TS4621ML STMICROELECTRONICS [STMicroelectronics], TS4621ML Datasheet - Page 26

• Manufacturer Part Number: TS4621ML
• Description: High-performance class-G stereo headphone amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Application information
Note:
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audio band DC/DC switching frequency keeps the audio quality at a high level (distortion,
noise, etc…).
Figure 65. Efficiency comparison
Most audio signals have a crest factor higher than 6 dB (10 dB on average), which means
that most of the time the music level is low. In this case, the setting of the internal DC/DC
converters is low (1.2 V) and in this way, helps to minimize the power dissipation.
When the audio signal amplitude increases due to a peak or louder music, the setting of the
internal DC/DC converters increases to 1.9 V, automatically increasing the output dynamic
range. This 1.9 V value remains until the end of the decay time.
Figure 66
Figure 66. Class-G operating with a music sample
HPVDD/PVSS voltages are created internally by DC/DC converters. To avoid destruction of
the TS4621ML power amplifier, do not connect any external power supply on these pins.
shows a music sample played at high levels.
100
0.1
10
1
0.1
Both channels enabled
RL = 32 Ω , F = 1KHz
Vcc = 3.6V, Ta = 25 C
Crest Factor = 3dB
Doc ID 023181 Rev 1
Total Output Power (mW)
1
TS4621ML
Class G
TS4601
Class AB
HPVDD
High 1.9V
HPVDD
Low 1.2V
Music
Sample
PVSS
Low -1.2V
PVSS
High -1.9V
10
TS4621ML