LM4897 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 1.1 Watt Audio Power Amplifier with Fade-In and Fade-Out

May 2003
LM4897
1.1 Watt Audio Power Amplifier with Fade-In and
Fade-Out
General Description
The LM4897 is an audio power amplifier primarily designed
for demanding applications in mobile phones and other por-
table communication device applications. It is capable of
delivering 1.1W of continuous average power to an 8Ω BTL
load with less than 1% distortion (THD+N) from a +5V_DC
power supply.
The LM4897 contains advanced pop and click circuitry that
eliminate noises which would otherwise occur during turn-on
and turn-off transitions. It also contains a fade-in/fade-out
feature that eliminates unnatural sound generated by
asserting/de-asserting the SHUTDOWN pin. The LM4897 is
unity-gain stable and can be configured by external gain-
setting resistors.
The LM4897 features a low-power consumption global shut-
down mode, which is achieved by driving the shutdown pin
with logic low. Additionally, the LM4897 features an internal
thermal shutdown protection mechanism.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4897 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for lower-power portable applications where
minimal space and power consumption are primary require-
ments.
Key Specifications
j Improved PSRR at 5V, 3V, & 217Hz
j Higher P_O at 5V, THD+N = 1%
j Higher P_O at 3V, THD+N = 1%
j Shutdown Current
62dB (typ)
1.1W (typ)
350mW (typ)
0.1µA (typ)
Features
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Unity gain stable
n Ultra low current shutdown mode
n Fade-In/Fade-Out
n BTL output can drive capacitive loads up to 100pF
n Advanced pop and click circuitry eliminates noises
during turn-on and turn-off transitions
n 2.6V - 5.5V operation
n Available in a space-saving SO package
Applications
n Mobile Phones
n PDAs
n Portable electronic devices
Connection Diagrams
Mini Small Outline (MSOP) Package
MSOP Marking
20050930
Top View
Order Number LM4897MM
See NS package Number MUB10A
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2003 National Semiconductor Corporation DS200509
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G - Boomer Family
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