Datasheet
DS1775
12 of 14
AC ELECTRICAL CHARACTERISTICS: 2-WIRE INTERFACE
(V
DD
= 2.7V to 5.5V, T
A
= -55°C to +125°C, unless otherwise noted.) (Figure 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
NOTES
SCL Clock Frequency f
SCL
Fast mode
400
kHz
Standard mode
100
Bus Free Time
Between a STOP and
START Condition
t
BUF
Fast mode 1.3
µs
Standard mode 4.7
Hold Time (Repeated)
START Condition
t
HD:STA
Fast mode
0.6
µs
5
Standard mode
4.0
Low Period of SCL t
LOW
Fast mode
1.3
µs
Standard mode
4.7
High Period of SCL t
HIGH
Fast mode
0.6
µs
Standard mode
4.0
Setup Time for a
Repeated START
t
SU:STA
Fast mode
0.6
µs
Standard mode
4.7
Data Hold Time t
HD:DAT
Fast mode
0
0.9
µs
6
Standard mode
0
0.9
Data Setup Time t
SU:DAT
Fast mode
100
ns 7
Standard mode
250
Rise Time of Both SDA
and SCL Signals
t
R
Fast mode
20 + 0.1C
B
300
ns 8
Standard mode
20 + 0.1C
B
1000
Fall Time of Both SDA
and SCL Signals
t
F
Fast mode
20 + 0.1C
B
300
ns 8
Standard mode
20 + 0.1C
B
300
Setup Time for STOP t
SU:STO
Fast mode
0.6
µs
Standard mode
4.0
Capacitive Load for
Each Bus Line
C
B
400 pF 8
Input Capacitance
C
I
5
pF
NOTES:
1. All voltages are referenced to ground.
2. I/O pins of fast mode devices must not obstruct the SDA and SCL lines if V
DD
is switched off.
3. I
DD
specified with O.S. pin open.
4. I
DD
specified with V
DD
at 5.0V and V
SDA
, V
SCL
= 5.0V, 0°C to +70°C.
5. After this period, the first clock pulse is generated.
6. The maximum t
HD:DAT
has only to be met if the device does not stretch the low period (t
LOW
) of the
SCL signal.
7. A fast mode device can be used in a standard mode system, but the requirement t
SU:DAT
≥ 250ns must
then be met. This is automatically the case if the device does not stretch the low period of the SCL
signal. If such a device does stretch the low period of the SCL signal, it must output the next data bit
to the SDA line t
R MAX
+t
SU:DAT
= 1000 + 250 = 1250ns before the SCL line is released.
8. C
B
= Total capacitance of one bus line in pF.
9. Internal heating caused by O.S. loading causes the DS1775 to read approximately 0.5ºC higher if O.S.
is sinking the max rated current.
10. Contact the factory for operation requiring temperature readings greater than +120°C.