LT3992EUH........................................ –40°C to 125°C
LT3992IUH......................................... –40°C to 125°C
LT3992EFE......................................... –40°C to 125°C
LT3992IFE.......................................... –40°C to 125°C
LT3992HFE ........................................ –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
pin conFiguraTion
TOP VIEW
NC
1
2
3
4
5
6
7
8
9
39
GND
38 SW1
37 NC
36 V
IN1
35 SHDN1
34 SS1
33 I
LIM1
32 V
C1
31 NC
30 RT/SYNC
29 CLKOUT
28 T
J
27 DIV
26 VC2
25 I
LIM2
24 SS2
23 SHDN2
22 V
IN2
21 NC
20 SW2
SHDN1
TOP VIEW
V
OUT1
DNC*
DNC*
IND1
SW1
V
IN1
IND1
NC
SS1
V
OUT1
NC
32 31 30 29 28 27 26 25
BST1 1
CMPO1 2
CMPI1 3
FB1 4
FB2 5
CMPI2 6
CMPO2 7
BST2 8
9 10 11 12 13 14 15 16
SHDN2
V
OUT2
DNC*
IND2
DNC*
SW2
V
IN2
SS2
33
GND
24 ILIM1
23 V
C1
22 RT/SYNC
21 CLKOUT
20 T
J
19 DIV
18 V
C2
17 ILIM2
BST1
CMPO1
CMPI1
FB1
NC 10
FB2 11
CMPI2 12
CMPO2 13
BST2 14
NC 15
V
OUT2
16
NC 17
IND2 18
NC 19
UH PACKAGE
32-LEAD (5mm
×
5mm) PLASTIC QFN
θ
JA
= 44°C/W,
θ
JC(PAD)
= 7.3°C/W
EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB
*DO NOT CONNECT
FE PACKAGE
38-LEAD PLASTIC TSSOP
θ
JA
= 17.5°C/W,
θ
JC(PAD)
= 10°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LT3992EUH#PBF
LT3992IUH#PBF
LT3992EFE#PBF
LT3992IFE#PBF
LT3992HFE#PBF
TAPE AND REEL
LT3992EUH#TRPBF
LT3992IUH#TRPBF
LT3992EFE#TRPBF
LT3992IFE#TRPBF
LT3992HFE#TRPBF
PART MARKING*
3992
3992
LT3992FE
LT3992FE
LT3992FE
PACKAGE DESCRIPTION
32-Lead (5mm
×
5mm) Plastic QFN
32-Lead (5mm
×
5mm) Plastic QFN
38-Lead Plastic TSSOP
38-Lead Plastic TSSOP
38-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 150°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/
2
3992fa
For more information
www.linear.com/LT3992
LT3992
elecTrical characTerisTics
PARAMETER
SHDN Voltage Threshold CH1/2
SHDN Input Current CH1/2
V
IN1
Undervoltage Lockout (Note 3)
V
IN1
Shutdown Current
V
IN2
Shutdown Current
V
IN1
Quiescent Current
V
IN2
Quiescent Current
Feedback Voltage CH1/2
Feedback Voltage Regulation
Feedback Voltage Offset CH1 to CH2
Feedback Bias Current CH1/2
T
J
Output Voltage (Note 4)
T
J
Error
Error Amp g
m
CH1/2
Error Amp Source Current CH1/2
Error Amp Sink Current CH1/2
Error Amp High Clamp CH1/2
Error Amp Switching Threshold CH1/2
Soft-Start Source Current CH1/2
Soft-Start V
OH
CH1/2
Soft-Start Sink Current CH1/2
Soft-Start V
OL
CH1/2
Soft-Start to Feedback Offset CH1/2
SS POR Threshold CH1/2
Soft-Start Sink Current CH1/2 POR
Soft-Start SW Disable CH1/2
CMPI Bias Current CH1/2
CMPO Leakage CH1/2
CMPI Threshold CH1/2
CMPI Threshold CH1/2 of V
FB1/2
CMPI Hysteresis CH1/2
CMPO Sink Current CH1/2
RT/SYNC Reference Current
RT/SYNC Reference Current
Minimum Switching Frequency
Switching Frequency
Maximum Switching Frequency
Switching Phase Angle CH1 ≥ CH2
DIV Reference Current
CH1 DIV 2 Threshold
V
DIV
= 1V
R
RT/SYNC
= 0V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
VIN1/2
= 15V unless otherwise specified. (Note 2)
CONDITIONS
l
MIN
1.24
–1
2.6
l
l
TYP
1.32
0
2.9
6
0.1
MAX
1.4
1
3.2
13
2
6
900
824
830
13
300
UNITS
V
µA
V
µA
µA
mA
µA
mV
mV
mV
nA
mV
V
mV
V
SHDN
= 1.35V
V
SHDN
= 0V
V
SHDN
= 0V
V
FB1/2
= 2V
V
FB1/2
= 2V
V
VC1/2
= 1V
V
VIN1/2
= 4V to 60V
V
VC1/2
= 1V
V
VC1/2
= 1V
T
J
= 25°C, I
TJ
= 25µA, Temperature = 25°C
I
TJ
= 25µA, Temperature = 125°C
I
TJ
= 25µA, Temperature = –40°C
Temperature = 25°C to 125°C
V
VC1/2
= 1V, I
VC1/2
= ±10µA
V
FB1/2
= 0.7V, V
VC1/2
= 1V
V
FB1/2
=0.9V, V
VC1/2
= 1V
V
FB1/2
= 0.7V
V
FB1/2
= 0V
V
FB1/2
= 2V, V
SS1/2
= 0.07V
V
FB1/2
= 2.0V
V
FB1/2
= 0.7V, V
SS1/2
= 2V
V
FB1/2
= 0V
V
VC1/2
= 1V, V
SS1/2
= 0.4V
V
FB1/2
= 2V, V
SS1/2
= 0.14V (Note 5)
V
FB1/2
= 0V (Note 5)
V
CMPI1/2
= 0.8V
V
CMP1/2
= 0.8V, V
CMPO1/2
= 60V
V
CMPI1/2
Rising
V
CMPI1/2
Rising (Note 6)
V
CMPI1/2
V
CMPI1/2
= 0.6V, V
CMPO1/2
= 0.2V
V
RT/SYNC
= 0.36V E- & I-Grade
V
RT/SYNC
= 0.36V H-Grade
R
RT/SYNC
=0Ω
R
RT/SYNC
= 28k
R
RT/SYNC
=100k
l
l
l
l
l
l
l
l
l
l
3
300
786
780
–13
0
4.2
530
806
806
0
85
250
1.23
–380
–100
250
15
15
1.7
0.8
9
1.9
0.4
130
16
70
150
80
–100
690
86
50
150
11.3
11.2
50
900
2.2
10.7
0.44
0
350
25
25
1.9
1.0
13.5
2.15
0.9
170
0
110
450
115
0
70
725
90
80
250
12
12
110
1000
2.5
185
12
0.5
100
450
40
40
2.1
1.2
17
2.4
2
210
16
140
600
150
100
500
760
94
105
12.7
13
150
1100
3.0
13.3
0.56
mV
µMho
µA
µA
V
V
µA
V
mA
mV
mV
mV
µA
mV
nA
nA
mV
%
mV
µA
µA
µA
kHz
kHz
MHz
Deg
µA
V
3992fa
For more information
www.linear.com/LT3992
3
LT3992
elecTrical characTerisTics
PARAMETER
CH1 DIV 4 Threshold
CH1 DIV 8 Threshold
CLKOUT V
OL
CLKOUT V
OH
CLKOUT to SW1ON Delay ( t
DCLKOSW1
)
CLKOUT to SW2ON Delay ( t
DCLKOSW2
)
RT/SYNC to CLKOUT Delay ( t
DRTSYNCH
)
RT/SYNC to CLKOUT Delay ( t
DRTSYNCL
)
SYNC Frequency Range
SYNC Phase Angle CH1 to CH2
Minimum Switch On-Time CH1/2
Minimum Switch Off-Time CH1/2
Minimum Boost for 100% DC CH1/2 (Note 7)
IND + V
OUT
Current CH1/2
ILIM1/2 Reference Current
IND to V
OUT
Maximum Current CH1/2
V
VOUT1/2
= 0V
V
VOUT1/2
= 5V
V
ILIM
= 0V
V
ILIM1/2
= 0.5V, V
VOUT
= 1V (Note 8)
V
ILIM1/2
= 0.5V, V
VOUT
= 5V (Note 8)
V
ILIM1/2
= 1.5V, V
VOUT
= 1V (Note 8)
V
ILIM1/2
= 1.5V, V
VOUT
= 5V (Note 8)
V
SW1/2
= 0V
I
SW1/2
= 500mA, V
BST1/2
= 18V
I
SW1/2
= 3A, V
BST1/2
= 18V
I
SW1/2
= 500mA, V
BST1/2
= 8V
I
SW1/2
= 3A, V
BST1/2
= 8V
I
SW1/2
= 3A, V
BST1/2
= 8V
5
35
1.0
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
VIN1/2
= 15V unless otherwise specified. (Note 2)
CONDITIONS
R
RT/SYNC
= 0V
R
RT/SYNC
= 0V
MIN
0.89
1.39
TYP
1.0
1.5
0.25
2
CLKOUT Rising
CLKOUT Falling
V
RT/SYNC
= 0V to 2V Rising Edge
V
RT/SYNC
= 2V to 0V Falling Edge
250
SYNC Frequency = 250kHz
180
160
200
1.6
2.2
1.5
0.5
10
0.5
0.7
3.5
3.5
12
1.5
1.8
4.6
4.6
1
200
325
8
55
2.2
25
85
3.0
2.6
5
5
16
3
3
6.4
6.4
10
60
30
300
150
2000
MAX
1.06
1.56
UNITS
V
V
V
V
ns
ns
ns
ns
kHz
Deg
ns
ns
V
µA
µA
µA
A
A
A
A
µA
mV
mV
mA
mA
V
l
l
l
Switch Leakage Current CH1/2
Switch Saturation Voltage CH1/2
Boost Current CH1/2
Minimum Boost Voltage CH1/2 (Note 9)
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 LT3992EUH/LT3992EFE 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 LT3992IUH/LT3992IFE is guaranteed over the full –40°C to 125°C
operating junction temperature range. The LT3992HFE is guaranteed
over the full –40°C to 150°C operating junction temperature range. High
junction temperatures degrade operating lifetimes. Operating lifetime is
derated at junction temperatures greater than 125°C.
Note 3:
V
IN
undervoltage lockout is defined as the voltage which the V
IN
pin must exceed for operation. The threshold guarantees that internal bias
lines are regulated and switching frequency is constant. Actual minimum
input voltage to maintain a regulated output will depend upon output
voltage and load current. See the Applications Information section.
Note 4:
The T
J
output voltage represents the temperature at the center
of the die while dissipating quiescent power. Due to switch power
dissipation and temperature gradients across the die, the T
J
output
voltage measurement does not guarantee that absolute maximum junction
temperature will not be exceeded.
Note 5:
An internal power on reset (POR) latch is set on the positive
transition of the SHDN1/2 pin through its threshold, thermal shutdown or
overvoltage lockout. The output of the latch activates current sources on
each SS pin which typically sink 450µA and discharge the SS capacitor.
The latch is reset when both SS pins are driven below the soft-start POR
threshold or the SHDN pin is taken below its threshold.
Note 6:
The threshold is expressed as a percentage of the feedback
reference voltage for the channel.
Note 7:
To enhance dropout operation, the output switch will be turned off
for the minimum off-time only when the voltage across the boost capacitor
drops below the minimum boost for 100% duty cycle threshold.
Note 8:
The IND to V
OUT
maximum current is defined as the value of
current flowing from the IND pin to the V
OUT
pin which resets the switch
latch when the V
C
pin is at its high clamp.
Note 9:
This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
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