LTC4270/LTC4271
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Notes 3 & 4)
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2
I C Timing
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
f
t
t
t
t
t
t
t
t
t
t
t
Clock Frequency
(Note 7)
1
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
μs
μs
ns
SCLK
Bus Free Time
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
Figure 5 (Notes 7, 9)
(Notes 7, 9, 10)
480
240
480
240
60
1
2
3
4
5
5
6
7
8
r
Start Hold Time
SCL Low Time
SCL High Time
SDAIN Data Hold Time
Data Clock to SDAOUT Valid
Data Set-Up Time
130
80
Start Set-Up Time
240
240
Stop Set-Up Time
SCL, SDAIN Rise Time
SCL, SDAIN Fall Time
Fault Present to INT Pin Low
Stop Condition to INT Pin Low
ARA to INT Pin High Time
SCL Fall to ACK Low
120
60
f
150
1.5
1.5
130
(Notes 7, 9, 10)
(Notes 7, 9)
(Notes 7, 9)
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. With the exception of (V
DGND), exposure to any Absolute Maximum Rating condition for extended
periods may affect device reliability and lifetime.
Note 7: Guaranteed by design, not subject to test.
Note 8: The IEEE 802.3af specification allows a PD to present its
Maintain Power Signature (MPS) on an intermittent basis without being
disconnected. In order to stay powered, the PD must present the MPS for
–
DD
Note 2: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 140ºC when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 3: All currents into device pins are positive; all currents out of device
pins are negative.
Note 4: The LTC4270 operates with a negative supply voltage (with respect
to AGND). To avoid confusion, voltages in this data sheet are referred to in
terms of absolute magnitude.
t
within any t
time window.
MPS
MPDO
Note 9: Values Measured at V and V
Note 10: If a fault condition occurs during an I C transaction, the INT pin
will not be pulled down until a stop condition is present on the I C bus.
Note 11: Load characteristics of the LTC4270 during Mark: 7V < (AGND –
ILD
IHD
2
2
V
) < 10V or I
OUTn
< 50μA.
OUT
Note 12: See the LTC4271 Software Programming documentation for
information on serial bus usage and device configuration and status
registers.
Note 13: Do not source or sink current from CAP1 and CAP2.
Note 5: t is the same as t
defined by IEEE 802.3at
DIS
MPDO
Note 6: The LTC4271 digital interface operates with respect to DGND. All
logic levels are measured with respect to DGND.
42701f
7
Linear [ Linear ]
