Elektronische Bauelemente

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Any changing of specification will not be informed individual

01-Jun-2002 Rev. A

Page

5 of 9

I

Chip Disable

The Chip Disable (Pin 1) can be used to power down the IC to conserve power, or for muting, or both. When at a Logic "0" (0 V to 0.8 V),

the

equivalent to a Logic "0", although good design practice dictates that an input should never be left open. Input impedance at Pin 1 is a

nominal 90 k . The power supply current (when disabled) is shown in Figure 19.

Muting, defined as the change in differential gain from normal operation to muted operation, is in excess of 70 dB. The turn-off time of

the audio output, from the application of the CD signal, is <2.0 us, and turn on-time is 12 ms-15 ms. Both times are independent of C1,C2,

When the

Power Dissipation

which can safely be dissipated within the

The power dissipated within the

SPW34119D, in a given application, is found from the following equation:

the load resistance.

Figures 8 to 10, along with Figures 11 to 13 (distortion curves), and a peak working load current of D200 mA, define the operating range

for the

SPW34119D. The operating range is further defined in terms of allowable load power in Figure 14 for loads of 8.0

, 16 and 32 . The

left (ascending) portion of each of the three curves is defined by the power level at which 10% distortion occurs. The center flat portion of

each curve is defined by the maximum output current capability of the

SPW34119D. The right (descending) portion of each curve is defined

by the maximum internal power dissipation of the IC at 25 : . At higher ambient temperatures, the maximum load power must be reduced

according to the above equations. Operating the device beyond the current and junction temperature limits will degrade long term

reliability.

Layout Considerations

Normally a snubber is not needed at the output of the

SPW34119D, unlike many other audio amplifiers. However, the PC board layout,

stray capacitances, and the manner in which the speaker wires are configured, may dictate otherwise. Generally, the speaker wires should

be twisted tightly, and not more than a few inches in length.

Characteristics Curve

Fig 1. Turn-On Time versus C1, C2 at Power-On

Fig 2. Amplifier #1 Open Loop Gain and Phase

SPW34119D

Low Power Audio

Amplifier