IL34119
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 RFC1 and RFC2).
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 KΩ and 125 KΩ resistors.
and load power.The maximum power which can
safely be dissipated within the IL34119 is found from
the following equation:
PD = (140°C - TA)/θJA
where TA is the operating temperature;
and θJA 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:
PD = (VCC x ICC) + (IRMS x VCC) - (RL x IRMS2).
where ICC is obtained from Figure 1;
and IRMS is the RMS current at the load;
and RL is the load resistance.
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 VCC 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 KΩ. 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 µs, and turn on-time is 12-15 ms. Both times are
independent of C1, C2, and VCC.
When the IL34119 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.
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 Ω, 16 Ω, and 32 Ω. 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.
POWER DISSIPATION
Figures 2-4 indicate the device dissipation (within
the IC) for various combinations of VCC, RL,
MAXIMUM RATINGS*
Symbol
VCC
Parameter
Value
1.0 to +18
Unit
V
Supply Voltage
IOUT
Maximum Output Current at VO1, VO2
MaximumInput Voltage(FC1, FC2, CD, VIN)
Applied Output Voltage to VO1, VO2 when disabled
Storage Temperature Range
mA
V
±250
VIN
-1.0 toVCC +1.0
-1.0 toVCC +1.0
-65 to +150
VVO
V
Tstg
°C
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
3
INTEGRAL [ INTEGRAL CORP. ]
