LN4990MM-G

The LN4990 is a differential-input audio power amplifier designed for mobile phones and other portable audio devices with built-in speakers. It delivers stable output of 1.25W into 8Ω loads and 2W into 4Ω loads, with total harmonic distortion plus noise not exceeding 1% at a 5V supply. The LN4990 employs a bridged-load (BTL) topology to provide high-quality audio power amplification while significantly reducing external component count, eliminating the need for output coupling capacitors and bootstrap capacitors. The LN4990 features an integrated standby circuit that enables low-power standby operation, with standby current not exceeding 100nA. An integrated pop-and-click suppression circuit eliminates audible noise during power-up and shutdown transitions. Gain is adjustable via external resistors.

Applications

• Mobile phones
• PDA portable electronic devices

Key features

• Ultra-small packages: WCSP, MSOP
• 100nA low-power shutdown mode
• Wide operating voltage range: 2.2–5.5V
• No clicks or pops during power-up/power-down
• No output coupling capacitors, snubber networks, or bootstrap capacitors required
• Thermal protection
• Fixed internal gain, adjustable external gain
• User-selectable active-high or active-low shutdown