TPA6139A2_16 Datasheet, PDF (10/28 Pages) Texas Instruments – 25mW Headphone Amplifier

TPA6139A2
SLOS700C – JANUARY 2011 – REVISED APRIL 2016
Feature Description (continued)
9-12 V
Conventional solution
+
+
Co
OPAMP
+
-
Mute Circuit
Output
GND
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VDD
VDD/2
MUTE
3.3 V
-
TPA6139A2
TPA 6139 A 2 Solution
Output
DirectPath
VDD
GND
VSS
MUTE
Figure 9. Conventional and DirectPath Line Driver
The DirectPath amplifier architecture operates from a single supply but makes use of an internal charge pump to
provide a negative voltage rail.
Combining the user-provided positive rail and the negative rail generated by the IC, the device operates in what
is effectively a split supply mode.
The output voltages are now centered at zero volts with the capability to swing to the positive rail or negative rail.
Combining this with the built-in click and pop reduction circuit, the DirectPath amplifier requires no output DC-
blocking capacitors.
The bottom block diagram and waveform of Figure 9 illustrate the ground-referenced line-driver architecture.
9.4 Device Functional Modes
9.4.1 Internal Undervoltage Detection
The TPA6139A2 contains an internal precision band-gap reference voltage and a comparator used to monitor
the supply voltage, VDD. The internal VDD monitor is set at 2.8 V with 200-mV hysteresis.
1.25 V
Bandgap
VDD 10
AMP Enable
Comparator
Internal VDD
10
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