FEATURE
・Anti-Clipping Function (ACF)
・Filter-less Modulation, Eliminating Output Filter
・Output Power
5.5W (VBAT=4.2V, PVDD = 6.5V, RL=4Ω,
THD+N=10%)
3.0W (VBAT=4.2V, PVDD = 6.5V, RL=8Ω,
THD+N=10%)
・Power Supply
-Boost Input VBAT：2.5V to 5.5V
-Boost Output PVDD：VBAT to 7.0V
・Adjustable BOOST Output Voltage
・Class AB / Class D
・Over Current Protection, Thermal Protection,
Low voltage malfunction prevention function
included
・Pb-Free Packages , SOP8L-PP

APPLICATIONS
・Bluetooth Speakers ・Portable Speakers
・2.1 Channel Speakers ・Megaphone
・iphone/ipod/ipod docking ・MP4/GPS
・Tablet PC/Note Book ・Smart Phones
・LCD TV/Monitor ・Portable Gamers

GENERAL DESCRIPTION
HT8691 integrates a boost converter with a
filter-less stereo class D audio power amplifier to
provide 5.5W continuous power into a into a 4Ω
speaker when operating from a Li-battery voltage
boosted to 6.5V. Meanwhile, the boost output
voltage is adjustable.
HT8691 features Anti-Clipping Function (ACF)
which detects output signal clip due to the over
input signal and suppresses the output signal clip
automatically. Also, the ACF function can adapt the
output clip caused by power supply voltage down
with battery. It can significantly improve the sound
quality, creating a very comfortable musical
enjoyment, and to protect the speakers from
overload damage. It also supplies ACF OFF mode.
Class AB amplifier mode is also available for
HT8691. Once the EMI Interference from class D
and Boost Converter becomes an annoying
problem, HT8691 can be changed into Class AB
mode.
HT8691 has a filter-less modulation circuit
which directly drives speakers while realizes low
distortion and low noise characteristics. Thanks to
filter-less, circuit design with fewer external parts
can be made in portable applications.
HT8691 has the independent Shutdown
function which can minimize the power
consumption at standby and MUTE function. As for
protection function, over current protection function
for speaker output terminals, over temperature
protection function, and low supply voltage
malfunction preventing function are also prepared.