CPC5902GS datasheet(11/14 Pages) IXYS

11 / 14 page

INTEGRATED CIRCUITS DIVISION

CPC5902

R03

www.ixysic.com

CPC5902 Side A devices may be connected to the

Side B bus.

For all modes, the minimum required voltage drop

across the Side B pull-up resistor at VDDB_max by the

external non-CPC5902 I2C bus drivers is:

Minimum RPUB Voltage = VDDB_max - (0.2 • VDDB_max - 60mV)

= 0.8 • VDDB_max + 60mV

which gives the calculation for the minimum value of

the pull-up resistor as:

RPUB_min = (0.8 • VDDB_max + 60mV) / IOL

where IOL is the guaranteed logic low drive current of

the non-CPC5902 bus drivers.

For Standard-mode designs, with output drivers rated

at 3mA and a maximum supply voltage of 3.6V, the

minimum value of the pull-up resistor is:

RPUB_min = (0.8 • 3.6 + 60mV) / 3mA = 980

The minimal standard value 1% resistor with a

100ppm/

C temperature coefficient that will not go

below the calculated minimum due to tolerance and

temperature is 1k

.

In Fast-mode designs with 6mA capable output drivers

and a supply voltage maximum of 5.5V, the minimum

Fast-mode pull-up resistor value is calculated to be:

RPUB_min = (0.8 • 5.5 + 60mV) / 6mA = 743.3

For a Fast-mode design with high capacitive bus

loading a 768

, 1%, 100ppm/C resistor would suffice.

When the bus does not have a heavy capacitive load

then a larger value pull-up resistor can be used

thereby reducing overall power consumption.

CPC5902GS Folha de dados(PDF) 11 Page - IXYS Corporation