Datasheet

3
LT3463/LT3463A
3463f
TYPICAL PERFOR A CE CHARACTERISTICS
UW
PI FU CTIO S
UUU
V
OUT1
(Pin 1): Output Voltage Switcher 1. This is the
cathode of an internal Schottky diode whose anode is
connected to the SW1 pin.
SW1 (Pin 2): Switch Pin for Switcher 1. This is the
collector of the internal NPN switch. Minimize the metal
trace area connected to this pin to minimize EMI.
V
IN
(Pin 3): Input Supply Pin. Bypass this pin with a
capacitor as close to the device as possible.
SW2 (Pin 4): Switch Pin for Switcher 2. This is the
collector of the internal NPN switch. Minimize the metal
trace area connected to this pin to minimize EMI.
D2 (Pin 5): Diode for Switcher 2. This is the anode of an
internal Schottky diode whose cathode connected to the
GND pin.
FB2 (Pin 6): Feedback Pin for Switcher 2. Set the output
voltage by selecting values for R3 and R4.
V
REF
(Pin 7): Voltage Reference Pin (1.25V). This pin is
used along with FB2 to set the negative output voltage for
Switcher 2.
SHDN2 (Pin 8): Shutdown Pin for Switcher 2. Pull this pin
above 1.5V to enable Switcher 2. Pull below 0.3V to turn
it off. Do not leave this pin floating.
V
CESAT
and V
DIODE
Voltage
V
REF
and V
FB1
Voltage V
FB2
Voltage
Switch Off Time
Switch Current Limit
Quiescent Current
V
CESAT
AND V
DIODE
VOLTAGE (V)
900
800
700
600
500
400
300
200
100
0
3463 G01
TEMPERATURE (°C)
–50 100
050–25 25 75 125
I
DIODE
= 150mA
I
SWITCH
= 150mA
FOR BOTH SWITCHERS
V
REF
AND V
FB1
VOLTAGE (V)
1.27
1.26
1.25
1.24
1.23
1.22
3463 G02
TEMPERATURE (°C)
–50 100
050–25 25 75 125
V
REF
V
FB1
V
FB2
VOLTAGE (mV)
10
8
6
4
2
0
3463 G03
TEMPERATURE (°C)
–50 25 75
–25 0
50 100 125
TEMPERATURE (°C)
–50
SWITCH OFF TIME (ns)
100
3463 G04
050
400
350
300
250
200
150
100
50
0
–25 25 75 125
TEMPERATURE (°C)
–50
SWITCH CURRENT LIMIT (mA)
100
3463 G05
050
450
400
350
300
250
200
150
100
50
0
–25 25 75 125
LT3463 SW1, SW2
LT3463A SW1
LT3463A SW2
TEMPERATURE (°C)
–50
QUIESCENT CURRENT (µA)
60
50
40
30
20
10
0
25 75
3463 G06
–25 0
50 100 125
NOT SWITCHING
V
FB1
= 1.3V
V
FB2
= –0.1V