LT1372/LT1377
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Maximum Switch Duty Cycle
Switch Current Limit Blanking Time
BV
Output Switch Breakdown Voltage
The
q
denotes specifcatons which appy over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
IN
= 5V, V
C
= 0.6V, V
FB
= V
REF
, V
SW
, S/S and NFB pins open, unless otherwise noted.
CONDITIONS
q
MIN
85
35
42
40
1.5
1.3
TYP
95
130
MAX
260
UNITS
%
ns
V
V
V
LT1372/LT1377
LT1372HV
0°C
≤
T
J
≤
125°C
– 40°C
≤
T
J
< 0°C (I Grade)
I
SW
= 1A
Duty Cycle = 50%
Duty Cycle = 80% (Note 2)
q
q
q
q
q
47
47
0.5
1.9
1.7
15
2
0.8
2.7
2.5
25
V
SAT
I
LIM
∆I
IN
∆I
SW
Output Switch “On” Resistance
Switch Current Limit
Supply Current Increase During Switch On-Time
Control Voltage to Switch Current
Transconductance
Minimum Input Voltage
Ω
A
A
mA/A
A/V
q
2.4
4
12
0.6
5
– 10
600
1.2
1.3
12
2.7
5.5
30
50
2
25
15
800
1.6
V
mA
µA
µA
V
µs
µA
kHz
MHz
I
Q
Supply Current
Shutdown Supply Current
2.7V
≤
V
IN
≤
25V
2.7V
≤
V
IN
≤
25V, V
S/S
≤
0.6V
0°C
≤
T
J
≤
125°C
– 40°C
≤
T
J
< 0°C (I Grade)
2.7V
≤
V
IN
≤
25V
0V
≤
V
S/S
≤
5V
LT1372
LT1377
q
q
q
q
q
q
q
Shutdown Threshold
Shutdown Delay
S/S Pin Input Current
Synchronization Frequency Range
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2:
For duty cycles (DC) between 50% and 90%, minimum
guaranteed switch current is given by I
LIM
= 0.667 (2.75 – DC).
TYPICAL PERFORMANCE CHARACTERISTICS
Switch Saturation Voltage
vs Switch Current
1.0
3.0
SWITCH SATURATION VOLTAGE (V)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
150°C
100°C
SWITCH CURRENT LIMIT (A)
INPUT VOLTAGE (V)
–55°C
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
SWITCH CURRENT (A)
LT1372 • G01
U W
25°C
Switch Current Limit
vs Duty Cycle
3.0
2.8
25°C AND
125°C
–55°C
1.5
1.0
0.5
0
0
10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
LT1372 • G02
Minimum Input Voltage
vs Temperature
2.5
2.0
2.6
2.4
2.2
2.0
1.8
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1372 • G03
3
LINER [ LINEAR TECHNOLOGY ]
