LTC4257IS8-1 Linear Technology, LTC4257IS8-1 Datasheet - Page 4

• Manufacturer Part Number: LTC4257IS8-1
• Description: IC CONTROLLER POE INTERFAC 8SOIC
• Manufacturer: Linear Technology
• Type: Power over Ethernet Switch (PoE)r

Specifications of LTC4257IS8-1

• Applications: IP Phones, Power over LAN, Network Routers and Switches
• Internal Switch(s): Yes
• Current Limit: 350mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC4257-1
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
0
Input Current vs Input Voltage
25k Detection Range
Power Good Output Low Voltage
vs Current
Input Current vs Input Voltage
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
42571 G04
42571 G07
4357 G01
U
–10
–60
10
V1:
V2:
120
50
40
30
20
10
26
25
24
22
90
60
30
28
27
23
0
0
–2
–1
0
0
Input Current vs Input Voltage
Signature Resistance
vs Input Voltage
V
LTC4257-1 ONLY
RESISTANCE =
DIODES: S1B
T
V
T
T
A
OUT
A
IN
A
= 25°C
= 25°C
= 25°C
= 0V
–10
Leakage Current
–3
–4
LTC4257-1 + 2 DIODES
V
OUT
INPUT VOLTAGE (V)
–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
42571 G05
42571 G02
–9
42571 G08
–60
60
11.0
10.0
12.0
11.5
10.5
400
300
200
100
9.0
9.5
–1
–2
1
2
0
–40
–12
–40
Input Current vs Input Voltage
Normalized UVLO Threshold
vs Temperature
Current Limit vs Input Voltage
CLASS 1 OPERATION
APPLICABLE TO TURN-ON
AND TURN-0FF THRESHOLDS
–20
–14
–45
INPUT VOLTAGE (V)
TEMPERATURE (°C)
INPUT VOLTAGE (V)
0
–40°C
–40°C
85°C
85°C
–16
–40°C
85°C
20
–50
HIGH CURRENT MODE
LOW CURRENT MODE
–18
40
–55
60
–20
42571 G03
42571 G09
42571 G06
42571fb
80
–60
–22