LMC1983 National Semiconductor, LMC1983 Datasheet - Page 8

• Manufacturer Part Number: LMC1983
• Description: Digitally-Controlled Stereo Tone and Volume Circuit with Three Selectable Stereo Inputs
• Manufacturer: National Semiconductor

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Application Information
at lower output levels. If the load impedance is DC-coupled,
an increased quiescent current can flow. Latch-up may occur
if the total emitter current exceeds 5 mA. Thus, maximum
output voltage can be increased and much lower distortion
levels can be achieved using load impedances of at least
25 k .
INPUT IMPEDANCE
The input impedance of pins 4, 5, 6, 23, 24 and 25 is defined
by internal bias resistors and is typically 50 k .
FIGURE 2. Input and Mode Select Circuitry
(Continued)
8
The SELECT IN pins have an input impedance that varies
with the BASS and TREBLE control settings. The input im-
pedance is 100 k at DC and 19 k at 1 kHz when the con-
trols are set at 0 dB. Minimum input impedance of 30.4 k at
DC and 16 k
lected. At 10 kHz the minimum input impedance, with the
tone controls flat, is 6.8 k
maximum boost, is 2.5 k .
at 1 kHz occurs when maximum boost is se-
and, with the tone controls at
DS011279-4