LT1939EDD ........................................ –40°C to 125°C
LT1939IDD ......................................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
DD PACKAGE
12-LEAD (3mm
×
3mm) PLASTIC DFN
θ
JA
= 45°C/W,
θ
JC(PAD)
= 10°C/W
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT1939EDD#PBF
LT1939IDD#PBF
TAPE AND REEL
LT1939EDD#TRPBF
LT1939IDD#TRPBF
PART MARKING*
LDJZ
LDJZ
PACKAGE DESCRIPTION
12-Lead (3mm
×
3mm) Plastic DFN
12-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C. V
VIN
= 15V, V
RT/SYNC
= 2V, unless otherwise specified.
PARAMETER
SHDN Threshold
SHDN Source Current
SHDN Current Hysterisis
Minimum Input Voltage (Note 3)
Supply Shutdown Current
Supply Quiescent Current
FB Voltage
FB Bias Current
Error Amplifier g
m
Error Amplifier Source Current
Error Amplifier Sink Current
Error Amplifier High Clamp
Error Amplifier Switching Threshold
SS Source Current
V
FB
= 0V
V
SHDN
= 0V
V
FB
= 0.9V
V
VC
= 1V
V
VC
= 0.6V to 1.6V, V
IN
= 3V to 25V
V
FB
= 0.8V, V
VC
= 1V
V
VC
= 1V, I
VC
= ±10μA
V
FB
= 0.6V, V
VC
= 1V
V
FB
= 1V, V
VC
= 1V
V
FB
= 0.6V
V
FB
= 0.6V
V
SHDN
= 1V, V
SS
= 0.4V, V
FB
= 0.9V
150
12
14
1.8
0.6
2.25
l
l
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
l
TYP
760
2.5
2
2.4
12
2.5
MAX
780
3.5
3.25
2.8
30
3.5
0.816
0.824
150
350
20
22
2.2
1.0
3.75
UNITS
mV
μA
μA
V
μA
mA
V
V
nA
μmho
μA
μA
V
V
μA
710
1.5
1.25
0.784
0.776
0.8
0.8
50
250
16
18
2.0
0.8
2.75
1939f
2
LT1939
ELECTRICAL CHARACTERISTICS
PARAMETER
SS Sink Current
SS POR Sink Current (Note 4)
SS POR Threshold
SS to FB Offset (V
SS
– V
FB
)
PG/PG Leakage
PG/
PG
Threshold
PG/
PG
Hysteresis
PG Sink Current
PG
Sink Current
R
T
/SYNC Reference Voltage
Switching Frequency
CONDITIONS
V
FB
= 0V, V
SS
= 2V
V
FB
= 0V, V
SS
= 2V, Cycle SHDN
V
FB
= 0V
V
VC
= 1V, V
SS
= 0.4V
V
FB
= 0.9V/0.7V, V
PG
/V
PG
= 25V
V
PG
= 0.4V
V
PG
= 0.4V
V
PG
= 0.4V, V
FB
= 0.7V
V
PG
= 0.4V, V
FB
= 0.9V
V
FB1/2
= 0.9V, R
RT/SYNC
= 15k
R
RT/SYNC
= 90.9k
R
RT/SYNC
= 90.9k
R
RT/SYNC
= 15k
V
FB
= 0.7V, R
RT/SYNC
= 90.9k
V
FB
= 0.7V, R
RT/SYNC
= 90.9k
V
SW
= 0V
I
SW
= 2A, V
BST
= 18V, V
FB
= 0.7V
V
BST
= 18V, V
FB
= 0.7V
I
SW
= 2A, V
BST
= 18V, V
FB
= 0.7V
I
SW
= 2A, V
FB
= 0.7V
V
LDRV
= 1.2V
V
VIN
= 3V to 25V, V
LDRV
= 8V
V
VC
= 1V, V
SS
= 0.8V, V
LDRV
= V
LFB
V
LFB
= 0.8V, V
VC
= 1V
V
LDRV
= 3V, I
LDRV
= 5mA
V
LDRV
= 0V
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C. V
VIN
= 15V, V
RT/SYNC
= 2V, unless otherwise specified.
MIN
300
400
50
70
0.685
20
250
500
0.75
450
425
2
250
140
120
1
450
2.3
2.1
20
0.784
0.776
90
0.8
9
2.8
2.8
30
2.2
0.8
0.8
115
115
1.2
13
3.5
3.5
45
3
0.816
0.824
140
300
1.6
18
10
TYP
600
600
100
100
0.1
0.708
30
500
800
0.850
500
500
2.4
MAX
900
800
150
120
1
0.730
40
750
1100
0.975
550
625
2.8
2500
UNITS
μA
μA
mV
mV
μA
V
mV
μA
μA
V
kHz
kHz
MHz
kHz
ns
ns
μA
mV
A
A
mA
V
V
V
mV
nA
V
mA
SYNC Frequency Range
Minimum Switch On Time
Minimum Switch Off Time
Switch Leakage Current
Switch Saturation Voltage
Switch Peak Current
Boost Current
Minimum Boost Voltage (Note 5)
LFB Voltage
LFB Line/Load Regulation
SS to LFB Offset (V
SS
– V
LFB
)
LFB Bias Current
LDRV Dropout
LDRV Maximum Current
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.
Note2:
The LT1939EDD is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT1939IDD is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 3:
Minimum input voltage is defined as the voltage where internal
bias lines are regulated so that the reference voltage and oscillator remain
constant. Actual minimum input voltage to maintain a regulated output
will depend upon output voltage and load current. See Applications
Information.
Note 4:
An internal power-on reset (POR) latch is set on the positive
transition of the SHDN pin through its threshold. The output of the latch
activates a current source on the SS pin which typically sinks 600μA,
discharging the SS capacitor. The latch is reset when the SS pin is driven
below the soft-start POR threshold or the SHDN pin is taken below its
threshold.
Note 5:
This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
Note 6:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
when overtemperature protection is active. Continuous operation above
the specified maximum operating junction temperature may impair device
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