Dual Single-Supply Audio Operational Amplifier SSM2135 FEATURES PIN CONNECTIONS Excellent sonic characteristics OUT A 1 8 V+ High output drive capability –IN A 2 SSM2135 7 OUT B TOP VIEW 5.2 nV/√Hz equivalent input noise @ 1 kHz +IN A 3 6 –IN B (Not to Scale) V–/GND 4 5 +IN B 0.003% THD + N (V = 1 V p-p @ 1 kHz) OUT 3.5 MHz gain bandwidth Figure 1. 8-Lead Narrow Body SOIC (R Suffix) Unity-gain stable Low cost APPLICATIONS Multimedia audio systems Microphone preamplifiers Headphone drivers Differential line receivers Balanced line drivers Audio ADC input buffers Audio DAC l-V converters and filters Pseudoground generators GENERAL DESCRIPTION The SSM2135 dual audio operational amplifier permits excel- and portable digital audio units, the SSM2135 can perform lent performance in portable or low power audio systems, with preamplification, headphone and speaker driving, and balanced an operating supply range of 4 V to 36 V or ±2 V to ±18 V. line driving and receiving. Additionally, the device is ideal for The unity-gain stable device has very low voltage noise of input signal conditioning in single-supply, Σ-Δ, analog-to- 5.2 nV/√Hz, and total harmonic distortion plus noise below digital converter subsystems such as the AD1877. The SSM2135 0.01% over normal signal levels and loads. Such characteristics makes an ideal single-supply stereo output amplifier for audio are enhanced by wide output swing and load drive capability. digital-to-analog converters (DACs) because of its low noise and distortion. A unique output stage permits output swing approaching the rail under moderate load conditions. Under severe loading, The SSM2135 is available in an 8-lead plastic SOIC package the SSM2135 still maintains a wide output swing with ultralow and is guaranteed for operation over the extended industrial distortion. Particularly well suited for computer audio systems temperature range of −40°C to +85°C. FUNCTIONAL BLOCK DIAGRAM V+ OUTx +INx 9V 9V –INx V–/GND Figure 2. Rev. G Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 ©2003–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 00349-001 00349-002 SSM2135 TABLE OF CONTENTS Features .............................................................................................. 1 Thermal Resistance.......................................................................4 Applications....................................................................................... 1 ESD Caution...................................................................................4 Pin Connections ............................................................................... 1 Typical Performance Characteristics ..............................................5 General Description ......................................................................... 1 Applications Information .............................................................. 10 Functional Block Diagram .............................................................. 1 Application Circuits ................................................................... 10 Revision History ............................................................................... 2 Outline Dimensions....................................................................... 14 Specifications..................................................................................... 3 Ordering Guide .......................................................................... 14 Absolute Maximum Ratings............................................................ 4 REVISION HISTORY 4/11—Rev. F to Rev. G Changes to Applications Information Section, Low Noise Stereo Changes to Figure 36...................................................................... 12 Headphone Driver Amplifier Section, Figure 31, and Figure 32 ........................................................................................................... 10 2/09—Rev. E to Rev. F Changes to Low Noise Microphone Preamplifier Section, Updated Format..................................................................Universal Figure 33, and Figure 34 ................................................................ 11 Changes to Features Section, General Description Section, and Changes to Figure 37...................................................................... 12 Figure 1 Caption ............................................................................... 1 Deleted Spice Macromodel Section ............................................. 12 Changes to Specifications Section Conditions ............................. 3 Changes to Digital Volume Control Circuit Section, Figure 38, Changed A Symbol to A ............................................................. 3 and Figure 39................................................................................... 13 VO V Changes to Supply Current Parameter, Table 1 ............................ 3 Updated Outline Dimensions....................................................... 14 Deleted ESD Ratings Table.............................................................. 3 Changes to Ordering Guide .......................................................... 14 Changes to Figure 4 and Figure 5................................................... 5 Changes to Figure 9.......................................................................... 6 2/03—Rev. D to Rev. E Changes to Figure 15, Figure 13, and Figure 18 ........................... 7 Removed 8-Lead Plastic DIP Package .............................Universal Changes to Figure 21, Figure 24 Caption, and Figure 25 ............ 8 Edits to Thermal Characteristics.....................................................4 Changes to Figure 27 and Figure 28............................................... 9 Edits to Outline Dimensions......................................................... 14 Deleted Figure 5; Renumbered Sequentially............................... 10 Updated Ordering Guide .............................................................. 14 Deleted 18-Bit Stereo CD-DAC Output Amplifier Section...... 10 Rev. G | Page 2 of 16 SSM2135 SPECIFICATIONS VS = 5 V, −40°C ≤ TA ≤ +85°C, unless otherwise noted. Typical specifications apply at TA = 25°C. Table 1. Parameter Symbol Conditions Min Typ Max Unit AUDIO PERFORMANCE Voltage Noise Density e f = 1 kHz 5.2 nV/√Hz n Current Noise Density in f = 1 kHz 0.5 pA/√Hz Signal-To-Noise Ratio SNR 20 Hz to 20 kHz, 0 dBu = 0.775 V rms 121 dBu Headroom HR Clip point = 1% THD + N, f = 1 kHz, RL = 10 kΩ 5.3 dBu Total Harmonic Distortion Plus Noise THD + N A = +1, V = 1 V p-p, f = 1 kHz, 80 kHz LPF V OUT R = 10 kΩ 0.003 % L R = 32 Ω 0.005 % L DYNAMIC PERFORMANCE Slew Rate SR R = 2 kΩ, T = 25°C 0.6 0.9 V/μs L A Gain Bandwidth Product GBW 3.5 MHz Settling Time tS To 0.1%, 2 V Step 5.8 μs INPUT CHARACTERISTICS Input Voltage Range VCM 0 4.0 V Input Offset Voltage VOS VOUT = 2 V 0.2 2.0 mV Input Bias Current IB VCM = 0 V, VOUT = 2 V 300 750 nA Input Offset Current I V = 0 V, V = 2 V 50 nA OS CM OUT Differential Input Impedance Z 4 MΩ IN Common-Mode Rejection CMR 0 V ≤ V ≤ 4 V, f = dc 87 112 dB CM Large Signal Voltage Gain AV 0.01 V ≤ VOUT ≤ 3.9 V, RL = 600 Ω 2 V/μV OUTPUT CHARACTERISTICS Output Voltage Swing High VOH RL = 100 kΩ 4.1 V RL = 600 Ω 3.9 V Output Voltage Swing Low VOL RL = 100 kΩ 3.5 mV R = 600 Ω 3.0 mV L Short-Circuit Current Limit I ±30 mA SC POWER SUPPLY Supply Voltage Range V Single supply 4 36 V S Dual supply ±2 ±18 V Power Supply Rejection Ratio PSRR V = 4 V to 6 V, f = dc 90 120 dB S Supply Current ISY VS = 5 V, VOUT = 2.0 V, no load 2.8 6.0 mA VS = ±18 V, VOUT = 0 V, no load 3.7 7.6 mA Rev. G | Page 3 of 16 SSM2135 ABSOLUTE MAXIMUM RATINGS Table 2. THERMAL RESISTANCE Parameter Rating Supply Voltage θ is specified for the worst-case conditions, that is, a device JA Single Supply 36 V soldered in a circuit board for surface-mount packages. Dual Supply ±18 V Table 3. Input Voltage ±VS Package Type θ θ Unit JA JC Differential Input Voltage 10 V 8-Lead SOIC (R-8) 158 43 °C/W Output Short-Circuit Duration Indefinite Storage Temperature Range −65°C to +150°C Operating Temperature Range −40°C to +85°C ESD CAUTION Junction Temperature Range (TJ) −65°C to +150°C Lead Temperature (Soldering, 60 sec) 300°C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Rev. G | Page 4 of 16 SSM2135 TYPICAL PERFORMANCE CHARACTERISTICS 10 V = 5V S A = +1 V f = 1kHz V = 1V p-p IN R = 10kΩ L 1 80kHz LOW-PASS FILTER 0.1 5V 500µF 0.01 R L 0.001 10 100 1k 10k 2.5V DC LOAD RESISTANCE (Ω) Figure 3. Test Circuit for Figure 4, Figure 5, and Figure 6 Figure 6. THD + N vs. Load (See Figure 3) 1 1 A = +1 V = 5V V S V = 5V f = 1kHz S f = 1kHz V = 2.5V p-p OUT NONINVERTING 80kHz LOW-PASS FILTER R = 100kΩ L 80kHz LOW-PASS FILTER R = 32Ω L 0.1 0.1 R = 10kΩ L 0.01 INVERTING 0.01 0.001 0.0005 0.001 50m 0.1 1 5 0 102030405060 INPUT VOLTAGE (V p-p) GAIN (dB) Figure 4. THD + N vs. Amplitude (See Figure 3) Figure 7. THD + N vs. Gain 1 1 A = +1 V = 5V V S V = 5V A = +1 S V V = 1V p-p f = 1kHz IN 80kHz LOW-PASS FILTER V = 1V p-p IN R = 10kΩ L 80kHz LOW-PASS FILTER 0.1 0.1 R = 32Ω L 0.01 0.01 R = 10kΩ L 0.001 0.0005 0.001 20 100 1k 10k 20k 0 5 10 15 20 25 30 FREQUENCY (Hz) SUPPLY VOLTAGE (V) Figure 5. THD + N vs. Frequency (See Figure 3) Figure 8. THD + N vs. Supply Voltage Rev. G | Page 5 of 16 THD + N (%) THD + N (%) 00349-003 00349-004 00349-005 THD + N (%) THD + N (%) THD + N (%) 00349-008 00349-007 00349-006 SSM2135 10 5 V = 5V V = 5V S S A = +1 T = 25°C V A f = 1kHz R = 10kΩ L 4 1 3 0.1 2 0.01 1 0.001 0 50m 0.1 1 5 1 10 100 1k AMPLITUDE (V p-p) FREQUENCY (Hz) Figure 9. SMPTE Intermodulation Distortion Figure 12. Current Noise Density vs. Frequency 2.0 A = +1 V V = 5V S 1.5 V = 1V p-p IN 1s R = 10kΩ L 1.0 100 90 0.5 0 –0.5 –1.0 10 –1.5 0% –2.0 10 100 1k 10k 100k FREQUENCY (Hz) Figure 10. Input Voltage Noise (20 nV/Div) Figure 13. Frequency Response 30 V = 5V S T = 25°C A 25 5µs 5µs 100 20 90 15 10 5 10 0% 0 20mV 20mV 1 10 100 1k FREQUENCY (Hz) Figure 11. Voltage Noise Density vs. Frequency Figure 14. Square Wave Response (VS = 5 V, AV = +1, RL = ∞) Rev. G | Page 6 of 16 e (nV/ Hz) SMPTE (%) n 00349-010 00349-009 00349-011 AMPLITUDE (dBu) i (pA/ Hz) n 00349-014 00349-012 00349-013 SSM2135 60 50 V = 5V V = 5V S S T = 25°C T = 25°C A A 40 A = +100 V R = 10kΩ L 40 20 30 0 A = +10 –20 V 20 –40 10 –60 A = +1 V –80 0 –100 –105 –10 –120 –140 –20 10 100 1k 10k 100k 1M 10M 1k 10k 100k 1M 10M FREQUENCY (Hz) FREQUENCY (Hz) Figure 15. Crosstalk vs. Frequency Figure 18. Closed-Loop Gain vs. Frequency 140 100 V = 5V V = 5V S S T = 25°C T = 25°C A A 120 80 0 100 60 45 GAIN 80 40 90 PHASE 60 20 135 40 0 180 20 0 –20 225 100 1k 10k 100k 1M 1k 10k 100k 1M 10M FREQUENCY (Hz) FREQUENCY (Hz) Figure 16. Common-Mode Rejection vs. Frequency Figure 19. Open-Loop Gain and Phase vs. Frequency 140 50 V = 5V S V = 5V S A = +1 V R = 2kΩ 45 L 120 T = 25°C A V = 100mV p-p IN T = 25°C A 40 A = +1 100 V 35 80 30 +PSRR NEGATIVE EDGE 60 25 –PSRR 20 40 POSITIVE EDGE 15 20 10 0 5 –20 0 10 100 1k 10k 100k 1M 0 100 200 300 400 500 FREQUENCY (Hz) LOAD CAPACITANCE (pF) Figure 17. Power Supply Rejection Ratio vs. Frequency Figure 20. Small Signal Overshoot vs. Load Capacitance Rev. G | Page 7 of 16 PSRR (dB) COMMON-MODE REJECTION (dB) CROSSTALK (dB) 00349-017 00349-016 00349-015 OPEN-LOOP GAIN (dB) OVERSHOOT (%) CLOSED-LOOP GAIN (dB) PHASE (Degrees) 00349-020 00349-018 00349-019 SSM2135 50 40 V = 5V V = 5V S S A = +1 T = 25°C 45 A V 35 R = 10kΩ L f = 1kHz 40 THD + N = 1% 30 T = 25°C A 35 A = +100 V 25 30 25 20 20 15 A = +10 V 15 10 10 5 5 A = +1 V 0 0 10 100 1k 10k 100k 1M 04 5 10 15 20 25 30 350 FREQUENCY (Hz) SUPPLY VOLTAGE (V) Figure 21. Output Impedance vs. Frequency Figure 24. Output Voltage vs. Supply Voltage 5.0 2.0 5 V = 5V V = 5V S S T = 25°C A A = +1 V f = 1kHz 4 THD + N = 1% 4.5 1.5 +SWING R = 2kΩ L 3 4.0 1.0 +SWING R = 600Ω L –SWING 2 R = 2kΩ L 3.5 0.5 1 –SWING R = 600Ω L 3.0 0 0 –75 –50 –25 0 25 50 75 100 125 1 10 100 1k 10k 100k LOAD RESISTANCE (Ω) TEMPERATURE (°C) Figure 25. Output Swing vs. Temperature and Load Figure 22. Maximum Output Voltage vs. Load Resistance 6 2.0 V = 5V S V = 5V S R = 2kΩ L 0.5V ≤ V ≤4V OUT T = 25°C A 5 A = +1 V 1.5 4 +SLEW RATE 3 1.0 –SLEW RATE 2 0.5 1 0 0 1k 10k 100k 1M 10M –75 –50 –25 0 25 50 75 100 125 FREQUENCY (Hz) TEMPERATURE (°C) Figure 23. Maximum Output Swing vs. Frequency Figure 26. Slew Rate vs. Temperature Rev. G | Page 8 of 16 MAXIMUM OUTPUT (V) MAXIMUM OUTPUT SWING (V) IMPEDANCE (Ω) 00349-021 00349-023 00349-022 POSITIVE OUTPUT SWING (V) OUTPUT VOLTAGE (V) SLEW RATE (V/µs) NEGATIVE OUTPUT SWING (mV) 00349-026 00349-024 00349-025 SSM2135 20 5 V = 5V S V = 3.9V 18 OUT 16 4 14 R = 2kΩ L V = ±18V S V = ±15V S 12 3 10 R = 600Ω L V = +5V S 8 2 6 4 1 2 0 0 –75 –50 –25 0 25 50 75 100 125 –75 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) Figure 27. Open-Loop Gain vs. Temperature Figure 29. Supply Current vs. Temperature 70 5 500 V = 5V S 400 65 4 V = +5V S 300 GBW 60 3 V = ±15V S Φ m 200 55 2 100 50 1 0 –75 –50 –25 0 25 50 75 100 125 –75 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) Figure 28. Gain Bandwidth Product and Phase Margin vs. Temperature Figure 30. Input Bias Current vs. Temperature Rev. G | Page 9 of 16 PHASE MARGIN (Degrees) OPEN-LOOP GAIN (V/µV) GAIN BANDWIDTH PRODUCT (MHz) 00349-027 00349-028 INPUT BIAS CURRENT (nA) SUPPLY CURRENT (mA) 00349-030 00349-029 SSM2135 APPLICATIONS INFORMATION The SSM2135 is a low voltage audio amplifier that has exception- 10kΩ 8.66kΩ 40 L_OUT ally low noise and excellent sonic quality even when driving loads 2 35/36 470µF V 5V as small as 25 Ω. Designed for single supply use, the inputs and CC 1 0.1µF 3 1/2 output can both swing very close to 0 V. Thus with a supply 34/37 SSM2135 GNDA LEFT V+ CHANNEL voltage at 5 V, both the input and output swing from 0 V to 4 V. 10µF 32 V Because of this, signal dynamic range can be optimized if the REF 0.1µF 10µF RIGHT amplifier is biased to a 2 V reference rather than at half the CHANNEL 8 0.1µF 5 supply voltage. AGND 7 AD1845 6 1/2 470µF SSM2135 The SSM2135 is unity-gain stable, even when driving into a fair 4 amount of capacitive load. Driving up to 500 pF does not cause 41 R_OUT any instability in the amplifier. However, overshoot in the 10kΩ 8.66kΩ 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 minimize supply modulation under heavy loads. A minimum of The SSM2135 is fully protected from phase reversal for inputs 10 μF bypass is recommended. going to the negative supply rail. However, internal ESD protec- 1 tion diodes turn on when either input is forced more than 0.5 V V = 5V S 80kHz LOW-PASS FILTER below the negative rail. Under this condition, input current in 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 even with the input pulled 1 V below the negative supply. 0.01 Hot plugging the input to a signal generally does not present a 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 10 100 1k 10k 20k no higher than the supply. FREQUENCY (Hz) 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 THD + N (%) 00349-032 00349-031 SSM2135 1 Low Noise Microphone Preamplifier V = 5V S A = 40dB V The 5.2 nV/√Hz input noise in conjunction with low distortion V = 1V rms OUT 80kHz LOW-PASS FILTER make the SSM2315 an ideal device for amplifying low level signals such as those produced by microphones. Figure 34 illustrates a stereo microphone input circuit feeding a multimedia sound codec. The gain is set at 100 (40 dB), although it can be set to 0.1 other gains depending on the microphone output levels. Figure 33 shows the harmonic distortion performance of the preamplifier with 1 V rms output, while operating from a single 5 V supply. The SSM2135 is biased to 2.25 V by the VREF pin of the AD1845 codec. The same voltage is buffered by the 2N4124 transistor to 0.01 provide phantom power to the microphone. A typical electrets 10 100 1k 10k 20k condenser microphone with an impedance range of 100 Ω to FREQUENCY (Hz) 1 kΩ works well with the circuit. This power booster circuit can Figure 33. MIC Preamp THD + N Performance be omitted for dynamic microphone elements. 10kΩ 5V 10µF 100Ω LEFT CHANNEL 2 8 MIC IN 1 29 10µF L_MIC 3 1/2 35/36 5V SSM2135 V CC 4 10kΩ 2kΩ 0.1µF 34/37 5V GNDA 2N4124 32 V REF 10µF 0.1µF RIGHT CHANNEL 10kΩ AD1845 2kΩ MIC IN 10µF 5 28 7 R_MIC 6 1/2 SSM2135 100Ω 10kΩ Figure 34. Low Noise Microphone Preamp for Multimedia Sound Codec Rev. G | Page 11 of 16 THD + N (%) 00349-033 00349-034 SSM2135 Single Supply Differential Line Driver Pseudoreference Voltage Generator Signal distribution and routing is often required in audio systems, For single-supply circuits, a reference voltage source is often particularly portable digital audio equipment for professional required for biasing purposes or signal offsetting purposes. The applications. Figure 35 shows a single-supply line driver circuit circuit in Figure 37 provides a supply splitter function with low that has differential output. The bottom amplifier provides a output impedance. The 1 μF output capacitor serves as a charge 2 V dc bias for the differential amplifier to maximize the output reservoir to handle a sudden surge in demand by the load as swing range. The amplifier can output a maximum of 0.8 V rms well as providing a low ac impedance to it. The 0.1 μF feedback signal with a 5 V supply. It is capable of driving into 600 Ω line capacitor compensates the amplifier in the presence of a heavy termination at a reduced output amplitude. capacitive load, maintaining stability. 1kΩ The output can source or sink up to 12 mA of current with a 5V 10µF + 0.1µF 5 V supply, limited only by the 100 Ω output resistor. Reducing the resistance increases the output current capability. Alternatively, increasing the supply voltage to 12 V also improves the output 1/2 100µF SSM2135 drive to more than 25 mA. AUDIO IN DIFFERENTIAL V+ = 5V TO 12V AUDIO OUT 1kΩ R3 1kΩ 2.5kΩ 10kΩ 1/2 C1 SSM2135 0.1µF R1 2V 2.5kΩ 5kΩ R4 100kΩ 5V 1/2 V+ OUTPUT SSM2135 2 0.1µF 5V C2 100Ω R2 1µF 1/2 7.5kΩ 5kΩ SSM2135 1µF 5kΩ Figure 37. Pseudoreference Generator Figure 35. Single-Supply Differential Line Driver Single-Supply Differential Line Receiver Receiving a differential signal with minimum distortion is achieved using the circuit in Figure 36. Unlike a difference amplifier (a subtractor), the circuit has a true balanced input impedance regardless of input drive levels; that is, each input always presents a 20 kΩ impedance to the source. For best common-mode rejection performance, all resistors around the differential amplifier must be very well matched. Best results can be achieved using a 10 kΩ precision resistor network. 20kΩ 5V 10µF + 0.1µF 20kΩ 1/2 SSM2135 20kΩ 20kΩ DIFFERENTIAL AUDIO IN 20kΩ 10µF 10Ω 1/2 SSM2135 2V AUDIO 5V OUT 1µF 7.5kΩ 5V 100Ω 1/2 SSM2135 5kΩ 0.1µF 2.5kΩ Figure 36. Single-Supply Balanced Differential Line Receiver Rev. G | Page 12 of 16 00349-036 00349-037 00349-038 SSM2135 Digital Volume Control Circuit Logarithmic Volume Control Circuit Figure 39 shows a logarithmic version of the volume control Working in conjunction with the AD7528 dual 8-bit DAC, 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 DGND V R DD FB 1 1.25 V rms. Total harmonic distortion measures a respectable LEFT AUDIO V I IN OUT IN 1/2 LEFT AUDIO AD7111 SSM2135 OUT 0.01% at 1 kHz and 0.1% at 20 kHz. The frequency response at 47µF D1 AGND 2 any attenuation level is flat to 20 kHz. 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 DGND V R DD FB 1 RIGHT AUDIO I IN V OUT IN 1/2 ranges from 0 dB to 48 dB. RIGHT AUDIO AD7111 SSM2135 OUT 47µF AGND D1 3 2 10 2kΩ DATA IN AD7528 AND 5V 10µF + 0.1µF 10 CONTROL 5V 5V R A FB 0.1µF 2 LEFT V A OUT A REF AUDIO IN 1/2 100Ω 7.5kΩ LEFT AUDIO 1/2 DAC A SSM2135 OUT 2V SSM2135 2V 47µF 1µF 5kΩ DATA IN Figure 39. Single-Supply Logarithmic Volume Control 6 DAC A/ DAC B CONTROL 15 SIGNAL CS 19 16 WR R B FB RIGHT 18 20 V B OUT B REF AUDIO IN 1/2 RIGHT AUDIO SSM2135 DACB OUT 1 47µF 2kΩ V DGND DD 5V 5V 17 5 0.1µF 7.5kΩ 100Ω 1/2 0.1µF 2V SSM2135 2V 5V 1µF 5kΩ Figure 38. Digital Volume Control Rev. G | Page 13 of 16 00349-040 00349-041 SSM2135 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 85 6.20 (0.2441) 4.00 (0.1574) 1 5.80 (0.2284) 3.80 (0.1497) 4 0.50 (0.0196) 1.27 (0.0500) 45° BSC 1.75 (0.0688) 0.25 (0.0099) 1.35 (0.0532) 0.25 (0.0098) 8° 0.10 (0.0040) 0° 0.51 (0.0201) COPLANARITY 1.27 (0.0500) 0.10 0.31 (0.0122) 0.25 (0.0098) SEATING 0.40 (0.0157) PLANE 0.17 (0.0067) COMPLIANT TO JEDEC STANDARDS MS-012-AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN. Figure 40. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) ORDERING GUIDE 1 Model Temperature Range Package Description Package Option SSM2135S −40°C to +85°C 8-Lead SOIC_N R-8 SSM2135S-REEL −40°C to +85°C 8-Lead SOIC_N R-8 SSM2135S-REEL7 −40°C to +85°C 8-Lead SOIC_N R-8 SSM2135SZ −40°C to +85°C 8-Lead SOIC_N R-8 SSM2135SZ-REEL −40°C to +85°C 8-Lead SOIC_N R-8 SSM2135SZ-REEL7 −40°C to +85°C 8-Lead SOIC_N R-8 1 Z = RoHS Compliant Part. Rev. G | Page 14 of 16 012407-A SSM2135 NOTES Rev. G | Page 15 of 16 SSM2135 NOTES ©2003–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D00349-0-4/11(G) Rev. G | Page 16 of 16