Datasheet

LTC4257-1
4
42571fb
Signature Resistance
vs Input Voltage
Normalized UVLO Threshold
vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
UW
V
OUT
Leakage Current Current Limit vs Input Voltage
Input Current vs Input Voltage
Input Current vs Input Voltage
25k Detection Range Input Current vs Input Voltage
INPUT VOLTAGE (V)
0
0
INPUT CURRENT (mA)
0.1
0.2
0.3
0.4
0.5
–2
–4 –6 –8
4357 G01
–10
T
A
= 25°C
INPUT VOLTAGE (V)
0
0
INPUT CURRENT (mA)
10
20
30
40
50
–10
–20 –30 –40
42571 G02
–50 –60
CLASS 4
CLASS 3
CLASS 2
CLASS 1
CLASS 0
T
A
= 25°C
INPUT VOLTAGE (V)
–12
9.0
INPUT CURRENT (mA)
9.5
10.5
11.0
11.5
–14
–16
42571 G03
10.0
–18
–20 –22
12.0
85°C
–40°C
CLASS 1 OPERATION
Input Current vs Input Voltage
INPUT VOLTAGE (V)
0
INPUT CURRENT (mA)
1
2
3
–45 –55
42571 G04
–60–40 –50
EXCLUDES ANY LOAD CURRENT
T
A
= 25°C
INPUT VOLTAGE (V)
–1
22
V1:
V2:
SIGNATURE RESISTANCE (kΩ)
23
25
26
27
–3
–5
42571 G05
24
–7
–9
–6 –10
–2 –4
–8
28
RESISTANCE =
DIODES: S1B
T
A
= 25°C
=
∆V
∆I
V2 – V1
I
2
– I
1
IEEE UPPER LIMIT
IEEE LOWER LIMIT
LTC4257-1 + 2 DIODES
LTC4257-1 ONLY
TEMPERATURE (°C)
–40
–2
NORMALIZED UVLO THRESHOLD (%)
–1
0
1
2
–20 0 20 40
42571 G06
60 80
APPLICABLE TO TURN-ON
AND TURN-0FF THRESHOLDS
Power Good Output Low Voltage
vs Current
CURRENT (mA)
0
V
PG_OUT
(V)
2
3
8
42571 G07
1
0
2
4
6
10
4
T
A
= 25°C
V
OUT
PIN VOLTAGE (V)
0
0
V
OUT
CURRENT (µA)
30
60
120
90
20 40
42571 G08
60
V
IN
= 0V
T
A
= 25°C
INPUT VOLTAGE (V)
–40
CURRENT LIMIT (mA)
200
–60
42571 G09
100
–45
–50
–55
400
300
85°C
85°C
–40°C
–40°C
HIGH CURRENT MODE
LOW CURRENT MODE