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.