3

SCD8657 Rev K 5/15/12

Aeroflex Plainview

The maximum Power dissipation is limited by the thermal shutdown function of each regulator chip in the

VG8657/8658. The graph above represents the achievable power before the chip shuts down. The first line in the

graph represents the maximum power dissipation of the VG8657/8658 with one regulator on (the other off) and the

other line represents both regulators on dissipating equal power. If both regulators are on and one regulator is

dissipating more power that the other, the maximum power dissipation of the VG8657/8658 will fall between the two

lines. This graph is based on the maximum junction temperature of 150°C and a thermal resistance (

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50

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0

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60

80

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140

Case Temperature (°C)

1 Regulator

0

Both Regulators

Maximum Power

Dissipation

(Watts)

FIGURE 2 – MAXIMUM POWER vs CASE TEMPERATURE