LM4990-2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level

LM4990-2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level.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. 

Circuit Diagram :

  2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level

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.

 Features

Available in space-saving packages: LLP, Exposed-DAP TSSOP, MSOP, and ITL

Ultra low current shutdown mode

Improved pop & click 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

Key Specification

Improved PSRR at 217Hz & 1KHz	62dB
Power Output at 5.0V, 1% THD+N, 4Ω (LD and MH 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)

Applications

• Mobile Phones
• PDAs
• Portable electronic devices

Source: national