SSM2161S Просмотр технического описания (PDF) - Analog Devices
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SSM2161S Datasheet PDF : 16 Pages
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SSM2160/SSM2161
APPLICATIONS INFORMATION
General
The SSM2160 and SSM2161 are six and four channel volume
controls intended for multichannel audio applications. While
dual channel controls sufficed for “stereo” applications, the
rapidly emerging home theater “surround sound” and auto
sound venues demand both six and four channel high perfor-
mance controls. The following information applies equally to
the SSM2160 and SSM2161, except where noted. Line level
signals are fed to the six high impedance inputs. The system
microcontroller sets the gain of the six channels via a three or
four wire data bus. In a home theater receiver, the outputs may
be fed to the power amplifiers or buffered and connected to pre-
out/amp-in ports on the rear panel. Refer to Figure 17 for a
typical signal chain using the SSM2160. The Master control
serves the “Volume” control function, and the channel control
serves the “Balance” function. The six channel capability allows
complete control of the front left, front right, center, rear left,
rear right, and sub-bass audio channels.
Power Supplies vs. Signal Levels
The SSM2160 can be operated from dual supplies from ± 5 V to
± 10 V and from single supplies from +10 V to +20 V. The
SSM2161 can be operated from dual supplies from ± 4.25 V to
± 10 V for automotive applications and from single supplies from
+8.5 V to +20 V. In order to keep power dissipation to a
minimum, use the minimum power supply voltages that will
support the maximum input and output signal levels. The peak-
to-peak output signal level must not exceed 1/4 of the total
power supply span, from V+ to V–. This restriction applies for all
conditions of input signal levels and gain/attenuation settings.
Table I shows supply voltages for several typical output signal
levels for both devices. An on-chip buffered voltage divider
provides the correct analog common voltage for single supply
applications.
Table I. Signal Levels vs. Power Supplies
SSM2160
Max Output,
V rms (V p-p)
0.9 (2.5)
1.1 (3.0)
1.3 (3.7)
1.8 (5.0)
Max Output,
dBu
+1.3
+3.0
+4.5
+7.3
Single +VS
10 V
12 V
15 V
20 V
Dual ؎ VS
±5 V
±6 V
± 7.5 V
± 10 V
Max Output,
V rms (V p-p)
0.75 (2.1)
1.1 (3.0)
1.3 (3.7)
1.8 (5.0)
SSM2161
Max Output,
dBu
+1.0
+3.0
+4.5
+7.3
Single +VS
8.5 V
12 V
15 V
20 V
Dual ؎ VS
± 4.25 V
±6 V
± 7.5 V
± 10 V
Dual Power Supplies
As shown in Figure 14, the AGND pin should be connected to
ground and VREF should be left floating. The digital ground pin,
DGND, should always be connected to ground for either single-
or dual-supply configurations. Pins 1 and 12 should each have
a 10 µF capacitor connected to ground, with a 0.1 µF capacitor
placed as close as possible to the SSM2160 device to help
reduce the effects of high frequency power supply noise. When
a switching power supply is used, or if the power supply lines
are noisy, additional filtering of the power supply lines may be
required.
V+
10µF
0.1µF
1
V+
SSM2160
2
AGND
VREF
V–
10µF
12
V–
0.1µF
13
DGND
Figure 14. Dual Supply Configuration
Single Power Supply
When a single supply is used, it is necessary to connect AGND
(Pin 2) to VREF (Pin 3) as shown in Figure 15. VREF supplies a
voltage midway between the V+ and V– pins from a buffered
resistive divider. When supplying this reference to stages ahead
of the SSM2160 (to eliminate the need for input dc blocking
capacitors, for example), the use of an additional external
buffer, as shown in Figure 16 may be necessary to eliminate any
noise pickup.
V+
10µF
10µF
1
V+
SSM2160
0.1µF
2
AGND
3
VREF
0.1µF 12
V–
13
DGND
Figure 15. Single Supply Configuration
–8–
REV. 0
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