1FEATURES
2• Available in Space-Saving Packages: WSON,
Exposed-DAP MSOP-PowerPAD, VSSOP, and
DSBGA
• Ultra Low Current Shutdown Mode
• Improved Click and Pop Circuitry Eliminates
Noise During Turn-On and Turn-Off
Transitions
• 2.2 - 5.5V Operation
• No Output Coupling Capacitors, Snubber
Networks or Bootstrap Capacitors Required
• Unity-Gain Stable
• External Gain Configuration Capability
• User Selectable Shutdown High or Low Logic
Level

APPLICATIONS
• Mobile Phones
• PDAs
• Portable Electronic Devices

KEY SPECIFICATIONS
• Improved PSRR at 217Hz & 1KHz: 62dB
• Power Output at 5.0V, 1% THD+N,
– 4Ω (NGZ and DGQ only): 2W (Typ)
• Power Output at 5.0V, 1% THD+N, 8Ω: 1.25W
(Typ)
• Power Output at 3.0V, 1% THD+N, 4Ω: 600mW
(Typ)
• Power Output at 3.0V, 1% THD+N, 8Ω: 425mW
(Typ)
• Shutdown Current: 0.1μA (Typ)

DESCRIPTION
The LM4990 is an audio power amplifier primarily
designed for demanding applications in mobile
phones and other portable communication device
applications. It is capable of delivering 1.25 watts of
continuous average power to an 8Ω BTL load and 2
watts of continuous average power (NGZ and DGQ
only) to a 4Ω BTL load with less than 1% distortion
(THD+N+N) from a 5VDC power supply.
Boomer audio power amplifiers were designed
specifically to provide high quality output power with a
minimal amount of external components. The
LM4990 does not require output coupling capacitors
or bootstrap capacitors, and therefore is ideally suited
for mobile phone and other low voltage applications
where minimal power consumption is a primary
requirement.
The LM4990 features a low-power consumption
shutdown mode. To facilitate this, Shutdown may be
enabled by either logic high or low depending on mode selection. Driving the shutdown mode pin either
high or low enables the shutdown pin to be driven in
a likewise manner to enable shutdown.
The LM4990 contains advanced pop & click circuitry
which eliminates noise which would otherwise occur
during turn-on and turn-off transitions.
The LM4990 is unity-gain stable and can be
configured by external gain-setting resistors.