IL34119 Datasheet, PDF (3/7 Pages) Integral Corp. – Low Power Audio Amplifier

IL34119
A line powered speakerphone, for example, will
require more filtering than a circuit powered by a well
requlated power supply. The amount of rejection is a
function of the capacitors, and the equivalent impedance
looking into FC1 and FC2 (listed in the Electrical
Characteristics as R_FC1 and R_FC2).
In addition to providing filtering, C1 and C2 also
affect the turn-on time of the circuit at power-up, since
the two capacitors must change up through the internal
50 K and 125 K resistors.
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 to 0.8 Volts), the IL34119 is enabled
for normal operation. When Pin 1 is at a Logic “1” (2.0
to V_CC Volts), 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 1.
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 s, and turn on-time
is 12-15 ms. Both times are independent of C1, C2, and
V_CC.
When the IL34119 is disabled, the voltages at FC1
and FC2 do not change as they are powered from V_CC.
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
V_CC and Ground.
POWER DISSIPATION
Figures 2-4 indicate the device dissipation (within the
IC) for various combinations of V_CC, R_L,
MAXIMUM RATINGS^*
and load power.The maximum power which can safely
be dissipated within the IL34119 is found from the
following equation:
P_D = (140C - T_A)/_JA
where T_A is the operating temperature;
and _JA is the package thermal resistance (100C/W for
the standard DIP package, and 180C/W for the surface
mount package).
The power dissipated within the IL34119, in a given
application, is found from the following eguation:
P_D = (V_CC x I_CC) + (I_RMS x V_CC) - (R_L x I_RMS2).
where I_CC is obtained from Figure 1;
and I_RMS is the RMS current at the load;
and R_L is the load resistance.
Figures 2-4, along with Figures 5-7 (distortion
curves), and a peak working load current of 200 mA,
define the operating range for the IL34119. The
operating range is further defined in terms of allowable
load power in Figure 8 for load 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
IL34119. The right (descending) portion of each curve is
defined by the maximum internal power dissipation of
the IC at 25C. At higher operating 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
IL34119, 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 be not more than a few inches in length.
Symbol
Parameter
Value
Unit
V_CC Supply Voltage
I_OUT Maximum Output Current at VO1, VO2
1.0 to +18
V
250
mA
V_IN MaximumInput Voltage(FC1, FC2, CD, V_IN)
-1.0 toV_CC +1.0
V
V_VO Applied Output Voltage to VO1, VO2 when disabled
-1.0 toV_CC +1.0
V
Tstg Storage Temperature Range
-65 to +150
C
* Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.
These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under
“recommended operating conditions” is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
2011, March, Ver. 01