Datasheet

© 2009-2012 Microchip Technology Inc. DS22203C-page 5
MCP9804
TIMING DIAGRAM
SENSOR SERIAL INTERFACE TIMING SPECIFICATIONS
Electrical Specifications: Unless otherwise indicated, V
DD
= 2.7V to 5.5V, T
A
= -40°C to +125°C, GND = Ground
and C
L
= 80 pF (Note 1).
(Note 6)
Parameters Sym Min Max
Min Max Units Conditions
2-Wire SMBus/I
2
C Interface
Serial port frequency f
SCL
0100 0 400 kHz (Note 2, Note 4)
Low Clock t
LOW
4700 — 1300 —ns(Note 2)
High Clock t
HIGH
4000 — 600 —ns(Note 2)
Rise Time t
R
— 1000 20 300 ns
Fall Time t
F
20 300 20 300 ns
Data in Setup Time t
SU-DI
250 — 100 —ns(Note 3)
Data in Hold Time t
HD-DI
0— 0 —ns(Note 5)
Data out Hold Time t
HD-DO
300 — 200 900 ns (Note 4)
Start Condition Setup Time t
SU-START
4700 — 600 —ns
Start Condition Hold Time t
HD-START
4000 — 600 —ns
Stop Condition Setup Time t
SU-STOP
4000 — 600 —ns
Bus Free t
B-FREE
4700 — 1300 —ns
Time-out t
OUT
25 50 25 50 ms
Bus Capacitive load C
b
—— — 400 pf
Note 1: All values referred to V
IL MAX
and V
IH MIN
levels.
2: If t
LOW
> t
OUT
or t
HIGH
> t
OUT
, the temperature sensor I
2
C interface will time-out. A Repeat Start command
is required for communication.
3: This device can be used in a Standard-mode I
2
C-bus system, but the requirement t
SU:DI MIN
must be met.
This device does not stretch SCL Low time.
4: As a transmitter, the device provides internal minimum delay time t
HD:DO MIN
, to bridge the undefined
region of the falling edge of SCL t
F MAX
to avoid unintended generation of Start or Stop conditions.
5: As a receiver, SDA should not be sampled at the falling edge of SCL. SDA can transition t
HD:DI
after SCL
toggles Low.
6: The I
2
C Fast Mode specification, or timing for bus frequency up to 400KHz, applies to devices starting
with date code of 1145.
t
SU-START
t
HD-START
t
SU-DI
t
SU-STOP
t
B-FREE
SCL
SDA
t
HD-DI/
t
HD-DO
t
HIGH
t
LOW
t
OUT
t
R
, t
F
START Condition
Data Transmission
STOP Condition