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SOFT START

The TPS61040/41 limits this inrush current by increasing the current limit in two steps starting from

I

LIM

4

for 256

cycles to

I

LIM

ENABLE

UNDERVOLTAGE LOCKOUT

ABSOLUTE MAXIMUM RATINGS

DISSIPATION RATING TABLE

TPS61040

TPS61041

SLVS413C – OCTOBER 2002 – REVISED AUGUST 2007

All inductive step-up converters exhibit high inrush current during start-up if no special precaution is made. This

can cause voltage drops at the input rail during start up and may result in an unwanted or early system shut

down.

Pulling the enable (EN) to ground shuts down the device reducing the shutdown current to 1

μA (typical).

Because there is a conductive path from the input to the output through the inductor and Schottky diode, the

output voltage is equal to the input voltage during shutdown. The enable pin needs to be terminated and should

not be left floating. Using a small external transistor disconnects the input from the output during shutdown as

shown in Figure 18.

An undervoltage lockout prevents misoperation of the device at input voltages below typical 1.5 V. When the

input voltage is below the undervoltage threshold, the main switch is turned off.

over operating free-air temperature (unless otherwise noted)

(1)

UNIT

(2)

–0.3 V to 7 V

30 V

Continuous power dissipation

See Dissipation Rating Table

Operating junction temperature

–40

°C to 150°C

Storage temperature

–65

°C to 150°C

Lead temperature (soldering 10 seconds)

260

°C

(1)

Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating

conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2)

All voltage values are with respect to network ground terminal.

DERATING

FACTOR

PACKAGE

POWER RATING

ABOVE

POWER RATING

POWER RATING

DBV

250

°C/W

357 mW

3.5 mW/

°C

192 mW

140 mW

DRV

76

°C/W

1300 mW

13 mW/

°C

688 mW

500 mW

4

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