SSM2163_15 Datasheet, PDF (11/16 Pages) Analog Devices – Digitally Controlled 8 3 2 Audio Mixer

SSM2163
SSM2163 power supply connections
V_DD
4
4
V_DD
V_DD ⁴
V_CC ¹⁰
10µF ₊
V+
0.1µF
10
V_CC
+
10µF
V+
0.1µF
V_CC ¹⁰
+
10µF
V+
0.1µF
AGND ¹⁷
17
AGND
17
AGND
EXTERNAL
ACOM (NC)
V_SS ²
13
ACOM
V_SS ²
+
10µF
VREF
OUT
0.1µF
ACOM _(NC)
V_SS ²
REFERENCE
V_EE
12
10µF
V–
12
V_EE
12
V_EE
OBSOLETE +
1
DGND
0.1µF
1
DGND
1
DGND
Figure 22a. Dual Supply
Figure 22b. Single Supply
Figure 22c. Single Supply Using External
Reference
stored in the attenuator control registers. To re-enable the
system after a mute, use the address byte to turn on the desired
mixer channel. The selected channel will then operate with the
previously set attenuator value.
Serial Data Input Format
As previously mentioned, data is written to the SSM2163 in two
8-bit bytes. The serial data format is shown in the Address and
Power Supplies and Decoupling
The SSM2163 operates from either single or dual (split) power
supplies. In either case, proper supply decoupling is important
to maximize audio performance.
To reduce noise, separate pins are provided for the digital and
analog power supply connections. These pins should be
connected together (V_DD to V_CC and V_EE to V_SS) as close to the
Data Decoding Truth Table, Figure 3. The first byte sent contains SSM2163 package as possible (Figures 22a, 22b, 22c, power
the channel address and the Left/Right output mixer control bits.
supply connections).
The address byte is identified by the MSB being high.
Single Supply Operation
The second byte contains the data (i.e., the attenuator value).
The SSM2163 will operate with a single power supply of +5 V
The six LSBs of this byte set the attenuation level, from 0 dB to to +14 V. Single supply operation simplifies design and reduces
–63 dB. The MSB of the data byte must be a logic zero.
system cost in multimedia applications, battery powered
The standard format for data sent to the SSM2163 is an address
byte followed by a data (attenuator level) byte. In some cases,
however, only one byte needs to be sent. For example,
systems, and similar designs. The SSM2163 provides about
2 dB of headroom (to 1% THD+N) when operating from a
single +5 V supply.
attenuation levels are not affected by the MUTE input. To turn The key to operating from a single supply is to reference all
a muted channel on, simply send an address byte with the Left analog common connections to a voltage midway between the
or Right mixer bit set. The addressed channel will immediately supply and ground. To simplify single supply operation, the
be enabled, using the previously-set attenuation level.
SSM2163 provides a buffered pseudo-ground reference (ACOM)
Furthermore, once a channel is addressed the attenuation level on Pin 13. This reference, shown in Figure 23, provides a low
can be varied by sending additional data bytes. For example,
impedance output at approximately one half of the supply
fading a channel can be accomplished by simply incrementing
voltage. Connect Analog Ground (Pin 17) to the ACOM output
the data value sent to the SSM2163.
(Pin 13) for single supply operation. To minimize noise caused
Serial Data Output
The MSB of the shift register is available on the serial DATA
by modulation of the pseudo-ground, Pin 13 should be bypassed to
power supply ground with 0.1 µF and 10 µF capacitors.
OUTPUT pin. This output can be connected to the input of
another SSM2163 to permit “daisy-chain” operation. See
Figure 26 for a typical application. The DATA OUTPUT pin
swings between the digital power supply rails (i.e., from V_DD to
V_SS).
Logic Levels
All of the SSM2163 logic inputs have TTL and CMOS
compatible thresholds. However, the allowable voltage range
for these inputs extends from V_DD to V_SS.
REV. 0
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