EVAL-SSM2160EB View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-SSM2160EB' PDF : 16 Pages View PDF
SSM2160/SSM2161
V+
10µF
REF
OUT
10µF
0.1µF
1
V+
SSM2160
2
AGND
CHnIN
VREF
3
0.1µF 12 V–
13
DGND
Figure 16. Single Supply Operation with VREF Buffer
Signal Chain Considerations
The SSM2160 is capable of providing an extremely wide control
range, from –127 dB of attenuation (limited only by the noise
floor) to +31 dB of gain. When configuring the system, the
SSM2160 should be in the signal chain where input signals allow
the minimum VCA gain to be used, thus ensuring the lowest
distortion operation. In consumer products, sources that
supply line level signals include FM/AM Tuner, Phono Preamp,
Cassette Deck, CD, Laserdisc, VCR, LINE, AUX and Micro-
phone Preamp. Figure 17 shows a typical application where the
SSM2160 has been placed between a surround-sound decoder
and the power amplification stages. This allows the user to
adjust both volume and balance between six speakers through the
use of the Master and Channel controls.
FM/AM TUNER
PHONO PREAMP
CASSETTE DECK
COMPACT DISK
LASER DISK
VCR
MICROPHONE
MUX
SURROUND
SOUND
DECODER
LINE LEVEL INPUTS – STEREO PAIRS
POWER AMPS
SSM2160
VOLUME AND
BALANCE
CONTROLS
TO
SPEAKERS
Figure 17. Typical Signal Chain Using the SSM2160
Digital Control Range Plan
The SSM2160 may be modelled as six ganged potentiometers
followed by individual programmable gain channel amplifiers, as
shown in Figure 18. In actuality, each channel’s signal level is
set by a VCA that can give gain or attenuation, depending upon
the control voltage supplied. The input potentiometers have a
maximum gain 0 dB (unity), a minimum gain of –127 dB, and
change in 1 dB steps. The channel amplifiers each have mini-
mum gain of 0 dB and a maximum gain of +31 dB and also
change in 1 dB steps. The data settings for the attenuation of
the master “potentiometer” and the channel “amplifier” are
shown in Table II.
INPUT
MASTER
0dB
–127dB
OUTPUT
31dB 0dB
CHANNEL
Figure 18. Potentiometer Representation of SSM2160
(One Channel Only)
Table II. Master and Channel Control
Data
dB
Hex
Binary
Master Min Atten
0
7F
Max Atten
–127
00
1111111
0000000
Channel Max Gain
+31
00
Midgain
+15
10
Min Gain
0
1F
00000
10000
11111
When using Channel controls as balance controls, the center
would be with Channel = 10h (or 0Fh if desired). Increasing the
gain to the maximum would occur at Channel = 00h. Reducing
the gain to minimum would occur at Channel = 1Fh.
SELECTION
7-BIT MASTER DAC
5-BIT CHANNEL DAC 1
5-BIT CHANNEL DAC 2
5-BIT CHANNEL DAC 3
5-BIT CHANNEL DAC 4
5-BIT CHANNEL DAC 5
5-BIT CHANNEL DAC 6
NO DAC SELECTED
MSB
LSB MSB
ADDRESS MODE
ADDRESS
LSB
DATA MODE
DATA
1X XXX0 0 0 0
1X XXX0 0 1 01X
1X XXX0 1 0 01X
1X XXX0 1 1 01X
1X XXX1 0 0 01X
1X XXX1 0 1 01X
1X XXX1 1 0 01X
1 X X X X 1 1 1 0 1 XX X X X X
X = "DON'T CARE"
SHADED AREA IS DATA
0 = MUTE,
1 = UN-MUTE
Figure 19. Interface Characteristics, DAC Address/Data Decoding Truth Table
REV. 0
–9–
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