SYNC Voltage .............................................................6V
Operating Junction Temperature Range (Note 2)
LT8640E/LT8640-1E .......................... –40°C to 125°C
LT8640I/LT8640-1I ............................ –40°C to 125°C
LT8640H/LT8640-1H ......................... –40°C to 150°C
Storage Temperature Range ......................–65 to 150°C
20 19 18
BIAS 1
INTV
CC
2
BST 3
V
IN1
4
GND1 6
UDC AND UDCF PACKAGES
18-LEAD (3mm
×
4mm) PLASTIC QFN
θ
JA
= 40°C/W,
θ
JC(PAD)
= 12°C/W (Note 3)
EXPOSED PAD (PINS 21, 22) ARE SW, SHOULD BE SOLDERED TO PCB
NOTE: PINS 5 AND 12 ARE REMOVED. CONFIGURATION DOES
NOT
MATCH
JEDEC 20-LEAD PACKAGE OUTLINE
ORDER INFORMATION
LEAD FREE FINISH
LT8640EUDC#PBF
LT8640IUDC#PBF
LT8640HUDC#PBF
LT8640EUDC-1#PBF
LT8640IUDC-1#PBF
LT8640HUDC-1#PBF
LT8640EUDCF#PBF
LT8640IUDCF#PBF
LT8640EUDCF-1#PBF
LT8640IUDCF-1#PBF
TAPE AND REEL
LT8640EUDC#TRPBF
LT8640IUDC#TRPBF
LT8640HUDC#TRPBF
LT8640EUDC-1#TRPBF
LT8640IUDC-1#TRPBF
LT8640HUDC-1#TRPBF
LT8640EUDCF#TRPBF
LT8640IUDCF#TRPBF
LT8640EUDCF-1#TRPBF
LT8640IUDCF-1#TRPBF
PART MARKING*
LGNJ
LGNJ
LGNJ
LGVT
LGVT
LGVT
LHJK
LHJK
LHGX
LHGX
PACKAGE DESCRIPTION
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic QFN
18-Lead (3mm
×
4mm) Plastic Side
Wettable QFN
18-Lead (3mm
×
4mm) Plastic Side
Wettable QFN
18-Lead (3mm
×
4mm) Plastic Side
Wettable QFN
18-Lead (3mm
×
4mm) Plastic Side
Wettable QFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications.
Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
PG
FB
Rev.C
2
For more information
www.analog.com
LT8640/LT8640-1
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Input Voltage
V
IN
Quiescent Current
V
EN/UV
= 0V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
CONDITIONS
l
MIN
TYP
2.9
0.75
0.75
1.7
1.7
0.3
21
220
MAX
3.4
3
10
4
10
0.5
50
350
0.976
0.982
0.02
20
UNITS
V
µA
µA
µA
µA
mA
µA
µA
V
V
%/V
nA
mA
ns
ns
ns
kHz
kHz
MHz
mΩ
A
mΩ
µA
V
mV
nA
%
%
%
nA
Ω
V
V
V
%
kHz
V
EN/UV
= 2V, Not Switching, V
SYNC
= 0V
l
V
EN/UV
= 2V, Not Switching, V
SYNC
= 2V (LT8640 Only)
V
IN
Current in Regulation
Feedback Reference Voltage
Feedback Voltage Line Regulation
Feedback Pin Input Current
BIAS Pin Current Consumption
Minimum On-Time
Minimum Off-Time
Oscillator Frequency
R
T
= 221k
R
T
= 60.4k
R
T
= 18.2k
I
SW
= 1A
l
l
l
l
V
OUT
= 0.97V, V
IN
= 6V, Output Load = 100µA
V
OUT
= 0.97V, V
IN
= 6V, Output Load = 1mA
V
IN
= 6V, I
LOAD
= 0.5A
V
IN
= 6V, I
LOAD
= 0.5A
V
IN
= 4.0V to 42V
V
FB
= 1V
V
BIAS
= 3.3V, f
SW
= 2MHz
I
LOAD
= 1.5A, SYNC = 0V
I
LOAD
= 1.5A, SYNC = 3.3V
l
l
l
l
0.964
0.958
–20
0.970
0.970
0.004
11
l
l
35
30
80
180
665
1.85
7.5
–15
210
700
2.00
67
10
28
50
50
110
240
735
2.15
12.5
15
Top Power NMOS On-Resistance
Top Power NMOS Current Limit
Bottom Power NMOS On-Resistance
SW Leakage Current
EN/UV Pin Threshold
EN/UV Pin Hysteresis
EN/UV Pin Current
PG Upper Threshold Offset from V
FB
PG Lower Threshold Offset from V
FB
PG Hysteresis
PG Leakage
PG Pull-Down Resistance
SYNC/MODE Threshold
V
INTVCC
= 3.4V, I
SW
= 1A
V
IN
= 42V, V
SW
= 0V, 42V
EN/UV Rising
V
EN/UV
= 2V
V
FB
Falling
V
FB
Rising
V
PG
= 3.3V
V
PG
= 0.1V
SYNC/MODE DC and Clock Low Level Voltage
SYNC/MODE Clock High Level Voltage
SYNC/MODE DC High Level Voltage
R
T
= 60.4k, V
SYNC
= 3.3V
V
SYNC
= 3.3V
l
l
l
l
l
0.94
–20
5
–5.25
–40
1.0
40
1.06
20
7.5
–8
0.2
10.25
–10.75
40
700
0.7
1.0
2.3
0.9
1.2
2.6
22
3
1.2
1.9
200
2000
1.1
1.4
2.9
Spread Spectrum Modulation
Frequency Range
Spread Spectrum Modulation Frequency
TR/SS Source Current
TR/SS Pull-Down Resistance
2.6
µA
Ω
Fault Condition, TR/SS = 0.1V
Rev.C
For more information
www.analog.com
3
LT8640/LT8640-1
ELECTRICAL CHARACTERISTICS
PARAMETER
LT8640-1 Output Sink Current in Forced
Continuous Mode
LT8640-1 V
IN
to Disable Forced Continuous
Mode
LT8640-1 V
FB
Offset from Feedback
Reference Voltage to Disable Forced
Continuous Mode
CONDITIONS
V
FB
= 1.01V, L = 6.8µH, R
T
= 60.4k
V
IN
Rising
V
FB
Rising
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
MIN
0.25
35
7
TYP
0.6
37
9.5
MAX
1
39
12
UNITS
A
V
%
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 LT8640E/LT8640-1E 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 LT8640I/LT8640-1I is guaranteed over the full –40°C to
125°C operating junction temperature range. The LT8640H/LT8640-1H 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.
The junction temperature (T
J
, in °C) is calculated from the ambient
temperature (T
A
in °C) and power dissipation (PD, in Watts) according to
the formula:
T
J
= T
A
+ (PD •
θ
JA
)
where
θ
JA
(in °C/W) is the package thermal impedance.
Note 3:
θ
values determined per JEDEC 51-7, 51-12. See Applications
Information section for information on improving the thermal resistance
and for actual temperature measurements of a demo board in typical
operating conditions.
Note 4:
This IC includes overtemperature protection that is intended to
protect the device during overload conditions. Junction temperature will
exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
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