max5952auaxt Maxim Integrated Products, Inc., max5952auaxt Datasheet - Page 22

• Manufacturer Part Number: max5952auaxt
• Description: Max5952 High-power, Quad, Pse Controller For Power-over-ethernet
• Manufacturer: Maxim Integrated Products, Inc.

High-Power, Quad, PSE Controller
for Power-Over-Ethernet
R1Dh, R1Eh, and R1F registers control the watchdog
operation. The watchdog function, when enabled, allows
the MAX5952 to gracefully take over control or securely
shuts down the power to the ports in case of software/
firmware crashes. Contact the factory for more details.
A3, A2, A1, and A0 represent the four LSBs of the chip
address. The complete chip address is 7 bits (see
Table 4).
The four LSBs latch on the low-to-high transition of RESET
or after a power-supply start (either on V
Address inputs default high through an internal 50kΩ
pullup resistor to V
call through a global address 30h (see the Global
Addressing and Alert Response Protocol section).
Table 4. MAX5952 Address
Figure 4. 2-Wire Serial Interface Timing Details
Figure 5. 3-Wire Serial Interface Timing Details
22
0
SDAIN/SDA
SDAIN
______________________________________________________________________________________
SCL
t
SCL
HD, STA
t
HD, STA
1
START CONDITION
START CONDITION
0
DD
. The MAX5952 also responds to the
A3
t
LOW
t
LOW
t
R
t
R
A2
t
HIGH
t
HIGH
t
SU, DAT
t
SU, DAT
t
F
t
F
Address Inputs
A1
t
HD, DAT
t
HD, DAT
Watchdog
DD
A0
or V
R/W
EE
).
t
SU, STA
t
SU, STA
REPEATED START CONDITION
REPEATED START CONDITION
The MAX5952 operates as a slave that sends and
receives data through an I
3-wire interface. The interface uses a serial-data input
line (SDAIN), a serial-data output line (SDAOUT), and a
serial-clock line (SCL) to achieve bidirectional commu-
nication between master(s) and slave(s). A master (typ-
ically a microcontroller) initiates all data transfers to and
from the MAX5952, and generates the SCL clock that
synchronizes the data transfer. In most applications,
connect the SDAIN and the SDAOUT lines together to
form the serial-data line (SDA).
Using the separate input and output data lines allows
optocoupling with the controller bus when an isolated
supply powers the microcontroller.
The MAX5952 SDAIN line operates as an input. The
MAX5952 SDAOUT operates as an open-drain output. A
pullup resistor, typically 4.7kΩ, is required on SDAOUT.
The MAX5952 SCL line operates only as an input. A
pullup resistor, typically 4.7kΩ, is required on SCL if
there are multiple masters, or if the master in a single-
master system has an open-drain SCL output.
t
HD, STA
t
HD, STA
I
2
C-Compatible Serial Interface
t
SU, STO
t
SU, STO
2
C-compatible, 2-wire or
CONDITION
CONDITION
STOP
STOP
t
BUF
t
BUF
CONDITION
CONDITION
START
START