TS4962M_07 STMICROELECTRONICS [STMicroelectronics], TS4962M_07 Datasheet - Page 30

• Manufacturer Part Number: TS4962M_07
• Description: 3W filter-free class D audio power amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Application information
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Decoupling of the circuit
A power supply capacitor, referred to as C
The TS4962M has a typical switching frequency at 250kHz and output fall and rise time
about 5ns. Due to these very fast transients, careful decoupling is mandatory.
A 1µF ceramic capacitor is enough, but it must be located very close to the TS4962M in
order to avoid any extra parasitic inductance created an overly long track wire. In relation
with dI/dt, this parasitic inductance introduces an overvoltage that decreases the global
efficiency and, if it is too high, may cause a breakdown of the device.
In addition, even if a ceramic capacitor has an adequate high frequency ESR value, its
current capability is also important. A 0603 size is a good compromise, particularly when a
4Ω load is used.
Another important parameter is the rated voltage of the capacitor. A 1µF/6.3V capacitor
used at 5V, loses about 50% of its value. In fact, with a 5V power supply voltage, the
decoupling value is about 0.5µF instead of 1µF. As C
THD+N in the medium-high frequency region, this capacitor variation becomes decisive. In
addition, less decoupling means higher overshoots, which can be problematic if they reach
the power supply AMR value (6V).
Wake-up time (t
When the standby is released to set the device ON, there is a wait of about 5ms. The
TS4962M has an internal digital delay that mutes the outputs and releases them after this
time in order to avoid any pop noise.
Shutdown time (t
When the standby command is set, the time required to put the two output stages into high
impedance and to put the internal circuitry in shutdown mode, is about 5ms. This time is
used to decrease the gain and avoid any pop noise during shutdown.
Consumption in shutdown mode
Between the shutdown pin and GND there is an internal 300kΩ resistor. This resistor forces
the TS4962M to be in standby mode when the standby input pin is left floating.
However, this resistor also introduces additional power consumption if the shutdown pin
voltage is not 0V.
For example, with a 0.4V standby voltage pin,
shows that you must add 0.4V/300kΩ = 1.3µA in typical (0.4V/273kΩ= 1.46µA in maximum)
to the shutdown current specified in
Single-ended input configuration
It is possible to use the TS4962M in a single-ended input configuration. However, input
coupling capacitors are needed in this configuration. The schematic in
single-ended input typical application.
WU
STBY
)
)
Table 4 on page
S,
is needed to correctly bypass the TS4962M.
Table 2: Operating conditions on page
S
5.
has particular influence on the
Figure 61
shows a
TS4962M
3,