Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

VIN to GND

-0.3V to 30V

VIN Clamp Continuous Current

5mA

CS to GND

-0.3V to 1.25V

RT to GND

-0.3V to 5.5V

All other pins to GND

-0.3V to 7.0V

ESD Rating (Note 2)

Human Body Model

2kV

Storage Temperature

-65˚C to +150˚C

Operating Junction Temperature

+150˚C

Operating Ratings (Note 1)

VIN Voltage (Note 5)

8V to 30V

Junction Temperature

-40˚C to +125˚C

type apply over the full Operating Junction Temperature Range. Unless otherwise specified: V

Ω.

(Note 3)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

STARTUP CIRCUIT

Start Up Current

Before VCC Enable

18

25

µA

VCC Regulator enable threshold

17

20

23

V

VCC Regulator disable

threshold

7.25

V

VIN ESD Clamp voltage

I = 5mA

30

36

40

V

I

VIN

Operating supply current

COMP = 0VDC

2.5

3.75

mA

VCC SUPPLY

Controller enable threshold

6.5

7

7.5

V

Controller disable threshold

5.3

5.8

6.3

V

VCC regulated output

No External Load

8

8.5

9

V

VCC dropout voltage (VIN -

VCC)

I=5mA

1.7

V

VCC regulator current limit

VCC = 7.5V (Note

4)

15

22

mA

SKIP CYCLE MODE COMPARATOR

Skip Cycle mode enable

threshold

1

75

125

175

mV

Skip Cycle mode hysteresis

5

mV

CURRENT LIMIT

CS limit to OUT delay

CS stepped from 0

to 0.6V, time to OUT

transition low, C

load

=0.

35

ns

CS limit threshold

0.45

0.5

0.55

V

Leading Edge Blanking time

90

ns

CS blanking sinking impedance

35

55

Ω

SOFT-START

V

SS-OCV

SS pin open-circuit voltage

4.3

5.2

6.1

V

Soft-start Current Source

15

22

30

µA

Soft-start to COMP Offset

0.35

0.55

0.75

V

COMP sinking impedance

During SS ramp

60

Ω

OSCILLATOR

Frequency1 (RT = 44.2K)

135

150

165

kHz

Frequency2 (RT = 13.3K)

440

500

560

kHz

Sync threshold

2.4

3.2

3.8

V

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