VNO – VCC
LA4571MB
SVRR – VCC
Supply voltage, VCC – V
Functional Decription (channl 1 only)
Tape Head Preamplifier
Tape head signal source are connected to the non-
inverting input of the op-amp, negative feedback pream-
plifier.
When PRE MUTE is open, the preamplifier output is
connected to SW OUT1, and when PRE MUTE is HIGH
(VCC ±0.2V at 60µA input current), SW OUT1 is open.
This can be used to switch, or mute, the preamplifier
output.
Supply voltage, VCC – V
The internal circuit of the PRE MUTE pin is shown in
the following figure.
The output pins, PRE OUT1 and SW OUT1, can both
drive a 10kΩ load resistance.
The preamplifier input pin, IN1, the negative feedback
input pin, NF1, and the output pin, PRE OUT, are
biased at 1.8V.
Power Amplifier
The power amplifier stage comprises an amplifier for
each channel and a common amplifier. The power
amplifier outputs are connected internally by 60Ω
resistors to prevent oscillation, as shown in the follow-
ing figure.
When POWER MUTE is LOW (less than 0.3V at
2.5µA input current), the power amplifier output signal
is muted. The power amplifier mute release time is set
by an external capacitor.
No.3534–7/9