LM27403

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SNVS896 A – AUGUST 2013 – REVISED SEPTEMBER 2013

THERMAL INFORMATION

LM27403

RTW (WQFN)

UNITS

24 PINS

Junction-to-ambient thermal resistance

32.7

Junction-to-case (top) thermal resistance

31.2

Junction-to-board thermal resistance

11.2

°C/W

Junction-to-top characterization parameter

0.2

Junction-to-board characterization parameter

11.2

Junction-to-case (bottom) thermal resistance

1.4

(1)

For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

RECOMMENDED OPERATING CONDITIONS

Over operating free-air temperature range (unless otherwise noted)

MIN

NOM

MAX

UNIT

VIN tied to VDD

3.0

5.5

V

VIN

VIN

3.0

20

V

SW

–0.3

20

V

VDD

VDD pin voltage

2.6

4.7

5.5

V

PGOOD

PGOOD pin voltage

0

5.5

V

UVLO/EN

UVLO/EN pin voltage

0

V

SS/TRACK

SS/TRACK pin voltage

0

V

SYNC

SYNC pin voltage

0

5.5

V

RS

RS pin voltage

–0.1

0.1

V

Operating junction temperature

–40

+125

°C

Operating free-air temperature

–40

+125

°C

(1)

Recommended Operating Conditions are conditions under which operation of the device is intended to be functional but does not

guarantee performance limits.

(2)

VDD is the output of the internal linear regulator bias supply. Under normal operating conditions, where VIN is greater than 5.5 V, VDD

must not be tied to any external voltage source. In an application where VIN is between 3.0 V and 5.5 V, connecting VIN to VDD

maximizes the bias supply rail voltage.

(3)

Given the body diode of the low-side MOSFET and the parasitic inductance, the SW voltage should not exceed –3 V in a real

application.

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