GP34119 Datasheet, PDF (4/8 Pages) List of Unclassifed Manufacturers – LOW POWER AUDIO AMPLIFIER

ISSUED DATE :2005/02/18
REVISED DATE :
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 GP34119 is enabled for normal operation. When Pin 1 is at a Logic "1" (2.0 V to VCC V), the IC is disabled. If Pin 1 is open, that is
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,
and VCC.
When the GP34119 is disabled, the voltages at FC1 and FC2 do not change as they are powered from VCC. The outputs, VO1 and
VO2, change to a high impedance condition, removing the signal from the speaker. If signals from other sources are to be applied to the
outputs (while disabled), they must be within the range of VCC and Ground.
Power Dissipation
Figures 8 to 10 indicate the device dissipation (within the IC) for various combinations of VCC, RL, and load power. The maximum power
which can safely be dissipated within the GP34119 is found from the following equation: PD = (140к-TA)/ JA where TA is the ambient
temperature; and JA is the package thermal resistance (100к/W for the standard DIP package.)
The power dissipated within the GP34119, in a given application, is found from the following equation:
PD = (VCC x ICC) + (IRMS x VCC) – (RL x IRMS²) where ICC is obtained from Figure 19; and IRMS is the RMS current at the load; and RL is
the load resistance.
Figures 8 to 10, along with Figures 11 to 13 (distortion curves), and a peak working load current of ̈́200 mA, define the operating range
for the GP34119. 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 GP34119. The right (descending) portion of each curve is defined
by the maximum internal power dissipation of the IC at 25к. 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 GP34119, 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
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