LM4781 Datasheet, PDF (1/25 Pages) National Semiconductor (TI) – Overture™ Audio Power Amplifier Series 3 Channel 35W Audio Power Amplifier with Mute

August 2003
LM4781 Overture^™ Audio Power Amplifier Series
3 Channel 35W Audio Power Amplifier with Mute
General Description
The LM4781 is a three channel audio amplifier capable of
typically delivering 35W per channel of continuous average
output power into an 8Ω load with less than 0.5% THD+N
from 20Hz - 20kHz.
The LM4781 is fully protected utilizing National’s Self Peak
Instantaneous Temperature (˚Ke) (SPiKe^TM) protection cir-
cuitry. SPiKe provides a dynamically optimized Safe Operat-
ing Area (SOA). SPiKe protection completely safeguards the
LM4781’s outputs against over-voltage, under-voltage, over-
loads, shorts to the supplies or GND, thermal runaway and
instantaneous temperature peaks. The advanced protection
features of the LM4781 places it in a class above discrete
and hybrid amplifiers.
Each amplifier of the LM4781 has an independent smooth
transition fade-in/out mute.
The LM4781 can easily be configured for bridge or parallel
operation for higher power and bi-amp solutions.
Key Specifications
j Output Power/Channel with 0.5% THD+N,
1kHz into 8Ω
35W (typ)
j THD+N at 3 x 20W into 8Ω (20Hz - 20kHz) 0.2% (typ)
j THD+N at 3 x 20W into 6Ω (20Hz - 20kHz) 0.3% (typ)
j THD+N at 3 x 20W into 4Ω (20Hz - 20kHz) 0.5% (typ)
j Mute Attenuation
110dB (typ)
j PSRR
85dB (min)
j Slew Rate
9V/µs (typ)
Features
n SPiKe Protection
n Low external component count
n Quiet fade-in/out mute mode
n Wide supply range: 20V - 70V
n Signal-to-Noise Ratio ≥ 93dB (ref. to P_O = 1W)
Applications
n Audio amplifier for component stereo
n Audio amplifier for compact stereo
n Audio amplifier for self-powered speakers
n Audio amplifier for high-end and HD TVs
Typical Application
200673B5
FIGURE 1. Typical Audio Amplifier Application Circuit
SPiKe™ Protection and Overture™ are trademarks of National Semiconductor Corporation.
© 2003 National Semiconductor Corporation DS200673
www.national.com