Datasheet

TPA0202
2-W STEREO AUDIO POWER AMPLIFIER
SLOS205B – FEBRUARY 1998 – REVISED DECEMBER 2000
37
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
mute and shutdown modes
The TPA0202 employs both a mute and a shutdown mode of operation designed to reduce supply current, I
DD
,
to the absolute minimum level during periods of nonuse for battery-power conservation. The SHUTDOWN input
terminal should be held low during normal operation when the amplifier is in use. Pulling SHUTDOWN high
causes the outputs to mute and the amplifier to enter a low-current state, I
DD
= 5 µA. SHUTDOWN or MUTE
IN should never be left unconnected because amplifier operation would be unpredictable. Mute mode alone
reduces I
DD
to 1.5 mA.
Table 3. Shutdown and Mute Mode Functions
INPUTS
†
OUTPUT
AMPLIFIER STATE
SE/BTL
HP/LINE
MUTE IN SHUTDOWN MUTE OUT
INPUT OUTPUT
Low Low Low Low Low L/R Line BTL
X X — High — X Mute
X X High — High X Mute
Low High Low Low Low L/R HP BTL
High Low Low Low Low L/R Line SE
High High Low Low Low L/R HP SE
†
Inputs should never be left unconnected.
X = do not care
using low-ESR capacitors
Low-ESR capacitors are recommended throughout this applications 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.
5-V versus 3.3-V operation
The TPA0202 operates over a supply range of 3 V to 5.5 V. This data sheet provides full specifications for 5-V
and 3.3-V operation, as these are considered to be the two most common standard voltages. There are no
special considerations for 3.3-V versus 5-V operation as far as supply bypassing, gain setting, or stability goes.
For 3.3-V operation, supply current is reduced from 19 mA (typical) to 13 mA (typical). The most important
consideration is that of output power. Each amplifier in TPA0202 can produce a maximum voltage swing of
V
DD
– 1 V. This means, for 3.3-V operation, clipping starts to occur when V
O(PP)
= 2.3 V as opposed to
V
O(PP)
= 4 V at 5 V. The reduced voltage swing subsequently reduces maximum output power into an 8-Ω load
before distortion becomes significant.
Operation from 3.3-V supplies, as can be shown from the efficiency formula in equation 4, consumes
approximately two-thirds the supply power for a given output-power level than operation from 5-V supplies.
When the application demands less than 500 mW, 3.3-V operation should be strongly considered, especially
in battery-powered applications to improve the efficiency.