LX1977

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 7

SMBus Ambient Light Sensor

TM

®

Copyright

© 2010

Rev. 1.0, 2010-03-25

The diagram below illustrates the various SMBus timings and sets the context for the specifications to follow. Note that the

following are not production tested specifications, but are common SMBus protocol specifications practiced.

Table 5: SMBus (I

FAST_MODE

Symbol

Parameter

MIN

MAX

Units

SMBus Operating Frequency

10

400

kHz

Bus free time between Stop and Start Condition

1.3

-

µs

Hold time after (Repeated) Start Condition. After this period, the

first clock is generated.

0.6

-

µs

Repeated Start Condition setup time

0.6

-

µs

Stop Condition setup time

0.6

-

µs

Data hold time

0

0.9

µs

Data setup time

100

-

ns

Clock low period

1.3

-

µs

Clock high period

0.6

-

µs

Clock / Data Fall Time

-

300

ns

Clock / Data Rise Time

-

300

ns

Time in which a device must be operational after power-on reset

500

ms

Capacitance for SCL or SDA pin

10

pF

P

S

S

P

SMBus Clock

(SCL)

SMBus Data

(SDA)

Figure 4 –

SMBus Timing Measurement