13/17

STA530

For example in the STA530 the Rth jc is 1°C/W. R case-to-heatsink with grease is about 0.5 °C/W. The maxi-

mum operating junction temperature is 130 °C, which for margin should be derated to 120 °C.

Buck Regulator Heatsink

The Buck regulator heatsink can be designed in a similar manner and does not change by varying power supply.

In general the efficiency will be in the order of 85%. The thermal impedances from the junction(s) to the heatsink

may be lower and the maximum operating temperature will be higher. Usually either the sub or the remaining

channels are tested at full power. The result is that usually the Buck heatsink is about ¼ the size of the linear

heatsink, but this can be strongly affected by the design.

Figure 8. PCBs AND COMPONENTS LAYOUT

SAM261 Specification

Parameter

Rating

Notes

Output Power

Sats @ 8

Ω -

55 Watts @ 10%

Sub @ 4

Ω - 100 Watts @ 10%

See Graphs

THD + N

< 0.05% @ 40 Watts

< 0.05% @ 75 Watts

Measured @ 1KHZ

SNR

-102 dB (relative to full power)

-110 dB (A-weighted)

Channel 5 terminated

Sensitivity

1 VRMS

Amplifier

Crosstalk

-87dB (relative to10W)

Channel 5 @ 10W 1KHz 8

Ω,

Channel 3 input terminated

Main Power Supply Inputs

50Volts @ 2 Amps

Maximum Voltage is 50Vdc

Minimum Voltage is 40Vdc

Aux Power Supply Inputs

+ 24 Volts @ 100mA

-24 Volts @ 100mA

R

th

T

jmax

T

am b

–

P

d

----------------------------------

R

th j c ase

–

R

th cas e to heatsink

–

–

=

4 Supply Connections

4 Pins Harness

Power Supply Connections

9 Pins Harness

Audio Connections

Main DC

Input

VS DC

Input

Mute

Audio

Inputs

Preamplifier PCB

Amplifier PCB