Datasheet

LT1941
4
1941fb
The l denotes the specifi cations which apply over the full operating temperature
range, otherwise specifi cations are at T
A
= 25°C. V
IN
, V
BIAS1
, V
BIAS2
= 5V, V
BOOST1
, V
BOOST2
= 8V, unless otherwise noted. (Note 2)
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Switch 2 Leakage Current 0.01 10 μA
Minimum Boost Voltage Above Switch (Note 4) 1.8 2.5 V
Maximum Duty Cycle
l
78 88 %
1.5A Inverting/Boost
FB3 Voltage
l
1.23
1.22
1.25 1.27
1.27
V
V
FB3 Pin Bias Current
l
800 1400 nA
NFB Voltage
l
–15 0 15 mV
NFB Pin Bias Current
l
60 500 nA
NFB3 Voltage (V
FB3
-V
NFB
)
l
1.212
1.205
1.24 1.258
1.260
V
V
FB3 Pin Output Current V
FB3
= 1.35V, V
NFB
= –0.1V
l
150 350 μA
PGOOD3 Threshold Offset V
FB
Rising 120 mV
Error Amplifi er Transconductance 800 μMhos
Error Amplifi er Voltage Gain 150 V/V
V
C
Switching Threshold 1.1 V
V
C3
to Switch Current Gain 5A/V
Frequency Shift Threshold on FB3 0.65 V
Switch 3 Current Limit (Note 5)
l
1.5 2 2.9 A
Switch 3 V
CESAT
I
SW
= 1A 240 320 mV
BIAS2 Pin Current I
SW
= 1A 30 45 mA
Switch 3 Leakage Current 0.01 10 μA
Maximum Duty Cycle
l
77 86 %
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 LT1941E 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
with statistical process controls.
Note 3: Current limit is guaranteed by design and/or correlation to static
test. Slope compensation reduces current limit at higher duty cycles.
Note 4: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
Note 5: Current limit is guaranteed by design and/or correlation to static
test.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Note 7: Guaranteed by design, not 100% tested.