LM48557TL/NOPB National Semiconductor, LM48557TL/NOPB Datasheet - Page 17

• Manufacturer Part Number: LM48557TL/NOPB
• Description: IC AMP AUDIO PWR MONO AB 16USMD
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM48557TL/NOPB

• Output Type: 1-Channel (Mono)
• Voltage - Supply: 2.7 V ~ 4.5 V
• Features: Depop, Differential Inputs, I²C, Mute, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 16-MicroSMD
• Operational Class: Class-AB
• Audio Amplifier Output Configuration: 1-Channel Mono
• Audio Amplifier Function: Speaker
• Single Supply Voltage (typ): Not RequiredV
• Dual Supply Voltage (typ): 3V
• Power Supply Requirement: Dual
• Rail/rail I/o Type: No
• Power Supply Rejection Ratio: 80dB
• Single Supply Voltage (min): Not RequiredV
• Single Supply Voltage (max): Not RequiredV
• Dual Supply Voltage (min): 1.7/2.7V
• Dual Supply Voltage (max): 4.5V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 16
• Package Type: uSMD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Max Output Power X Channels @ Load: -
• Lead Free Status / Rohs Status: Compliant
• Other names: LM48557TLTR

SINGLE-ENDED INPUT CONFIGURATION
Ground-Referenced Audio Source
The LM48557 input stage is compatible with ground-refer-
enced input sources, such as CODECs with an integrated
headphone amplifier. Connect either input, IN+ or IN- to the
NON-GROUND REFERENCED AUDIO SOURCE
Stereo-to-Mono Conversion
The LM48557 can convert a single-ended stereo signal to a
mono BTL signal (Figure 10). Connect the left and right
FIGURE 9. Single-Ended Input Configuration with a Ground-Referenced Source
FIGURE 10. Single-Ended Stereo-to-Mono BTL Conversion
17
CODEC output, and connect the unused input and VCM to
the CODEC output ground (Figure 9). An input coupling ca-
pacitor in series with the source and device input is recom-
mended to block the CODEC output offset voltage, minimiz-
ing click and pop and zipper noise during volume transitions.
CODEC outputs in parallel through two equal value resistors
to either IN+ or IN-, and connect the unused input and VCM
to the CODEC ground. Select the value of the resistors based
on the desired frequency response created by the combina-
tion of the input resistor and the input coupling capacitor.
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