LM48100QMH/NOPB National Semiconductor, LM48100QMH/NOPB Datasheet - Page 17

• Manufacturer Part Number: LM48100QMH/NOPB
• Description: IC AMP AUDIO PWR 1.6W 14ETSSOP
• Manufacturer: National Semiconductor
• Series: Boomer®, PowerWise®r
• Type: Class ABr

Specifications of LM48100QMH/NOPB

• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 1.6W x 1 @ 8 Ohm
• Voltage - Supply: 3 V ~ 5.5 V
• Features: Depop, I²C, Input Multiplexer, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 14-TSSOP Exposed Pad, 14-eTSSOP 14-HTSSOP
• Amplifier Class: AB
• No. Of Channels: 1
• Output Power: 1.3W
• Supply Voltage Range: 3V To 5.5V
• Load Impedance: 8ohm
• Operating Temperature Range: -40°C To +105°C
• Amplifier Case Style: TSSOP
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM48100QMH

SHUTDOWN FUNCTION
The LM48100Q features an I
down mode that disables the device, reducing quiescent cur-
rent consumption to 0.01μA. Set bit B4 (POWER_ON) in the
Mode Control Register to 0 to disable the device. Set B0 to 1
to enable the device.
POWER DISSIPATION
The increase in power delivered by a BTL amplifier leads to
a direct increase in internal power dissipation. The maximum
power dissipation for a BTL amplifier for a given supply volt-
age and load is given by equation (2):
The maximum power dissipation of the TSSOP package is
calculated by equation (3):
where T
θ
mum Ratings.
If the power dissipation for a given operating condition ex-
ceeds the package maximum, either decrease the ambient
temperature, increase air flow, add heat sinking to the device,
or increase the load impedance and/or supply voltage. The
LM48100Q TSSOP package features an exposed die attach
pad (DAP) that can be used to increase the maximum power
dissipation of the package, see Exposed DAP Mounting Con-
siderations.
The LM48100Q features thermal overload protection that dis-
ables the amplifier output stage when the die temperature
exceeds +170°C. See the Thermal Overload Detection sec-
tion.
JA
is the thermal resistance specified in the Absolute Maxi-
P
JMAX
DMAX (PKG)
P
DMAX
is 150°C, T
= 4 x V
= T
JMAX
DD
A
2
/ 2
— T
is the ambient temperature and
π
2
C selectable low power shut-
2
A
R
L
/ θ
JA
(Watts)
(Watts)
(2)
(3)
17
PROPER SELECTION OF EXTERNAL COMPONENTS
Power Supply Bypassing/Filtering
Proper power supply bypassing is critical for low noise per-
formance and high PSRR. Place the supply bypass capaci-
tors as close to the device as possible. Place a 1µF ceramic
capacitor from V
be added as required.
Input Capacitor Selection
Input capacitors may be required for some applications, or
when the audio source is single-ended. Input capacitors block
the DC component of the audio signal, eliminating any conflict
between the DC component of the audio source and the bias
voltage of the LM48100Q. The input capacitors create a high-
pass filter with the input resistors R
high-pass filter is found using Equation (4) below.
Where the value of R
tics Table.
High pass filtering the audio signal helps protect the speakers.
When the LM48100Q is using a single-ended source, power
supply noise on the ground is seen as an input signal. Setting
the high-pass filter point above the power supply noise fre-
quencies, filters out the noise such that it is not amplified and
heard on the output. Capacitors with a tolerance of 10% or
better are recommended for impedance matching and im-
proved PSRR.
Bias Capacitor Selection
The LM48100Q internally generates a V
bias voltage. The BIAS capacitor C
THD+N by reducing noise at the BIAS node. Use a 2.2µF ce-
ramic placed as close to the device as possible.
f = 1 / 2
DD
to GND. Additional bulk capacitance may
IN
π
is given in the Electrical Characteris-
R
IN
C
IN
(Hz)
BIAS
IN
. The -3dB point of the
, improves PSRR and
DD
/2 common-mode
www.national.com
(4)