DS1775 Datasheet, PDF (12/14 Pages) Dallas Semiconductor – SOT23-5 Digital Thermometer and Thermostat

DS1775
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
SCL Clock Frequency
f_SCL
Fast mode
Standard mode
400
100
kHz
Bus Free Time
Fast mode
1.3
Between a STOP and
t_BUF
µs
START Condition
Standard mode
4.7
Hold Time (Repeated)
START Condition
t_HD:STA
Fast mode
Standard mode
0.6
4.0
µs
Low Period of SCL
t_LOW
Fast mode
Standard mode
1.3
4.7
µs
High Period of SCL
t_HIGH
Fast mode
Standard mode
0.6
4.0
µs
Setup Time for a
Repeated START
t_SU:STA
Fast mode
Standard mode
0.6
4.7
µs
Data Hold Time
t_HD:DAT
Fast mode
Standard mode
0
0
0.9
0.9
µs
Data Setup Time
t_SU:DAT
Fast mode
Standard mode
100
250
ns
Rise Time of Both SDA
and SCL Signals
t_R
Fast mode
20 + 0.1C_B
Standard mode 20 + 0.1C_B
300
1000
ns
Fall Time of Both SDA
and SCL Signals
t_F
Fast mode
20 + 0.1C_B
Standard mode 20 + 0.1C_B
300
300
ns
Setup Time for STOP
t_SU:STO
Fast mode
Standard mode
0.6
4.0
µs
Capacitive Load for
Each Bus Line
C_B
400
pF
Input Capacitance
C_I
5
pF
NOTES
5
6
7
8
8
8
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.
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