SMM665B

Preliminary Information

Summit Microelectronics, Inc

2089 1.1 10/20/04

20

TRIM

A

VM

TRIM

B

VM

SMM665B

IR

iP1202

VSW1

SDA

SCL

I2C BUS

12V

12V

CS

FB1

VOUT1

1.5V

FB1S

Rtrim

1.6K

VSW2

FB2

VOUT2

2.5V

FB2S

Rtrim

3.3K

Not all components Shown

For interface purposes only

Part designators are from

the International Rectifier

iP1202 Demo board .

SS2

PUP

A

SS1

PUP

B

R9

R7

C8

C7

R10

R8

Figure 12 – The SMM665B can be used to sequence and control discrete DC switching regulators. The ADOC

function sets the output voltage of the IR iP1202 Regulator through the FBX feedback pins. Accuracy is

improved even under full load, essentially acting as a “SENSE” pin. The sequence function is applied

through the iP1202 SSX soft start pins.

Figure 13 – Ch1 is set to 2.5V and Ch2 is set to

1.5V on the ip1202 board. Ch1 is set to sequence

on first followed by Ch2 after 50ms. Then Ch1 is

margined high while Ch2 is margined low. Ch2 is

then sequenced off followed by Ch1 after 50ms.

Figure 14 – This is the same sequencing-on

function but with a shorter delay between

channels, the HEALTHY and RESET flags are also

shown.

APPLICATIONS INFORMATION (CONTINUED)