TA1101B Datasheet, PDF (9/13 Pages) Tripath Technology Inc. – Stereo 10W (4Ω) Class-T™ Digital Audio Amplifier using Digital Power Processing™ Technology

TECHNICAL INFORMATION
Amplifier Gain
The gain of the TA1101B is set by the ratio of two external resistors, R_I and R_F, and is given by the
following formula:
V_{O = 12} R _F
V_I
R_I
where V_I is the input signal level and V_O is the differential output signal level across the speaker.
9 Watts of RMS output power results from an 8.485V RMS signal across an 8Ω speaker load. If
R_F = R_I, then 9 Watts will be achieved with 0.707V RMS of input signal.
8.485V_RMS = (R_L ∗ P_O ) = (8Ω ∗ 9W )
Protection Circuits
The TA1101B is guarded against over-temperature and over-current conditions. When the device goes
into an over-temperature or over-current state, the FAULT pin goes to a logic HIGH state indicating a fault
condition. When this occurs, the amplifier is muted, all outputs are TRI-STATED, and will float to 1/2 of
V_DD.
Over-temperature Protection
An over-temperature fault occurs if the junction temperature of the part exceeds approximately 155°C.
The thermal hysteresis of the part is approximately 45°C, therefore the fault will automatically clear when
the junction temperature drops below 110°C.
Over-current Protection
An over-current fault occurs if more than approximately 7 amps of current flows from any of the amplifier
output pins. This can occur if the speaker wires are shorted together or if one side of the speaker is
shorted to ground. An over-current fault sets an internal latch that can only be cleared if the MUTE pin is
toggled or if the part is powered down. Alternately, if the MUTE pin is connected to the FAULT pin, the
HIGH output of the FAULT pin will toggle the MUTE pin and automatically reset the fault condition.
Overload
The OVERLOADB pin is a 5V logic output. When low, it indicates that the level of the input signal has
overloaded the amplifier resulting in increased distortion at the output. The OVERLOADB signal can be
used to control a distortion indicator light or LED through a simple buffer circuit, as the OVERLOADB
cannot drive an LED directly.
TA1101B, Rev. 2.2, 08.17.00
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