Specifications in standard type face are for T

ture Range (T

Symbol

Parameter

Conditions

Min

(Note 4)

Typ

(Note 5)

Max

(Note 4)

Units

Th

SHDN1

Buck SHDN Threshold

Output High

1.37

2

V

Output Low

0.8

1.35

Th

SHDN2

Boost SHDN Threshold

Output High

1.37

2

V

Output Low

0.8

1.35

I

SS1

Buck Soft Start Pin Current

6

9.5

12

µA

I

SS2

Boost Soft Start Pin Current

15

19

22

µA

UVP

On Threshold

3.35

3.8

4.0

V

Off Threshold

3.10

3.6

3.9

θ

JA

Thermal Resistance

(Note 9)

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. The machine model is a 200pF capacitor discharged

directly 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 8: Bias current flows into FB pin.

Note 9: Refer to National’s packaging website for more detailed thermal information and mounting techniques for the TSSOP package.

www.national.com

6