max5965a Maxim Integrated Products, Inc., max5965a Datasheet - Page 39

• Manufacturer Part Number: max5965a
• Description: High-power, Quad, Monolithic, Pse Controllers For Power Over Ethernet
• Manufacturer: Maxim Integrated Products, Inc.

Setting EN_WHDOG (Table 27) high activates the
watchdog counter. When the counter reaches zero, the
port switches to the hardware-controlled mode deter-
mined by the corresponding HWMODE_ bit. A low in
HWMODE_ switches the port into shutdown by setting
The CLC_EN enables the large capacitor detection fea-
ture. When CLC_EN is set the device can recognize a
capacitor load up to 150µF. If the CLC_EN is reset, the
MAX5965A/MAX5965B perform normal detection.
AC_TH allows programming of the threshold of the AC
disconnect comparator. The threshold is defined as a
current since the comparators verify that the peak of
the current pulses sensed at the DET_ input exceed a
preset threshold. The current threshold is defined as
follows:
Table 27. Switch Mode Register
Table 28. Program Register
EN_WHDOG
WD_INT_EN
Reserved
Reserved
HWMODE4
HWMODE3
HWMODE2
HWMODE1
Reserved
Reserved
CLC_EN
DET_BY
OSCF_RS
AC_TH
High-Power, Quad, Monolithic, PSE Controllers
SYMBOL
SYMBOL
ADDRESS = 1Fh
ADDRESS = 23h
______________________________________________________________________________________
BIT
BIT
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
—
A logic-high enables the watchdog function
Enables interrupt on SMODE_ bits
Reserved
Reserved
Port 4 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
Port 3 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
Port 2 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
Port 1 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
Reserved
Reserved
Large capacitor detection enable
Enables skipping detection in AUTO mode
OSC_FAIL reset bit
AC_TH[2]
AC_TH[1]
AC_TH[0]
for Power over Ethernet
the bits in register R12h to 00. A high in HWMODE_
switches the port into auto mode by setting the bits in
register R12h to 11. If WD_INT_EN is set, an interrupt is
sent if any of the SMODE bits are set. A reset sets R1Fh
= 00h.
where NAC_TH is the decimal value of AC_TH.
When set low, DET_BY inhibits port power-on if the dis-
covery detection was bypassed in auto mode. When
set high, DET_BY allows the device to turn on power to
a non-IEEE 802.3af load without doing detection. If
OSCF_RS is set high, the OSC_FAIL bit is ignored. A
reset or power-up sets R23h = 04h. Default IAC_TH is
340µA.
IAC_TH = 226.68µA + 28.33 x NAC_TH
DESCRIPTION
DESCRIPTION
39