Datasheet

3
LT1615/LT1615-1
sn16151 16151fas
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Switch Saturation Voltage
(V
CESAT
) Quiescent Current
Feedback Pin Voltage and
Bias Current
TEMPERATURE (°C)
–50
–25 0 25 50 75 100
SWITCH VOLTAGE (V)
1615/-1 G01
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
I
SWITCH
= 500mA
I
SWITCH
= 300mA
TEMPERATURE (°C)
–50
FEEDBACK VOLTAGE (V)
1615/-1 G02
1.25
1.24
1.23
1.22
1.21
1.20
BIAS CURRENT (nA)
50
40
30
20
10
0
CURRENT
VOLTAGE
–25 0 25 50 75 100
TEMPERATURE (°C)
QUIESCENT CURRENT (µA)
1615/-1 G03
25
23
21
19
17
15
–50 –25 0 25 50 75 100
V
IN
= 12V
V
IN
= 1.2V
V
FB
= 1.23V
NOT SWITCHING
PI FU CTIO S
UUU
SW (Pin 1): Switch Pin. This is the collector of the internal
NPN power switch. Minimize the metal trace area con-
nected to this pin to minimize EMI.
GND (Pin 2): Ground. Tie this pin directly to the local
ground plane.
FB (Pin 3): Feedback Pin. Set the output voltage by
selecting values for R1 and R2 (see Figure 1):
RR
V
OUT
12
123
1=−






.
SHDN (Pin 4): Shutdown Pin. Tie this pin to 0.9V or higher
to enable the device. Tie below 0.25V to turn off the device.
V
IN
(Pin 5): Input Supply Pin. Bypass this pin with a
capacitor as close to the device as possible.
TEMPERATURE (°C)
SWITCH OFF TIME (ns)
1615/-1 G04
550
500
450
400
350
300
250
–50 –25 0 25 50 75 100
V
IN
= 1.2V
V
IN
= 12V
TEMPERATURE (°C)
PEAK CURRENT (mA)
1615/-1 G05
400
350
300
250
200
150
100
50
0
–50 –25 0 25 50 75 100
V
IN
= 12V
V
IN
= 1.2V
V
IN
= 12V
LT1615-1
LT1615
V
IN
= 1.2V
SHUTDOWN PIN VOLTAGE (V)
SHUTDOWN PIN CURRENT (µA)
1615/-1 G03
25
20
15
10
5
0
0 5 10 15
25°C
100°C
Switch Off Time Shutdown Pin CurrentSwitch Current Limit
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