Datasheet SSM2135 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | Dual Single-Supply Audio Operational Amplifier |
| Pages / Page | 16 / 10 — SSM2135. APPLICATIONS INFORMATION. 10kΩ. 8.66kΩ. L_OUT. 35/36. 470µF. … |
| Revision | G |
| File Format / Size | PDF / 305 Kb |
| Document Language | English |
SSM2135. APPLICATIONS INFORMATION. 10kΩ. 8.66kΩ. L_OUT. 35/36. 470µF. VCC. 0.1µF. 1/2. 34/37. GNDA. LEFT. CHANNEL. 10µF. VREF. RIGHT. 8 0.1µF. AGND. AD1845
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Text Version of Document
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SSM2135 APPLICATIONS INFORMATION
The SSM2135 is a low voltage audio amplifier that has exception-
40 10kΩ 8.66kΩ L_OUT
ally low noise and excellent sonic quality even when driving loads
35/36 2 470µF
as small as 25 Ω. Designed for single supply use, the inputs and
VCC 5V 1 0.1µF
output can both swing very close to 0 V. Thus with a supply
3 1/2 34/37 GNDA SSM2135 LEFT
voltage at 5 V, both the input and output swing from 0 V to 4 V.
V+ CHANNEL 10µF 32
Because of this, signal dynamic range can be optimized if the
VREF 0.1µF 10µF RIGHT
amplifier is biased to a 2 V reference rather than at half the
8 0.1µF CHANNEL 5
supply voltage.
7 AGND AD1845 6 1/2
The SSM2135 is unity-gain stable, even when driving into a fair
470µF SSM2135 4
amount of capacitive load. Driving up to 500 pF does not cause
41
31
R_OUT
0 9- any instability in the amplifier. However, overshoot in the
10kΩ 8.66kΩ
34 00 frequency response increases slightly. Figure 31. A Stereo Headphone Driver for Multimedia Sound Codec The SSM2135 makes an excellent output amplifier for 5 V only Figure 32 shows the total harmonic distortion characteristics vs. audio systems such as a multimedia workstation, a CD output frequency driving into a 32 Ω load, which is a very typical amplifier, or an audio mixing system. The amplifier has large impedance for a high quality stereo headphone. The SSM2135 output swing even at this supply voltage because it is designed has excellent power supply rejection, and, as a result, is tolerant to swing to the negative rail. In addition, it easily drives load of poorly regulated supplies. However, for best sonic quality, the impedances as low as 25 Ω with low distortion. power supply should be well regulated and heavily bypassed to The SSM2135 is fully protected from phase reversal for inputs minimize supply modulation under heavy loads. A minimum of going to the negative supply rail. However, internal ESD protec- 10 μF bypass is recommended. tion diodes turn on when either input is forced more than 0.5 V
1 VS = 5V
below the negative rail. Under this condition, input current in
80kHz LOW-PASS FILTER
excess of 2 mA may cause erratic output behavior, in which case, a current limiting resistor should be included in the offending
0.1
input if phase integrity is required with excessive input voltages.
)
A 500 Ω or higher series input resistor prevents phase inversion
% ( N
even with the input pulled 1 V below the negative supply.
+ HD
Hot plugging the input to a signal generally does not present a
T 0.01
problem for the SSM2135, assuming that the signal does not have any voltage exceeding the supply voltage of the device. If so, it is advisable to add a series input resistor to limit the
0.001
current, as well as a Zener diode to clamp the input to a voltage
0.005
2 no higher than the supply.
10 100 1k 10k 20k
03 9-
FREQUENCY (Hz)
34 00
APPLICATION CIRCUITS
Figure 32. Headphone Driver THD + N vs. Frequency into a 32 Ω Load
Low Noise Stereo Headphone Driver Amplifier
Figure 31 shows the SSM2135 used in a stereo headphone driver for multimedia applications with the AD1845, a 16-bit stereo codec. The SSM2135 is equally well suited for the serial-bused AD1849 stereo codec. The impedance of the headphone can be as low as 25 Ω, which covers most commercially available high fidelity headphones. Although the amplifier can operate at up to ±18 V supply, it is just as efficient powered by a single 5 V. At this voltage, the amplifier has sufficient output drive to deliver distortion-free sound to a low impedance headphone. Rev. G | Page 10 of 16 Document Outline FEATURES APPLICATIONS PIN CONNECTIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION APPLICATION CIRCUITS Low Noise Stereo Headphone Driver Amplifier Low Noise Microphone Preamplifier Single Supply Differential Line Driver Single-Supply Differential Line Receiver Pseudoreference Voltage Generator Digital Volume Control Circuit Logarithmic Volume Control Circuit OUTLINE DIMENSIONS ORDERING GUIDE
SSM2135 APPLICATIONS INFORMATION
The SSM2135 is a low voltage audio amplifier that has exception-
40 10kΩ 8.66kΩ L_OUT
ally low noise and excellent sonic quality even when driving loads
35/36 2 470µF
as small as 25 Ω. Designed for single supply use, the inputs and
VCC 5V 1 0.1µF
output can both swing very close to 0 V. Thus with a supply
3 1/2 34/37 GNDA SSM2135 LEFT
voltage at 5 V, both the input and output swing from 0 V to 4 V.
V+ CHANNEL 10µF 32
Because of this, signal dynamic range can be optimized if the
VREF 0.1µF 10µF RIGHT
amplifier is biased to a 2 V reference rather than at half the
8 0.1µF CHANNEL 5
supply voltage.
7 AGND AD1845 6 1/2
The SSM2135 is unity-gain stable, even when driving into a fair
470µF SSM2135 4
amount of capacitive load. Driving up to 500 pF does not cause
41
31
R_OUT
0 9- any instability in the amplifier. However, overshoot in the
10kΩ 8.66kΩ
34 00 frequency response increases slightly. Figure 31. A Stereo Headphone Driver for Multimedia Sound Codec The SSM2135 makes an excellent output amplifier for 5 V only Figure 32 shows the total harmonic distortion characteristics vs. audio systems such as a multimedia workstation, a CD output frequency driving into a 32 Ω load, which is a very typical amplifier, or an audio mixing system. The amplifier has large impedance for a high quality stereo headphone. The SSM2135 output swing even at this supply voltage because it is designed has excellent power supply rejection, and, as a result, is tolerant to swing to the negative rail. In addition, it easily drives load of poorly regulated supplies. However, for best sonic quality, the impedances as low as 25 Ω with low distortion. power supply should be well regulated and heavily bypassed to The SSM2135 is fully protected from phase reversal for inputs minimize supply modulation under heavy loads. A minimum of going to the negative supply rail. However, internal ESD protec- 10 μF bypass is recommended. tion diodes turn on when either input is forced more than 0.5 V
1 VS = 5V
below the negative rail. Under this condition, input current in
80kHz LOW-PASS FILTER
excess of 2 mA may cause erratic output behavior, in which case, a current limiting resistor should be included in the offending
0.1
input if phase integrity is required with excessive input voltages.
)
A 500 Ω or higher series input resistor prevents phase inversion
% ( N
even with the input pulled 1 V below the negative supply.
+ HD
Hot plugging the input to a signal generally does not present a
T 0.01
problem for the SSM2135, assuming that the signal does not have any voltage exceeding the supply voltage of the device. If so, it is advisable to add a series input resistor to limit the
0.001
current, as well as a Zener diode to clamp the input to a voltage
0.005
2 no higher than the supply.
10 100 1k 10k 20k
03 9-
FREQUENCY (Hz)
34 00
APPLICATION CIRCUITS
Figure 32. Headphone Driver THD + N vs. Frequency into a 32 Ω Load
Low Noise Stereo Headphone Driver Amplifier
Figure 31 shows the SSM2135 used in a stereo headphone driver for multimedia applications with the AD1845, a 16-bit stereo codec. The SSM2135 is equally well suited for the serial-bused AD1849 stereo codec. The impedance of the headphone can be as low as 25 Ω, which covers most commercially available high fidelity headphones. Although the amplifier can operate at up to ±18 V supply, it is just as efficient powered by a single 5 V. At this voltage, the amplifier has sufficient output drive to deliver distortion-free sound to a low impedance headphone. Rev. G | Page 10 of 16 Document Outline FEATURES APPLICATIONS PIN CONNECTIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION APPLICATION CIRCUITS Low Noise Stereo Headphone Driver Amplifier Low Noise Microphone Preamplifier Single Supply Differential Line Driver Single-Supply Differential Line Receiver Pseudoreference Voltage Generator Digital Volume Control Circuit Logarithmic Volume Control Circuit OUTLINE DIMENSIONS ORDERING GUIDE
