IC AMP AUDIO PWR 93W D 32TSSOP

TAS5111ADADRG4

Manufacturer Part NumberTAS5111ADADRG4
DescriptionIC AMP AUDIO PWR 93W D 32TSSOP
ManufacturerTexas Instruments
SeriesPurePath Digital™
TypeClass D
TAS5111ADADRG4 datasheet
 


Specifications of TAS5111ADADRG4

Output Type1-Channel (Mono)Max Output Power X Channels @ Load93W x 1 @ 4 Ohm
Voltage - Supply3 V ~ 3.6 VFeaturesDigital Inputs, Mute, Short-Circuit and Thermal Protection, Shutdown
Mounting TypeSurface MountPackage / Case32-TSSOP Exposed Pad, 32-eTSSOP, 32-HTSSOP
Lead Free Status / RoHS StatusLead free / RoHS Compliant  
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If this rule is observed, the TAS5111A does not have
distortion issues due to the output inductors, and
overcurrent conditions do not occur due to inductor
saturation in the output filter.
Another parameter to be considered is the idle current loss
in the inductor. This can be measured or specified as
inductor dissipation (D). The target specification for
dissipation is less than 0.05.
In general, 10-µH inductors suffice for most applications.
The frequency response of the amplifier is slightly altered
by the change in output load resistance; however, unless
tight control of frequency response is necessary (better
than 0.5 dB), it is not necessary to deviate from 10 µH.
The graph in Figure 11 displays the inductance vs current
characteristics of two inductors that are recommended for
use with the TAS5111A.
INDUCTANCE
vs
CURRENT
11
DBF1310A
10
9
DASL983XX−1023
8
7
6
5
4
0
5
10
I − Current − A
Figure 11. Inductance Saturation
The selection of the capacitor that is placed across the
output of each inductor (C2 in Figure 10) is simple. To
complete the output filter, use a 0.47-µF capacitor with a
voltage rating at least twice the voltage applied to the
output stage (PVDD).
This capacitor should be a good quality polyester dielectric
such as a Wima MKS2-047ufd/100/10 or equivalent.
In order to minimize the EMI effect of unbalanced ripple
loss in the inductors, 0.1-µF, 50-V, SMD capacitors (X7R
or better) (C1A and C1B in Figure 10) should be added
from the output of each inductor to ground.
THERMAL INFORMATION
The thermally augmented package provided with the
TAS5111A is designed to be interfaced directly to a
heatsink using a thermal interface compound (for
example, Wakefield Engineering type 126 thermal
grease.) The heatsink then absorbs heat from the ICs and
couples it to the local air. If the heatsink is carefully
designed, this process can reach equilibrium and heat can
be continually removed from the ICs. Because of the
efficiency of the TAS5111A, heatsinks are smaller than
those required for linear amplifiers of equivalent
performance.
R
is a system thermal resistance from junction to
θJA
ambient air. As such, it is a system parameter with roughly
the following components:
D
R
(the thermal resistance from junction to
θJC
case, or in this instance the metal pad)
D
Thermal grease thermal resistance
D
Heatsink thermal resistance
R
has been provided in the General Information
θJC
section.
The thermal grease thermal resistance can be calculated
from the exposed pad area and the thermal grease
manufacturer’s area thermal resistance (expressed in
°C-in
2
/W). The area thermal resistance of the example
thermal grease with a 0.001-inch thick layer is about 0.054
°C-in
2
/W. The approximate exposed pad area is
2
0.0164 in
.
Dividing the example thermal grease area resistance by
the area of the pad gives the actual resistance through the
thermal grease, 3.3 °C/W.
Heatsink thermal resistance is generally predicted by the
heatsink vendor, modeled using a continuous flow
dynamics (CFD) model, or measured.
Thus, for a single monaural IC, the system R
thermal grease resistance + heatsink resistance.
15
The following table indicates modeled parameters for one
TAS5111A IC on a heatsink. The junction temperature is
set at 110°C in both cases while delivering 70 W RMS into
4-Ω loads with no clipping. It is assumed that the thermal
grease is about 0.001 inch thick (this is critical).
Ambient temperature
Power to load
Delta T inside package
Delta T through thermal grease
Required heatsink thermal resistance
Junction temperature
System R θJA
R θJA × power dissipation
TAS5111A
SLES111 − AUGUST 2005
= R
+
θJA
θJC
32-Pin TSSOP
25°C
70 W
12.3°C
21.1°C
8.2°C/W
110°C
13.2°C/W
85°C
13