TPA2054D4 Datasheet, PDF (20/30 Pages) Texas Instruments – 1.4 W/CH STEREO CLASS-D AUDIO SUBSYSTEM WITH DirectPath™ HEADPHONE AMPLIFIER AND 3:1 INPUT MUX

TPA2054D4
SLOS607 – APRIL 2009 ..................................................................................................................................................................................................... www.ti.com
INPUT VOLUME CONTROL
The TPA2054D4 has three independent volume controls: one for the Mono differential input, one for the
STEREO1 input pair (LIN_1 and RIN_1), and one for the STEREO2 input pair (LIN_2 and RIN_2). Each has 5-bit
(32-step) resolution and are audio tapered; gain step changes are smaller at higher gain settings. The volume
control range is –66 dB to +24 dB.
Total input-to-output gain is input gain plus the headphone or Class-D amplifier gain. The Class-D amplifier gain
is fixed at +6 dB. The headphone gain is programmable at +6 dB (default), 0 dB, –6 dB, and –14 dB. Headphone
gain is set via the I2C interface.
The Mono Input volume control byte is located at Register 4, Bits 4 – 0. The Stereo Input 1 volume control byte is
located at Register 5, Bits 4–0. The Stereo Input 2 volume control byte is at Register 6, Bits 4–0. Gain matching
between the left and right channels for STEREO1 and STEREO2 is within 0.1 dB. In differential input mode, the
Stereo Input 1 byte (Register 5) controls left and right channel gain.
The input impedance to the TPA2054D4 decreases as channel gain increases. See the Operating
Characteristics section for specifications. Values listed in Audio Taper Gain Values table are nominal values.
AUDIO TAPER GAIN VALUES
For input channel volume controls
VOLUME CONTROL
REGISTER BYTE: VOL[4:0]
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
NOMINAL GAIN
–66 dB
–56 dB
–48 dB
–44 dB
–40 dB
–36 dB
–32 dB
–28 dB
–24 dB
–21 dB
–18 dB
–15 dB
–12 dB
–9 dB
–6 dB
–3 dB
VOLUME CONTROL
REGISTER BYTE: VOL[4:0]
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
NOMINAL GAIN
0 dB
+3 dB
+5 dB
+7 dB
+9 dB
+11 dB
+13 dB
+15 dB
+17 dB
+18 dB
+19 dB
+20 dB
+21 dB
+22 dB
+23 dB
+24 dB
20
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