LT11
11
TYPICAL PERFOR A CE CHARACTERISTICS
Quiescent Current
400
380
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
360
340
320
300
280
260
240
220
200
0
3
6
9 12 15 18 21 24 27 30
INPUT VOLTAGE (V)
LT1111 • TPC10
SWITCH CURRENT (A)
Set Pin Bias Current
100
90
80
BIAS CURRENT (nA)
60
50
40
30
20
10
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
BIAS CURRENT (nA)
70
PI FU CTI
S
GND (Pin 5):
Ground.
A0 (Pin 6):
Auxiliary Gain Block (GB) Output. Open collector,
can sink 300µA.
SET (Pin 7):
GB Input. GB is an op amp with positive input
connected to SET pin and negative input connected to
1.25V reference.
FB/SENSE (Pin 8):
On the LT1111 (adjustable) this pin
goes to the comparator input. On the LT1111-5 and
LT1111-12, this pin goes to the internal application resistor
that sets output voltage.
I
LIM
(Pin 1):
Connect this pin to V
IN
for normal use. Where
lower current limit is desired, connect a resistor between
I
LIM
and V
IN
. A 220Ω resistor will limit the switch current
to approximately 400mA.
V
IN
(Pin 2):
Input Supply Voltage.
SW1 (Pin 3):
Collector of Power Transistor. For step-up
mode connect to inductor/diode. For step-down mode
connect to V
IN
.
SW2 (Pin 4):
Emitter of Power Transistor. For step-up
mode connect to ground. For step-down mode connect to
inductor/diode. This pin must never be allowed to go more
than a Schottky diode drop below ground.
U W
Quiescent Current
500
450
400
350
300
250
200
150
100
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Maximum Switch Current
vs R
LIM
STEP-UP
2V
≤
V
IN
≤
5V
STEP-DOWN
V
IN
= 12V
10
100
R
LIM
(Ω)
1000
LT1111 • TPC12
LT1111 • TPC11
Feedback Bias Current
100
90
80
70
60
50
40
30
20
10
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
LT1111 • TPC13
LT1111 • TPC14
UO
U
U
1111fd
5
LINER [ LINEAR TECHNOLOGY ]
