LT1108-12 Linear Technology, LT1108-12 Datasheet - Page 3

• Manufacturer Part Number: LT1108-12
• Description: Micropower DC/DC Converter Adjustable and Fixed 5V/ 12V
• Manufacturer: Linear Technology

SYMBOL
V
A
V
The
temperature range.
Note 1: This specification guarantees that both the high and low trip points
of the comparator fall within the 1.2V to 1.3V range.
TYPICAL PERFOR
ELECTRICAL C
SAT
V
SW2
1000
900
800
700
600
500
400
300
200
100
1.2
1.0
0.8
0.6
0.4
0.2
0
0
100
0
denotes specifications which apply over the full operating
Saturation Voltage Step-Up Mode
(SW2 Pin Grounded)
Saturation Voltage Step-Up Mode
(SW2 Pin Grounded)
0.2
PARAMETER
SW
Gain Block Gain
Current Limit
Current Limit Temperature Coefficient
Switch OFF Leakage Current
Maximum Excursion Below GND
L = 250 H
V
SAT
IN
SWITCH CURRENT (A)
0.4
= 12V
Voltage, Step-Down Mode
V
L = 500 H
IN
R
V
= 24V
LIM
IN
0.6
V
= 2V
( )
IN
HARA TERISTICS
= 3V
V
0.8
IN
= 5V
V
W
LT1108 • TPC04
OUT
LT1108 • TPC01
1.0
A
= 5V
C
1000
U
1.2
CE
C
HARA TERISTICS
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
10
50
40
30
20
0
0
Supply Current vs Switch Current
Switch ON Voltage
Step-Down Mode
(SW1 Pin Connected to V
0
0.1
CONDITIONS
V
R
220 from I
Measured at SW1 Pin
I
SW1
IN
L
200
T
C
V
A
= 100k (Note 3)
0.2
= 12V, I
IN
SWITCH CURRENT (mA)
= 25 C, V
SWITCH CURRENT (A)
= 5V
10 A, Switch OFF
0.3
400
V
SW
IN
LIM
0.4
= 2V
Note 2: The output voltage waveform will exhibit a sawtooth shape due to
the comparator hysteresis. The output voltage on the fixed output versions
will always be within the specified range.
Note 3: 100k resistor connected between a 5V source and the A0 pin.
= 650mA
IN
to V
600
0.5
= 3V, unless otherwise noted.
IN
0.6
IN
800
)
LTC1108 • TPC05
LT1108 • TPC02
0.7
1000
0.8
1200
1100
1000
900
800
700
600
500
400
300
200
100
120
115
110
105
100
95
90
85
80
–50
10
Maximum Switch Current
vs R
Quiescent Current
MIN
400
LIM
–25
– 400
TEMPERATURE (°C)
1000
– 0.3
TYP
400
1.1
0
1
R
LIM
100
25
( )
– 350
MAX
1.5
1.7
10
50
LT1108
2V V
LT1108 • TPC03
IN
75
LT1108 • TPC06
UNITS
5V
%/ C
3
1000
V/ V
mA
mV
100
V
V
A