OBSOLETE

LM4546A

SNOS991E – NOVEMBER 2002 – REVISED APRIL 2013

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ANALOG I/O (continued)

Name

Pin

I / O

Functional Description

Right Stereo Channel Input

This line level input (1 Vrms nominal) is selectable at the right channel of the stereo Input Mux for

conversion by the right channel ADC. It can also be mixed into the right channel of the Stereo Mix 3D

CD_R

20

I

signal at MIX1 under the control of the CD Volume register, 12h. The CD_R level can be muted (along

with CD_L) or adjusted from +12 dB to -34.5 dB in 1.5 dB steps. Stereo Mix 3D is combined into the

Stereo Mix signal at MIX2 for access to the stereo outputs Line Out and Line Level Out.

Mono microphone input

Either MIC1 or MIC2 can be muxed to a programmable boost amplifier with selection by the MS bit (bit

D8) in the General Purpose register, 20h. The boost amplifier gain (0 dB or 20 dB) is set by the 20dB

bit (D6) in the Mic Volume register, 0Eh. Nominal input levels at the two gain settings are 1 Vrms and

0.1 Vrms respectively. The amplifier output is selectable (Record Select register, 1Ah) by either the

MIC1

21

I

right or left channels of the Record Select Mux for conversion on either or both channels of the stereo

ADCs. The amplifier output can also be accessed at the stereo mixer MIX1 (muting and mixing

adjustments via Mic Volume register, 0Eh) where it is mixed equally into both left and right channels of

Stereo Mix 3D for access to the stereo outputs Line Out and Line Level Out. Access to the Mono

analog output is selected by a mux controlled by the MIX bit (D9) in General Purpose register, 20h.

Mono microphone input

Either MIC1 or MIC2 can be muxed to a programmable boost amplifier with selection by the MS bit (bit

D8) in the General Purpose register, 20h. The boost amplifier gain (0 dB or 20 dB) is set by the 20dB

bit (D6) in the Mic Volume register, 0Eh. Nominal input levels at the two gain settings are 1 Vrms and

0.1 Vrms respectively. The amplifier output is selectable (Record Select register, 1Ah) by either the

MIC2

22

I

right or left channels of the Record Select Mux for conversion on either or both channels of the stereo

ADCs. The amplifier output can also be accessed at the stereo mixer MIX1 (muting and mixing

adjustments via Mic Volume register, 0Eh) where it is mixed equally into both left and right channels of

Stereo Mix 3D for access to the stereo outputs Line Out and Line Level Out. Access to the Mono

analog output is selected by a mux controlled by the MIX bit (D9) in General Purpose register, 20h.

Left Stereo Channel Input

This line level input (1 Vrms nominal) is selectable at the left channel of the stereo Record Select Mux

for conversion by the left channel ADC. It can also be mixed into the left channel of the Stereo Mix 3D

LINE_IN_L

23

I

signal at MIX1 under the control of the Line In Volume register, 10h. The LINE_IN_L level can be

muted (along with LINE_IN_R) or adjusted from +12 dB to -34.5 dB in 1.5 dB steps. Stereo Mix 3D is

combined into the Stereo Mix signal at MIX2 for access to the stereo outputs Line Out and Line Level

Out.

Right Stereo Channel Input

This line level input (1 Vrms nominal) is selectable at the right channel of the stereo Input Mux for

conversion by the right channel ADC. It can also be mixed into the right channel of the Stereo Mix 3D

LINE_IN_R

24

I

signal at MIX1 under the control of the Line In Volume register, 10h. The LINE_IN_R level can be

muted (along with LINE_IN_L) or adjusted from +12 dB to -34.5 dB in 1.5 dB steps. Stereo Mix 3D is

combined into the Stereo Mix signal at MIX2 for access to the stereo outputs Line Out and Line Level

Out.

Left Stereo Channel Output

This line level output (1 Vrms nominal) is fed from the left channel of the Stereo Mix signal from MIX2

LINE_OUT_L

35

O

via the Master Volume register, 02h. The LINE_OUT_L amplitude can be muted (along with

LINE_OUT_R) or adjusted from 0 dB to -46.5 dB in 1.5 dB steps.

Right Stereo Channel Output

This line level output (1 Vrms nominal) is fed from the right channel of the Stereo Mix signal from MIX2

LINE_OUT_R

36

O

via the Master Volume register, 02h. The LINE_OUT_R amplitude can be muted (along with

LINE_OUT_L) or adjusted from 0 dB to -46.5 dB in 1.5 dB steps.

Mono Output

This mono line level output (1 Vrms nominal) is fed from either a microphone input (MIC1 or MIC2,

after boost amplifier) or from the mono sum of the left and right Stereo Mix 3D channels from MIX1.

MONO_OUT

37

O

The optional Texas Instruments 3D Sound enhancement can be disabled (default) by the 3D bit (bit

D13) in the General Purpose register, 20h. Choice of input is by the MIX bit (D9) in the same register.

MIX=0 selects a microphone input. Output level can be muted or adjusted from 0 dB to -46.5 dB in 1.5

dB steps via the Mono Volume register, 06h.

10

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