EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
FE PACKAGE
16-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 40°C/W,
θ
JC(PAD)
= 10°C/W
orDer inForMation
LEAD FREE FINISH
LT3518EUF#PBF
LT3518IUF#PBF
LT3518HUF#PBF
LT3518EFE#PBF
LT3518IFE#PBF
LT3518HFE#PBF
TAPE AND REEL
LT3518EUF#TRPBF
LT3518IUF#TRPBF
LT3518HUF#TPBF
LT3518EFE#TRPBF
LT3518IFE#TRPBF
LT3518HFE#TRPBF
http://www.linear.com/product/LT3518#orderinfo
PART MARKING*
3518
3518
3518
3518FE
3518FE
3518FE
PACKAGE DESCRIPTION
16-Lead (4mm
×
4mm) Plastic QFN
16-Lead (4mm
×
4mm) Plastic QFN
16-Lead (4mm
×
4mm) Plastic QFN
16-Lead Plastic TSSOP
16-Lead Plastic TSSOP
16-Lead Plastic TSSOP
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
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
3518ff
For more information
www.linear.com/LT3518
LT3518
electrical characteristics
PARAMETER
Minimum V
IN
Operating Voltage
Maximum V
IN
Operating Voltage
Current Sense Voltage (V
ISP
– V
ISN
)
10% Scale Current Sense Voltage (V
ISP
– V
ISN
)
Current Sense Voltage Line Regulation
V
IN
Supply Current
Switching Frequency
Continuous Operation (Note 3)
V
CTRL
= 2V, V
ISP
= 24V, VC = 1V
V
CTRL
= 2V, V
ISP
= 0V, VC = 1V
V
CTRL
= 100mV, V
ISP
= 24V, VC = 1V
2V < V
ISP
< 45V
PWM > 1.5V, VC = 0V
PWM = 0V
SHDN
= 0V
R
T
= 16.7k
R
T
= 4.03k
R
T
= 91.5k
SS = 0.5V, Out of Pin
V
SYNC
= 2V
1.5
R
T
= 91.5k (250kHz)
SYNC = 300kHz Clock Signal, R
T
= 91.5k
R
T
= 16.7k (1MHz)
R
T
= 4.03k (2.5MHz)
I
SW
= 1.5A
V
SW
= 45V, PWM = 0V
Current Out of Pin, V
CTRL
= 0.1V
20
550
1000
PWM = 0, VC = 1V
Current Out of Pin, V
FB
= 0.5V
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2) V
IN
= 5V,
SHDN
= 5V, PWM = 5V unless otherwise noted.
CONDITIONS
MIN
30
96
100
100
9
0.03
6
4.5
0.1
0.85
2.25
220
6
1.0
2.5
250
1
9
60
0.4
95
94
85
2.3
97
96
90
74
2.8
400
2
100
3.5
12
10
1
1.15
2.7
270
103
TYP
MAX
3
UNITS
V
V
mV
mV
mV
%/V
mA
mA
µA
MHz
MHz
kHz
V
µA
µA
V
V
%
%
%
%
A
mV
µA
nA
µS
kΩ
20
100
1.04
300
20
l
R
T
Voltage
Soft-Start Pin Current
SYNC Pull-Down Current (Into the Pin)
SYNC Input Low
SYNC Input High
Maximum Duty Cycle
l
Switch Current Limit
Switch V
CESAT
Switch Leakage Current
CTRL Input Bias Current
Error Amplifier Transconductance
VC Output Impedance
VC Idle Input Bias Current
FB Pin Input Bias Current
FB Pin Threshold
ISP , ISN Idle Input Bias Current
ISP , ISN Full-Scale Input Bias Current
SHDN
Voltage High
SHDN
Voltage Low
SHDN
Pin Bias Current
PWM Input High Voltage
PWM Input Low Voltage
PWM Pin Bias Current
–40°C ≤ T
J
≤ 125°C
125°C < T
J
≤ 150°C
l
–20
0.98
0
20
1.01
nA
nA
V
nA
µA
V
PWM = 0V
ISP Tied to ISN, V
ISP
= 24V, V
CTRL
= 2V
1.2
–40°C ≤ T
J
≤ 125°C
125°C < T
J
≤ 150°C
60
1.2
0.45
0.40
100
0.45
0.40
60
120
V
V
µA
V
V
V
µA
For more information
www.linear.com/LT3518
3
3518ff
LT3518
electrical characteristics
PARAMETER
TGEN Input High Voltage
TGEN Input Low Voltage
TGEN Pin Bias Current
V
REF
Pin Voltage
V
REF
Pin Voltage Line Regulation
Gate Turn-On Delay
Gate Turn-Off Delay
Top Gate Drive V
GS
(V
ISP
– V
TG
)
TGEN = 5V
I
REF
= –100µA
3V < V
IN
< 40V
C
LOAD
= 1nF Between ISP and TG
C
LOAD
= 1nF Between ISP and TG
V
ISP
= 24V, TGEN = 5V
PWM = 0V
200
200
7
0
0.3
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2) V
IN
= 5V,
SHDN
= 5V, PWM = 5V unless otherwise noted.
CONDITIONS
MIN
1.5
0.4
100
1.96
2
200
2.04
0.03
TYP
MAX
UNITS
V
V
µA
V
%/V
ns
ns
V
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 LT3518E 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
LT3518I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3518H 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:
Absolute maximum voltage at V
IN
,
SHDN,
PWM and TGEN pins
is 40V for nonrepetitive 1 second transients and 30V for continuous
operation.
Note 4:
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