Datasheet SSM2135 (Analog Devices) - 13

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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,
1/2
increasing the supply voltage to 12 V also improves the output
100µF SSM2135
drive to more than 25 mA.
AUDIO IN DIFFERENTIAL AUDIO OUT V+ = 5V TO 12V 1kΩ R3 1kΩ 2.5kΩ 10kΩ 1/2 C1 SSM2135 0.1µF 2V R1 2.5kΩ 5kΩ R4 5V 1/2 100kΩ V+ SSM2135 OUTPUT 0.1µF 5V 2 C2 100Ω 1/2 R2 1µF 7.5kΩ
38
SSM2135 5kΩ
-0 49 03 0
1µF 5kΩ
36 0 9- Figure 37. Pseudoreference Generator 34 00 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 DIFFERENTIAL 20kΩ AUDIO IN 20kΩ 10µF 1/2 10Ω SSM2135 2V AUDIO 5V OUT 1µF 7.5kΩ 100Ω 5V 1/2 SSM2135 5kΩ 0.1µF
7 -03
2.5kΩ
00349 Figure 36. Single-Supply Balanced Differential Line Receiver Rev. G | Page 12 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