TS4990IST STMicroelectronics, TS4990IST Datasheet - Page 20

IC AMP AUDIO PWR 1.2W MONO 8MSOP

TS4990IST

Manufacturer Part Number
TS4990IST
Description
IC AMP AUDIO PWR 1.2W MONO 8MSOP
Manufacturer
STMicroelectronics
Type
Class ABr
Datasheet

Specifications of TS4990IST

Output Type
1-Channel (Mono)
Max Output Power X Channels @ Load
1.2W x 1 @ 8 Ohm
Voltage - Supply
2.2 V ~ 5.5 V
Features
Depop, Differential Inputs, Standby, Thermal Protection
Mounting Type
Surface Mount
Package / Case
8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
For Use With
497-6383 - BOARD DEMO FOR TS4990
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
497-4451-2
Application information
Note:
4.5
20/32
Therefore, the power dissipated by each amplifier is:
and the maximum value is obtained when:
and its value is:
This maximum value is only dependent on power supply voltage and load values.
The efficiency is the ratio between the output power and the power supply:
The maximum theoretical value is reached when V
Decoupling of the circuit
Two capacitors are needed to correctly bypass the TS4990: a power supply bypass
capacitor C
C
an indirect influence on power supply disturbances. With a value for C
expect THD+N levels similar to those shown in the datasheet.
In the high frequency region, if C
on the power supply rail are less filtered.
On the other hand, if C
more filtered.
C
result of PSRR (with input grounded and in the lower frequency region).
If C
If C
to PSRR is substantial.
Note that C
of C
s
b
has particular influence on the THD+N in the high frequency region (above 7 kHz) and
has an influence on THD+N at lower frequencies, but its function is critical to the final
b
b
in
P
is lower than 1 µF, THD+N increases at lower frequencies and PSRR worsens.
is higher than 1 µF, the benefit on THD+N at lower frequencies is small, but the benefit
, the higher the PSRR.
diss
= P
in
s
and a bias voltage bypass capacitor C
has a non-negligible effect on PSRR at lower frequencies. The lower the value
supply
- P
out
s
is higher than 1 µF, those disturbances on the power supply rail are
(W)
s
P
is lower than 1 µF, it increases THD+N and disturbances
diss
η =
max
P
diss
------------------ - =
P
=
P
π
---- - = 78.5%
supply
δP
----------------- - = 0
4
δP
2V
-------------- -
out
π
diss
2
=
out
R
2
CC
2 2V
---------------------- P
L
π R
---------------------- -
πV
PEAK
4V
b
.
CC
L
PEAK
CC
(W)
= V
out
CC
P
, so:
out
s
of 1 µF, you can
TS4990

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