MAX5971B Maxim Integrated Products, MAX5971B Datasheet - Page 30

• Manufacturer Part Number: MAX5971B
• Description: PSE Controller
• Manufacturer: Maxim Integrated Products

Single-Port, 40W, IEEE 802.3af/at,
PSE Controller with I
Table 14. Detection Result Decoding Chart
Table 15. Classification Result Decoding Chart
Table 16. Power Status Register
Registers R0Dh to R0Fh are unconnected; writing to
them has no effect (address autoincrement still func-
tions) and a read always returns logical zeros.
The power status register (R10h, Table 16) records the
current status of port power. On power-up or after a reset
condition, the port is initially unpowered and the power
30
SYMBOL
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
PWR_EN
PGOOD
_____________________________________________________________________________________
(ADDRESS = 0Ch)
DET_ST[2:0]
ADDRESS = 10h
000
001
010
011
100
101
110
111
BIT NO.
7
6
5
4
3
2
1
0
Reserved Registers (R0Dh to R0Fh)
(ADDRESS = 0Ch)
CLASS[2:0]
Power Status Register (R10h)
TYPE
—
—
—
—
—
—
R
R
000
001
010
011
100
101
110
111
Reserved
Reserved
Reserved
Power-good condition on the port
Reserved
Reserved
Reserved
Power is enabled on the port
DETECTED
HIGH CAP
DET_OK
RHIGH
RLOW
OPEN
None
DCN
DCP
2
C
Detection status unknown (default)
Positive DC supply connected at the port (V
High capacitance at the port (> 8.5FF, typ)
Low resistance at the port (R
Detection pass (15kI > R
High resistance at the port (R
Open port (I
Negative DC bias on the port (V
status register is set to its default value of 00h. PGOOD
(R10h[4]) is set to 1 at the end of the power-up startup
period. PGOOD is reset to 0 whenever a fault condition
occurs. PWR_EN (R10h[0]) is set to 1 when the port
power is turned on. PWR_EN resets to 0 as soon as the
port turns off. Any transition of PGOOD and PWR_EN
bits set the corresponding bit in the power event register
(R02h/R03h, Table 9).
DET
DESCRIPTION
< 20FA)
DET
DESCRIPTION
CLASS RESULT
DET
DET
> 33kI)
Class FAIL
Unknown
OUT
< 15kI)
> 33kI)
1
2
3
4
5
0
- V
EE
< 2V)
AGND
- V
OUT_
< 1V)