LM4830

LM4830 Two-Way Audio Amplification System with Volume Control January 1999 LM4830 Two-Way Audio Amplification System with Volume Control General Description The LM4830 is an integrated solution for two-way audio amplification. It contains a bridge-connected audio power amplifier capable of delivering 1W of continuous average power to an 8Ω load with less than 1% THD from a 5V power supply. It also has the capability of driving 100 mW into a single-ended 32Ω impedance for headset operation. There is a 30 dB attenuator in front of a bridged power amplifier with 6 dB of gain. The attenuation is controlled through 4 bits of parallel digital control; 15 steps of 2 dB each. The device also contains a microphone preamp with two selectable inputs. Mic2 is selected when HS is high and A1 is in single-ended mode. Mic1 is selected when HS is low and A1 is in bridged mode. This configuration is optimum for switching between an internal system speaker and external headset with microphone. The device also incorporates a buffer used for driving capacitive loads. The LM4830 also provides a low-current consumption shutdown mode making it optimally suited for low-power portable systems. In addition, the device has an internal thermal shutdown protection mechanism. Key Specifications n n n n THD at 1W cont. avg PO into 8Ω: 1% (max) Instantaneous peak output power: 1.4W Shutdown current: 0.5 µA (typ) Supply voltage range: 2.7V ≤ V DD ≤ 5.5V Features 4-bit digital control for 30 dB of volume ...