Specifications in standard type face are for T

ture Range (T

Symbol

Parameter

Conditions

Min

(Note 4)

Typ

(Note 5)

Max

(Note 4)

Units

F

SW

Switching Frequency

R

240

300

360

kHz

R

480

600

720

kHz

I

SHDN1

−5

5

µA

I

SHDN2

−5

5

µA

I

L1

Buck 1 Switch Leakage

Current

V

0.01

5

µA

I

L2

Buck 2 Switch Leakage

Current

V

0.01

5

µA

R

DSON1

Buck 1 Switch R

DSON (Note

9)

I

160

180

300

m

Ω

R

DSON2

Buck 2 Switch R

DSON (Note

9)

I

160

180

300

m

Ω

Th

SHDN1

Buck 1 SHDN Threshold

Output High

1.8

1.36

V

Output Low

1.33

0.7

Th

SHDN2

Buck 2 SHDN Threshold

Output High

1.8

1.36

V

Output Low

1.33

0.7

I

SS1

Buck 1 Soft Start Pin Current

4

9

15

µA

I

SS2

Buck 2 Soft Start Pin Current

4

9

15

µA

UVP

On Threshold

4

3.8

V

Off Threshold

3.6

3.3

θ

JA

Thermal Resistance

(Note 10)

TSSOP, package only

115

˚C/W

Note 1: Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to

be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see the Electrical Characteristics.

regulator will go into thermal shutdown.

Note 3: The human body model is a 100 pF capacitor discharged through a 1.5k

Ω resistor into each pin.

Note 4: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are 100% tested

or guaranteed through statistical analysis. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

All limits are used to calculate Average Outgoing Quality Level (AOQL).

Note 5: Typical numbers are at 25˚C and represent the most likely norm.

Note 6: Duty cycle affects current limit due to ramp generator.

Note 7: Current limit at 0% duty cycle. See TYPICAL PERFORMANCE section for Switch Current Limit vs. Input Voltage.

Note 8: Bias current flows into FB pin.

Note 10: Refer to National’s packaging website for more detailed thermal information and mounting techniques for the TSSOP package.

www.national.com

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