FeaTures
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LTM4618
6A DC/DC µModule
Regulator with Tracking and
Frequency Synchronization
DescripTion
The
LTM
®
4618
is a complete 6A output switch mode
DC/DC power supply. Included in the package are the
switching controller, power FETs, inductor and all support
components. Operating over an input voltage range of
4.5V to 26.5V, the LTM4618 supports an output voltage
range of 0.8V to 5V set by a single external resistor. Its
high efficiency design delivers 6A continuous current (8A
peak). Only a few input and output capacitors are needed.
High switching frequency and a current mode architecture
enable a very fast transient response to line and load
changes without sacrificing stability. The device supports
frequency synchronization and output voltage tracking for
supply rail sequencing. Burst Mode operation or pulse-
skipping mode can be selected for light load conditions.
Fault protection features include overvoltage protection,
overcurrent protection and foldback current limit for
short-circuit protection.
The LTM4618 is offered in 9mm
×
15mm
×
4.32mm LGA
and 9mm
×
15mm
×
4.92mm BGA packages with RoHS
compliant terminal finish.
L,
LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and µModule are registered
trademarks and LTpowerCAD is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
Complete Standalone Power Supply
Wide Input Voltage Range: 4.5V to 26.5V
6A DC Typical, 8A Peak Output Current
0.8V to 5V Output
Output Voltage Tracking
±1.75% Maximum Total DC Error
Current Mode Control/Fast Transient Response
Phase-Lockable Fixed Frequency 250kHz to 780kHz
On-Board Frequency Synchronization
Selectable Burst Mode
®
Operation
Power Good Voltage Indicator
Output Overvoltage Protection
Output Current Foldback Limiting
9mm
×
15mm
×
4.32mm LGA and
9mm
×
15mm
×
4.92mm BGA Packages
applicaTions
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Telecom and Networking Equipment
Servers
Storage Cards
ATCA Cards
Industrial Equipment
Point of Load Regulation
Medical Systems
Typical applicaTion
2.5V/6A DC/DC Power µModule
®
with 6V to 26.5V Input
Efficiency and Power Loss vs Load Current
95
EFFICIENCY
90
EFFICIENCY (%)
3.0
2.5
2.0
85
1.5
80
1.0
POWER LOSS
75
12V
IN
TO 2.5V
OUT
24V
IN
TO 2.5V
OUT
0
1
2
4
3
LOAD CURRENT (A)
5
6
4618 TA01b
V
IN
6V to 26.5V
C
IN
MODE/PLLIN INTV
CC
EXTV
CC
V
IN
FREQ
COMP
TK/SS
LTM4618
V
OUT
V
FB
PGOOD
SGND
PGND
4618 TA01
POWER LOSS (W)
C
OUT
28k
V
OUT
2.5V/6A
0.1µF
RUN
0.5
0
70
4618fb
For more information
www.linear.com/LTM4618
1
LTM4618
absoluTe MaxiMuM raTings
(Note 1)
V
IN
, SW ...................................................... –0.3V to 28V
INTV
CC
, RUN, EXTV
CC
, PGOOD .................... –0.3V to 6V
COMP V
FB
................................................. –0.3V to 2.7V
,
MODE/PLLIN, TK/SS,
FREQ ..................................................... –0.3V to INTV
CC
V
OUT
............................................................... 0.8V to 5V
Internal Operating Temperature Range
(Note 2)..................................................–40°C to 125°C
Storage Temperature Range................... –55°C to 125°C
Peak Solder Reflow Body Temperature ................. 245°C
pin conFiguraTion
TOP VIEW
7
SW
7
TOP VIEW
SW
V
IN
6
5
PGND
V
IN
6
5
PGND
EXTV
CC
SGND/PGND
MODE/
PLLIN
FREQ
RUN
4
3
2
1
A
B
C
D
E
F
G
H
J
K
L
M
EXTV
CC
SGND/PGND
V
OUT
MODE/
PLLIN
FREQ
RUN
4
3
2
1
A
B
C
D
E
F
G
H
J
K
L
M
V
OUT
TK/SS COMP V
FB
PGOOD
INTV
CC
TK/SS COMP V
FB
PGOOD
INTV
CC
LGA PACKAGE
84-LEAD (15mm
×
9mm
×
4.32mm)
BGA PACKAGE
84-LEAD (15mm
×
9mm
×
4.92mm)
Θ
JA
= 16°C/W,
Θ
JCtop
= 18°C/W,
Θ
JCbottom
= 4°C/W, WEIGHT = 1.7g,
θ
JB
= 5°C/W,
θ
JA
DERIVED FROM 95mm
×
76mm PCB WITH FOUR LAYERS
Θ
JA
= 16°C/W,
Θ
JCtop
= 18°C/W,
Θ
JCbottom
= 4°C/W, WEIGHT = 1.8g,
θ
JB
= 5°C/W,
θ
JA
DERIVED FROM 95mm
×
76mm PCB WITH FOUR LAYERS
orDer inForMaTion
PART MARKING*
PART NUMBER
LTM4618EV#PBF
LTM4618IV#PBF
LTM4618EY#PBF
LTM4618IY#PBF
PAD OR BALL FINISH
Au (RoHS)
Au (RoHS)
SA305 (RoHS)
SA305 (RoHS)
DEVICE
LTM4618V
LTM4618V
LTM4618Y
LTM4618Y
FINISH CODE
e4
e4
e1
e1
PACKAGE
TYPE
LGA
LGA
BGA
BGA
MSL
RATING
3
3
3
3
TEMPERATURE RANGE
(SEE NOTE 2)
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
• Consult Marketing for parts specified with wider operating temperature
ranges. *Device temperature grade is identified 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
• Recommended LGA and BGA PCB Assembly and Manufacturing
Procedures:
www.linear.com/umodule/pcbassembly
• LGA and BGA Package and Tray Drawings: www.linear.com/packaging
4618fb
2
For more information
www.linear.com/LTM4618
LTM4618
elecTrical characTerisTics
SYMBOL
V
IN(DC)
V
OUT(DC)
PARAMETER
Input DC Voltage
Output Voltage Total Variation with
Line and Load
The
l
denotes the specifications which apply over the full internal
operating temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
IN
= 12V, per typical application in Figure 21.
CONDITIONS
(Note 5)
C
IN
= 10µF
×2,
R
FB
= 28.0kΩ
C
OUT
= 100µF
×3
X7R Ceramic
MODE/PLLIN = 0V, V
FREQ
= 2.4V
V
IN
= 6V to 26.5V, I
OUT
= 0A to 6A (Note 4)
V
INTVCC
Rising
V
INTVCC
Falling
I
OUT
= 0A, C
IN
= 10µF
×2,
C
OUT
= 100µF
×3
V
OUT
= 2.5V
V
IN
= 12V
V
IN
= 26.5V
V
IN
= 12V, V
OUT
= 2.5V, I
OUT
= 0A
V
IN
= 26.5V, V
OUT
= 2.5V, I
OUT
= 0A
Shutdown, RUN = 0, V
IN
= 26.5V
V
IN
= 12V, V
OUT
= 2.5V, I
OUT
= 6A
V
IN
= 26.5V, V
OUT
= 2.5V, I
OUT
= 6A
V
IN
= 12V, V
RUN
> 2V, No Load
EXTV
CC
Ramping Positive
INTV
CC
= 20mA, V
EXTVCC
= 5V
l
l
MIN
4.5
TYP
MAX
26.5
UNITS
V
l
2.476
2.52
2.557
V
Input Specifications
V
IN(UVLO)
I
INRUSH(VIN)
Undervoltage Lockout Thresholds
Input Inrush Current at Start-Up
2.00
1.85
2.20
2.00
2.35
2.15
V
V
0.3
0.2
26
20
80
1.430
0.675
4.8
4.5
5
4.7
50
200
100
5.2
A
A
mA
mA
µA
A
A
V
V
mV
mV
6
A
%/V
%
I
Q(VIN)
I
S(VIN)
INTV
CC
V
EXTVCC
VLDO External
V
EXTVCC
Hysteresis
I
OUT(DC)
ΔV
OUT(LINE)
V
OUT
ΔV
OUT(LOAD)
V
OUT
V
OUT(AC)
f
S
ΔV
OUT(START)
Input Supply Bias Current
Input Supply Current
Internal V
CC
Voltage
EXTV
CC
Switchover Voltage
EXTV
CC
Voltage Drop
EXTV
CC
Hysteresis
Output Continuous Current Range
Line Regulation Accuracy
Load Regulation Accuracy
Output Ripple Voltage
Output Specifications
V
IN
= 12V, V
OUT
= 2.5V (Note 4)
V
OUT
= 2.5V, V
IN
from 6V to 26.5V
I
OUT
= 0A
V
IN
= 12V, V
OUT
= 2.5V, 0 to 6A (Note 4)
I
OUT
= 0A, C
OUT
= 100µF
×3
X5R Ceramic
V
IN
= 12V, V
OUT
= 2.5V
V
IN
= 26.5V, V
OUT
= 2.5V
I
OUT
= 2A, V
IN
= 12V, V
OUT
= 2.5V, V
FREQ
= INTV
CC
C
OUT
= 100µF
×3
X5R Ceramic
V
OUT
= 2.5V, I
OUT
= 0A
V
IN
= 12V
V
IN
= 26.5V
C
OUT
= 100µF
×3
X5R Ceramic,
V
OUT
= 2.5V, I
OUT
= 0A, TK/SS Capacitor = 0.01µF
V
IN
= 12V
V
IN
= 26.5V
Load: 0% to 50% of Full Load
C
OUT
= 100µF
×3
X5R Ceramic, V
OUT
= 2.5V
V
IN
= 12V
Load: 0% to 50% of Full Load
C
OUT
= 100µF
×3
X5R Ceramic, V
OUT
= 2.5V
V
IN
= 12V
C
OUT
= 100µF
×3
X5R Ceramic
V
IN
= 6V, V
OUT
= 2.5V
V
IN
= 26.5V, V
OUT
= 2.5V
l
l
0
0.02
0.3
0.04
0.6
10
12
780
mV
mV
kHz
Output Ripple Voltage Frequency
Turn-On Overshoot
20
20
mV
mV
t
START
Turn-On Time
0.75
0.70
ms
ms
ΔV
OUTLS
t
SETTLE
I
OUT(PK)
Peak Deviation for Dynamic Load
15
mV
Settling Time for Dynamic Load Step
10
11
11
µs
A
A
4618fb
Output Current Limit
For more information
www.linear.com/LTM4618
3
LTM4618
elecTrical characTerisTics
SYMBOL
Control Section
V
FB
I
FB
V
OVL
I
TK/SS
DF
MAX
t
ON(MIN)
f
NOM
f
LOW
f
HIGH
V
IH(MODE/PLLIN)
V
IL(MODE/PLLIN)
R
MODE/PLLIN
I
FREQ
V
RUN
V
RUN
Hysteresis
R
FBHI
PGOOD Output
V
PGL
I
PGOOD
V
PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–5
5
–7.5
7.5
0.1
0.3
±2
–10
10
V
µA
%
%
Error Amplifier Feedback Voltage
Error Amplifier Feedback Current
Feedback Voltage Lockout
Soft-Start Charge Current
Maximum Duty Factor
Minimum On-Time
Nominal Frequency
Lowest Frequency
Highest Frequency
Synchronous Clock High Level
Synchronous Clock Low Level
MODE/PLLIN Input Resistance
FREQ Pin
Sinking Current
Sourcing Current
RUN Pin On Threshold
RUN Pin Hysteresis
Resistor Between V
OUT
and V
FB
Pins
60.1
f
MODE/PLLIN
> f
OSC
f
MODE/PLLIN
< f
OSC
RUN Rising
1.1
250
–13
13
1.22
120
60.4
60.7
1.35
I
OUT
= 0A, V
OUT
= 2.5V
l
The
l
denotes the specifications which apply over the full internal
operating temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
IN
= 12V, per typical application in Figure 21.
PARAMETER
CONDITIONS
MIN
0.792
0.788
0.84
0.9
TYP
0.8
0.8
–10
0.86
1.3
97
90
450
210
700
2.0
0.8
500
250
780
550
290
860
MAX
0.808
0.808
–50
0.88
1.7
UNITS
V
V
nA
V
µA
%
ns
kHz
kHz
kHz
V
V
kΩ
µA
µA
V
mV
kΩ
(Note 3)
Measured at V
FB
V
TK/SS
= 0V
In Dropout (Note 3)
(Note 3)
V
FREQ
= 1.2V
V
FREQ
= 0V
2.4V ≤ V
FREQ
≤ INTV
CC
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 LTM4618 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTM4618E is guaranteed to meet performance specifications
over the 0°C to 125°C internal operating temperature range. 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 LTM4618I is guaranteed to meet specifications over the full
internal operating temperature range. Note that the maximum ambient
temperature consistent with these specifications is determined by specific
operating conditions in conjunction with board layout, the rated package
thermal resistance and other environmental factors.
Note 3:
100% tested at wafer level only.
Note 4:
See Output Current Derating curves for different V
IN
, V
OUT
and T
A
.
Note 5:
For input voltages less than 6V, tie the V
IN
, INTV
CC
and EXTV
CC
together. The LTM4618 will operate from 5V inputs, but V
IN
, INTV
CC
and
EXTV
CC
need to be tied together.
4618fb
4
For more information
www.linear.com/LTM4618
LTM4618
Typical perForMance characTerisTics
Efficiency vs Load Current with
5V
IN
(CCM)
100
95
EFFICIENCY (%)
EFFICIENCY (%)
90
85
80
75
70
100
95
EFFICIENCY (%)
90
85
80
75
70
Efficiency vs Load Current with
12V
IN
(CCM)
95
Efficiency vs Load Current with
24V
IN
(CCM)
90
85
80
5V TO 0.8V
OUT
5V TO 1.2V
OUT
5V TO 1.5V
OUT
5V TO 2.5V
OUT
5V TO 3.3V
OUT
0
1
2
4
3
LOAD CURRENT (A)
5
6
4618 G01
12V TO 1.2V
OUT
12V TO 1.5V
OUT
12V TO 2.5V
OUT
12V TO 3.3V
OUT
12V TO 5V
OUT
0
1
2
4
3
LOAD CURRENT (A)
5
6
4618 G02
75
70
24V TO 2.5V
OUT
24V TO 3.3V
OUT
24V TO 5V
OUT
0
1
3
2
4
LOAD CURRENT (A)
5
6
4618 G03
Efficiency vs Load Current with
Different Mode Settings
(12V to 3.3V)
100
V
IN
= 12V
90 V
OUT
= 3.3V
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.01
0.1
LOAD CURRENT (A)
BURST
PULSE SKIP
CCM
1
4618 G04
1.2V Transient Response
1.5V Transient Response
I
OUT
1A/DIV
V
OUT
50mV/DIV
50µs/DIV
V
IN
= 12V AND V
OUT
= 1.2V AT 3A/µs LOAD STEP
C
OUT
= 2× 22µF 6.3V CERAMIC CAPACITOR
1× 100µF 6.3V CERAMIC CAPACITOR
1× 220µF SANYO POSCAP
4618 G05
I
OUT
1A/DIV
V
OUT
50mV/DIV
50µs/DIV
V
IN
= 12V AND V
OUT
= 1.5V AT 3A/µs LOAD STEP
C
OUT
= 2× 22µF 6.3V CERAMIC CAPACITOR
1× 100µF 6.3V CERAMIC CAPACITOR
1× 220µF SANYO POSCAP
4618 G06
2.5V Transient Response
3.3V Transient Response
5V Transient Response
I
OUT
1A/DIV
V
OUT
50mV/DIV
50µs/DIV
V
IN
= 12V AND V
OUT
= 2.5V AT 3A/µs LOAD STEP
C
OUT
= 2× 22µF 6.3V CERAMIC CAPACITOR
1× 100µF 6.3V CERAMIC CAPACITOR
1× 220µF SANYO POSCAP
4618 G07
I
OUT
1A/DIV
V
OUT
50mV/DIV
50µs/DIV
V
IN
= 12V AND V
OUT
= 3.3V AT 3A/µs LOAD STEP
C
OUT
= 2× 22µF 6.3V CERAMIC CAPACITOR
1× 100µF 6.3V CERAMIC CAPACITOR
1× 220µF SANYO POSCAP
4618 G08
I
OUT
1A/DIV
V
OUT
100mV/DIV
50µs/DIV
V
IN
= 12V AND V
OUT
= 5V AT 3A/µs LOAD STEP
C
OUT
= 2× 22µF 6.3V CERAMIC CAPACITOR
1× 100µF 6.3V CERAMIC CAPACITOR
1× 220µF SANYO POSCAP
4618 G09
4618fb
For more information
www.linear.com/LTM4618
5
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