (DYR) of 106 dB can be achieved with a 1-μF input ac-coupling capacitor.
9.4.2 Mute Mode
The DRV632 can be muted using the low-active Mute pin (pin 5). The click-and-pop suppression capacity
ensures that when the mute mode is used, it does not generate an additional click or pop.
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