LM4840LQ/NOPB National Semiconductor, LM4840LQ/NOPB Datasheet - Page 13

• Manufacturer Part Number: LM4840LQ/NOPB
• Description: IC AMP AUDIO PWR 2.2W STER 28LLP
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM4840LQ/NOPB

• Output Type: 2-Channel (Stereo) with Stereo Headphones
• Max Output Power X Channels @ Load: 2.2W x 2 @ 3 Ohm; 95mW x 2 @ 32 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Depop, Input Multiplexer, Mute, Shutdown, Thermal Protection, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 28-LLP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM4840LQ; LM4840LQ; LM4840LQNOPB; LM4840LQNOPBTR; LM4840LQNOPBTR; LM4840LQTR

Application Information
case when a BTL is connected to the amplifier, the compara-
tor forces the LM4840 to maintain bridged−amplifier opera-
tion. When the HP−Sense pin is externally floated, such as
when headphones are connected to the jack shown in Figure
2 , and internal pull−up forces V
tor’s HP−Sense inputs. This changes the comparator’s out-
put state and enables the headphone function: it turns off
Amp2B, switches Amp2A’s input signal from an audio signal
to the V
bridge-connected loads. Amp1A and Amp1B drive the head-
phones.
Figure 2 also shows the suggested headphone jack electri-
cal connections. The jack is designed to mate with a
FIGURE 2. The ESDAxxxL provides additional ESD protection beyond the 8000V shown in the Absolute Maximum
DD
/2 voltage present on pin 14, and mutes the
DD
on the internal compara-
FIGURE 3. Volume Control Timing Diagram
(Continued)
Ratings for the AMP2A output
13
three−wire plug. The plug’s tip and ring should each carry
one of the two stereo output signals, whereas the sleeve
provides the return to Amp2A. A headphone jack with one
control pin contact is sufficient to drive the HP−Sense pin
when connecting headphones.
A switch can replace the headphone jack contact pin. When
a switch shorts the HP−Sense pin to V
speakers are muted and Amp1A and Amp2A drive a pair of
headphones. When a switch shorts the HP−Sense pin to
GND, the LM4840 operates in bridge mode. If headphone
drive is not needed, short the HP−Sense pin to the −OUTB
pin.
DS200104-74
DS200104-75
DD
, bridge−connected
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