TS4995EIJT View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TS4995EIJT

1.2 W fully differential audio power amplifier with selectable standby and 6 dB fixed gain

STMicroelectronics 

TS4995

Application information

Note:

Therefore, the power dissipated by each amplifier is:

Pdiss = Psupply - Pout (W)

Pdiss

=

2--------2----V----C----C--

π RL

Pout–Pout

and the maximum value is obtained when:

∂----P----d----i-s----s---

∂Pout

=

0

and its value is:

Equation 3

Pdiss max

=

2 Vcc2

π2RL

(W)

This maximum value is only dependent on the power supply voltage and load values.

The efficiency is the ratio between the output power and the power supply:

Equation 4

η=

-----P----o---u---t---

Psupply

=

--π----V----p---e---a---k-

4VCC

The maximum theoretical value is reached when Vpeak = VCC, so:

η= -π--- = 78.5%

4

The maximum die temperature allowable for the TS4995 is 125° C. However, in case of

overheating, a thermal shutdown set to 150° C, puts the TS4995 in standby until the

temperature of the die is reduced by about 5° C.

To calculate the maximum ambient temperature Tamb allowable, you need to know:

● The power supply voltage, VCC

● The load resistor value, RL

● The package type, Rthja

Example: VCC=5 V, RL=8 Ω, Rthja-flipchip= 100° C/W (100 mm2 copper heatsink).

Using the power dissipation formula given above in Equation 3, this gives a result of:

Pdissmax = 633mW

Tamb is calculated as follows:

Equation 5

Tamb= 125° C – Rthja × Pdissmax

Therefore, the maximum allowable value for Tamb is:

Tamb = 125-100x0.633=61.7° C

19/26

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