package. Included in the package are the switching con-
troller, 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 operations.
Fault protection features include overvoltage protection,
overcurrent protection and foldback current limit for
short-circuit protection.
The LTM4618 is Pb-free and RoHS compliant.
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 Package
APPLICATIONS
n
n
n
n
n
n
n
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 (%)
V
IN
6V to 26.5V
MODE/PLLIN INTV
CC
EXTV
CC
FREQ
V
IN
C
IN
COMP
LTM4618
TK/SS
0.1μF
RUN
SGND
PGND
4618 TA01
3.0
2.5
POWER LOSS (W)
2.0
V
OUT
V
FB
PGOOD
28.7k
C
OUT
V
OUT
2.5V/6A
85
1.5
80
1.0
POWER LOSS
75
12V
IN
TO 2.5V
OUT
24V
IN
TO 2.5V
OUT
0
1
3
2
4
LOAD CURRENT (A)
5
6
4618 TA01b
0.5
0
70
4618fa
1
LTM4618
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
7
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 Package Body Temperature .......................... 250°C
SW
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
V
OUT
TK/SS COMP V
FB
PGOOD
INTV
CC
LGA PACKAGE
84-LEAD (15mm 9mm 4.32mm)
Θ
JA
= 16°C/W,
Θ
JCtop
= 15°C/W,
Θ
JCbottom
= 4°C/W, WEIGHT = 2.3g,
θ
JB
+
θ
BA
= 16°C/W,
θ
BA
= BOARD-TO-AMBIENT RESISTANCE,
θ
VALUES DEFINED PER JESD51-12
ORDER INFORMATION
LEAD FREE FINISH
LTM4618EV#PBF
LTM4618IV#PBF
PART MARKING*
LTM4618V
LTM4618V
PACKAGE DESCRIPTION
84-Lead (15mm
×
9mm
×
4.32mm) LGA
84-Lead (15mm
×
9mm
×
4.32mm) LGA
TEMPERATURE RANGE
–40°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.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/
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
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
A
A
4618fa
2
LTM4618
ELECTRICAL CHARACTERISTICS
SYMBOL
I
Q(VIN)
PARAMETER
Input Supply Bias Current
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
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
MIN
TYP
26
20
80
1.430
0.675
MAX
UNITS
mA
mA
μA
A
A
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)
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
4.8
4.5
5
4.7
50
200
5.2
100
V
V
mV
mV
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
I
OUT
= 0A, V
OUT
= 2.5V
(Note 3)
Measured at V
FB
V
TK/SS
= 0V
In Dropout (Note 3)
(Note 3)
V
FREQ
= 1.2V
V
FREQ
= 0V
450
210
0.84
0.9
0.792
0.788
l
l
0
0.02
0.3
6
0.04
0.6
A
%/V
%
10
12
780
mV
mV
kHz
f
S
ΔV
OUT(START)
Output Ripple Voltage Frequency
Turn-On Overshoot
20
20
mV
mV
t
START
Turn-On Time
0.75
0.70
ms
ms
ΔV
OUTLS
Peak Deviation for Dynamic Load
15
mV
t
SETTLE
Settling Time for Dynamic Load Step
10
11
11
0.8
0.8
–10
0.86
1.3
97
90
500
250
550
290
0.808
0.808
–50
0.88
1.7
μs
A
A
V
V
nA
V
μA
%
ns
kHz
kHz
4618fa
I
OUT(PK)
Output Current Limit
Control Section
V
FB
I
FB
V
OVL
I
TK/SS
DF
MAX
t
ON(MIN)
f
NOM
f
LOW
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
l
3
LTM4618
ELECTRICAL CHARACTERISTICS
SYMBOL
f
HIGH
V
IH(MODE/PLLIN)
V
IL(MODE/PLLIN)
R
MODE/PLLIN
I
FREQ
PARAMETER
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
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
60.1
f
MODE/PLLIN
> f
OSC
f
MODE/PLLIN
< f
OSC
RUN Rising
1.1
250
–13
13
1.22
120
60.4
0.1
60.7
0.3
±2
–10
10
1.35
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
V
FREQ
≥ 2.4V, INTV
CC
MIN
700
2.0
0.8
TYP
780
MAX
860
UNITS
kHz
V
V
kΩ
μA
μA
V
mV
kΩ
V
μA
%
%
V
RUN
V
RUN
Hysteresis
R
FBHI
PGOOD Output
V
PGL
I
PGOOD
V
PG
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
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