LT1110 Linear Technology, LT1110 Datasheet - Page 5

• Manufacturer Part Number: LT1110
• Description: Micropower DC-DC Converter Adjustable and Fixed 5V/ 12V
• Manufacturer: Linear Technology

TYPICAL PERFOR
PI
LT1110
I
lower current limit is desired, connect a resistor between
I
to approximately 400mA.
V
SW1 (Pin 3): Collector of power transistor. For step-up
mode connect to inductor/diode. For step-down mode
connect to V
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.
LIM
LIM
IN
160
140
120
100
80
60
40
20
U
0
(Pin 2): Input supply voltage.
–50
(Pin 1): Connect this pin to V
and V
Set Pin Bias Current
FU
–25
IN
U
BLOCK
. A 220 resistor will limit the switch current
IN
TEMPERATURE ( C)
C
0
.
TI
O
25
U
S
I D AGRA
50
W
LT1110 • TPC13
75
A
REFERENCE
IN
220mV
U
100
GND
V
for normal use. Where
IN
CE
W
SET
C
HARA TERISTICS
FB
120
110
100
90
60
30
20
10
80
70
50
40
0
–50
FB Pin Bias Current
+
–
–25
A2
A1
COMPARATOR
C
GAIN BLOCK/ERROR AMP
TEMPERATURE ( C)
0
25
GND (Pin 5): Ground.
AO (Pin 6): Auxiliary Gain Block (GB) output. Open collector,
can sink 300 A.
SET (Pin 7): GB input. GB is an op amp with positive input
connected to SET pin and negative input connected to
220mV reference.
FB/SENSE (Pin 8): On the LT1110 (adjustable) this pin
goes to the comparator input. On the LT1110-5 and
LT1110-12, this pin goes to the internal application resistor
that sets output voltage.
OSCILLATOR
AO
50
LT1110 • TPC14
75
DRIVER
100
I
LIM
LT1110 • BD01
SW1
SW2
Q1
226
224
222
220
218
216
214
212
–50
Reference Voltage
–25
TEMPERATURE ( C)
0
25
50
LT1110
LT1110 • TPC15
75
5
100