SA7267

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.1

2006.05.25

Http: www.silan.com.cn

Page 4 of 11

(Continued)

Pin No.

HSIP-11

HSIP-15

Pin Name

I/O

Pin Description

6

8

-Vs

--

Negative power

7

9

IN+(2)

I

Inverting Input 2

8

10

IN-(2)

I

Non inverting input 2

9

12

GND

--

Ground

10

13

IN-(1)

I

Non inverting input 1

11

14

IN+(1)

I

Inverting input 1

1,4,11,15

NC

--

Not connected

FUNCTION DESCRIPTION

MUTE STAND-BY FUNCTION

The MUTE/ST-BY controls the amplifier status by two different thresholds, referred to +Vs.

Ø

When MUTE/ST-BY higher than +Vs - 2.5V, the amplifier is in Stand-by mode and the final stage

generators are off.

Ø

When MUTE/ST-BY is between +Vs - 2.5V and +Vs- 6V, the final stage current generators are

switched on and the amplifier is in mute mode

Ø

When MUTE/ST-BY is lower than +Vs - 6V, the amplifier is in play mode.

Power Dissipation and Heat Sinking

The SA7267 must always be operated with a heat sink. In order to determine the appropriate heat sink for a

given application, the power dissipation of the SA7267 in that application must be known. When the load is a

resistor, the maximum average power of the IC is approximately:

Where VS is the total power supply voltage across the SA7267, RL is the load resistance and PQ is the

quiescent power dissipation of the amplifier. The above equation is only an approximation which assumes an

“ideal”class B output stage and constant power dissipation in all other parts of the circuit. The curves of “Power

Dissipation vs. Power Output”give a better representation of the behavior of the SA7267 with various power

supply voltages and resistors. As an example, if the SA7267 is operated on a ±15V power supply with a

resistance of 4

Ω, it can develop up to 24.5W of internal power dissipation. If the die temperature is to remain

below 150

°C for ambient temperatures up to 50°C, the total junction-to-ambient thermal resistance must be less

than:

(150

°C 50°C)/24.5W 4.1°C/W

Using Rth(j-c) = 2

°C /W, the sum of the case-to-heat-sink interface thermal resistance and the heat-sink-to-

ambient thermal resistance must be less than 2.1

°C/W. The case-to-heat-sink thermal resistance of the HSIP-11

package varies with the mounting method used. A metal-to-metal interface will be about 1

°C /W if use the thermal

resistance, and about 1.2

°C /W if not.

If a mica insulator is used, the thermal resistance will be about 1.6

°C /W lubricated and 3.4°C /W dry. For this

example, we assume a lubricated mica insulator between the SA7267 and the heat sink. The heat sink thermal

resistance must then be less than:

4.1

°C/W-2°C/W-1.6°C/W 0.5°C/W