TPS23750
TPS23770
www.ti.com
SLVS590A–JULY 2005–REVISED AUGUST 2005
TYPICAL CHARACTERISTICS (continued)
(VDD + RTN + SENP) DETECTION
CURRENT
PoE CURRENT LIMIT
vs
JUNCTION TEMPERATURE
MAXIMUM DUTY CYCLE
vs
vs
OSCILLATOR FREQUENCY
SUPPLY VOLTAGE
6
49.50
452
During PoE Detection
450
o
= 25 C
5
T
J
448
446
444
442
440
438
436
o
= 125 C
T
J
49.25
o
= 125 C
T
J
4
o
= 25 C
T
J
3
49.00
o
= -40 C
T
J
2
o
= -40 C
48.75
T
J
1
434
48.50
432
0
0
100
200
300
400
500
600
-40 -20
0
20 40
60 80 100 120 140
0
2
4
6
8
10
12
o
- Junction Temperature - C
Oscillator Frequency - kHz
V
DD
- Supply Voltage - V
T
J
Figure 21.
Figure 22.
Figure 23.
CONVERTER CURRENT LIMIT
RESPONSE TIME
BLANKING TIME
vs
JUNCTION TEMPERATURE
OSCILLATOR FREQUENCY
vs
vs
15000/RFREQ
JUNCTION TEMPERATURE
130
120
110
700
75
70
65
600
BL = V
BIAS
500
100
90
400
80
300
60
BL = RTN
70
200
60
55
100
50
50
40
0
-40 -20
0
20 40
60 80 100 120 140
-40 -20
0
20 40
60 80 100 120 140
0
100
200
300
400
- kHz
500
600
700
o
- Junction Temperature - C
o
- Junction Temperature - C
T
J
T
J
15000 / R
FREQ
Figure 24.
Figure 25.
Figure 26.
PD DETECTION RESISTANCE
OPERATING CURRENT ( IVDD
)
vs
vs
VOLTAGE, VPI
JUNCTION TEMPERATURE
30.0
27.5
25.0
1.6
Includes 24.9 kW and HD01 Bridge
1.5
Operating
1.4
R
= 30 kW
(FREQ)
802.3af Limits
1.3
1.2
1.1
1.0
0.9
0.8
Operating
= 150 kW
(FREQ)
802.3af Limits
R
22.5
20.0
17.5
Quiescent
1
R(V ) =
PI
( I(V ) - I(V ) -1))
PI
0.7
PI
0.6
1
2
3
4
5
6
7
8
9
10 11
-40 -20
0
20 40
60 80 100 120 140
Voltage, V - V
PI
o
- Junction Temperature - C
T
J
Figure 27.
Figure 28.
14
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