NCP1252

http://onsemi.com

2

Vout

NCP1252

Vbulk

Vcc

1

2

3

4

8

6

7

5

100 nF*

*Minimum recommended

decoupling capacitor value

Figure 1. Typical Application

Table 1. PIN FUNCTIONS

Pin No.

Pin Name

Function

Pin Description

1

FB

Feedback

This pin directly connects to an optocoupler collector.

2

BO

Brown−out input

This pin monitors the input voltage image to offer a Brown−out protection.

3

CS

Current sense

Monitors the primary current and allows the selection of the ramp com-

pensation amplitude.

4

Timing element

A resistor connected to ground fixes the switching frequency.

5

GND

−

The controller ground pin.

6

Drv

Driver

This pin connects to the MOSFET gate

7

This pin accepts voltage range from 8 V up to 28 V

8

SSTART

Soft−start

A capacitor connected to ground selects the soft−start duration. The soft

start is grounded during the delay timer

Symbol

Rating

Value

Unit

30

V

Power Supply voltage, Vcc pin, continuous voltage

28

V

Maximum current injected into pin 7

20

mA

Maximum voltage on low power pins (except pin 6, 7)

−0.3 to 10

V

Thermal Resistance Junction−to−Air – PDIP8

131

°C/W

Thermal Resistance Junction−to−Air – SOIC8

169

°C/W

Maximum Junction Temperature

150

°C

Storage Temperature Range

−60 to +150

°C

ESD Capability, HBM model

1.8

kV

ESD Capability, Machine Model

200

V

Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the

Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect

device reliability.

1. This device series contains ESD protection and exceeds the following tests: Human Body Model 1800 V per JEDEC Standard

JESD22−A114E. Machine Model Method 200 V per JEDEC Standard JESD22−A115A.

2. This device contains latch−up protection and exceeds 100 mA per JEDEC Standard JESD78.