This output stage adapts the bias current of the receiver
to the user's listening environment. In relatively loud
environments, the receiver is fully biased, similar to a
traditional class A amplifier. However, as the loudness
of the environment decreases, the bias current of the
receiver adjusts to a minimum level required to cleanly
pass the signal. At the same time, the system maintains
adequate headroom should the amplitude of the signal
suddenly increase.
By adapting the bias of the output
stage to the requirements of the signal being
processed, significant current savings can be realized
compared to traditional class A amplifiers.
The rate at which the bias adapts is associated with a
capacitor connected from pad CC of the hybrid to
ground. For optimum performance, it is recommended
that a 0.22 μF capacitor be used.
The two low noise
preamplifiers, Stage A and Stage B, can be used as
Volume Control and Gain Trim elements, or Stage A as
a filter shaping element and Stage B as the Volume
Control. As the output stage is current drive, frequency
shaping is relatively easy via the addition of a capacitor
across the receiver.
Features
Complete linear system
Current mode class H output stage
Current drive power amp
Low distortion / low noise
Low amplifier current (190mA typical)
Small size for CIC applications
RoHS compliant hybrid
Standard Packaging
Hybrid typical dimensions:
0.180 in x 0.075 in x 0.055 in
(4.57 mm x 1.91 mm x 1.40 mm)
Block Diagram
To see this Block Diagram in higher resolution please click on the image.
