© Semiconductor Components Industries, LLC, 2005

September, 2005 − Rev. 2

1

Publication Order Number:

NCP1215A/D

NCP1215A

Low Cost Variable OFF

Time Switched Mode Power

Supply Controller

The NCP1215A is a controller for low power off−line flyback

Switched Mode Power Supplies (SMPS) featuring low size, weight

and cost constraints together with a good low standby power

performance. The operating principle uses switching frequency

reduction at light load by increasing the OFF Time. Also, when OFF

Time expands, the peak current is gradually reduced down to

approximately 1/4 of the maximum peak current to prevent from

exciting the transformer mechanical resonances. The risk of acoustic

noise is thus greatly diminished while keeping good standby power

performance.

A low power internal supply block also ensures very low current

consumption at startup without hampering the standby power

performance.

A special primary current sensing technique minimizes the impact

of SMPS switching on control IC operation. The choice of peak

voltage across the current sense resistor allows dissipation to be

further reduced. The negative current sensing technique offers

advantages over a traditional approach by avoiding the voltage drop

incurred by traditional MOSFET source sensing. Thus, the IC drive

capability is greatly improved.

Finally, the bulk input ripple ensures a natural frequency dithering

which smooths the EMI signature.

Features

Typical Applications

MARKING

DIAGRAM

FAC

= Specific Device Code

A

= Assembly Location

L

= Wafer Lot

Y

= Year

W

= Work Week

G

= Pb−Free Package

http://onsemi.com

1

8

SOIC−8

D SUFFIX

CASE 751

1215A

ALYW

G

1

8

1

6

TSOP−6

(SOT23−6, SC59−6)

SN SUFFIX

CASE 318G

1

6

18

5

3

4

(Top View)

FB

CS

NC

PIN CONNECTIONS

7

6

2

NC

CT

GND

Gate

SOIC−8

1

3

FB

CS

2

GND

CT

4

Gate

6

(Top View)

5

TSOP−6

FACAYW

G

G

See detailed ordering and shipping information in the package

dimensions section on page 3 of this data sheet.

ORDERING INFORMATION

(Note: Microdot may be in either location)