SSM2135S Analog Devices Inc, SSM2135S Datasheet - Page 13

• Manufacturer Part Number: SSM2135S
• Description: IC AMP AUDIO STER CLASS AB 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of SSM2135S

• Slew Rate: 0.9 V/µs
• Mounting Type: Surface Mount
• Rohs Status: RoHS non-compliant
• Amplifier Type: Audio
• Number Of Circuits: 1
• Gain Bandwidth Product: 3.5MHz
• Current - Input Bias: 300nA
• Voltage - Input Offset: 200µV
• Current - Supply: 3.7mA
• Current - Output / Channel: 30mA
• Voltage - Supply, Single/dual (±): 4 V ~ 36 V, ±2 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 2
• Bandwidth: 3.5MHz
• No. Of Pins: 8
• Gain: 126dB
• Supply Voltage Min: 4V
• Peak Reflow Compatible (260 C): No
• Input Bias Current: 300nA
• Output Type: -
• -3db Bandwidth: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Digital Volume Control Circuit
Working in conjunction with the
the SSM2135 makes an efficient audio attenuator, as shown in
Figure 38. The circuit works off a single 5 V supply. The DACs
are biased to a 2 V reference level, which is sufficient to keep
the internal R-2R ladder switches of the DACs operating prop-
erly. This voltage is also the optimal midpoint of the SSM2135
common-mode and output swing range. With the circuit as
shown in Figure 38, the maximum input and output swing is
1.25 V rms. Total harmonic distortion measures a respectable
0.01% at 1 kHz and 0.1% at 20 kHz. The frequency response at
any attenuation level is flat to 20 kHz.
Each DAC can be controlled independently via the 8-bit parallel
data bus. The attenuation level is linearly controlled by the
binary weighting of the digital data input. Total attenuation
ranges from 0 dB to 48 dB.
CONTROL
AUDIO IN
AUDIO IN
DATA IN
SIGNAL
RIGHT
LEFT
15
16
6
18
DAC A/
DAC B
CS
WR
V
V
REF
REF
5V
V
DD
Figure 38. Digital Volume Control
17
AD7528
A
DAC A
B
DACB
0.1µF
R
R
DGND
OUT B
OUT A
FB
FB
A
B
5
1µF
19
20
2V
3
2
1
AD7528
0.1µF
100Ω
SSM2135
SSM2135
5V 10µF + 0.1µF
1/2
1/2
dual 8-bit DAC,
2kΩ
SSM2135
1/2
5V
47µF
47µF
7.5kΩ
RIGHT AUDIO
OUT
LEFT AUDIO
OUT
2V
5kΩ
5V
Rev. G | Page 13 of 16
Logarithmic Volume Control Circuit
Figure 39 shows a logarithmic version of the volume control
function. Similar biasing is used. With an 8-bit bus, the
provides an 88.5 dB attenuation range. Each bit resolves a 0.375 dB
attenuation. Refer to the AD7111 data sheet for attenuation levels
for each input code.
RIGHT AUDIO
LEFT AUDIO
CONTROL
DATA IN
AND
IN
IN
Figure 39. Single-Supply Logarithmic Volume Control
10
47µF
47µF
10
10
DGND
DGND
V
D1
V
D1
3
3
IN
IN
0.1µF
0.1µF
AD7111
AD7111
14
14
V
V
5V
5V
DD
DD
AGND
AGND
16
16
R
R
FB
FB
I
OUT
I
OUT
1µF
2V
1
2
1
2
0.1µF
100Ω
SSM2135
SSM2135
5V
1/2
1/2
10µF + 0.1µF
2kΩ
SSM2135
1/2
5V
47µF
47µF
SSM2135
RIGHT AUDIO
OUT
7.5kΩ
LEFT AUDIO
OUT
2V
5kΩ
AD7111
5V