LM4891IBP/NOPB

Audio Amplifiers Overview

The LM4891IBP/NOPB is a 1-watt audio power amplifier from the Boomer series, designed for mobile phones and portable devices. It operates on a 2.2V to 5.5V supply and delivers 1W into an 8Ω BTL load at 5V with less than 1% THD+N. Key electrical parameters include a quiescent current of 4mA (max 10mA) at 5V, shutdown current of 0.1µA, and PSRR of 62dB at 217Hz. The device features thermal shutdown protection and requires no output coupling capacitors.

Audio Amplifiers Feature Summary

• Ultra-low current shutdown mode minimizes power consumption when disabled.
• Advanced pop and click circuitry eliminates noise during turn-on and turn-off transitions.
• Bridge-tied load (BTL) configuration drives capacitive loads without output coupling capacitors.
• Internal thermal shutdown protects the device from overheating.

Audio Amplifiers Applications

• Mobile phones
• Personal Digital Assistants (PDAs)
• Portable electronic devices

Audio Amplifiers Procurement Notes

Verify component authenticity through authorized channels as this part is obsolete. Confirm package type matches design requirements since multiple packages were available. Check datasheet revisions for any parameter updates. Ensure ESD precautions are followed during handling due to limited built-in protection.

Audio Amplifiers Selection Notes

Select based on required output power and supply voltage constraints. Consider external gain-setting resistors for system flexibility. Evaluate PCB copper area for thermal management if operating near maximum dissipation limits. Verify input signal levels match the unity-gain stability characteristics.

Audio Amplifiers Part Context

Part of Texas Instruments' Boomer audio power amplifier series. Designed specifically for low-voltage, battery-powered applications where minimal external components and high efficiency are critical. Offers bridge-tied load operation for increased power output compared to single-ended configurations.

Audio Amplifiers Replacement Considerations

LM4891 is obsolete. No direct public substitute part numbers are confirmed in the provided documentation. Designers should consult Texas Instruments for current alternatives or evaluate similar Boomer series amplifiers with compatible pinouts and performance specifications.

Audio Amplifiers FAQ

How is the shutdown function activated?

The shutdown pin must be driven with a logic high voltage (connected to VDD) to minimize supply current draw.

What is the recommended bypass capacitor value?

A 1.0 µF bypass capacitor (CB) is recommended to minimize turn-on pops, though 0.1 µF may function in cost-sensitive designs.

Can the LM4891 drive capacitive loads?

Yes, the BTL output configuration is capable of driving capacitive loads directly.