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) (SPiKeTM) protection circuitry.
SPiKe provides a dynamically optimized Safe Operating
Area (SOA). SPiKe protection completely safeguards the
LM4781’s outputs against over-voltage, under-voltage, overloads,
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 PO = 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