RT9108NL datasheet(4/13 Pages) RICHTEK

4 / 13 page

RT9108NL

DS9108NL-01

June 2012

www.richtek.com

is a registered trademark of Richtek Technology Corporation.

Operation

The RT9108NL is a 9W (per channel) efficient Class-D

audio power amplifier for driving bridged-tied stereo

speakers. The RT9108NL uses the three-level modulation

scheme (BD model) that allows operation without the

classic LC reconstruction filter when the amplifier drives

is driving an inductive load. The internal close-loop

modulator enables the negative error feedback, which

improves the THD+N of output signal.

An adjustable power limiter is included in the modulator

to protect the load speaker. The adjustable power limiter

allows the user to set a

“virtual” voltage rail lower than

the chip supply to limit the amount of current through the

speaker.

RT9108NL has protection from over current conditions

caused by a short circuit on the output stage. The short

circuit protection fault is reported on the FAULT pin as a

low state. The amplifier outputs are switched to a Hi-Z

state when the short circuit protection latch is engaged.

The latch can be cleared by cycling the SD pin through

the low state. If automatic recovery from the short circuit

protection latch is desired, connect the FAULT pin directly

to the SD pin. This allows the FAULT pin function to

automatically drive the SD pin low which clears the short-

circuit protection latch.

The RT9108NL can drive stereo speakers as low as 4

Ω.

The high efficiency of the RT9108NL, 88%, eliminates the

need for an external heat sink when playing music.

RT9108NL Arkusz danych(PDF) 4 Page - Richtek Technology Corporation