7

SC2308A

Pin Descriptions

Pin #

Pin Name

Pin Function



COMP

Error Amplifier Output. The voltage at this pin controls the peak switch current. A series RC network from this pin

to ground compensates the control loop.

2

FB

The Inverting Input of the Error Amplifier. Tie to an external resistive divider to set the output voltage.

3

EN

Enable Pin. Pulling this pin below 0.3V shuts down the SC2308A to less than mA of quiescent current. Applying

more than 2V at this pin enables the SC2308A. For normal operation, this pin can be tied to IN or driven from a

logic gate with V

4

GND

Ground. Tie to the ground plane. The converter output capacitor must be closely bypassed to the ground pin.

5

SW

Collector of the Internal Power Transistor. Connect to a boost inductor and a freewheeling diode. The maximum

switching voltage spike at this pin should be limited to less than 45V.

6

IN

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

7

NC

No connection.

8

NC

No connection.

Block Diagram

REF NOT READY

EA

-

FB

2

IN

6

3

EN

SHUTDOWN

THERMAL

1.22V

+

+

R

Q

S

PWM

-

+

+

+

-

ISEN

ILIM

+

-

18mV

S

GND

4

SW

5

600kHz

OSCILLATOR

J

START

SOFT-

+

SS

SUPPLY

INTERNAL

OC

6.3mΩ

COMP

1

REFERENCE

VOLTAGE

T > 160°C

CLK

SLOPE COMP

Figure 2. SC2308A Block Diagram