LT1110_15 Datasheet, PDF (5/16 Pages) Linear Technology – Micropower DC-DC Converter Adjustable and Fixed 5V, 12V

TYPICAL PERFOR A CE CHARACTERISTICS
LT1110
Set Pin Bias Current
160
140
120
100
80
60
40
20
0
–50 –25 0
25 50 75 100
TEMPERATURE (°C)
LT1110 • TPC13
FB Pin Bias Current
120
110
100
90
80
70
60
50
40
30
20
10
0
–50 –25 0
25 50
75 100
TEMPERATURE (°C)
LT1110 • TPC14
Reference Voltage
226
224
222
220
218
216
214
212
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
LT1110 • TPC15
PI FU CTI S
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.
GND (Pin 5): Ground.
AO (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
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.
LT1110 BLOCK DIAGRA
SET
V _IN
220mV
REFERENCE
GND
FB
+
A2
AO
–
GAIN BLOCK/ERROR AMP
I _LIM
SW1
A1
OSCILLATOR
COMPARATOR
DRIVER
Q1
SW2
LT1110 • BD01
5