LTC3455
TYPICAL PERFOR A CE CHARACTERISTICS
Feedback Pins (FB1, FB2)
and AI Pin Voltage
815
2.0
SWITCHING FREQUENCY (MHz)
810
805
800
FB2
795
790
785
–50 –25
AI
VOLTAGE (mV)
FOR BOTH SWITCHERS
1.0
CURRENT LIMIT (mA)
FB1
50
25
75
0
TEMPERATURE (°C)
USB Pin Current Limit
500
USBHP = 2V
5.0
4.5
V
MAX
CURRENT LIMIT (A)
400
USB PIN CURRENT (mA)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
STARTUP
HSO PIN CURRENT LIMIT (mA)
300
200
100
USBHP = 0V
0
–50 –25
V
USB
= 5V
50
25
75
0
TEMPERATURE (°C)
100
125
Battery Undervoltage Lockout
4.00
3.75
BATTERY UVLO (V)
RISING
FALLING
WALLFB TRIP VOLTAGE (V)
USB UVLO (V)
3.50
3.25
RISING
3.00
2.75
FALLING
2.50
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
U W
100
3455 G04
3455 G07
3455 G10
Switching Regulator Oscillator
Frequency
1000
Switching Regulator Current Limit
SWITCHER 2
1.5
800
600
SWITCHER 1
400
0.5
200
125
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
3455 G05
3455 G06
V
MAX
Pin Current Limit
200
NORMAL OPERATION
HSO Pin Current Limit
150
100
50
V
HSI
= 3.3V
V
HSO
= 2.5V
50
25
75
0
TEMPERATURE (°C)
100
125
0.5
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
0
–50 –25
3455 G08
3455 G09
USB Undervoltage Lockout
4.00
3.75
3.50
3.25
3.00
2.75
2.50
–50 –25
1.26
1.24
WALLFB Trip Voltage
RISING
1.22
1.20
1.18
1.16
1.14
1.12
FALLING
50
25
75
0
TEMPERATURE (°C)
100
125
1.10
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
3455 G11
3455 G12
3455f
5
LINER [ LINEAR TECHNOLOGY ]
