LTC4257CDD Linear Technology, LTC4257CDD Datasheet - Page 4

IC CONTROLLER POE INTERFACE 8DFN

LTC4257CDD

Manufacturer Part Number
LTC4257CDD
Description
IC CONTROLLER POE INTERFACE 8DFN
Manufacturer
Linear Technology
Type
Power over Ethernet Switch (PoE)r
Datasheet

Specifications of LTC4257CDD

Applications
IP Phones, Power over LAN, Network Routers and Switches
Internal Switch(s)
Yes
Current Limit
350mA
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
8-WFDFN Exposed Pad
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LTC4257CDD
Manufacturer:
LT
Quantity:
10 000
Part Number:
LTC4257CDD-1
Manufacturer:
LT
Quantity:
10 000
LTC4257
4
TYPICAL PERFOR A CE CHARACTERISTICS
0.5
0.4
0.3
0.2
0.1
0
3
2
1
0
4
3
2
1
0
–40
0
Input Current vs Input Voltage
25k Detection Range
0
Input Current vs Input Voltage
Power Good Output Low Voltage
vs Current
T
EXCLUDES ANY LOAD CURRENT
T
T
A
A
A
= 25°C
= 25°C
= 25°C
–2
2
–45
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
CURRENT (mA)
–4
4
–50
–6
6
–55
W
–8
8
4357 G02
4257 G04
4257 G07
U
–10
–60
10
V1:
V2:
120
50
40
30
20
10
26
24
22
90
60
30
28
27
25
23
0
0
–2
–1
0
Input Current vs Input Voltage
0
Signature Resistance
vs Input Voltage
V
T
RESISTANCE =
DIODES: S1B
T
V
T
OUT
A
A
IN
A
LTC4257 ONLY
= 25°C
= 25°C
= 25°C
= 0V
–10
Leakage Current
–3
–4
V
LTC4257 + 2 DIODES
INPUT VOLTAGE (V)
OUT
–20
INPUT VOLTAGE (V)
20
CLASS 3
CLASS 2
CLASS 1
CLASS 0
CLASS 4
∆V
∆I
PIN VOLTAGE (V)
–5
–6
=
–30
V2 – V1
IEEE LOWER LIMIT
I
IEEE UPPER LIMIT
2
– I
1
–40
–7
–8
40
–50
–10
–9
42571 G09
4257 G05
4257 G01
–60
60
12.0
11.5
11.0
10.5
10.0
375
365
355
345
335
325
9.0
9.5
–2
–1
2
1
0
–40
–12
–40
Current Limit vs Input Voltage
Input Current vs Input Voltage
Normalized UVLO Threshold
vs Temperature
CLASS 1 OPERATION
APPLICABLE TO TURN-ON
AND TURN-0FF THRESHOLDS
V
OUT
–20
= V
–14
–45
IN
–40°C
85°C
+ 5V
TEMPERATURE (°C)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
0
–40°C
85°C
25°C
–16
20
–50
–18
40
–55
60
–20
4257 G03
4257 G09
4257 G06
80
4257fb
–60
–22

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