Datasheet

LTC1644
4
1644f
TYPICAL PERFOR A CE CHARACTERISTICS
UW
3.3V and 5V Current Foldback
Profile 12V Output Current –12V Output Current
OUTPUT VOLTAGE (V)
012345
OUTPUT CURRENT (A)
1644 G01
11
10
9
8
7
6
5
4
3
2
1
0
3V
OUT
5V
OUT
T
A
= 25°C
R
SENSE
= 0.005Ω
OUTPUT VOLTAGE (V)
024681012
OUTPUT CURRENT (A)
1644 G02
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
T
A
= 25°C
12V
IN
= 12V
OUTPUT VOLTAGE (V)
0 –2–4–6–8–10–12
OUTPUT CURRENT (A)
1644 G03
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
T
A
= 25°C
V
EEIN
= –12V
12V
IN
Supply Current
vs Temperature
12V
IN
Undervoltage Lockout
vs Temperature
5V
IN
UVLO Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–50
3.2
3.1
3.0
2.9
2.8
25 75
1644 G04
–25 0
50 100
12V
IN
SUPPLLY CURRENT (mA)
TEMPERATURE (°C)
–50
8.20
12V
IN
UNDERVOLTAGE LOCKOUT (V)
8.40
–25
0
25 50
1644 G05
75
8.45
8.50
8.25
8.30
8.35
100
RAMPING
UP
RAMPING
DOWN
TEMPERATURE (°C)
–50
5V
IN
UVLO THRESHOLD VOLTAGE (V)
2.49
2.50
2.51
25
75
1644 G06
2.48
2.47
2.46
–25 0 50
2.52
2.53
2.54
2.55
100
RAMPING
UP
RAMPING
DOWN
3V
IN
UVLO Threshold Voltage
vs Temperature
5V Foldback Current Limit Voltage
vs Temperature
3V Foldback Current Limit Voltage
vs Temperature
TEMPERATURE (°C)
–50
2.47
3V
IN
UVLO THRESHOLD VOLTAGE (V)
2.48
2.50
2.51
2.52
50
2.56
1644 G07
2.49
0
–25
75
25 100
2.53
2.54
2.55
RAMPING
UP
RAMPING
DOWN
TEMPERATURE (°C)
–50
0
5V FOLDBACK CURRENT LIMIT VOLTAGE (mV)
10
20
30
40
60
–25
02550
1644 G08
75 100
50
TIMER = 0V
5V
OUT
= 3V
5V
OUT
= 0V
TEMPERATURE (°C)
–50
0
3V FOLDBACK CURRENT LIMIT VOLTAGE (mV)
10
20
30
40
60
–25
02550
1644 G09
75 100
50
TIMER = 0V
3V
OUT
= 2V
3V
OUT
= 0V