LT1270 Linear Technology, LT1270 Datasheet - Page 3

• Manufacturer Part Number: LT1270
• Description: 8A and 10A High Efficiency Switching Regulators
• Manufacturer: Linear Technology

ELECTRICAL CHARACTERISTICS
SYMBOL
I
I
f
DC
The
temperature range.
Note 1: Measured with V
Note 2: For duty cycles (DC) between 50% and 80%, minimum guaranteed
TYPICAL PERFOR
LIM
LIM
I
I
SW
IN
MAX
denotes specifications which apply over the full operating
PARAMETER
Switch Current Limit (LT1270)
(Note 3)
Switch Current Limit (LT1270A)
(Note 3)
Supply Current Increase
During Switch-ON Time
Switching Frequency
Maximum Switch Duty Cycle
Flyback Sense Delay Time
Shutdown Mode Supply Current
Shutdown Mode Threshold Voltage
2.4
1.8
1.2
0
6
Switch Current Limit vs Duty Cycle
0
C
–55°C
125°C
in Hi Clamp, V
20
DUTY CYCLE (%)
40
W
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
FB
A
25°C
60
= 0.8V.
U
CE
80
LT1270 • TA03
CONDITIONS
Duty Cycle = 50%, T
Duty Cycle = 80%, T
Duty Cycle = 50%, T
Duty Cycle = 80%, T
3V V
3V V
C
HARA TERISTICS
100
IN
IN
V
V
MAX
MAX
C
V
, V
IN
C
= 15V, V
J
J
J
J
= 0.05V
100 C
100 C
100 C
100 C
switch current is given by I
8.33 (1.7 – DC) for the LT1270A.
Note 3: Minimum current limit is reduced by 0.5A at 125 C. 100 C test
limits are guaranteed by correlation to 125 C tests.
C
= 0.5V, V
1.6
1.2
0.8
0.4
0
FB
Switch Saturation Voltage
0
= V
T
J
= 25°C
REF
10.0
MIN
100
2
7.5
50
50
80
50
8
6
, switch pin open, unless otherwise noted.
LIM
SWITCH CURRENT (A)
= 6.67 (1.7 – DC) for the LT1270 and I
4
LT1270A/LT1270
TYP
100
150
1.5
25
60
92
6
8
LT1270 • TA04
MAX
16.0
14.0
400
250
300
16
14
40
70
70
95
10
UNITS
mA/A
LIM
3
kHz
kHz
mV
mV
%
A
A
A
A
A
s
=