Datasheet

f
s
+
6.6
ROSC COSC
t
startup
+ 8.2 ms ) 2 100 kW C11
TPA3001D1
SLOS398E –DECEMBER 2002–REVISED AUGUST 2010 www.ti.com
DIFFERENTIAL INPUT
The differential input stage of the amplifier cancels any noise that appears on both input lines of the channel. To
use the TPA3001D1 EVM with a differential source, connect the positive lead of the audio source to the INP
input and the negative lead from the audio source to the INN input. To use the TPA3001D1 with a single-ended
source, ac ground the INN input through a capacitor and apply the audio signal to the INP input. In a
single-ended input application, the INN input should be ac-grounded at the audio source instead of at the device
input for best noise performance.
SWITCHING FREQUENCY
The switching frequency is determined using the values of the components connected to ROSC (pin 20) and
COSC (pin 21) and may be calculated with Equation 8:
(8)
The frequency may be varied from 225 kHz to 275 kHz by adjusting the values chosen for ROSC and COSC.
SHUTDOWN OPERATION
The TPA3001D1 employs a shutdown mode of operation designed to reduce supply current (I
CC
) to the absolute
minimum level during periods of nonuse for battery-power conservation. The SHUTDOWN input terminal should
be held high during normal operation when the amplifier is in use. Pulling SHUTDOWN low causes the outputs to
mute and the amplifier to enter a low-current state, I
CC(SD)
= 1 mA. SHUTDOWN should never be left
unconnected, because amplifier operation would be unpredictable.
Ideally, the device should be held in shutdown when the system powers up and brought out of shutdown once
any digital circuitry has settled. However, if SHUTDOWN is to be left unused, the terminal may be connected
directly to V
CC
.
USING LOW-ESR CAPACITORS
Low-ESR capacitors are recommended throughout this application section. A real (as opposed to ideal) capacitor
can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor
minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance
the more the real capacitor behaves like an ideal capacitor.
START-UP TIME
The start-up time can be calculated with Equation 9:
(9)
where C11 is the value of the bypass capacitor as shown in Figure 30.
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