BIAS Current ...............................................................1A
Internal Operating Temperature (Note 2).... –40 to 125°C
Storage Temperature Range....................... –45 to 125°C
BIAS
SHDN
ADJ
GND
BANK 2
RT
GND
V
IN
LPWR
BANK 3
T
JMAX
= 125°C,
θ
JA
= 250°C/W, WEIGHT = 1.083g
60 Lead (15mm
×
9mm
×
2.82mm)
θ
JA
DERIVED FROM 6.35cm
×
6.35cm 4 LAYER PCB
ORDER INFORMATION
LEAD FREE FINISH
LTM8040EV#PBF
LTM8040IV#PBF
PART MARKING*
LTM8040V
LTM8040V
PACKAGE DESCRIPTION
60-Lead 15mm × 9mm LGA Package
60-Lead 15mm × 9mm LGA Package
TEMPERATURE RANGE (NOTE 3)
0°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/
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Input Voltage
Input Quiescent Current
Shutdown Current
LEDA Current
Not Switching
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, BIAS = LPWR, V
OUT
= 4V, ADJ open, RT open, V
PWM
= 5V,
unless otherwise noted (Note 3).
MIN
l
TYP
3.5
2.6
0.01
MAX
4
4
2
1.02
1.035
0.51
0.525
5.22
530
1
1.2
UNITS
V
mA
μA
A
A
A
A
μA
kΩ
kHz
V
V
V
V
SHDN
=0.3V, BIAS = 0V, LEDA = 0V
ADJ open
R
ADJ
= 5.11k
l
l
0.98
0.965
0.49
0.481
5
1
0.5
24.5
5.11
500
ADJ Bias Current
ADJ Pull-up Resistor
Switching Frequency
SHDN
Threshold
PWM Threshold
ADJ = 0V, Current flows out of pin
RT open
V
IH
V
IL
V
IH
V
IL
470
2.60
0.4
8040p
2
LTM8040
ELECTRICAL CHARACTERISTICS
PARAMETER
LEDA Clamp Voltage
Minimum BIAS Voltage
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:
This μModule includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, BIAS = LPWR, V
OUT
= 4V, ADJ open, RT open, V
PWM
= 5V,
unless otherwise noted (Note 3).
MIN
13.2
2.0
TYP
MAX
14.5
2.6
UNITS
V
V
Note 3:
The LTM8040E is guaranteed to meet performance specifications
from 0°C to 125°C internal. Specifications over the full –40°C to
125°C internal operating temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTM8040I is guaranteed to meet specifications over the full –40°C to 125°C
internal operating temperature range. Note that the maximum internal
temperature is determined by specific operating conditions in conjunction
with board layout, the rated package thermal resistance and other
environmental factors.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency - Single 2.66V at
1A LED
90
80
70
EFFICIENCY (%)
EFFICIENCY (%)
60
50
40
30
20
10
0
0
24 V
IN
12 V
IN
5 V
IN
200
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G01
Efficiency - Three 2.66V at
1A LEDs
100
90
80
EFFICIENCY (%)
24 V
IN
12 V
IN
0
200
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G02
Efficiency - Four 2.66V at
1A LEDs
100
90
80
70
60
50
40
30
20
10
0
0
200
24 V
IN
12 V
IN
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G03
70
60
50
40
30
20
10
0
Efficiency - Single 3.3V at
1A LED
90
80
70
EFFICIENCY (%)
EFFICIENCY (%)
60
50
40
30
20
10
0
0
24 V
IN
12 V
IN
5 V
IN
200
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G04
Efficiency - Two 3.3V at
1A LEDs
100
90
80
EFFICIENCY (%)
24 V
IN
12 V
IN
0
200
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G05
Efficiency - (3 x 3.3V at
1A LEDs)
100
90
80
70
60
50
40
30
20
10
0
0
200
24 V
IN
12 V
IN
800
400
600
OUTPUT CURRENT (mA)
1000
8040 G06
70
60
50
40
30
20
10
0
8040p
3
LTM8040
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Running Voltage vs
Output Voltage 2.7V at 1A LEDs
14
12
INPUT VOLTAGE
INPUT VOLTAGE
10
8
6
4
2
0
5
10
OUTPUT VOLTAGE
1A LOAD
0.5A LOAD
0.1A LOAD
15
8040 G07
Minimum Running Voltage vs
Output Voltage 3.3V at 1A LEDs
14
12
INPUT VOLTAGE
10
8
6
4
2
0
2
4
6
8
OUTPUT VOLTAGE
1A LOAD
0.5A LOAD
0.1A LOAD
10
12
8040 G08
Minimum Start Voltage vs Load
2.7V at 1A LEDs
14
12
10
8
6
4
2
0
200
400
600
I
LOAD
(mA)
800
SINGLE LED
2 LEDs
3 LEDs
4 LEDs
1000
8040 G09
Minimum Start Voltage vs Load
3.3V at 1A LEDs
14
12
INPUT VOLTAGE
10
8
6
4
2
0
200
400
600
I
LOAD
(mA)
800
SINGLE LED
2 LEDs
3 LEDs
60
50
SHUTDOWN CURRENT (mA)
40
30
20
10
0
SHDN
Current vs Voltage
12
10
BIAS CURRENT (mA)
8
6
4
2
0
BIAS Current vs Load Current
12V
IN
, Single 2.7V at 1A LED
V
BIAS
= 5V
V
BIAS
= 3.2V
V
BIAS
= 12V
1000
8040 G10
0
5
10 15 20 25 30
SHUTDOWN VOLTAGE
35
40
0
200
400
600
800
LOAD CURRENT (mA)
1000
8040 G12
8040 G11
BIAS Current vs Load Current
24V
IN
, Three 3.3V at 1A LEDs
20
18
16
BIAS CURRENT (mA)
14
12
10
8
6
4
2
0
0
200
400
600
800
LOAD CURRENT (mA)
1000
8040 G13
Input Current vs Input Voltage
Output Short Circuited
120
100
80
60
40
20
0
0
5
10
TEMPERATURE RISE (°C)
INPUT CURRENT (mA)
32
27
22
17
12
7
2
Temp Rise vs Load 2.7V at 1A
LEDs, 12V
IN
SINGLE LED
2 LEDs
3 LEDs
4 LEDs
V
BIAS
= 5V
V
BIAS
= 3.2V
V
BIAS
= 12V
15 20 25 30
INPUT VOLTAGE (V)
35
40
0
200
400
600
I
LOAD
(mA)
800
1000
8040 G15
8040 G14
8040p
4
LTM8040
TYPICAL PERFORMANCE CHARACTERISTICS
Temp Rise vs Load 2.7V at 1A
LEDs, 36V
IN
47
42
TEMPERATURE RISE (°C)
37
32
27
22
17
12
7
2
0
200
400
600
I
LOAD
(mA)
800
1000
8040 G16
Temp Rise vs Load 3.3V at 1A
LEDs, 12V
IN
27
SINGLE LED
2 LEDs
3 LEDs
TEMPERATURE RISE (°C)
SINGLE LED
2 LEDs
3 LEDs
4 LEDs
22
17
12
7
2
0
200
400
600
I
LOAD
(mA)
800
1000
8040 G17
Temp Rise vs Load 3.3V at 1A
LEDs, 36V
IN
37
32
TEMPERATURE RISE (°C)
27
22
17
12
7
2
0
200
400
600
I
LOAD
(mA)
800
SINGLE LED
2 LEDs
3 LEDs
1200
1000
LED CURRENT (mA)
1000
8040 G18
LED Current vs Adjust Voltage
800
600
400
200
0
0
200
400
600 800
ADJUST VOLTAGE
1000 1200
8040 G19
PIN FUNCTIONS
LEDA (Bank 1):
This pin is the regulated current source
of the LTM8040. Connect the anode of the LED string to
this pin. This voltage must be at least 2.4V for accurate
current regulation.
SHDN
(Pin L4):
The
SHDN
pin is used to shut down the
switching regulator and the internal bias circuits. The
2.65V switching threshold can function as an accurate
undervoltage lockout. Pull below 0.3V to shut down the
LTM8040. Pull above 2.65V to enable the LTM8040. Tie
to V
IN
if the SHDN function is unused.
BIAS (Pin L5):
The BIAS pin connects through an internal
Schottky diode to provide power to internal housekeeping
circuits. Connect to a voltage source (usually LPWR or V
IN
)
greater than 3.2V. Note that this pin is adjacent to the LPWR
pin to ease layout. If this pin is powered by an external
power source, a decoupling cap may be necessary.
LPWR (Pin K5):
This is the output of the buck regulator
that sources the LED current. If the LEDA voltage is above
3.2V, connect this pin to BIAS. It is pinned out primarily
for the convenience of the user. If it is not used, leave this
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