RT Voltage ..................................................................6V
CPOR, CWDT, SS Voltage ...........................................3V
Operating Junction Temperature Range
LT8495E, LT8495I (Notes 2, 3) .......... –40°C to 125°C
LT8495H (Notes 2, 3) ........................ –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
FE Package ....................................................... 300°C
PIN CONFIGURATION
CWDT
TOP VIEW
BIAS
FB
FB
NC
CPOR
CWDT
RST
SS
NC
1
2
3
4
5
6
7
8
9
21
GND
20 SW
19 NC
18 V
IN
17 NC
16 WDI
15
WDO
14 GND
13 WDE
12 SWEN
11
RSTIN
SS 1
RT 2
GND 3
GND 4
RSTIN
5
6
SWEN
7
WDE
8
WDO
9 10
WDI
V
IN
21
GND
RST
TOP VIEW
CPOR
BIAS
15 GND
14 GND
13 GND
12 SW
11 GND
FB
20 19 18 17 16
RT 10
FE PACKAGE
20-LEAD PLASTIC TSSOP
θ
JA
= 38°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
UF PACKAGE
20-LEAD (4mm
×
4mm) PLASTIC QFN
θ
JA
= 47°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT8495EUF#PBF
LT8495IUF#PBF
LT8495EFE#PBF
LT8495IFE#PBF
LT8495HFE#PBF
TAPE AND REEL
LT8495EUF#TRPBF
LT8495IUF#TRPBF
LT8495EFE#TRPBF
LT8495IFE#TRPBF
LT8495HFE#TRPBF
http://www.linear.com/product/LT8495#orderinfo
PART MARKING*
8495
8495
LT8495FE
LT8495FE
LT8495FE
PACKAGE DESCRIPTION
20-Lead (4mm × 4mm) Plastic QFN
20-Lead (4mm × 4mm) Plastic QFN
20-Lead Plastic TSSOP
20-Lead Plastic TSSOP
20-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.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
8495fb
For more information
www.linear.com/LT8495
LT8495
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
SWEN
= 12V, V
BIAS
= V
WDE
= 5V, unless otherwise noted
(Note 2).
PARAMETER
Minimum V
IN
Operating Voltages
Minimum BIAS Operating Voltages
CONDITIONS
V
BIAS
< 2.5V
V
BIAS
≥ 2.5V
V
IN
< 2.5V
V
IN
≥ 2.5V
l
l
l
l
l
l
ELECTRICAL CHARACTERISTICS
MIN
TYP
2.4
2.4
MAX
2.5
0
2.5
0
36.5
36.4
UNITS
V
V
V
V
V
V
mV
Power Switch Driver (PSD) Overvoltage Threshold V
IN
or BIAS Rising
V
IN
or BIAS Falling
(Note 4)
Power Switch Driver (PSD) Overvoltage Threshold
Hysteresis (Note 4)
Quiescent Current from V
IN
V
SWEN
= 0V, V
WDE
= 0V, V
RSTIN
= 0V
V
SWEN
= 5V, V
WDE
= 0V, V
FB
= V
RSTIN
= 1.25V
V
SWEN
= 5V, V
WDE
= 5V, V
FB
= V
RSTIN
= 1.25V
V
SWEN
= 5V, V
WDE
= 0V, V
FB
= V
RSTIN
= 1.25V
(LT8495E, LT8495I)
(LT8495H)
V
SWEN
= 5V, V
WDE
= 5V, V
FB
= V
RSTIN
= 1.25V
(LT8495E, LT8495I)
(LT8495H)
V
SWEN
= 0V, V
WDE
= 0V, V
RSTIN
= 0V
V
SWEN
= 5V, V
WDE
= 0V, V
FB
= V
RSTIN
= 1.25V
V
SWEN
= 5V, V
WDE
= 5V, V
FB
= V
RSTIN
= 1.25V
V
SWEN
= 5V, V
WDE
= 0V, V
FB
= V
RSTIN
= 1.25V
(LT8495E, LT8495I)
(LT8495H)
V
SWEN
= 5V, V
WDE
= 5V, V
FB
= V
RSTIN
= 1.25V
(LT8495E, LT8495I)
(LT8495H)
V
BIAS
-V
IN
, V
BIAS
Rising, V
IN
= 12V
V
BIAS
-V
IN
, V
BIAS
Falling, V
IN
= 12V
Hysteresis (Rising-Falling Threshold)
V
FB
= 1.202V
5V ≤ V
IN
≤ 32V, V
BIAS
= 5V
5V ≤ V
IN
≤ 32V, V
BIAS
= 0V
32.1
32
34
33.9
100
0.3
3.0
3.1
0.9
4.8
4.9
6.2
8.0
6.3
8.0
0.5
2.8
8.5
4.0
11
10.0
15.5
1.2
0.57
0.80
1.230
20
10
10
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
V
V
V
V
nA
m%/V
m%/V
ns
ns
l
l
l
l
3.0
3.0
3.1
3.1
0.07
1.7
6.0
Quiescent Current from BIAS
l
l
l
l
l
l
l
l
1.7
1.7
6.0
6.0
0.55
0.17
0.20
1.178
0.90
0.37
0.53
1.202
0.1
0.2
0.2
70
95
BIAS to V
IN
Comparator Threshold
Feedback Voltage
FB Pin Bias Current (Note 7)
FB Voltage Line Regulation
Minimum Switch Off-Time
Minimum Switch On-Time
Switching Frequency
Switch Current Limit at Min. Duty Cycle (Note 5)
Switch Current Limit at Max. Duty Cycle (Note 6)
Switch V
CESAT
Switch Leakage Current (Note 7)
Soft-Start Charging Current (Note 7)
SWEN Pin Current (Note 7)
R
T
= 68.1k
R
T
= 324k
l
l
l
l
0.92
219
2.1
1.3
1.0
250
2.55
1.85
340
0.01
1.06
280
2.95
2.4
1
12.2
25
200
550
1.1
MHz
kHz
A
A
mV
μA
μA
nA
nA
nA
V
mV
I
SW
= 1.2A
V
SW
= 12V, V
SWEN
= 0V
V
SS
= 100mV
V
SWEN
= 1.2V
V
SWEN
= 5V
V
SWEN
= 12V
l
l
5.2
8.2
0
35
240
SWEN Rising Voltage Threshold
SWEN Voltage Hysteresis
0.9
1
30
8495fb
For more information
www.linear.com/LT8495
3
LT8495
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
SWEN
= 12V, V
BIAS
= V
WDE
= 5V, unless otherwise noted
(Note 2).
PARAMETER
RSTIN
Pin Current (Note 7)
CONDITIONS
V
RSTIN
= 1.2V
V
RSTIN
= 5V
V
RSTIN
= 12V
l
ELECTRICAL CHARACTERISTICS
MIN
TYP
0
35
240
MAX
25
200
550
97
60
11.85
20.9
812
150
150
150
0.3
1.0
420
0.25
0.1
1.25
UNITS
nA
nA
nA
%
µs
ms
ms
µs
mV
mV
mV
µA
μA
mV
μA
µA
V
mV
ns
RSTIN
Threshold as % of V
FB
Regulation Voltage
RSTIN
Low to
RST
Asserted (t
UV
)
Watchdog Timeout and Reset Delay Period (t
RST
)
(Note 8)
Watchdog Upper Boundary (t
WDU
) (Note 8)
Watchdog Lower Boundary (t
WDL
) (Note 8)
RST
Output Voltage Low
Step V
RSTIN
from 1.3V to 0.9V
C
POR
= 4700pF, Watchdog Timeout Not Occurring
at Same Time as the Reset Delay
C
WDT
= 1000pF
C
WDT
= 1000pF
I
SINK
= 1.25mA
I
SINK
= 100μA, V
BIAS
= 1.3V, V
IN
= 0V
I
SINK
= 100μA, V
IN
= 1.3V, V
BIAS
= 0V
V
RSTIN
= 1.2V, V
RST
= 5V (LT8495E, LT8495I)
V
RSTIN
= 1.2V, V
RST
= 5V (LT8495H)
I
SINK
= 1.25mA
V
WDO
= 5V
V
WDI
= 5V
86
8
8.5
14.9
580
92
23
9.5
16.7
650
33
15
15
0
0
120
0
0
l
l
l
l
l
l
l
l
l
l
l
RST
Leakage Current
WDO
Output Voltage Low
WDO
Leakage Current
WDI Pin Current
WDI Input Rising Threshold
WDI Voltage Hysteresis
WDI Input Pulse Width
WDE Pin Current (Note 7)
l
0.4
300
0.8
58
l
V
WDE
= 1.2V
V
WDE
= 5V
V
WDE
= 12V
l
0
35
240
0.9
1
30
25
200
550
1.1
nA
nA
nA
V
mV
WDE Rising Voltage Threshold
WDE Voltage Hysteresis
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. Voltages are with respect to GND pin unless
otherwise noted.
Note 2:
The LT8495E 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
LT8495I is guaranteed to meet performance specifications from –40°C
to 125°C junction temperature. The LT8495H is guaranteed over the full
–40°C to 150°C operating junction temperature range. Operating lifetime is
derated at junction temperatures greater than 125°C.
Note 3:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions.
Junction temperature will exceed the maximum operating range when
overtemperature protection is active. Continuous operation above the
specified maximum operating junction temperature may impair device
reliability.
Note 4:
See Power Supplies and Operating Limits in the Applications
Information section for more details.
Note 5:
Current limit guaranteed by design and/or correlation to static test.
Slope Compensation reduces current limit at higher duty cycles.
Note 6:
Max duty cycle current limit measured at 1MHz switching
frequency.
Note 7:
Polarity specification for all currents into pins is positive. All
voltages are referenced to GND unless otherwise specified.
Note 8:
This specification is guaranteed for only the exact capacitance as
listed in the conditions. Variation of the capacitance from the exact listed
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