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 (LD and
MH 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.