LT1512 Linear Technology, LT1512 Datasheet - Page 3

• Manufacturer Part Number: LT1512
• Description: SEPIC Constant-Current/ Constant-Voltage Battery Charger
• Manufacturer: Linear Technology

TYPICAL PERFORMANCE CHARACTERISTICS
V
SYMBOL
V
I
I
The
temperature range.
Note 1: For duty cycles (DC) between 50% and 85%, minimum
guaranteed switch current is given by I
Note 2: The I
Note 3: Commercial devices are guaranteed over 0 C to 125 C junction
temperature range and 0 C to 70 C ambient temperature range. These
parts are also designed, characterized and expected to operate over the
– 20 C to 85 C extended ambient temperature range, but are not tested at
– 20 C or 85 C. Devices with full guaranteed electrical specifications over
ELECTRICAL C
LIM
Q
SAT
IN
I
I
SW
IN
1.0
0.9
0.8
0.7
0.2
0.1
0.6
0.5
0.4
0.3
= 5V, V
0
denotes specifications which apply over the full operating
Switch Saturation Voltage
vs Switch Current
0
0.2
PARAMETER
Output Switch ON Resistance
Switch Current Limit
Supply Current Increase During Switch ON Time
Control Voltage to Switch Current
Transconductance
Minimum Input Voltage
Supply Current
Shutdown Supply Current
Shutdown Threshold
Shutdown Delay
S/S Pin Input Current
Synchronization Frequency Range
C
FB
0.4
= 0.6V, V
pin is servoed to its regulating state with V
SWITCH CURRENT (A)
0.6
0.8
FB
1.0
100 C
= V
HARA TERISTICS
1.2
REF
–55 C
150 C
1.4
, I
W
1.6
FB
LIM
25 C
= 0V, V
1.8
C
1512 G01
= 0.667 (2.75 – DC).
U
2.0
SW
and S/S pins open, unless otherwise noted.
3.0
2.5
2.0
1.5
1.0
0.5
C
0
= 0.8V.
0
Switch Current Limit
vs Duty Cycle
10
CONDITIONS
I
Duty Cycle = 50%
Duty Cycle = 80% (Note 1)
2.7V V
2.7V V
2.7V V
0V V
SW
0 C T
– 40 C T
20
= 2A
S/S
30
IN
IN
IN
DUTY CYCLE (%)
J
40
5V
25V
25V, V
25V
J
125 C
50
the ambient temperature range – 40 C to 85 C are available as industrial
parts with an “I” suffix.
Maximum allowable ambient temperature may be limited by power
dissipation. Parts may not necessarily be operated simultaneously at
maximum power dissipation and maximum ambient temperature.
Temperature rise calculations must be done as shown in the Applications
Information section to ensure that maximum junction temperature does
not exceed 125 C limit. With high power dissipation, maximum ambient
temperature may be less than 70 C.
0 C (LT1512I)
60
–55 C
S/S
70
25 C AND
125 C
0.6V
80
90
1512 G02
100
2.4
3.0
2.8
2.6
2.2
2.0
1.8
–50
MIN
– 10
600
1.5
1.3
0.6
Minimum Input Voltage
vs Temperature
5
–25
0
TEMPERATURE ( C)
TYP
0.5
1.9
1.7
2.4
1.3
15
12
12
2
4
25
50
75
MAX
800
LT1512
0.8
2.7
2.5
2.7
5.5
25
30
50
25
15
2
100
125
UNITS
1512 G03
mA/A
3
A/V
kHz
mA
150
A
A
V
A
A
V
A
s