SM6800A Datasheet, PDF (7/12 Pages) Nippon Precision Circuits Inc – Class-D Mono Amplifier for Mobile Telephones

SM6800A
FUNCTIONAL DESCRIPTION
Power-down (PDWN)
The device enters power-down mode when PDWN goes LOW. When powered-down, the outputs become high
impedance and the internal oscillation stops. In power-down mode, the MUTEN pin should be held LOW.
Mute (MUTEN)
Mute operation occurs when MUTEN goes LOW. In mute mode, the outputs become high impedance. During
mute operation, the protection circuit operation is disabled, but the outputs are protected against output short
circuits by their high impedance state. When power is applied, MUTEN should be held LOW for a short inter-
val, shown in the timing diagram below, to prevent pop noise from the speaker. Also, applying and releasing
mute operation after power is applied can occur at high speed without generating pop noise.
min. 40msec
PDWN
MUTEN
Note. VREF1 load capacitance = 1µF
Protection Circuit
The protection circuit operates if there is an output short-circuit to the supply, short-circuit to ground, or other
excessive load abnormal condition lasting longer than approximately 1µs. Normal operation resumes after
approximately 5 seconds. When the protection circuit becomes active, the PROT output goes HIGH and the
outputs become high impedance.
NIPPON PRECISION CIRCUITS INC.—7