4

Electrical Characteristics (continued)

Pin Descriptions

Pin #

Pin Name

Pin Function



FB

Inverting input of the error amplifier. The FB pin is tied to a resistive divider between the output and ground. The

voltage divider sets the output voltage.

2

BIAS

Anode of the internal bootstrap diode. BIAS also powers the internal control circuit if V

of the DC-DC converter if V

3

BST

Power transistor driver supply. Connect an external bootstrap capacitor from the SW pin to this pin to generate a

drive voltage higher than V

4

SW

The power transistor emitter and the cathode of the freewheeling diode. The SW pin is connected to an inductor

and a bootstrap capacitor.

5

GND

Connect this pin to the PC board power ground plane.

6

IN

Power supply to the SC4530. It must be closely bypassed to the ground pin.

7

NC

No Connection.

8

EN

The enable pin for the SC4530. Driving this pin below 0.2V completely shuts off the SC4530. Applying more than 2V

to this pin enables the SC4530. If not driven from a control circuit, tie this pin to IN.

9

Exposed Pad

The exposed pad at the bottom of the package serves as a thermal contact to the circuit board. It is to be soldered

to the ground plane of the PC board.

SC4530

Parameter

Name

Conditions

Min

Typ

Max

Units

Switch Current Limit

I

LIM

V

0.39

0.50

0.66

A

V

65

mA

Switch Saturation Voltage

I

200

300

mV

Switch Leakage Current

V

2

µA

Switch Minimum Bootstrap Voltage

I

.7

2.2

V

BST Pin Current

I

7.

2

mA

Freewheeling Diode Forward Voltage

V

D

I

700

mV

Freewheeling Diode Reverse Leakage

V

5

µA

Bootstrap Diode Forward Voltage

I

700

mV

Bootstrap Diode Reverse Leakage

V



µA

Notes:

() The inductor current hysteresis is the difference between the switch current limit and the freewheeling diode valley current.

Unless otherwise noted, T