Rainbow Electronics LM84 - Manual (Page 6)

Logic Electrical Characteristics
(Continued)
SMBus DIGITAL SWITCHING CHARACTERISTICS
Unless otherwise noted, these specifications apply for V
CC
=+3.0 Vdc to +3.6 Vdc, C
L
(load capacitance) on output lines = 80
pF. Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= +25˚C, unless otherwise noted.
The switching characteristics of the LM84 fully meet or exceed the published specifications of the SMBus or I 2 C bus. The fol-
lowing parameters are the timing relationships between SMBCLK and SMBData signals related to the LM84. They are not nec-
essarily the I
2 C or SMBus bus specifications.
Symbol Parameter Conditions Typical Limits Units
(Note 6) (Note 7) (Limit)
f
SMB
SMBus Clock Frequency 400
10
kHz (max)
kHz (min)
t
LOW
SMBus Clock Low Time 10% to 10% 1.3
25
µs (min)
ms (max)
t
LOW
SEXT Cumulative Clock Low Extend Time 25 ms (max)
t
HIGH
SMBus Clock High Time 90% to 90% 0.6 µs (min)
t
R;SMB
SMBus Rise Time 10% to 90% 1 µs
t
F;SMB
SMBus Fall Time 90% to 10% 0.3 µs
t
OF
Output Fall Time C
L
= 400 pF
I
O
= 3 mA
250 ns (max)
t
TIMEOUT
SMBData and SMBCLK Time Low for
Reset of Serial Interface (Note 13) 25
40 ms (min)
ms (max)
t
1
SMBCLK (Clock) Period 2.5 µs (min)
t
2
,
t
SU;DAT
Data In Setup Time to SMBCLK High 100 ns (min)
t
3
,
t
HD;DAT
Data Out Stable after SMBCLK Low 0
0.9
ns (min)
µs (max)
t
4
,
t
HD;STA
SMBData Low Setup Time to SMBCLK
Low 100 ns (min)
t
5
,
t
SU;STO
SMBData High Delay Time after
SMBCLK High (Stop Condition Setup) 100 ns (min)
t
6
,
t
SU;STA
SMBus Start-Condition Setup Time 0.6 µs (min)
t
BUF
SMBus Free Time 1.3 µs (min)
SMBus Communication
DS100961-4
LM84
www.national.com 6