LINER LTM8033 40vin, 3.5a step-down silent switcher î¼module regulator Datasheet

LTM8003
40VIN, 3.5A Step-Down
Silent Switcher µModule
Regulator
DESCRIPTION
FEATURES
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Complete Step-Down Switch Mode Power Supply
Low Noise Silent Switcher® Architecture
Wide Input Voltage Range: 3.4V to 40V
Wide Output Voltage Range: 0.97V to 18V
Wide Temperature Range: –40°C to 150°C (H-Grade)
3.5A Continuous Output Current, 6A peak
FMEA Compliant Pinout (LTM8003-3.3)
Output Stays at or Below Regulation Voltage During
Adjacent Pin Short or if a Pin Is Left Floating
Selectable Switching Frequency: 200kHz to 3MHz
External Synchronization
Low Quiescent Current: 25µA (5VOUT)
Tiny, Low Profile 6.25mm × 9mm × 3.32mm RoHS
Compliant BGA Package
APPLICATIONS
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The LTM®8003 is a 40VIN, 6A peak, 3.5A continuous stepdown Silent Switcher µModule® (power module) regulator.
Included in the package are the switching controller, power
switches, inductor, and all support components. Operating
over an input voltage range of 3.4V to 40V, the LTM8003
supports an output voltage range of 0.97V to 18V and a
switching frequency range of 200kHz to 3MHz, each set by
a single resistor. Only the input and output filter capacitors
are needed to finish the design.
The low profile package enables utilization of unused
space on the bottom of PC boards for high density point of
load regulation. The LTM8003 is packaged in a thermally
enhanced, compact over-molded ball grid array (BGA) package suitable for automated assembly by standard surface
mount equipment. The LTM8003 is RoHS compliant.
All registered trademarks and trademarks are the property of their respective owners.
Automotive Battery Regulation
Power for Portable Products
Distributed Supply Regulation
Industrial Supplies
Wall Transformer Regulation
TYPICAL APPLICATION
5VOUT from 7VIN to 40VIN Step-Down Converter
Efficiency, VOUT = 5V
95
LTM8003
VIN
85
RUN
4.7µF
VOUT
BIAS
RT
41.2k
1MHz
GND
SYNC
FB
24.3k
47µF
VOUT
5V
3.5A
6A PEAK
EFFICIENCY (%)
VIN
7V TO 40V
12VIN
8003 TA01a
75
65
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
55
0
1
2
3
LOAD CURRENT (A)
4
8003 TA01
8003fc
For more information www.linear.com/LTM8003
1
LTM8003
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Maximum Internal Temperature (I-Grade) ........... 125°C
Maximum Internal Temperature (H-Grade) ......... 150°C
Storage Temperature (I-Grade) ........................... 125°C
Storage Temperature (H-Grade) ........... –50°C to 150°C
Peak Reflow Solder Body Temperature ............... 250°C
VIN, RUN, PG Voltage .............................................. 42V
VOUT, BIAS Voltage ................................................. 19V
FB, TR/SS Voltage ..................................................... 4V
SYNC Voltage ............................................................ 6V
PIN CONFIGURATION
TOP VIEW
ADJUSTABLE VERSION
TOP VIEW
FIXED OUTPUT VERSION
SYNC TR/SS
SYNC TR/SS
GND
A
GND
A
RT
GND
RT
GND
RUN
RUN
B
B
PG
PG
C
C
BANK2
VIN
D
BANK2
VIN
D
BANK 1 GND
BANK 1 GND
E
NC
E
NC
FB
F
F
BIAS
BIAS
G
G
BANK 3 VOUT
BANK 3 VOUT
H
H
1
2
3
4
5
1
6
2
3
4
5
6
BGA PACKAGE
48-LEAD (9mm × 6.25mm × 3.32mm) BGA PACKAGE
BGA PACKAGE
48-LEAD (9mm × 6.25mm × 3.32mm) BGA PACKAGE
TJMAX = 150°C, θJA = 23.5°C/W, θJCbottom = 3.2°C/W
θJCtop = 17.9°C/W, θJB = 3.1°C/W, WEIGHT = 0.5g
θ VALUES DETERMINED PER JEDEC51-9, 51-12
TJMAX = 150°C, θJA = 23.5°C/W, θJCbottom = 3.2°C/W
θJCtop = 17.9°C/W, θJB = 3.1°C/W, WEIGHT = 0.5g
θ VALUES DETERMINED PER JEDEC51-9, 51-12
ORDER INFORMATION (http://www.linear.com/product/LTM8003#orderinfo)
PART MARKING*
PART NUMBER
TERMINAL FINISH
DEVICE
FINISH CODE
PACKAGE
TYPE
MSL
RATING
LTM8003IY#PBF
SAC305 (RoHS)
LTM8003
e1
BGA
3
LTM8003HY#PBF
SAC305 (RoHS)
LTM8003
e1
BGA
3
–40°C to 150°C
SnPb (63/37)
LTM8003
e0
BGA
3
–40°C to 125°C
LTM8003IY
LTM8003HY
TEMPERATURE RANGE
–40°C to 125°C
SnPb (63/37)
LTM8003
e0
BGA
3
–40°C to 150°C
LTM8003-3.3IY#PBF
SAC305 (RoHS)
LTM8003-3.3
e1
BGA
3
–40°C to 125°C
LTM8003-3.3HY#PBF
SAC305 (RoHS)
LTM8003-3.3
e1
BGA
3
–40°C to 150°C
• Consult Marketing for parts specified with wider operating temperature
ranges. *Device temperature grade is indicated by a label on the shipping
container. Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Terminal Finish Part Marking: www.linear.com/leadfree
2
• Recommended BGA PCB Assembly and Manufacturing Procedures:
www.linear.com/umodule/pcbassembly
• BGA Package and Tray Drawings: www.linear.com/packaging
8003fc
For more information www.linear.com/LTM8003
LTM8003
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
temperature range, otherwise specifications are at TJ = 25°C. VIN = 12V, RUN = 2V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
Minimum Input Voltage
VIN Rising
Output DC Voltage
LTM8003, RFB Open
LTM8003, RFB = 5.62kΩ, VIN = 40V
LTM8003-3.3
MAX
Peak Output DC Current
VOUT = 3.3V, fSW = 1MHz
Quiescent Current into VIN
RUN = 0V
BIAS = 0V, No Load, SYNC = 0V, Not Switching
3
8
µA
µA
Quiescent Current into BIAS
BIAS = 5V, RUN = 0V
BIAS = 5V, No Load, SYNC = 0V, Not Switching
BIAS = 5V, VOUT = 3.3V, IOUT = 3.5A, fSW = 1MHz
1
5
12
µA
µA
mA
Line Regulation
5.5V < VIN < 36V, IOUT = 1A
0.5
3.4
l
0.97
18
3.3
UNITS
V
V
6
A
%
Load Regulation
0.1A < IOUT < 3.5A
0.5
%
Output Voltage Ripple
IOUT = 3.5A
10
mV
Switching Frequency
RT = 232kΩ
RT = 41.2kΩ
RT = 10.7kΩ
200
0.95
3
kHz
MHz
MHz
Voltage at FB
LTM8003
Minimum BIAS Voltage
(Note 5)
l
RUN Threshold Voltage
950
970
0.9
RUN Current
TR/SS Current
TR/SS = 0V
980
mV
3.2
V
1.06
V
1
µA
2
µA
TR/SS Pull Down
TR/SS = 0.1V
200
Ω
PG Threshold Voltage at FB (Upper)
FB Falling (Note 6, LTM8003)
1.05
V
PG Threshold Voltage at FB (Lower)
FB Rising (Note 6, LTM8003)
0.89
V
PG Threshold Voltage at VOUT (Upper)
VOUT Falling (Note 6, LTM8003-3.3)
3.57
V
PG Threshold Voltage at VOUT (Lower)
VOUT Rising (Note 6, LTM8003-3.3)
3.03
V
PG Leakage Current
PG = 42V
PG Sink Current
PG = 0.1V
SYNC Threshold Voltage
Synchronization
0.4
1.5
SYNC Voltage
To Enable Spread Spectrum
2.9
4.2
V
SYNC Current
SYNC = 0V
35
µA
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: Unless otherwise noted, the absolute minimum voltage is zero.
Note 3: The LTM8003I is guaranteed to meet specifications over the full
–40°C to 125°C internal operating temperature range. The LTM8003H
is guaranteed to meet specifications over the full –40°C to 150°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. High junction temperatures degrade operating
lifetimes. Operating lifetime is derated at junction temperatures greater
than 125°C.
1
150
µA
µA
V
Note 4: The LTM8003 contains overtemperature protection that is
intended to protect the device during momentary overload conditions. The
internal temperature exceeds the maximum operating junction temperature
when the overtemperature protection is active. Continuous operation
above the specified maximum operating junction temperature may impair
device reliability.
Note 5: Below this specified voltage, internal circuitry will draw power
from VIN.
Note 6: PG transitions from low to high.
8003fc
For more information www.linear.com/LTM8003
3
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
90
65
55
45
0
1
2
3
LOAD CURRENT (A)
70
60
12VIN
24VIN
36VIN
50
4
1
2
3
LOAD CURRENT (A)
80
80
80
2
3
LOAD CURRENT (A)
70
60
12VIN
24VIN
36VIN
1
EFFICIENCY (%)
90
0
50
4
0
1
2
3
LOAD CURRENT (A)
55
4
85
85
1
2
3
LOAD CURRENT (A)
EFFICIENCY (%)
85
EFFICIENCY (%)
95
0
4
8003 G07
0
1
2
3
LOAD CURRENT (A)
75
55
1
2
3
LOAD CURRENT (A)
75
65
12VIN
24VIN
36VIN
0
4
Efficiency vs Load Current,
VOUT = 8V, BIAS = 5V
95
55
12VIN
24VIN
36VIN
8003 G06
95
65
4
70
Efficiency vs Load Current,
VOUT = 5V, BIAS = 5V
12VIN
24VIN
36VIN
2
3
LOAD CURRENT (A)
8003 G05
Efficiency vs Load Current,
VOUT = 3.3V, BIAS = 5V
65
1
60
12VIN
24VIN
36VIN
8003 G04
75
0
Efficiency vs Load Current,
VOUT = 2.5V, BIAS = 5V
90
50
12VIN
24VIN
36VIN
8003 G03
Efficiency vs Load Current,
VOUT = 2V, BIAS = 5V
EFFICIENCY (%)
EFFICIENCY (%)
50
4
90
60
EFFICIENCY (%)
60
12VIN
24VIN
36VIN
0
70
8003 G02
Efficiency vs Load Current,
VOUT = 1.8V, BIAS = 5V
70
Efficiency vs Load Current,
VOUT = 1.5V, BIAS = 5V
80
8003 G01
4
90
80
EFFICIENCY (%)
EFFICIENCY (%)
75
Efficiency vs Load Current,
VOUT = 1.2V, BIAS = 5V
EFFICIENCY (%)
85
Efficiency vs Load Current,
VOUT = 0.97V, BIAS = 5V
TA = 25°C, unless otherwise noted.
4
8003 G08
55
12VIN
24VIN
36VIN
0
1
2
3
LOAD CURRENT (A)
4
8003 G09
8003fc
For more information www.linear.com/LTM8003
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
100
75
70
1
2
3
LOAD CURRENT (A)
24VIN
36VIN
60
4
0
1
2
3
LOAD CURRENT (A)
60
80
80
80
1
2
3
LOAD CURRENT (A)
70
60
5VIN
12VIN
24VIN
36VIN
0
EFFICIENCY (%)
90
EFFICIENCY (%)
90
50
50
4
0
1
2
3
LOAD CURRENT (A)
50
4
Efficiency vs Load Current,
VOUT = –15V, BIAS Tied to
LTM8003 GND
80
80
0
1
2
LOAD CURRENT (A)
EFFICIENCY (%)
80
EFFICIENCY (%)
90
50
70
60
3
8003 G16
1
2
3
LOAD CURRENT (A)
50
0.5
1
1.5
LOAD CURRENT (A)
2
70
60
12VIN
24VIN
0
4
Efficiency vs Load Current,
VOUT = –18V, BIAS Tied to
LTM8003 GND
90
5VIN
12VIN
24VIN
0
8003 G15
90
60
5VIN
12VIN
24VIN
8003 G14
Efficiency vs Load Current,
VOUT = –12V, BIAS Tied to
LTM8003 GND
4
70
60
5VIN
12VIN
24VIN
36VIN
8003 G13
70
2
3
LOAD CURRENT (A)
Efficiency vs Load Current,
VOUT = –8V, BIAS Tied to
LTM8003 GND
90
60
1
8003 G12
Efficiency vs Load Current,
VOUT = –5V, BIAS Tied to
LTM8003 GND
70
0
8003 G11
Efficiency vs Load Current,
VOUT = –3.3V, BIAS Tied to
LTM8003 GND
EFFICIENCY (%)
24VIN
36VIN
4
8003 G10
EFFICIENCY (%)
80
70
24VIN
36VIN
0
Efficiency vs Load Current,
VOUT = 18V, BIAS = 5V
90
80
65
55
100
90
EFFICIENCY (%)
EFFICIENCY (%)
85
Efficiency vs Load Current,
VOUT = 15V, BIAS = 5V
EFFICIENCY (%)
95
Efficiency vs Load Current,
VOUT = 12V, BIAS = 5V
TA = 25°C, unless otherwise noted.
2.5
8003 G17
50
12VIN
24VIN
0
0.5
1
1.5
LOAD CURRENT (A)
2
8003 G18
8003fc
For more information www.linear.com/LTM8003
5
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
1.00
0.6
0.4
0.2
0
0
2
4
LOAD CURRENT (A)
Input vs Load Current
VOUT = 1.2V, BIAS = 5V
0.75
0.50
0.25
0
6
0
2
4
LOAD CURRENT (A)
8003 G19
0.50
0.25
0
2
4
LOAD CURRENT (A)
0.9
0.6
0
6
0
2
4
LOAD CURRENT (A)
8003 G22
INPUT CURRENT (A)
INPUT CURRENT (A)
3.00
12VIN
24VIN
36VIN
1.5
1.0
0.5
0
0
2
4
LOAD CURRENT (A)
6
8003 G25
6
2
4
LOAD CURRENT (A)
12VIN
24VIN
36VIN
0.8
0.4
0
2
4
LOAD CURRENT (A)
5.0
12VIN
24VIN
36VIN
0.75
0
Input vs Load Current
VOUT = 8V, BIAS = 5V
12VIN
24VIN
36VIN
4.0
1.50
6
8003 G24
Input vs Load Current
VOUT = 5V, BIAS = 5V
2.25
6
Input vs Load Current
VOUT = 2.5V, BIAS = 5V
8003 G23
Input vs Load Current
VOUT = 3.3V, BIAS = 5V
2.0
0
1.2
0
6
INPUT CURRENT (A)
2.5
0.3
1.6
12VIN
24VIN
36VIN
0.3
0
0.6
8003 G21
Input vs Load Current
VOUT = 2V, BIAS = 5V
1.2
INPUT CURRENT (A)
INPUT CURRENT (A)
1.5
12VIN
24VIN
36VIN
0.75
12VIN
24VIN
36VIN
8003 G20
Input vs Load Current
VOUT = 1.8V, BIAS = 5V
1.00
Input vs Load Current
VOUT = 1.5V, BIAS = 5V
0.9
0
6
INPUT CURRENT (A)
1.25
1.2
12VIN
24VIN
36VIN
INPUT CURRENT (A)
12VIN
24VIN
36VIN
INPUT CURRENT (A)
INPUT CURRENT (A)
0.8
Input vs Load Current
VOUT = 0.97V, BIAS = 5V
TA = 25°C, unless otherwise noted.
3.0
2.0
1.0
0
2
4
LOAD CURRENT (A)
6
8003 G26
0
0
2
4
LOAD CURRENT (A)
6
8003 G27
8003fc
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LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
4
3
2
1
0
0
2
4
LOAD CURRENT (A)
5
24VIN
36VIN
2
1
0
2
4
LOAD CURRENT (A)
0
0.0
6
1.0
4
12VIN
24VIN
36VIN
2
1
0
6
0
2
4
LOAD CURRENT (A)
1
0
1
2
LOAD CURRENT (A)
1
3
8003 G34
0
1
2
3
LOAD CURRENT (A)
4
12VIN
24VIN
2
1
0
0.5
1
1.5
LOAD CURRENT (A)
5
Input vs Load Current
VOUT = –18V, BIAS Tied to
LTM8003 GND
3
0
4
8003 G33
INPUT CURRENT (A)
INPUT CURRENT (A)
INPUT CURRENT (A)
4
2
0
2
Input vs Load Current
VOUT = –15V, BIAS Tied to
LTM8003 GND
12VIN
24VIN
6
12VIN
24VIN
8003 G32
Input vs Load Current
VOUT = –12V, BIAS Tied to
LTM8003 GND
3
5.0
3
0
6
8003 G31
4
2.0
3.0
4.0
LOAD CURRENT (A)
Input vs Load Current
VOUT = –8V, BIAS Tied to
LTM8003 GND
0.5
2
4
LOAD CURRENT (A)
1.0
8003 G30
INPUT CURRENT (A)
INPUT CURRENT (A)
INPUT CURRENT (A)
3
12VIN
24VIN
36VIN
0
2
Input vs Load Current
VOUT = –5V, BIAS Tied to
LTM8003 GND
1.5
0
3
8003 G29
Input vs Load Current
VOUT = –3.3V, BIAS Tied to
LTM8003 GND
2.0
24VIN
36VIN
1
8003 G28
2.5
Input vs Load Current
VOUT = 18V, BIAS = 5V
4
3
0
6
Input vs Load Current
VOUT = 15V, BIAS = 5V
INPUT CURRENT (A)
24VIN
36VIN
INPUT CURRENT (A)
INPUT CURRENT (A)
4
Input vs Load Current
VOUT = 12V, BIAS = 5V
TA = 25°C, unless otherwise noted.
2
2.5
8003 G35
12VIN
24VIN
3
2
1
0
0
0.5
1
1.5
LOAD CURRENT (A)
2
8003 G36
8003fc
For more information www.linear.com/LTM8003
7
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
BIAS Current vs Load Current
VOUT = 0.97V, BIAS = 5V
BIAS Current vs Load Current
VOUT = 1.2V, BIAS = 5V
5.0
BIAS CURRENT (mA)
BIAS CURRENT (mA)
4.0
3.5
3.0
2.5
12VIN
24VIN
36VIN
0
2
4
LOAD CURRENT (A)
5.0
4.5
4.0
3.5
3.0
6
5.5
0
2
4
LOAD CURRENT (A)
4.5
4.0
3.5
12VIN
24VIN
36VIN
3.0
6
8003 G37
BIAS Current vs Load Current
VOUT = 2V, BIAS = 5V
5.5
6.0
4.5
4.0
5.0
4.5
4.0
12VIN
24VIN
36VIN
2
4
LOAD CURRENT (A)
BIAS CURRENT (mA)
5.0
BIAS CURRENT (mA)
6.5
0
3.5
6
0
2
4
LOAD CURRENT (A)
6.0
5.5
12VIN
24VIN
36VIN
6
8003 G43
8
12VIN
24VIN
36VIN
0
2
4
LOAD CURRENT (A)
6
8003 G42
BIAS Current vs Load Current
VOUT = 8V, BIAS = 5V
9
10
8
9
BIAS CURRENT (mA)
BIAS CURRENT (mA)
BIAS CURRENT (mA)
6.5
2
4
LOAD CURRENT (A)
4.0
6
BIAS Current vs Load Current
VOUT = 5V, BIAS = 5V
7.0
0
5.0
8003 G41
BIAS Current vs Load Current
VOUT = 3.3V, BIAS = 5V
4.5
6
5.5
4.5
12VIN
24VIN
36VIN
8003 G40
5.0
2
4
LOAD CURRENT (A)
BIAS Current vs Load Current
VOUT = 2.5V, BIAS = 5V
6.0
3.0
0
8003 G39
5.5
3.5
12VIN
24VIN
36VIN
8003 G38
BIAS Current vs Load Current
VOUT = 1.8V, BIAS = 5V
BIAS CURRENT (mA)
BIAS Current vs Load Current
VOUT = 1.5V, BIAS = 5V
BIAS CURRENT (mA)
4.5
2.0
TA = 25°C, unless otherwise noted.
7
6
5
12VIN
24VIN
36VIN
0
2
4
LOAD CURRENT (A)
6
8003 G44
8
7
6
12VIN
24VIN
36VIN
0
2
4
LOAD CURRENT (A)
6
8003 G45
8003fc
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LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
BIAS Current vs Load Current
VOUT = 12V, BIAS = 5V
BIAS Current vs Load Current
VOUT = 15V, BIAS = 5V
12
9
8
10
9
8
2
4
LOAD CURRENT (A)
6
6
24VIN
36VIN
0
2
4
LOAD CURRENT (A)
300
750
0
3
16
4
3
2
–3.3VOUT
–5VOUT
–8VOUT
1
0
40
0
3.0
6
1.5
–12VOUT
–15VOUT
–18VOUT
30
8003 G52
5
4
3
2
0
12VIN
24VIN
36VIN
0
20
30
INPUT VOLTAGE (V)
40
8003 G51
Derating, H-Grade, VOUT = 1.2V,
BIAS = 5V, DC2416A Demo Board
7
0 LFM
1
10
8003 G50
MAXIMUM LOAD CURRENT (A)
7
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
5
Derating, H-Grade, VOUT = 0.97V,
BIAS = 5V, DC2416A Demo Board
3.5
10
20
INPUT VOLTAGE (V)
28
VIN (V)
Maximum Load Current vs VIN
BIAS Open
0
6
SYNC Grounded
SYNC Floating
8003 G49
2.0
6
Maximum Load Current vs VIN
BIAS Open
1500
6
2.5
2
4
LOAD CURRENT (A)
8003 G48
MAXIMUM LOAD CURRENT (A)
INPUT CURRENT (mA)
DROPOUT VOLTAGE (mV)
2250
600
0.5
0
Input Current vs VIN
VOUT Short Circuited
900
1.0
24VIN
36VIN
8003 G47
Dropout Voltage vs Load Current,
VOUT = 5V, BIAS = 5V
2
4
LOAD CURRENT (A)
9
7
6
8003 G46
0
10
8
7
24VIN
36VIN
0
11
BIAS CURRENT (mA)
BIAS CURRENT (mA)
BIAS CURRENT (mA)
12
11
10
0
BIAS Current vs Load Current
VOUT = 18V, BIAS = 5V
12
11
7
TA = 25°C, unless otherwise noted.
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G53
0 LFM
6
5
4
3
2
12VIN
24VIN
36VIN
1
0
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G54
8003fc
For more information www.linear.com/LTM8003
9
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
Derating, H-Grade, VOUT = 1.5V,
BIAS = 5V, DC2416A Demo Board
7
5
4
3
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
5
4
3
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
8003 G55
3
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
6
5
4
3
2
12VIN
24VIN
36VIN
1
0
150
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G61
10
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
7
0 LFM
5
4
3
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
4
3
2
1
0
24VIN
36VIN
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G62
150
8003 G60
Derating, H-Grade, VOUT = 15V,
BIAS = 5V, DC2416A Demo Board
6
0 LFM
5
150
6
0
150
MAXIMUM LOAD CURRENT (A)
3
0
6
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
4
12VIN
24VIN
36VIN
1
Derating, H-Grade, VOUT = 12V,
BIAS = 5V, DC2416A Demo Board
0 LFM
5
2
8003 G59
Derating, H-Grade, VOUT = 8V,
BIAS = 5V, DC2416A Demo Board
6
3
Derating, H-Grade, VOUT = 5V,
BIAS = 5V, DC2416A Demo Board
0 LFM
8003 G58
7
4
8003 G57
MAXIMUM LOAD CURRENT (A)
4
0
7
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
5
5
Derating, H-Grade, VOUT = 3.3V,
BIAS = 5V, DC2416A Demo Board
0 LFM
6
6
0
150
0 LFM
8003 G56
Derating, H-Grade, VOUT = 2.5V,
BIAS = 5V, DC2416A Demo Board
7
7
0 LFM
6
0
150
Derating, H-Grade, VOUT = 2V,
BIAS = 5V, DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
0 LFM
6
0
Derating, H-Grade, VOUT = 1.8V,
BIAS = 5V, DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
7
TA = 25°C, unless otherwise noted.
0 LFM
5
4
3
2
1
0
24VIN
36VIN
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G63
8003fc
For more information www.linear.com/LTM8003
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
Derating, H-Grade, VOUT = –3.3V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
Derating, H-Grade, VOUT = 18V,
BIAS = 5V, DC2416A Demo Board
4
3
2
24VIN
36VIN
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
5
4
3
2
12VIN
24VIN
36VIN
1
0
150
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
8003 G64
2
1
12VIN
24VIN
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
3
2
1
0
150
0.5
12VIN
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
150
8003 G70
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
0 LFM
1.5
1.0
0.5
0
150
12VIN
24VIN
0
25
50
75
100
125
AMBIENT TEMPERATURE (°C)
5
4
3
2
12VIN
24VIN
36VIN
1
0
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
125
8003 G71
150
8003 G69
Derating, I-Grade, VOUT = 1.2V,
BIAS = 5V, DC2416A Demo Board
7
0 LFM
6
150
2.0
12VIN
24VIN
7
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
1.0
0
2.5
Derating, I-Grade, VOUT = 0.97V,
BIAS = 5V, DC2416A Demo Board
0 LFM
1.5
12VIN
24VIN
36VIN
8003 G68
Derating, H-Grade, VOUT = –18V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
0
1
Derating, H-Grade, VOUT = –15V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
0 LFM
8003 G67
2.0
2
8003 G66
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
4
0 LFM
0
3
Derating, H-Grade, VOUT = –12V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
3
0
4
0
150
0 LFM
8003 G65
Derating, H-Grade, VOUT = –8V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
4
5
0 LFM
MAXIMUM LOAD CURRENT (A)
1
Derating, H-Grade, VOUT = –5V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
5
0
6
0 LFM
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
6
TA = 25°C, unless otherwise noted.
0 LFM
6
5
4
3
2
12VIN
24VIN
36VIN
1
0
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
125
8003 G72
8003fc
For more information www.linear.com/LTM8003
11
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
Derating, I-Grade, VOUT = 1.5V,
BIAS = 5V, DC2416A Demo Board
7
4
3
2
12VIN
24VIN
36VIN
1
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
6
5
4
3
2
12VIN
24VIN
36VIN
1
0
125
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
8003 G73
4
3
2
12VIN
24VIN
36VIN
1
0
7
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
5
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
6
5
4
3
2
12VIN
24VIN
36VIN
1
0
125
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
12VIN
24VIN
36VIN
1
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
125
8003 G79
12
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
6
0 LFM
5
4
3
2
12VIN
24VIN
36VIN
1
0
125
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
4
3
2
1
0
24VIN
36VIN
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
125
8003 G80
125
8003 G78
Derating, I-Grade, VOUT = 15V,
BIAS = 5V, DC2416A Demo Board
6
0 LFM
5
125
Derating, I-Grade, VOUT = 5V,
BIAS = 5V, DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
2
0
6
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
3
12VIN
24VIN
36VIN
1
Derating, I-Grade, VOUT = 12V,
BIAS = 5V, DC2416A Demo Board
0 LFM
4
2
8003 G77
Derating, I-Grade, VOUT = 8V,
BIAS = 5V, DC2416A Demo Board
5
3
8003 G75
0 LFM
8003 G76
6
4
Derating, I-Grade, VOUT = 3.3V,
BIAS = 5V, DC2416A Demo Board
0 LFM
6
5
0
125
0 LFM
6
8003 G74
Derating, I-Grade, VOUT = 2.5V,
BIAS = 5V, DC2416A Demo Board
7
7
0 LFM
MAXIMUM LOAD CURRENT (A)
5
Derating, I-Grade, VOUT = 2V,
BIAS = 5V, DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
0 LFM
6
0
Derating, I-Grade, VOUT = 1.8V,
BIAS = 5V, DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
7
TA = 25°C, unless otherwise noted.
0 LFM
5
4
3
2
1
0
24VIN
36VIN
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
125
8003 G81
8003fc
For more information www.linear.com/LTM8003
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
Derating, I-Grade, VOUT = –3.3V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
Derating, I-Grade, VOUT = 18V,
BIAS = 5V, DC2416A Demo Board
4
3
2
1
25
50
75
100
AMBIENT TEMPERATURE (°C)
4
3
2
12VIN
24VIN
36VIN
1
0
125
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
8003 G82
3
2
1
12VIN
24VIN
25
50
75
100
AMBIENT TEMPERATURE (°C)
1
0
125
12VIN
24VIN
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
0.5
125
8003 G88
0 LFM
0.5
12VIN
24VIN
0
25
50
75
100
AMBIENT TEMPERATURE (°C)
CISPR25 Class 5 Average Radiated
DC2416A Demo Board, VOUT = 5V
Spread Spectrum Enabled
50
40
40
30
20
10
VERTICAL POLARIZATION
fSW = 2MHz
IOUT = 3.5A
–10
0
10
20
FREQUENCY (MHz)
125
8003 G87
50
0
12VIN
125
1.0
0
125
AMPLITUDE (dBuV/m)
AMPLITUDE (dBuV/m)
MAXIMUM LOAD CURRENT (A)
1.0
25
50
75
100
AMBIENT TEMPERATURE (°C)
1.5
CISPR25 Class 5 Peak Radiated
DC2416A Demo Board, VOUT = 5V
Spread Spectrum Enabled
1.5
25
50
75
100
AMBIENT TEMPERATURE (°C)
0
8003 G86
0 LFM
0
12VIN
24VIN
36VIN
2.0
2
Derating, I-Grade, VOUT = –18V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
0
1
Derating, I-Grade, VOUT = –15V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
0 LFM
8003 G85
2.0
2
8003 G84
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
3
0 LFM
0
3
Derating, I-Grade, VOUT = –12V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
4
0
4
0
125
0 LFM
8003 G83
Derating, I-Grade, VOUT = –8V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
5
5
0 LFM
5
24VIN
36VIN
0
Derating, I-Grade, VOUT = –5V,
BIAS Tied to LTM8003 GND,
DC2416A Demo Board
MAXIMUM LOAD CURRENT (A)
5
0
6
0 LFM
MAXIMUM LOAD CURRENT (A)
MAXIMUM LOAD CURRENT (A)
6
TA = 25°C, unless otherwise noted.
VERTICAL POLARIZATION
fSW = 2MHz
IOUT = 3.5A
30
20
10
0
30
8053 G89
–10
0
10
20
FREQUENCY (MHz)
30
8053 G90
8003fc
For more information www.linear.com/LTM8003
13
LTM8003
TYPICAL PERFORMANCE CHARACTERISTICS
CISPR25 Class 5 Average Radiated
DC2416A Demo Board, VOUT = 5V
Spread Spectrum Enabled
50
50
40
40
AMPLITUDE (dBuV/m)
AMPLITUDE (dBuV/m)
CISPR25 Class 5 Peak Radiated
DC2416A Demo Board, VOUT = 5V
Spread Spectrum Enabled
30
20
10
0
–10
fSW = 2MHz
IOUT = 3.5A
0
200
400
600
FREQUENCY (MHz)
800
1000
TA = 25°C, unless otherwise noted.
VERTICAL POLARIZATION
fSW = 2MHz
IOUT = 3.5A
30
20
10
0
–10
0
200
8053 G91
400
600
FREQUENCY (MHz)
800
1000
8053 G92
PIN FUNCTIONS
GND (Bank 1, A1, A6): Tie these GND pins to a local ground
plane below the LTM8003 and the circuit components.
In most applications, the bulk of the heat flow out of the
LTM8003 is through these pads, so the printed circuit
design has a large impact on the thermal performance of
the part. See the PCB Layout and Thermal Considerations
sections for more details.
VIN (Bank 2): VIN supplies current to the LTM8003’s internal regulator and to the internal power switch. These
pins must be locally bypassed with an external, low ESR
capacitor; see Table 1 for recommended values.
VOUT (Bank 3): Power Output Pins. Apply the output filter
capacitor and the output load between these pins and
GND pins.
BIAS (Pins G1, G2): The BIAS pin connects to the internal
power bus. Connect to a power source greater than 3.2V
and less than 18V. If VOUT is greater than 3.2V, connect
this pin there. If the output voltage is less, connect this to a
voltage source above 3.2V. Decouple this pin with at least
1µF if the voltage source for BIAS is remote. If unused or
generating a negative output, tie BIAS to LTM8003 GND.
RUN (Pins B5, B6): Pull the RUN pin below 0.9V to shut
down the LTM8003. Tie to 1.06V or more for normal
operation. If the shutdown feature is not used, tie this
pin to the VIN pin.
14
RT (Pins A4, A5): The RT pin is used to program the
switching frequency of the LTM8003 by connecting a resistor from this pin to ground. The Applications Information
section of the data sheet includes a table to determine the
resistance value based on the desired switching frequency.
Minimize capacitance at this pin. Do not drive this pin.
SYNC (Pins A2, B2): External clock synchronization input
and operational mode. This pin programs four different
operating modes:
1. Burst Mode®. Tie this pin to ground for Burst Mode
operation at low output loads—this will result in ultralow
quiescent current.
2. Pulse-skipping mode. Float this pin for pulse-skipping
mode. This mode offers full frequency operation down
to low output loads before pulse skipping occurs.
3. Spread spectrum mode. Tie this pin high (between
2.9V and 4.2V) for pulse-skipping mode with spread
spectrum modulation.
4. Synchronization mode. Drive this pin with a clock source
to synchronize to an external frequency. During synchronization the part will operate in pulse-skipping mode.
PG (Pin B1, C1): The PG pin is the open-collector output
of an internal comparator. PG remains low until the FB
pin voltage is within about 10% of the final regulation
8003fc
For more information www.linear.com/LTM8003
LTM8003
PIN FUNCTIONS
voltage. The PG signal is valid when VIN is above 3.4V. If
VIN is above 3.4V and RUN is low, PG will drive low. If this
function is not used, leave this pin floating.
current in combination with an external capacitor tied to
this pin creates a voltage ramp. If TR/SS is less than 0.97V,
the output voltage tracks to this value. For tracking, tie a
resistor divider to this pin from the tracked output. This
pin is pulled to ground with an internal MOSFET during
shutdown and fault conditions; use a series resistor if
driving from a low impedance output. This pin may be left
floating if the tracking function is not needed.
FB (Pin F1, F2): The LTM8003 regulates its FB pin to 0.97V.
Connect the adjust resistor from this pin to ground. The
value of RFB is given by the equation RFB = 97/(VOUT – 0.97),
where RFB is in kΩ.
TR/SS (Pin A3, B3): The TR/SS pin is used to provide a
soft-start or tracking function. The internal 2μA pull-up
BLOCK DIAGRAM
NC (Pins C5, D5, E5, E6): These pins are not connected,
either to any other net or each other.
LTM8003 Block Diagram
VIN
BIAS
0.2µF
1.3µH
CURRENT
MODE
CONTROLLER
VOUT
100k
10pF
0.01µF
GND
FB
RUN
TR/SS
SYNC
RT
PG
8003 BD01
LTM8003-3.3 Block Diagram
VIN
BIAS
0.2µF
1.3µH
CURRENT
MODE
CONTROLLER
INTERNAL
0.97V
FEEDBACK
RUN
VOUT
10pF
0.01µF
GND
TR/SS
SYNC
RT
PG
8003 BD02
For more information www.linear.com/LTM8003
8003fc
15
LTM8003
OPERATION
The LTM8003 is a stand-alone non-isolated step-down
switching DC/DC power supply that can deliver up to
6A. The continuous current is determined by the internal
operating temperature. It provides a precisely regulated
output voltage programmable via one external resistor
from 0.97V to 18V. The input voltage range is 3.4V to 40V.
Given that the LTM8003 is a step-down converter, make
sure that the input voltage is high enough to support the
desired output voltage and load current. Simplified Block
Diagrams are given on the previous page.
The LTM8003 contains a current mode controller, power
switching elements, power inductor and a modest amount
of input and output capacitance. The LTM8003 is a fixed
frequency PWM regulator. The switching frequency is set
by simply connecting the appropriate resistor value from
the RT pin to GND.
An internal regulator provides power to the control circuitry. This bias regulator normally draws power from the
VIN pin, but if the BIAS pin is connected to an external
voltage higher than 3.2V, bias power is drawn from the
external source (typically the regulated output voltage).
This improves efficiency. The RUN pin is used to place
the LTM8003 in shutdown, disconnecting the output and
reducing the input current to a few µA.
To enhance efficiency, the LTM8003 automatically switches
to Burst Mode operation in light or no load situations.
Between bursts, all circuitry associated with controlling
the output switch is shut down reducing the input supply
current to just a few µA.
16
The oscillator reduces the LTM8003’s operating frequency
when the voltage at the FB pin is low. This frequency foldback helps to control the output current during start-up
and overload.
The TR/SS node acts as an auxiliary input to the error
amplifier. The voltage at FB servos to the TR/SS voltage
until TR/SS goes above about 0.97V. Soft-start is implemented by generating a voltage ramp at the TR/SS pin
using an external capacitor which is charged by an internal
constant current. Alternatively, driving the TR/SS pin with
a signal source or resistive network provides a tracking
function. Do not drive the TR/SS pin with a low impedance
voltage source. See the Applications Information section
for more details.
The LTM8003 contains a power good comparator which
trips when the FB pin is at about 90% to 110% of its
regulated value. The PG output is an open-drain transistor
that is off when the output is in regulation, allowing an
external resistor to pull the PG pin high. The PG signal
is valid when VIN is above 3.4V. If VIN is above 3.4V and
RUN is low, PG will drive low.
The LTM8003 is equipped with a thermal shutdown that
inhibits power switching at high junction temperatures.
The activation threshold of this function is above the maximum temperature rating to avoid interfering with normal
operation, so prolonged or repetitive operation under a
condition in which the thermal shutdown activates may
damage or impair the reliability of the device.
8003fc
For more information www.linear.com/LTM8003
LTM8003
APPLICATIONS INFORMATION
For most applications, the design process is straightforward, summarized as follows:
1. Look at Table 1 and find the row that has the desired
input range and output voltage.
2. Apply the recommended CFF, CIN, COUT, RFB and RT
values.
3. Apply the CFF (from VOUT to FB) as required.
4. Connect BIAS as indicated.
While these component combinations have been tested
for proper operation, it is incumbent upon the user to
verify proper operation over the intended system’s line,
load and environmental conditions. Bear in mind that the
maximum output current is limited by junction temperature, the relationship between the input and output voltage
magnitude and polarity and other factors. Please refer to
the graphs in the Typical Performance Characteristics
section for guidance.
The maximum frequency (and attendant RT value) at
which the LTM8003 should be allowed to switch is given
in Table 1 in the Maximum fSW column, while the recommended frequency (and RT value) for optimal efficiency
over the given input condition is given in the fSW column.
There are additional conditions that must be satisfied if
the synchronization function is used. Please refer to the
Synchronization section for details.
Table 1. Recommended Component Values and Configuration (TA = 25°C)
CIN2
VIN
VOUT
(V)
RFB
(kΩ)
3.4V to 40V
0.97
Open 4.7µF 50V 1206 X5R
COUT
2x 100µF 6.3V 1210 X5R
CFF
(pF)
BIAS
(V)
fSW
RT
(kΩ)
47
5
450kHz
97.6
Maximum Minimum RT
fSW
(kΩ)
675kHz
63.4
3.4V to 40V
1.2
402
4.7µF 50V 1206 X5R
2x 100µF 6.3V 1210 X5R
47
5
550kHz
78.7
850kHz
49.9
3.4V to 40V
1.5
174
4.7µF 50V 1206 X5R
100µF 6.3V 1210 X5R
27
5
600kHz
71.5
1.1MHz
36.5
3.4V to 40V
1.8
115
4.7µF 50V 1206 X5R
100µF 6.3V 1210 X5R
10
5
600kHz
71.5
1.3MHz
30.9
3.4V to 40V
2.0
90.9
4.7µF 50V 1206 X5R
100µF 0805 4V X5R
5
650kHz
64.9
1.4MHz
28.0
4V to 40V1
2.5
63.4
4.7µF 50V 1206 X5R
100µF 0805 4V X5R
5
750kHz
56.2
1.8MHz
20.5
5V to 40V1
3.3
41.2
4.7µF 50V 1206 X5R
100µF 0805 4V X5R
5
850kHz
48.7
2.3MHz
14.7
7V to 40V1
5
24.3
4.7µF 50V 1206 X5R
47µF 6.3V 0805 X5R
5
1MHz
40.2
3MHz
10.7
11V to 40V1
8
13.7
4.7µF 50V 1206 X5R
22µF 1206 10V X7R
5
1.2MHz
33.2
3MHz
10.7
16V to 40V1
12
8.66
4.7µF 50V 1206 X5R
10µF 0805 16V X7S
5
1.5MHz
25.5
3MHz
10.7
19.5 to 40V1
15
6.81
4.7µF 50V 1206 X5R
10µF 0805 16V X7S
5
1.5MHz
25.5
3MHz
10.7
23.5V to 40V1
18
5.62
4.7µF 50V 1206 X5R
10µF 1206 25V X5R
5
1.5MHz
25.5
3MHz
10.7
5V to 22V1
–18
5.62
4.7µF 50V 1206 X5R
10µF 1206 25V X5R
LTM8003 GND 1.5MHz
25.5
3MHz
10.7
4.5V to 25V1
–15
6.81
4.7µF 50V 1206 X5R
10µF 0805 16V X7S
LTM8003 GND 1.5MHz
25.5
3MHz
10.7
3.4V to 28V1
–12
8.66
4.7µF 50V 1206 X5R
10µF 0805 16V X7S
LTM8003 GND 1.5MHz
25.5
3MHz
10.7
3.4V to 32V1
–8
13.7
4.7µF 50V 1206 X5R
22µF 1206 10V X7R
LTM8003 GND 1.2MHz
33.2
3MHz
10.7
3.4V to 351
–5
24.3
4.7µF 50V 1206 X5R
47µF 6.3V 0805 X5R
LTM8003 GND
40.2
3MHz
10.7
3.4V to 36V1
–3.3
41.2
4.7µF 50V 1206 X5R
100µF 0805 4V X5R
LTM8003 GND 850kHz
48.7
2.3MHz
14.7
1MHz
1. The LTM8003 may be capable of lower input voltages but may skip switching cycles.
2. An input bulk capacitor is required
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17
LTM8003
APPLICATIONS INFORMATION
Capacitor Selection Considerations
Frequency Selection
The CIN and COUT capacitor values in Table 1 are the
minimum recommended values for the associated operating conditions. Applying capacitor values below those
indicated in Table 1 is not recommended and may result
in undesirable operation. Using larger values is generally
acceptable, and can yield improved dynamic response, if
it is necessary. Again, it is incumbent upon the user to
verify proper operation over the intended system’s line,
load and environmental conditions.
The LTM8003 uses a constant frequency PWM architecture that can be programmed to switch from 200kHz to
3MHz by using a resistor tied from the RT pin to ground.
Table 2 provides a list of RT resistor values and their
resultant frequencies.
Ceramic capacitors are small, robust and have very low
ESR. However, not all ceramic capacitors are suitable.
X5R and X7R types are stable over temperature and applied voltage and give dependable service. Other types,
including Y5V and Z5U have very large temperature and
voltage coefficients of capacitance. In an application circuit they may have only a small fraction of their nominal
capacitance resulting in much higher output voltage ripple
than expected.
Ceramic capacitors are also piezoelectric. In Burst Mode
operation, the LTM8003’s switching frequency depends
on the load current, and can excite a ceramic capacitor
at audio frequencies, generating audible noise. Since the
LTM8003 operates at a lower current limit during Burst
Mode operation, the noise is typically very quiet to a
casual ear.
If this audible noise is unacceptable, use a high performance electrolytic capacitor at the output. It may also be
a parallel combination of a ceramic capacitor and a low
cost electrolytic capacitor.
A final precaution regarding ceramic capacitors concerns
the maximum input voltage rating of the LTM8003. A
ceramic input capacitor combined with trace or cable
inductance forms a high-Q (underdamped) tank circuit.
If the LTM8003 circuit is plugged into a live supply, the
input voltage can ring to twice its nominal value, possibly exceeding the device’s rating. This situation is easily
avoided; see the Hot-Plugging Safely section.
18
Table 2. SW Frequency vs RT Value
fSW (MHz)
RT (kΩ)
0.2
232
0.3
150
0.4
110
0.5
88.7
0.6
71.5
0.7
60.4
0.8
52.3
1.0
40.2
1.2
33.2
1.4
28.0
1.6
23.7
1.8
20.5
2.0
18.2
2.2
15.8
3.0
10.7
Operating Frequency Trade-Offs
It is recommended that the user apply the optimal RT
value given in Table 1 for the input and output operating
condition. System level or other considerations, however,
may necessitate another operating frequency. While the
LTM8003 is flexible enough to accommodate a wide
range of operating frequencies, a haphazardly chosen
one may result in undesirable operation under certain
operating or fault conditions. A frequency that is too
high can reduce efficiency, generate excessive heat or
even damage the LTM8003 if the output is overloaded
or short-circuited. A frequency that is too low can result
in a final design that has too much output ripple or too
large of an output capacitor.
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APPLICATIONS INFORMATION
BIAS Pin Considerations
Burst Mode Operation
The BIAS pin is used to provide drive power for the internal power switching stage and operate other internal
circuitry. For proper operation, it must be powered by at
least 3.2V. If the output voltage is programmed to 3.2V
or higher, BIAS may be simply tied to VOUT. If VOUT is less
than 3.2V, BIAS can be tied to VIN or some other voltage
source. If the BIAS pin voltage is too high, the efficiency
of the LTM8003 may suffer. The optimum BIAS voltage
is dependent upon many factors, such as load current,
input voltage, output voltage and switching frequency. In
all cases, ensure that the maximum voltage at the BIAS pin
is less than 19V. If BIAS power is applied from a remote
or noisy voltage source, it may be necessary to apply a
decoupling capacitor locally to the pin. A 1µF ceramic
capacitor works well. The BIAS pin may also be left open
at the cost of a small degradation in efficiency. If unused
or generating a negative output, tie BIAS to LTM8003 GND.
To enhance efficiency at light loads, the LTM8003 automatically switches to Burst Mode operation which keeps
the output capacitor charged to the proper voltage while
minimizing the input quiescent current. During Burst
Mode operation, the LTM8003 delivers single cycle bursts
of current to the output capacitor followed by sleep periods
where most of the internal circuitry is powered off and
energy is delivered to the load by the output capacitor.
During the sleep time, VIN and BIAS quiescent currents
are greatly reduced, so, as the load current decreases
towards a no load condition, the percentage of time that
the LTM8003 operates in sleep mode increases and the
average input current is greatly reduced, resulting in
higher light load efficiency.
Maximum Load
The LTM8003 is a step-down converter, so a minimum
amount of headroom is required to keep the output in
regulation. Keep the input above 3.4V to ensure proper
operation. Voltage transients or ripple valleys that cause
the input to fall below 3.4V may turn off the LTM8003.
The maximum practical continuous load that the LTM8003
can drive, while rated at 3.5A, actually depends upon both
the internal current limit and the internal temperature.
The internal current limit is designed to prevent damage
to the LTM8003 in the case of overload or short-circuit.
The internal temperature of the LTM8003 depends upon
operating conditions such as the ambient temperature,
the power delivered, and the heat sinking capability of the
system. For example, if the LTM8003H is configured to
regulate at 1.2V, it may continuously deliver 6A from 12VIN
if the ambient temperature is controlled to less than 50°C.
This is quite a bit higher than the 3.5A continuous rating.
Please see the “Derating, H-Grade, VOUT = 1.2V” curve in
the Typical Performance Characteristics section. Similarly,
if the output voltage is 18V and the ambient temperature
is 100°C, the LTM8003H will deliver at most 2.7A from
24VIN, which is less than the 3.5A continuous rating.
Load Sharing
Neither the LTM8003 nor LTM8003-3.3 are designed to
load share.
Burst Mode operation is enabled by tying SYNC to GND.
Minimum Input Voltage
Output Voltage Tracking and Soft-Start
The LTM8003 allows the user to adjust its output voltage
ramp rate by means of the TR/SS pin. An internal 2μA pulls
up the TR/SS pin to about 2.4V. Putting an external capacitor on TR/SS enables soft starting the output to reduce
current surges on the input supply. During the soft-start
ramp the output voltage will proportionally track the TR/
SS pin voltage. For output tracking applications, TR/SS
can be externally driven by another voltage source. From
0V to 0.97V, the TR/SS voltage will override the internal
0.97V reference input to the error amplifier, thus regulating the FB pin voltage to that of the TR/SS pin. When TR/
SS is above 0.97V, tracking is disabled and the feedback
voltage will regulate to the internal reference voltage. The
TR/SS pin may be left floating if the function is not needed.
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19
LTM8003
APPLICATIONS INFORMATION
An active pull-down circuit is connected to the TR/SS pin
which will discharge the external soft-start capacitor in
the case of fault conditions and restart the ramp when the
faults are cleared. Fault conditions that clear the soft-start
capacitor are the RUN pin transitioning low, VIN voltage
falling too low, or thermal shutdown.
Pre-Biased Output
As discussed in the Output Voltage Tracking and SoftStart section, the LTM8003 regulates the output to the
FB voltage determined by the TR/SS pin whenever TR/
SS is less than 0.97V. If the LTM8003 output is higher
than the target output voltage, the LTM8003 will attempt
to regulate the output to the target voltage by returning a
small amount of energy back to the input supply. If there
is nothing loading the input supply, its voltage may rise.
Take care that it does not rise so high that the input voltage
exceeds the absolute maximum rating of the LTM8003.
Frequency Foldback
The LTM8003 is equipped with frequency foldback which
acts to reduce the thermal and energy stress on the internal
power elements during a short circuit or output overload
condition. If the LTM8003 detects that the output has
fallen out of regulation, the switching frequency is reduced
as a function of how far the output is below the target
voltage. This in turn limits the amount of energy that can
be delivered to the load under fault. During the start-up
time, frequency foldback is also active to limit the energy
delivered to the potentially large output capacitance of
the load. When a clock is applied to the SYNC pin, the
SYNC pin is floated or held high, the frequency foldback
is disabled, and the switching frequency will slow down
only during overcurrent conditions.
20% to 80% duty cycle) to the SYNC pin. The square
wave amplitude should have valleys that are below 0.4V
and peaks above 1.5V.
The LTM8003 will not enter Burst Mode operation at low
output loads while synchronized to an external clock, but
instead will pulse skip to maintain regulation. The LTM8003
may be synchronized over a 200kHz to 3MHz range. The RT
resistor should be chosen to set the switching frequency
equal to or below the lowest synchronization input. For
example, if the synchronization signal will be 500kHz and
higher, the RT should be selected for 500kHz.
For some applications it is desirable for the LTM8003 to
operate in pulse-skipping mode, offering two major differences from Burst Mode operation. The first is that the
clock stays awake at all times and all switching cycles
are aligned to the clock. The second is that full switching
frequency is reached at lower output load than in Burst
Mode operation. These two differences come at the expense
of increased quiescent current. To enable pulse-skipping
mode, the SYNC pin is floated.
The LTM8003 features spread spectrum operation to
further reduce EMI/EMC emissions. To enable spread
spectrum operation, apply between 2.9V and 4.2V to the
SYNC pin. In this mode, triangular frequency modulation
is used to vary the switching frequency between the value
programmed by RT to about 20% higher than that value.
The modulation frequency is about 3kHz. For example, when
the LTM8003 is programmed to 2MHz, the frequency will
vary from 2MHz to 2.4MHz at a 3kHz rate. When spread
spectrum operation is selected, Burst Mode operation is
disabled, and the part will run in pulse-skipping mode.
The LTM8003 does not operate in forced continuous mode
regardless of SYNC signal.
Synchronization
Negative Output
To select low ripple Burst Mode operation, tie the SYNC
pin below about 0.4V (this can be ground or a logic low
output). To synchronize the LTM8003 oscillator to an
external frequency, connect a square wave (with about
The LTM8003 is capable of generating a negative output
voltage by connecting its VOUT to system GND and the
LTM8003 GND to the negative voltage rail. An example
of this is shown in the Typical Applications section. The
20
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LTM8003
APPLICATIONS INFORMATION
most versatile way to generate a negative output is to
use a dedicated regulator that was designed to generate
a negative voltage, but using a buck regulator like the
LTM8003 to generate a negative voltage is a simple and
cost effective solution, as long as certain restrictions are
kept in mind.
FAST VIN
TRANSIENT
OUTPUT EXPERIENCES
A POSITIVE TRANSIENT
VIN
VIN
CIN
VOUT
LTM8003
GND
VIN
AC DIVIDER
VIN
VOUT
LTM8003
OPTIONAL
SCHOTTKY
DIODE
8003 F03
Figure 3. A Schottky Diode Can Limit the Transient Caused by
a Fast Rising VIN to Safe Levels
GND
NEGATIVE
OUTPUT VOLTAGE
8003 F01
Figure 1. The LTM8003 Can Be Used to Generate a Negative Voltage
Figure 1 shows a typical negative output voltage application.
Note that LTM8003 VOUT is tied to system GND and input
power is applied from VIN to LTM8003 VOUT. As a result,
the LTM8003 is not behaving as a true buck regulator,
and the maximum output current depends upon the input
voltage. In the example shown in the Typical Applications
section, there is an attending graph that shows how much
current the LTM8003 can deliver for given input voltages.
VIN
VIN
COUT
The CIN and COUT capacitors in Figure 3 form an AC divider
at the negative output voltage node. If VIN is hot-plugged
or rises quickly, the resultant VOUT will be a positive transient, which may be unhealthy for the application load.
An anti-parallel Schottky diode may be able to prevent
this positive transient from damaging the load. The location of this Schottky diode is important. For example, in
a system where the LTM8003 is far away from the load,
placing the Schottky diode closest to the most sensitive
load component may be the best design choice. Carefully evaluate whether the negative buck configuration is
suitable for the application. When generating a negative
output voltage, tie BIAS to LTM8003 GND.
Shorted Input Protection
VOUT
LTM8003
GND
FAST LOAD
TRANSIENT
8003 F02
OUTPUT TRANSIENT
RESPONSE
Figure 2. Any Output Voltage Transient Appears on LTM8003 GND
Note that this configuration requires that any load current
transient will directly impress the transient voltage onto
the LTM8003 GND, as shown in Figure 2, so fast load
transients can disrupt the LTM8003’s operation or even
cause damage.
Care needs to be taken in systems where the output is held
high when the input to the LTM8003 is absent. This may
occur in battery charging applications or in battery backup
systems where a battery or some other supply is diode
ORed with the LTM8003’s output. If the VIN pin is allowed
to float and the RUN pin is held high (either by a logic signal
or because it is tied to VIN), then the LTM8003’s internal
circuitry pulls its quiescent current through its internal
power switch. This is fine if your system can tolerate a
few milliamps in this state. If you ground the RUN pin, the
internal current drops to essentially zero. However, if the
VIN pin is grounded while the output is held high, parasitic
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21
LTM8003
APPLICATIONS INFORMATION
diodes inside the LTM8003 can pull large currents from
the output through the VIN pin. Figure 4 shows a circuit
that runs only when the input voltage is present and that
protects against a shorted or reversed input.
VIN
A few rules to keep in mind are:
1. Place CFF, RFB and RT as close as possible to their
respective pins.
2. Place the CIN capacitor as close as possible to the VIN
and GND connection of the LTM8003.
VIN
3. Place the COUT capacitor as close as possible to the
VOUT and GND connection of the LTM8003.
LTM8003
RUN
8003 F04
4. Place the CIN and COUT capacitors such that their
ground current flow directly adjacent to or underneath
the LTM8003.
Figure 4. The Input Diode Prevents a Shorted Input from
Discharging a Backup Battery Tied to the Output. It Also
Protects the Circuit from a Reversed Input. The LTM8003 Runs
Only When the Input Is Present
PCB Layout
5. Connect all of the GND connections to as large a copper
pour or plane area as possible on the top layer. Avoid
breaking the ground connection between the external
components and the LTM8003.
Most of the headaches associated with PCB layout have
been alleviated or even eliminated by the high level of
integration of the LTM8003. The LTM8003 is nevertheless a switching power supply, and care must be taken to
minimize EMI and ensure proper operation. Even with the
high level of integration, you may fail to achieve specified
operation with a haphazard or poor layout. See Figure 5
for a suggested layout. Ensure that the grounding and
heat sinking are acceptable.
6. Use vias to connect the GND copper area to the board’s
internal ground planes. Liberally distribute these GND
vias to provide both a good ground connection and
thermal path to the internal planes of the printed circuit
board. Pay attention to the location and density of the
thermal vias in Figure 5. The LTM8003 can benefit from
the heat-sinking afforded by vias that connect to internal
GND planes at these locations, due to their proximity
to internal power handling components. The optimum
GND
CIN
RUN
VIN
RT
COUT
TR/SS
SYNC
PG
FB BIAS
VOUT
GND/ THERMAL VIAS
8003 F05
Figure 5. Layout Showing Suggested External Components, GND Plane and Thermal Vias
22
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LTM8003
APPLICATIONS INFORMATION
number of thermal vias depends upon the printed
circuit board design. For example, a board might use
very small via holes. It should employ more thermal
vias than a board that uses larger holes.
Hot-Plugging Safely
The small size, robustness and low impedance of ceramic
capacitors make them an attractive option for the input
bypass capacitor of LTM8003. However, these capacitors
can cause problems if the LTM8003 is plugged into a live
supply (see Linear Technology Application Note 88 for a
complete discussion). The low loss ceramic capacitor
combined with stray inductance in series with the power
source forms an underdamped tank circuit, and the voltage at the VIN pin of the LTM8003 can ring to more than
twice the nominal input voltage, possibly exceeding the
LTM8003’s rating and damaging the part. If the input supply
is poorly controlled or the LTM8003 is hot-plugged into an
energized supply, the input network should be designed
to prevent this overshoot. This can be accomplished by
installing a small resistor in series to VIN, but the most
popular method of controlling input voltage overshoot is
add an electrolytic bulk cap to the VIN net. This capacitor’s
relatively high equivalent series resistance damps the circuit
and eliminates the voltage overshoot. The extra capacitor
improves low frequency ripple filtering and can slightly
improve the efficiency of the circuit, though it is likely to
be the largest component in the circuit.
Thermal Considerations
The LTM8003 output current may need to be derated if it
is required to operate in a high ambient temperature. The
amount of current derating is dependent upon the input
voltage, output power and ambient temperature. The
derating curves given in the Typical Performance Characteristics section can be used as a guide. These curves
were generated by the LTM8003 mounted to a 58cm2
4-layer FR4 printed circuit board. Boards of other sizes
and layer count can exhibit different thermal behavior, so
it is incumbent upon the user to verify proper operation
over the intended system’s line, load and environmental
operating conditions.
For increased accuracy and fidelity to the actual application, many designers use FEA (Finite Element Analysis)
to predict thermal performance. To that end, Page 2 of
the data sheet typically gives four thermal coefficients:
θJA – Thermal resistance from junction to ambient
θJCbottom – Thermal resistance from junction to the
bottom of the product case
θJCtop – Thermal resistance from junction to top of the
product case
θJB – Thermal resistance from junction to the printed
circuit board.
While the meaning of each of these coefficients may
seem to be intuitive, JEDEC has defined each to avoid
confusion and inconsistency. These definitions are given
in JESD 51-12, and are quoted or paraphrased below:
θJA is the natural convection junction-to-ambient air
thermal resistance measured in a one cubic foot sealed
enclosure. This environment is sometimes referred to as
“still air” although natural convection causes the air to
move. This value is determined with the part mounted to
a JESD 51-9 defined test board, which does not reflect an
actual application or viable operating condition.
θJCbottom is the junction-to-board thermal resistance with
all of the component power dissipation flowing through the
bottom of the package. In the typical µModule regulator,
the bulk of the heat flows out the bottom of the package,
but there is always heat flow out into the ambient environment. As a result, this thermal resistance value may
be useful for comparing packages but the test conditions
don’t generally match the user’s application.
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LTM8003
APPLICATIONS INFORMATION
θJCtop is determined with nearly all of the component power
dissipation flowing through the top of the package. As the
electrical connections of the typical µModule regulator are
on the bottom of the package, it is rare for an application
to operate such that most of the heat flows from the junction to the top of the part. As in the case of θJCbottom, this
value may be useful for comparing packages but the test
conditions don’t generally match the user’s application.
θJB is the junction-to-board thermal resistance where
almost all of the heat flows through the bottom of the
µModule regulator and into the board, and is really the
sum of the θJCbottom and the thermal resistance of the
bottom of the part through the solder joints and through a
portion of the board. The board temperature is measured
a specified distance from the package, using a two sided,
two layer board. This board is described in JESD 51-9.
Given these definitions, it should now be apparent that none
of these thermal coefficients reflects an actual physical
operating condition of a µModule regulator. Thus, none
of them can be individually used to accurately predict the
thermal performance of the product. Likewise, it would
be inappropriate to attempt to use any one coefficient to
correlate to the junction temperature vs load graphs given
in the product’s data sheet. The only appropriate way to
use the coefficients is when running a detailed thermal
analysis, such as FEA, which considers all of the thermal
resistances simultaneously.
A graphical representation of these thermal resistances
is given in Figure 6. The blue resistances are contained
within the µModule regulator, and the green are outside.
The die temperature of the LTM8003 must be lower than
the maximum rating, so care should be taken in the layout
of the circuit to ensure good heat sinking of the LTM8003.
The bulk of the heat flow out of the LTM8003 is through
the bottom of the package and the pads into the printed
circuit board. Consequently a poor printed circuit board
design can cause excessive heating, resulting in impaired
performance or reliability. Please refer to the PCB Layout
section for printed circuit board design suggestions.
JUNCTION-TO-AMBIENT RESISTANCE (JESD 51-9 DEFINED BOARD)
JUNCTION-TO-CASE (TOP)
RESISTANCE
JUNCTION
CASE (TOP)-TO-AMBIENT
RESISTANCE
JUNCTION-TO-BOARD RESISTANCE
JUNCTION-TO-CASE
CASE (BOTTOM)-TO-BOARD
(BOTTOM) RESISTANCE
RESISTANCE
AMBIENT
BOARD-TO-AMBIENT
RESISTANCE
8003 F06
µMODULE DEVICE
Figure 6. Graphical Representation of the Thermal Resistances Between the Device Junction and Ambient
24
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LTM8003
Fault Tolerance
The fixed output version of LTM8003 is designed to tolerate a single fault condition. Shorting two adjacent pins
together or leaving one single pin floating does not raise
VOUT or cause damage to the LTM8003 µModule regulator.
Table 2 describe the effects that result from shorting adjacent pins. Note that, since all pins are redundant, there
is no analysis describing what happens when a single pin
opens. The NC pins must be left floating to ensure fault
tolerance.
Table 3. Table 2. FMEA Analysis — Adjacent Pin Short Test
PIN NAME
HEAT
SMOKE
EFFECT
VIN–NC
NO
NO
Circuit behaves normally.
VIN–RUN
NO
NO
Circuit behaves normally.
RUN–NC
NO
NO
Circuit behaves normally.
RUN–RT
NO
NO
VOUT falls to 0V. Device can be damaged if EN/UV voltage is higher than RT ABS MAX.
RUN–GND
NO
NO
Vout falls to 0V.
RT–GND
NO
NO
SW frequency increases. VOUT may fall below regulation voltage.
RT–GND BANK1
NO
NO
SW frequency increases. VOUT may fall below regulation voltage.
RT–TRSS
NO
NO
VOUT will fall below regulation voltage.
TR/SS–SYNC
NO
NO
VOUT will fall below regulation voltage.
TR/SS–GND BANK1
NO
NO
VOUT will fall below regulation voltage.
SYNC–GND
NO
NO
Circuit behaves normally.
SYNC–PG
NO
NO
Circuit behaves normally.
SYNC–GND BANK1
NO
NO
Circuit behaves normally.
BIAS–GND BANK1
NO
NO
Efficiency may decrease.
BIAS–VOUT BANK3
NO
NO
Efficiency may decrease. If BIAS is tied to a voltage source > VOUT, VOUT may rise.
If BIAS is tied to a votlage source < VOUT, VOUT may be reduced.
VOUT BANK3–GND BANK1
NO
NO
VOUT will fall to 0V.
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25
LTM8003
TYPICAL APPLICATIONS
3.3VOUT from 5VIN to 40VIN Step-Down Converter. BIAS Is Tied to VOUT
VIN
VIN
5V TO 40V
LTM8003-3.3
RUN
4.7µF
VOUT
3.3V
4A
VOUT
BIAS
RT
49.9k
850kHz
GND
100µF
SYNC
8003 TA02
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
1.2VOUT from 3.4VIN to 40VIN Step-Down Converter. BIAS Is Tied to an External 3.3V Source
VIN
VIN
3.4V TO 40V
LTM8003
RUN
BIAS
4.7µF
3.3V
VOUT
47pF
RT
78.7k
550kHz
GND
SYNC
FB
402k
VOUT
1.2V
100µF 4A
×2
8003 TA03
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
2.5VOUT from 5.5VIN to 15VIN Step-Down Converter. BIAS Is Tied to VIN
VIN
VIN
5.5V TO 15V
LTM8003
BIAS
RUN
VOUT
4.7µF
RT
56.2k
750kHz
GND
SYNC
FB
63.4k
100µF
VOUT
2.5V
4A
8003 TA04
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
26
8003fc
For more information www.linear.com/LTM8003
LTM8003
TYPICAL APPLICATIONS
–5VOUT from 5VIN to 35VIN Positive to Negative Converter, BIAS tied to LTM8003 GND
Maximum Load Current vs VIN. BIAS Open
INPUT BULK CAP
VIN
5V TO 35V
+
6
VIN
MAXIMUM LOAD CURRENT (A)
LTM8003
RUN
41.2k
1MHz
OPTIONAL
SCHOTTKY
DIODE
VOUT
4.7µF
RT
FB
BIAS
GND
SYNC
24.3k
47µF
8003 TA05a
VOUT
–5V
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
5
4
3
2
1
0
0
10
20
30
INPUT VOLTAGE (V)
40
8003 TA05b
PACKAGE PHOTO
PACKAGE DESCRIPTION
Table 4
LTM8003 Pinout (Adjustable Version, Sorted by Pin Number)
PIN PIN NAME PIN PIN NAME PIN PIN NAME PIN PIN NAME
A 1
GND
B 1
PG
C 1
PG
D 1
GND
A 2
SYNC
B 2
SYNC
C 2
GND
D 2
GND
A 3
SS
B 3
SS
C 3
GND
D 3
GND
A 4
RT
B 4
GND
C 4
GND
D 4
GND
A 5
RT
B 5
RUN
C 5
NC
D 5
NC
A 6
GND
B 6
RUN
C 6
VIN
D 6
VIN
PIN PIN NAME
E 1
GND
E 2
GND
E 3
GND
E 4
GND
E 5
NC
E 6
NC
PIN PIN NAME
F 1
FB
F 2
FB
F 3
GND
F 4
GND
F 5
GND
F 6
GND
PIN PIN NAME
G 1
BIAS
G 2
BIAS
G 3
VOUT
G 4
VOUT
G 5
VOUT
G 6
VOUT
PIN PIN NAME
H 1
VOUT
H 2
VOUT
H 3
VOUT
H 4
VOUT
H 5
VOUT
H 6
VOUT
LTM8003 Pinout (Fixed Output Voltage, Sorted by Pin Number)
PIN PIN NAME PIN PIN NAME PIN PIN NAME PIN PIN NAME
A 1
GND
B 1
PG
C 1
PG
D 1
GND
A 2
SYNC
B 2
SYNC
C 2
GND
D 2
GND
A 3
SS
B 3
SS
C 3
GND
D 3
GND
A 4
RT
B 4
GND
C 4
GND
D 4
GND
A 5
RT
B 5
RUN
C 5
NC
D 5
NC
A 6
GND
B 6
RUN
C 6
VIN
D 6
VIN
PIN PIN NAME
E 1
GND
E 2
GND
E 3
GND
E 4
GND
E 5
NC
E 6
NC
PIN PIN NAME
F 1
GND
F 2
GND
F 3
GND
F 4
GND
F 5
GND
F 6
GND
PIN PIN NAME
G 1
BIAS
G 2
BIAS
G 3
VOUT
G 4
VOUT
G 5
VOUT
G 6
VOUT
PIN PIN NAME
H 1
VOUT
H 2
VOUT
H 3
VOUT
H 4
VOUT
H 5
VOUT
H 6
VOUT
8003fc
For more information www.linear.com/LTM8003
27
For more information www.linear.com/LTM8003
aaa Z
0.50 ±0.025 Ø 48x
4
2.5
0.000
1.5
2.5
SUGGESTED PCB LAYOUT
TOP VIEW
0.5
PACKAGE TOP VIEW
E
0.5
PIN “A1”
CORNER
1.5
28
Y
3.5
2.5
1.5
0.5
0.000
0.5
1.5
2.5
3.5
X
D
SYMBOL
A
A1
A2
b
b1
D
E
e
F
G
H1
H2
aaa
bbb
ccc
ddd
eee
aaa Z
NOM
3.32
0.50
2.82
0.60
0.50
9.00
6.25
1.00
7.00
5.00
0.32
2.50
DIMENSIONS
0.37
2.55
0.15
0.10
0.20
0.25
0.10
MAX
3.52
0.60
2.92
0.70
0.53
TOTAL NUMBER OF BALLS: 48
0.27
2.45
H1
SUBSTRATE
ddd M Z X Y
eee M Z
DETAIL A
Øb (48 PLACES)
MIN
3.12
0.40
2.72
0.50
0.47
b1
DETAIL B
H2
MOLD
CAP
ccc Z
A1
MOLD CAP HT
SUBSTRATE THK
BALL DIMENSION
PAD DIMENSION
BALL HT
NOTES
DETAIL B
PACKAGE SIDE VIEW
A2
A
Z
e
b
6
4
G
3
e
2
1
DETAIL A
PACKAGE BOTTOM VIEW
b
5
PIN 1
3
SEE NOTES
H
G
F
E
D
C
B
A
7
SEE NOTES
DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL,
BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.
THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE
BALL DESIGNATION PER JEP95
7
TRAY PIN 1
BEVEL
!
PACKAGE IN TRAY LOADING ORIENTATION
LTMXXXXXX
µModule
BGA 48 0217 REV A
PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
LAYOUT CAREFULLY
6. SOLDER BALL COMPOSITION IS 96.5% Sn/3.0% Ag/0.5% Cu
5. PRIMARY DATUM -Z- IS SEATING PLANE
4
3
2. ALL DIMENSIONS ARE IN MILLIMETERS
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994
F
COMPONENT
PIN “A1”
(Reference LTC DWG # 05-08-1999 Rev A)
// bbb Z
BGA Package
48-Lead (9mm × 6.25mm × 3.32mm)
LTM8003
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTM8003#packaging for the most recent package drawings.
8003fc
LTM8003
REVISION HISTORY
REV
DATE
DESCRIPTION
A
2/17
Added “Silent Switcher” to product description and features
PAGE NUMBER
Added EMI performance graph
Added Fault Tolerance section and FMEA analysis table
B
5/17
Added LTM8003IY and LTM8003HY
Changed recommended BIAS pin connection from Open to GND for negative output applications.
C
12/17
Changed Peak Reflow Body Temperature from 260°C to 250°C
1
13, 14
25
2
5, 7, 11, 13, 14,
17, 19, 21, 27
2
8003fc
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its information
circuits as described
herein will not infringe on existing patent rights.
For more
www.linear.com/LTM8003
29
LTM8003
TYPICAL APPLICATION
0.97VOUT from 3.4VIN to 40VIN Step Down Converter with Spread Spectrum. BIAS is Tied to an External 3.3V Source
VIN
VIN
3.4V TO 40V
LTM8003
RUN
4.7µF
VOUT
47pF
RT
84k
450kHz
FB
GND
SYNC BIAS
100µF
×2
VOUT
0.97V
4A
8003 TA06
EXTERNAL
3.3V
PINS NOT USED IN THIS CIRCUIT: TR/SS, PG
DESIGN RESOURCES
SUBJECT
DESCRIPTION
µModule Design and Manufacturing Resources
Design:
• Selector Guides
• Demo Boards and Gerber Files
• Free Simulation Tools
µModule Regulator Products Search
1. Sort table of products by parameters and download the result as a spread sheet.
Manufacturing:
• Quick Start Guide
• PCB Design, Assembly and Manufacturing Guidelines
• Package and Board Level Reliability
2. Search using the Quick Power Search parametric table.
TechClip Videos
Quick videos detailing how to bench test electrical and thermal performance of µModule products.
Digital Power System Management
Linear Technology’s family of digital power supply management ICs are highly integrated solutions that
offer essential functions, including power supply monitoring, supervision, margining and sequencing,
and feature EEPROM for storing user configurations and fault logging.
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTM8053
40V, 4A Step-Down µModule Regulator
3.4V ≤ VIN ≤ 40V. 0.97V ≤ VOUT ≤ 15V. 6.25mm x 9mm x 3.32mm BGA Package.
LTM8032
36V, 2A Low EMI Step-Down µModule Regulator
3.6V ≤ VIN ≤ 36V, 0.8V ≤ VOUT ≤ 10V. EN55022B Compliant.
LTM8033
36V, 3A Low EMI Step-Down µModule Regulator
3.6V ≤ VIN ≤ 36V. 0.8V ≤ VOUT ≤ 24V. EN55022B Compliant.
LTM8026
36V, 5A CVCC Step-Down µModule Regulator
6V ≤ VIN ≤ 36V. 1.2V ≤ VOUT ≤ 24V. Constant Voltage Constant Current Operation.
LTM4613
36V, 8A Low EMI Step-Down µModule Regulator
5V ≤ VIN ≤ 36V. 3.3V ≤ VOUT ≤ 15V. EN55022B Compliant
LTM8027
60V, 4A Step-Down µModule Regulator
4.5V ≤ VIN ≤ 60V, 2.5V ≤ VOUT ≤ 24V.
LTM8050
58V, 2A Step-Down µModule Regulator
3.6V ≤ VIN ≤ 58V, 0.8V ≤ VOUT ≤ 24V.
30
8003fc
LT 1217 REV C • PRINTED IN USA
For more information www.linear.com/LTM8003
www.linear.com/LTM8003
 LINEAR TECHNOLOGY CORPORATION 2016