Datasheet

LT1936
3
1936fd
LOAD CURRENT (A)
0
60
EFFICIENCY (%)
70
80
90
100
0.5 1.0
1936 G02
1.5
V
OUT
= 3.3V
T
A
= 25°C
D1 = DFLS140L
L1 = 10μH, TOKO D63CB
V
IN
= 5V
V
IN
= 12V
V
IN
= 24V
LOAD CURRENT (A)
0
60
EFFICIENCY (%)
70
80
90
100
0.5 1.0
1936 G01
1.5
V
OUT
= 5V
T
A
= 25°C
D1 = DFLS140L
L1 = 15μH, TOKO D63CB
V
IN
= 12V
V
IN
= 24V
DUTY CYCLE (%)
0
0
CURRENT LIMIT (A)
0.5
1.0
1.5
2.0
2.5
3.0
20 40
TYP
MIN
60 80
1936 G03
100
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT1936E is guaranteed to meet performance specifi cations
from 0°C to 70°C. Specifi cations over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
The denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 12V, V
BOOST
= 17V, unless otherwise noted. (Note 2)
V
C
Clamp 1.8 V
V
C
Switch Threshold 0.7 V
Internal Compensation R 50
Internal Compensation C V
COMP
= 1V 150 pF
COMP Pin Leakage V
COMP
= 1.8V, E and I Grades
H Grade
1
2
μA
μA
Switching Frequency V
FB
= 1.1V
V
FB
= 0V
400 500
40
600 kHz
kHz
Maximum Duty Cycle
87 92 %
Switch Current Limit (Note 3) 1.9 2.2 2.6 A
Switch V
CESAT
I
SW
= 1.2A 410 520 mV
Switch Leakage Current A
Minimum BOOST Voltage Above SW I
SW
= 1.2A 2 2.2 V
BOOST Pin Current I
SW
= 1.2A 28 50 mA
BOOST Pin Leakage V
SW
= 0V 0.1 1 μA
SHDN Input Voltage High 2.3 V
SHDN Input Voltage Low 0.3 V
SHDN Pin Current V
SHDN
= 2.3V (Note 5)
V
SHDN
= 12V (Note 5)
V
SHDN
= 0V
34
140
0.01
50
240
0.1
μA
μA
μA
with statistical process controls. The LT1936I specifi cations are
guaranteed over the –40°C to 125°C temperature range. The LT1936H
specifi cations are guaranteed over the –40°C to 150°C temperature range.
Note 3: Current limit guaranteed by design and/or correlation to static test.
Slope compensation reduces current limit at higher duty cycle.
Note 4: Current fl ows out of pin.
Note 5: Current fl ows into pin.
TYPICAL PERFORMANCE CHARACTERISTICS
Effi ciency, V
OUT
= 5V Effi ciency, V
OUT
= 3.3V Switch Current Limit