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Rainbow Electronics MAX8719 User Manual

Page 8

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MAX8718/MAX8719

Current Limit

Output current is limited to 210mA (typ). The current
limit exceeds the 100mA (min) safe operating limit. The
output can be shorted to ground for 30 seconds without
damaging the part.

Thermal-Overload Protection

When the junction temperature exceeds T

J

= +165°C,

an internal thermal sensor sends a signal to the shut-
down logic, turning off the pass transistor and allowing
the IC to cool. The thermal sensor turns the pass tran-

sistor on again after the IC’s junction temperature cools
by 20°C (typ), causing the output to pulse on and off
during continuous thermal-overload conditions.

Operating Region and Power Dissipation

Maximum power dissipation depends on the thermal
resistance of the case and circuit board, the tempera-
ture difference between the die junction and ambient
air, and the rate of airflow. The device’s power dissipa-
tion is P = I

OUT

x (V

IN

- V

OUT

). The power dissipation at

+70°C ambient is 1951mW (see the Absolute Maximum

High-Voltage, Low-Power Linear Regulators for
Notebook Computers

8

_______________________________________________________________________________________

V

CC

5/3

(MAX8718)

FB

(MAX8719)

SHDN

BIAS

REF

CURRENT

LIMIT

IN

OUT

MAX8718
MAX8719

GND

PGOOD

DELAY

THRESHOLD

THERMAL

SHUTDOWN

Figure 3. MAX8718/MAX8719 Functional Diagram