Datasheet
LM4936
SNAS269A –APRIL 2005–REVISED APRIL 2013
www.ti.com
A
VD
= 2(R
F
+ R
BS
) / R
i
(10)
Using the component values shown in Figure 3 (R
F
= 20kΩ, R
BS
= 20kΩ, and C
BS
= 0.068µF), a first-order, -6dB
pole is created at 120Hz. Assuming R
i
= 20kΩ, the low frequency differential gain is 4V/V or 12dB. The input (C
i
)
and output (C
OUT
) capacitor values must be selected for a low frequency response that covers the range of
frequencies affected by the desired bass-boost operation.
VOLUME CONTROL
The LM4936 has an internal stereo volume control whose setting is a function of the digital values in the V4 – V0
bits. See Table 4.
The LM4936 volume control consists of 31 steps that are individually selected. The range of the steps, are from
0dB - 78dB. The gain levels are 1dB/step from 0dB to -6dB, 2dB/step from -6dB to -36dB, 3dB/step from -36dB
to -47dB, 4dB/step from -47dB to -51dB, 5dB/step from -51dB to -66dB, and 12dB to the last step at -78dB.
Table 4. Volume Control Table
Serial Number V4 V3 V2 V1 V0 Gain (dB)
0 0 0 0 0 0 –90
1 0 0 0 0 1 –90
2 0 0 0 1 0 –68
3 0 0 0 1 1 –63
4 0 0 1 0 0 –57
5 0 0 1 0 1 –51
6 0 0 1 1 0 –47
7 0 0 1 1 1 –45
8 0 1 0 0 0 –42
9 0 1 0 0 1 –39
10 0 1 0 1 0 –36
11 0 1 0 1 1 –34
12 0 1 1 0 0 –32
13 0 1 1 0 1 –30
14 0 1 1 1 0 –28
15 0 1 1 1 1 –26
16 1 0 0 0 0 –24
17 1 0 0 0 1 –22
18 1 0 0 1 0 –20
19 1 0 0 1 1 –18
20 1 0 1 0 0 –16
21 1 0 1 0 1 –14
22 1 0 1 1 0 –12
23 1 0 1 1 1 –10
24 1 1 0 0 0 –8
25 1 1 0 0 1 –6
26 1 1 0 1 0 –5
27 1 1 0 1 1 –4
28 1 1 1 0 0 –3
29 1 1 1 0 1 –2
30 1 1 1 1 0 –1
31 1 1 1 1 1 0
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