LM4867MT National Semiconductor, LM4867MT Datasheet - Page 10

• Manufacturer Part Number: LM4867MT
• Description: Output-Transient-Free Dual 2.1W Audio Amplifier Plus No Coupling Capacitor Stereo Headphone Function
• Manufacturer: National Semiconductor

Application Information
(Continued)
The LM4867’s pin configuration simplifies the process of
upgrading systems that use the LM4863. Except for its four
MUX function pins, the LM4867’s pin configuration matches
the LM4863’s pin configuration. If the LM4867’s MUX func-
tionality is not needed when replacing an LM4863, connect
the MUX CTRL pin to either V
or ground. To ensure
DD
correct amplifier operation, unused MUX inputs must be
tied to GND. As shown in Table 1, grounding the MUX CTRL
pin selects stereo input 1 (−IN A1 and −IN B1), whereas
applying V
to the MUX CTRL pin selects stereo input 2
DD
(−IN A2 and −IN B2).
The LM4867’s unique headphone sense circuit requires a
dual switch headphone jack. Replace the four-terminal head-
DS200013-57
phone jack used with the LM4863 and LM4873 with the
FIGURE 3. Single-ended output signal (Trace B) is
five-terminal headphone jack, such as the Switchcraft
devoid of transients. The SHUTDOWN pin is driven by
35RAPC4BH3, shown in Figure 4. Connect the +OUT A
a shutdown signal (Trace A). The inverting output
(Amp2A) pin to the five-terminal headphone jack’s sleeve
(Trace C) and the V
output (Trace D) are applied
BYPASS
pin.
across a 32
BTL load.
DS200013-31
FIGURE 4. Typical Audio Amplifier Application Circuit
(Pin out shown for the 24-pin Exposed-DAP LLP package. Numbers in ( ) are for the 20-pin MTE and MT packages.)
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