Datasheet SSM2135 (Analog Devices) - 14
| 制造商 | Analog Devices |
| 描述 | Dual Single-Supply Audio Operational Amplifier |
| 页数 / 页 | 17 / 14 — SSM2135. Digital Volume Control Circuit. Logarithmic Volume Control … |
| 修订版 | G |
| 文件格式/大小 | PDF / 328 Kb |
| 文件语言 | 英语 |
SSM2135. Digital Volume Control Circuit. Logarithmic Volume Control Circuit. 0.1µF. 5V 10µF + 0.1µF. 47µF. DGND. LEFT AUDIO. OUT. 1/2
该数据表的模型线
SSM2135
文件文字版本
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SSM2135 Digital Volume Control Circuit Logarithmic Volume Control Circuit
Working in conjunction with the AD7528 dual 8-bit DAC, Figure 39 shows a logarithmic version of the volume control the SSM2135 makes an efficient audio attenuator, as shown in function. Similar biasing is used. With an 8-bit bus, the AD7111 Figure 38. The circuit works off a single 5 V supply. The DACs provides an 88.5 dB attenuation range. Each bit resolves a 0.375 dB are biased to a 2 V reference level, which is sufficient to keep attenuation. Refer to the AD7111 data sheet for attenuation levels the internal R-2R ladder switches of the DACs operating prop- for each input code. erly. This voltage is also the optimal midpoint of the SSM2135
5V 0.1µF
common-mode and output swing range. With the circuit as
5V 10µF + 0.1µF
shown in Figure 38, the maximum input and output swing is
3 14 16 47µF
1.25 V rms. Total harmonic distortion measures a respectable
DGND V R LEFT AUDIO DD FB 1 V I IN IN OUT 1/2 LEFT AUDIO
0.01% at 1 kHz and 0.1% at 20 kHz. The frequency response at
AD7111 SSM2135 OUT 47µF
any attenuation level is flat to 20 kHz.
D1 AGND 2 10 5V 0.1µF
Each DAC can be controlled independently via the 8-bit parallel data bus. The attenuation level is linearly controlled by the
3 14 16
binary weighting of the digital data input. Total attenuation
47µF RIGHT AUDIO DGND VDD RFB 1 IN V I IN OUT 1/2
ranges from 0 dB to 48 dB.
AD7111 RIGHT AUDIO SSM2135 OUT AGND 47µF D1 3 2 AD7528 DATA IN 10 2kΩ 5V AND 10µF + 0.1µF CONTROL 10 5V 5V RFBA 0.1µF LEFT 2 V AUDIO IN REFA OUT A 1/2 100Ω LEFT AUDIO 1/2 7.5kΩ DAC A SSM2135 OUT 2V SSM2135 47µF 2V 1µF 5kΩ
41 0
DATA IN
00349-
6 DAC A/
Figure 39. Single-Supply Logarithmic Volume Control
DAC B CONTROL 15 SIGNAL CS 19 16 WR RFBB RIGHT 18 20 V AUDIO IN REFB OUT B 1/2 RIGHT AUDIO DACB SSM2135 1 OUT 47µF 2kΩ VDD DGND 5V 17 5 5V 0.1µF 100Ω 1/2 0.1µF 7.5kΩ 2V SSM2135 2V 5V 1µF 5kΩ
0 04 49- 03 0 Figure 38. Digital Volume Control Rev. G | Page 13 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 Digital Volume Control Circuit Logarithmic Volume Control Circuit
Working in conjunction with the AD7528 dual 8-bit DAC, Figure 39 shows a logarithmic version of the volume control the SSM2135 makes an efficient audio attenuator, as shown in function. Similar biasing is used. With an 8-bit bus, the AD7111 Figure 38. The circuit works off a single 5 V supply. The DACs provides an 88.5 dB attenuation range. Each bit resolves a 0.375 dB are biased to a 2 V reference level, which is sufficient to keep attenuation. Refer to the AD7111 data sheet for attenuation levels the internal R-2R ladder switches of the DACs operating prop- for each input code. erly. This voltage is also the optimal midpoint of the SSM2135
5V 0.1µF
common-mode and output swing range. With the circuit as
5V 10µF + 0.1µF
shown in Figure 38, the maximum input and output swing is
3 14 16 47µF
1.25 V rms. Total harmonic distortion measures a respectable
DGND V R LEFT AUDIO DD FB 1 V I IN IN OUT 1/2 LEFT AUDIO
0.01% at 1 kHz and 0.1% at 20 kHz. The frequency response at
AD7111 SSM2135 OUT 47µF
any attenuation level is flat to 20 kHz.
D1 AGND 2 10 5V 0.1µF
Each DAC can be controlled independently via the 8-bit parallel data bus. The attenuation level is linearly controlled by the
3 14 16
binary weighting of the digital data input. Total attenuation
47µF RIGHT AUDIO DGND VDD RFB 1 IN V I IN OUT 1/2
ranges from 0 dB to 48 dB.
AD7111 RIGHT AUDIO SSM2135 OUT AGND 47µF D1 3 2 AD7528 DATA IN 10 2kΩ 5V AND 10µF + 0.1µF CONTROL 10 5V 5V RFBA 0.1µF LEFT 2 V AUDIO IN REFA OUT A 1/2 100Ω LEFT AUDIO 1/2 7.5kΩ DAC A SSM2135 OUT 2V SSM2135 47µF 2V 1µF 5kΩ
41 0
DATA IN
00349-
6 DAC A/
Figure 39. Single-Supply Logarithmic Volume Control
DAC B CONTROL 15 SIGNAL CS 19 16 WR RFBB RIGHT 18 20 V AUDIO IN REFB OUT B 1/2 RIGHT AUDIO DACB SSM2135 1 OUT 47µF 2kΩ VDD DGND 5V 17 5 5V 0.1µF 100Ω 1/2 0.1µF 7.5kΩ 2V SSM2135 2V 5V 1µF 5kΩ
0 04 49- 03 0 Figure 38. Digital Volume Control Rev. G | Page 13 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