3

 2007 Semtech Corp.

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SC4503

POWER MANAGEMENT

Parameter

Conditions

Min

Typ

Max

Units

SHDN/SS Switching Threshold

V

1.4

V

Shutdown Input High Voltage

2

V

Shutdown Input Low Voltage

0.4

SHDN/SS Pin Bias Current

V

22

50

µA

V

20

45

V

0.1

Thermal Shutdown Temperature

155

°C

Thermal Shutdown Hysteresis

10

Electrical Characteristics (Cont.)

Unless specified: V

Pin Configuration - TSOT - 23

Ordering Information

IN

FB

GND

SW

SHDN/SS

5

4

1

2

3

Top View

Top Mark

Package

SC4503TSKTRT

BH00

TSOT-23

SC4503EVB

Evaluation Board

Notes:

(1) Available in tape and reel only. A reel contains 3,000 devices.

(2) Available in lead-free package only. Device is WEEE and

RoHS compliant.

Pin

Pin Name Pin Functions

1SW

Collector of the internal power transistor. Connect to the boost inductor and the freewheeling

diode. The maximum switching voltage spike at this pin should be limited to 34V.

2

GND

Ground. Tie to ground plane.

3FB

The inverting input of the error amplifier. Tie to an external resistive divider to set the output volt-

age.

4

SHDN/SS

Shutdown and Soft-start Pin. Pulling this pin below 0.4 shuts down the converter. Applying more

than 2V at this pin enables the SC4503. An external resistor and an external capacitor con-

nected to this pin soft-start the switching regulator. The SC4503 will try to pull the SHDN/SS pin

below its 1.4V switching threshold regardless of the external circuit attached to the pin if VIN

is below the under-voltage lockout threshold. Tie this pin through an optional resistor to IN or

to the output of a controlling logic gate if soft-start is not used. See Applications Information for

more details.

5IN

Power Supply Pin. Bypassed with capacitor close to the pin.

Pin Descriptions - TSOT -23

5-LEAD TSOT-23