Datasheet

3
LT1372/LT1377
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum Switch Duty Cycle ● 85 95 %
Switch Current Limit Blanking Time 130 260 ns
BV Output Switch Breakdown Voltage LT1372/LT1377 ● 35 47 V
LT1372HV
0°C ≤ T
J
≤ 125°C ● 42 47 V
–40°C ≤ T
J
< 0°C (I Grade) 40 V
V
SAT
Output Switch “On” Resistance I
SW
= 1A ● 0.5 0.8 Ω
I
LIM
Switch Current Limit Duty Cycle = 50% ● 1.5 1.9 2.7 A
Duty Cycle = 80% (Note 2)
● 1.3 1.7 2.5 A
∆I
IN
Supply Current Increase During Switch On-Time 15 25 mA/A
∆I
SW
Control Voltage to Switch Current 2A/V
Transconductance
Minimum Input Voltage ● 2.4 2.7 V
I
Q
Supply Current 2.7V ≤ V
IN
≤ 25V ● 4 5.5 mA
Shutdown Supply Current 2.7V ≤ V
IN
≤ 25V, V
S/S
≤ 0.6V
0°C ≤ T
J
≤ 125°C ● 12 30 µA
–40°C ≤ T
J
< 0°C (I Grade) 50 µA
Shutdown Threshold 2.7V ≤ V
IN
≤ 25V ● 0.6 1.3 2 V
Shutdown Delay ● 51225µs
S/S Pin Input Current 0V ≤ V
S/S
≤ 5V ● –10 15 µA
Synchronization Frequency Range LT1372 ● 600 800 kHz
LT1377
● 1.2 1.6 MHz
Switch Saturation Voltage
vs Switch Current
TEMPERATURE (°C)
–50
1.8
INPUT VOLTAGE (V)
2.0
2.2
2.4
2.6
050
100
150
LT1372 • G03
2.8
3.0
–25 25
75
125
Minimum Input Voltage
vs Temperature
DUTY CYCLE (%)
0
SWITCH CURRENT LIMIT (A)
1.0
2.0
3.0
0.5
1.5
2.5
20 40 60 80
LT1372 • G02
10010
0
30 50 70 90
25°C AND
125°C
–55°C
Switch Current Limit
vs Duty Cycle
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
SWITCH CURRENT (A)
0
SWITCH SATURATION VOLTAGE (V)
0.6
0.8
1.0
1.6
LT1372 • G01
0.4
0.2
0.5
0.7
0.9
0.3
0.1
0
0.4
0.8
1.2
2.0
1.4
0.2
0.6
1.0
1.8
100°C
150°C
25°C
–55°C
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
The ● 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.
ELECTRICAL CHARACTERISTICS
Note 2: For duty cycles (DC) between 50% and 90%, minimum
guaranteed switch current is given by I
LIM
= 0.667 (2.75 – DC).