LM4949TLEVAL National Semiconductor, LM4949TLEVAL Datasheet - Page 36

• Manufacturer Part Number: LM4949TLEVAL
• Description: BOARD EVALUATION LM4949TL
• Manufacturer: National Semiconductor
• Series: Boomer®r

Specifications of LM4949TLEVAL

• Amplifier Type: Class D
• Output Type: 2-Channel (Stereo) with Stereo Headphones
• Max Output Power X Channels @ Load: 2.5W x 2 @ 4 Ohm; 190mW x 2 @ 16 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Board Type: Fully Populated
• Utilized Ic / Part: LM4949
• Lead Free Status / RoHS Status: Not applicable / Not applicable

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shutdown/turn on the individual channels. HPR_ON (D3) con-
trols the right channel headphone output, HPL_ON (D2) con-
trols the left channel headphone output, LSR_ON (D1)
controls the right channel loudspeaker output, and LRL_ON
(D0) controls the left channel loudspeaker output. The
PWR_ON bit takes precedence over the individual channel
controls.
Audio Amplifier Gain Setting
The each channel of the LM4949 has two separate gain
stages. Each input stage features a 32 step volume control
with a range of -57dB to +18dB (Table 7). Each speaker out-
put stage has 4 gain settings (Table 8); 0dB, 2dB, 4dB, and
6dB when either a fully differential signal or two single ended
signals are applied on the _IN+ and _IN- pins; and 6dB, 8dB,
36
10dB and 12dB in single-ended input mode with only one sig-
nal applied. The headphone gain is not affected by the input
mode. Each headphone output stage has 3 gain settings (Ta-
ble 9), 0dB, -6dB, and -12dB. This allows for a maximum
separation of 24dB between the speaker and headphone out-
puts when both are active.
Calculate the total gain of a given signal path as follows:
Where A
of the output stage, and A
path.
VOL
is the volume control level, A
A
VOL
+ A
TOTAL
OS
= A
is the total gain for the signal
TOTAL
OS
is the gain setting