FeaTures
Wide Operating Input Voltage Range: 4.5V to 38V
n
10A DC Typical, 12A Peak Output Current
n
Output Range: 0.6V to 6V
n
±1.5% Maximum Total Output DC Voltage Error
n
Differential Remote Sense Amplifier for POL Regulation
n
Internal Temperature, Analog Indicator Output
n
Overcurrent Foldback and Overtemperature
Protection
n
Current Mode Control/Fast Transient Response
n
Parallelable for Higher Output Current
n
Selectable Pulse-Skipping Operation
n
Soft-Start/Voltage Tracking/Pre-Bias Start-Up
n
15mm
×
15mm
×
5.01mm BGA Package
n
SnPb or RoHS Compliant Finish
Input Protection
n
UVLO, Overvoltage Shutdown and Latchoff Thresholds
n
N-Channel Overvoltage Power-Interrupt MOSFET Driver
n
Surge Stopper Capable with Few External Components
Load Protection
n
Robust, Resettable Latchoff Overvoltage Protection
n
N-Channel Overvoltage Crowbar Power MOSFET Driver
n
LTM4641
38V, 10A DC/DC µModule
Regulator with Advanced
Input and Load Protection
DescripTion
The
LTM
®
4641
is a switch mode step-down DC/DC
µModule
®
(micromodule) regulator with advanced input
and load protection features. Trip detection thresholds for
the following faults are customizable: input undervoltage,
overtemperature, input overvoltage and output overvolt-
age. Select fault conditions can be set for latchoff or
hysteretic restart response—or disabled. Included in the
package are the switching controller and housekeeping ICs,
power MOSFETs, inductor, overvoltage drivers, biasing
circuitry and supporting components. Operating from input
voltages of 4V to 38V (4.5V start-up), the device supports
output voltages from 0.6V to 6V, set by an external resis-
tor network remote sensing the point-of-load’s voltage.
The LTM4641’s high efficiency design can deliver up to
10A continuous current with a few input and output ca-
pacitors. The regulator’s constant on-time current mode
control architecture enables high step-down ratios and
fast response to transient line and load changes. The
LTM4641 is offered in a 15mm
×
15mm
×
5.01mm with
SnPb or RoHS compliant terminal finish.
L,
LT, LTC, LTM, µModule, Burst Mode, Linear Technology and the Linear logo are registered
trademarks and LTpowerCAD is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents including
5481178, 5847554, 6100678, 6304066, 6580258, 6677210, 8163643.
Click to view associated TechClip Videos.
applicaTions
n
n
Ruggedized Electronics
Avionics and Industrial Equipment
Typical applicaTion
µModule Regulator with Input Disconnect and Fast Crowbar Output Overvoltage Protection
4
V
IN
4V TO 38V
4.5V START-UP
+
MSP*
100µF
50V
10µF
50V
×2
3
V
ING
V
INGP
V
INH
M
TOP
V
INL
750k
f
SET
UVLO
INTV
CC
DRV
CC
RUN
TRACK/SS
10nF
LTM4641
V
OSNS–
GND
OV
PGM
5.6M
4641 TA01a
1V Load Protected from M
TOP
Short-Circuit at 38V
IN
SW
V
OUT
CROWBAR
M
BOT
V
OSNS+
5.49k
5.49k
LOAD
2
MCB**
1
V
OUT
1V
100µF 10A
×3
V
INL
, V
INH
(25V/DIV)
CROWBAR (5V/DIV)
1.1V
OUT
PEAK
SHORT-CIRCUIT APPLIED
4
3
2
V
OUT
(200mV/DIV)
1
4µs/DIV
TESTED AT WORST-CASE CONDITION: NO LOAD
4641 TA01b
IOVRETRY OVLO FCB
LATCH
SGND
SGND CONNECTS TO GND INTERNAL TO µMODULE REGULATOR
* MSP: (OPTIONAL) SERIES-PASS OVERVOLTAGE POWER INTERRUPT MOSFET, NXP PSMN014-60LS
** MCB: (OPTIONAL) OUTPUT OVERVOLTAGE CROWBAR MOSFET, NXP PH2625L
4641fe
For more information
www.linear.com/LTM4641
1
LTM4641
Table oF conTenTs
Features ..................................................... 1
Applications ................................................ 1
Typical Application ........................................ 1
Description.................................................. 1
Absolute Maximum Ratings .............................. 3
Order Information .......................................... 3
Pin Configuration .......................................... 3
Electrical Characteristics ................................. 4
Typical Performance Characteristics ................... 8
Pin Functions .............................................. 10
Simplified Block Diagram ............................... 15
Decoupling Requirements ............................... 15
Operation................................................... 16
Introduction ............................................................ 16
Motivation............................................................... 16
Power µModule Regulator Reliability ...................... 16
Overview ................................................................. 16
Applications Information—Power Supply Features . 17
Power (V
INH
) and Bias (V
INL
) Input Pins................. 17
Switching Frequency (On Time) Selection and
Voltage Dropout Criteria (Achievable V
IN
-to-V
OUT
Step-Down Ratios).................................................. 18
Setting the Output Voltage; the Differential
Remote Sense Amplifier ......................................... 21
Input Capacitors .....................................................23
Output Capacitors and
Loop Stability/Loop Compensation.........................23
Pulse-Skipping Mode vs
Forced Continuous Mode ....................................... 24
Soft-Start, Rail-Tracking and Start-Up Into
Pre-Bias .................................................................. 24
INTV
CC
and DRV
CC ............................................................... 27
1V
REF ......................................................................................... 28
TEMP, OTBH and Overtemperature Protection........ 28
Input Monitoring Pins: UVLO, IOVRETRY, OVLO ....29
Applications Information—Input Protection
Features .................................................... 29
Start-Up/Shutdown and Run Enable;
Power-On Reset and Timeout Delay Time ............... 31
Applications Information—Load Protection
Features .................................................... 32
Overcurrent Foldback Protection ............................ 32
Power Good Indicator and Latching Output
Overvoltage Protection ........................................... 32
Power-Interrupt MOSFET (MSP), CROWBAR Pin
and Output CROWBAR MOSFET (MCB) ..................33
Fast Output Overvoltage Comparator Threshold .....34
The Switching Node: SW Pin ..................................35
Applications Information—EMI Performance ........ 35
Applications Information—Multimodule
Parallel Operation ........................................ 36
Applications Information—Thermal Considerations
and Output Current Derating ............................ 38
Thermal Considerations and
Output Current Derating .........................................38
Applications Information—Output Capacitance
Table ........................................................ 45
Applications Information—Safety and Layout
Guidance ................................................... 46
Safety Considerations .............................................46
Layout Checklist/Example ......................................46
Typical Applications ...................................... 48
Appendices ................................................ 56
Appendix A. Functional Block Diagram and
Features Quick Reference Guide .............................56
Appendix B. Start-Up/Shutdown State Diagram ..... 57
Appendix C. Switching Frequency Considerations
and Usage of R
fSET
.................................................58
Appendix D. Remote Sensing in
Harsh Environments ............................................... 59
Appendix E. Inspiration For Pulse-Skipping
Mode Operation ......................................................60
Appendix F. Adjusting the Fast Output Overvoltage
Comparator Threshold ............................................60
Package Description ..................................... 63
Package Photo ............................................ 63
Package Description ..................................... 64
Revision History .......................................... 65
Typical Application ....................................... 66
Related Parts .............................................. 66
4641fe
2
For more information
www.linear.com/LTM4641
LTM4641
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
SGND
M
TRACK/SS
PGOOD L
SGND
K
COMP
J
f
SET
V
INL
H
V
OSNS+
V
OSNS–
G
F
V
ORB+
V
ORB
E
INTV
CC
TOP VIEW
V
ING
V
INGP
V
INH
FCB
DRV
CC
GND
SW
GND
GND
Terminal Voltages
V
INL
, V
INH
, SW, f
SET
............................... –0.3V to 40V
V
OUT
...................................................... –0.3V to 9.2V
V
ING
............................................ –0.3V to V
INH
+ 20V
INTV
CC
, DRV
CC
, RUN, TRACK/SS, PGOOD,
CROWBAR, HYST .................................... –0.3V to 6V
FCB, TMR................................-0.3V to INTV
CC
+ 0.3V
COMP ................................................... –0.3V to 2.7V
V
OSNS+
, V
ORB+
...................................... –0.6V to 9.7V
V
OSNS –
, V
ORB –
..........V
OSNS+
– 2.7V to V
OSNS+
+ 0.3V
OTBH, UVLO, IOVRETRY, OVLO,
LATCH
....................................................–0.3V to 7.5V
TEMP, OV
PGM
....................................... –0.3V to 1.5V
Terminal Currents
INTV
CC
(Continuous)....................................... –30mA
INTV
CC
(Continuous; CROWBAR
Sourcing 15mA) ...............................................–15mA
CROWBAR (Continuous) ..................................–15mA
V
INGP
(Continuous) ........................... –50mA to 15mA
1V
REF
(Continuous) ................................–1mA to 1mA
Internal Operating Temperature Range (Note 2)
E- and I-Grades.................................. –40°C to 125°C
MP-Grade .......................................... –55°C to 125°C
Storage Temperature Range .................. –55°C to 125°C
Peak Package Body Temperature (SMT Reflow) ... 245°C
D
–
C
B
A
1
2
OTBH TMR RUN
LATCH
SGND
GND
3
UVLO
HYST
4
5
TEMP
6
7
8
9 10 11
IOVRETRY CROWBAR OV
PGM
OVLO
12
V
OUT
1V
REF
BGA PACKAGE
144-LEAD (15mm
×
15mm
×
5.01mm)
T
JMAX
= 125°C,
θ
JCtop
= 11°C/W,
θ
JCbottom
= 2.5°C/W
θ
JB
= 3°C/W,
θ
JA
= 10.4°C/W
θ
VALUES DETERMINED PER JESD51-12
WEIGHT = 2.9 GRAMS
orDer inForMaTion
PART NUMBER
LTM4641EY#PBF
LTM4641IY#PBF
LTM4641IY
LTM4641MPY#PBF
LTM4641MPY
PAD OR BALL FINISH
SAC305 (RoHS)
SAC305 (RoHS)
SnPb (63/37)
SAC305 (RoHS)
SnPb (63/37)
PART MARKING*
DEVICE
LTM4641Y
LTM4641Y
LTM4641Y
LTM4641Y
LTM4641Y
FINISH CODE
e1
e1
e0
e1
e0
PACKAGE
TYPE
BGA
BGA
BGA
BGA
BGA
MSL
RATING
4
4
4
4
4
TEMPERATURE RANGE
(Note 2)
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–55°C to 125°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.
•
Pb-free and Non-Pb-free Part Markings:
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
4641fe
For more information
www.linear.com/LTM4641
3
LTM4641
elecTrical characTerisTics
SYMBOL
V
IN
V
OUT
V
OUT(DC)
Input Specifications
V
RUN(ON,OFF)
I
RUN(ON)
I
RUN(OFF)
V
INL(UVLO)
I
INRUSH(VINH)
I
Q(VINH)
RUN On/Off Threshold
RUN Pull-Up Current
RUN Pull-Down Current, Switching
Inhibited
V
INL
Undervoltage Lockout
Input Inrush Current Through V
INH
,
at Start-Up
Power Stage Bias Current (I
VINH
) at
No Load
Run Rising, Turn On
Run Falling, Turn Off
V
RUN
= 0V
V
RUN
= 3.3V
V
RUN
= 3.3V, UVLO = 0V (M
HYST
On)
V
INL
Rising
V
INL
Falling
Hysteresis
C
SS
= Open
I
OUT
= 0A and:
FCB ≥ 0.84V (Pulse-Skipping Mode)
FCB ≤ 0.76V (Forced Continuous Mode)
Shutdown, RUN = 0
INTV
CC
Connected to DRV
CC
and:
V
IN
= 28V, I
OUT
= 0A
V
IN
= 28V, I
OUT
= 10A
V
IN
= 28V, Shutdown, RUN = 0
I
OUT
= 10A and:
V
IN
= 4.5V
V
IN
= 28V
V
IN
= 38V
(Note 3)
V
IN
from 4.5V to 38V, I
OUT
= 0A
I
OUT
from 0A to 10A (Note 3)
I
OUT
= 0A
I
OUT
= 0A
I
OUT
= 10A
I
OUT
= 0A
RUN Electrically Open Circuit, Time Between
Application of V
IN
to V
OUT
Becoming Regulated,
OV
PGM
= 1.5V, C
TMR
= C
SS
= Open
V
IN
Established, (TMR-Set POR Time Expired)
Time Between RUN Releasing from GND to
PGOOD Going Logic High, C
SS
= Open,
OV
PGM
= 1.5V
I
OUT
from 0A to 5A at 5A/µs
I
OUT
from 5A to 0A at 5A/µs
l
l
l
l
l
l
l
l
l
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
= V
INH
= V
INL
= 28V, per the typical application
shown in Figure 45, unless otherwise noted.
PARAMETER
Input DC Voltage
Output Voltage Range
Output Voltage, Total Variation with
Line and Load, and Prior to UVLO
Use R
SET1A
= R
SET1B
≤ 8.2kΩ. R
fSET
Values
Recommended in Table 1
4.5V ≤ V
IN
≤ 38V, 0A ≤ I
OUT
≤ 10A
V
IN
= 4V (Ramped Down from 4.5V), I
OUT
= 0A
CONDITIONS
l
l
l
l
MIN
4.5
0.6
1.773
1.773
TYP
MAX
38
6
UNITS
V
V
V
V
V
V
µA
µA
nA
1.800
1.800
1.25
1.15
–520
–165
1
4.2
3.8
400
230
1.827
1.827
2
–460
–110
0.8
–580
–220
3.5
300
4.5
4
V
V
mV
mA
8
29
0.2
14.5
15.5
5
4.65
790
590
0
0.02
0.04
16
290
330
10
3
10
0.15
0.15
mA
mA
mA
mA
mA
mA
A
mA
mA
A
%
%
mV
P-P
kHz
kHz
mV
ms
I
Q(VINL)
Control Bias Current (I
VINL
)
I
S(VINH)
Power Stage Input Current (I
VINH
) at
Full Load
Output Specifications
I
OUT(DC)
∆V
OUT(LINE)
/V
OUT
∆V
OUT(LOAD)
/V
OUT
V
OUT(AC)
f
S
V
OUT(START)
t
START
t
RUN(ON-DELAY)
Output Continuous Current Range
Line Regulation Accuracy
Load Regulation Accuracy
Output Voltage Ripple Amplitude
Output Voltage Ripple Frequency
Turn-On Overshoot
V
IN
-to-V
OUT
Start-Up Time
RUN-to-V
OUT
Turn-On Response
Time
175
400
μs
∆V
OUT(LS)
t
SETTLE(LS)
Peak Deviation for Dynamic Load
Step
40
40
20
20
mV
mV
μs
µs
4641fe
Settling Time for Dynamic Load Step I
OUT
from 0A to 5A at 5A/µs
I
OUT
from 5A to 0A at 5A/µs
4
For more information
www.linear.com/LTM4641
LTM4641
elecTrical characTerisTics
SYMBOL
I
OUT(PK)
I
VINH(IOUT_SHORT)
Control Section
V
FB
I
TRACK/SS
V
FCB
I
FCB
t
ON(MIN)
t
OFF(MIN)
V
OSNS(DM)
V
OSNS(CM)
R
IN(VOSNS
+
)
INTV
CC
, DRV
CC
, 1V
REF
V
INTVCC
∆V
INTVCC(LOAD)
V
INTVCC
V
INTVCC(LOWLINE)
DRV
CC(UVLO)
I
DRVCC
INTV
CC
Voltage at Low Line
DRV
CC
Undervoltage Lockout
DRV
CC
Current
Internal V
CC
Voltage
INTV
CC
Load Regulation
6V ≤ V
IN
≤ 38V, INTV
CC
Not Connected to DRV
CC
,
l
DRV
CC
= 5.3V
RUN = 0V, INTV
CC
Not Connected to DRV
CC
,
DRV
CC
= 5.3V and:
I
INTVCC
Varied from 0mA to –20mA
I
INTVCC
Varied from 0mA to –30mA
V
IN
= 4.5V, R
SET1A
= R
SET1B
= 0Ω (~0.6V
OUT
,
R
fSET
Value Recommended in Table 1)
DRV
CC
Rising
DRV
CC
Falling
INTV
CC
Not Connected to DRV
CC
, DRV
CC
= 5.3V,
R
SET1A
, R
SET1B
and R
SET2
Setting V
OUT
to:
1.8V
OUT
, R
fSET
= 2MΩ, 0A ≤ I
OUT
≤ 10A
6.0V
OUT
, R
fSET
= Open, 0A ≤ I
OUT
≤ 10A
(Use R
SET1A
= R
SET1B
≤ 8.2k)
I
1VREF
= 0mA
I
1VREF
= ±1mA
Ramping Differential V
OSNS+
– V
OSNS–
Voltage:
Up, PGOOD Goes Logic Low
→
High
Up, PGOOD Goes Logic High
→
Low
Down, PGOOD Goes Logic Low
→
High
Down, PGOOD Goes Logic High
→
Low
Differential V
OSNS+
– V
OSNS–
Voltage Returning
I
PGOOD
= 5mA
Delay Between Differential V
OSNS+
– V
OSNS–
Voltage Exiting PGOOD Valid Window to PGOOD
Going Logic Low (Note 4)
l
l
l
l
l
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
= V
INH
= V
INL
= 28V, per the typical application
shown in Figure 45, unless otherwise noted.
PARAMETER
Output Current Limit
CONDITIONS
5.1kΩ Pull-Up from PGOOD to 5V Source, I
OUT
Ramped Up Until V
OUT
Below PGOOD Lower
Threshold, PGOOD Pulls Logic Low
V
OUT
Electrically Shorted to GND
MIN
TYP
24
MAX
UNITS
A
Power Stage Input Current During
Output Short Circuit
Differential Feedback Voltage from
V
OSNS+
to V
OSNS–
TRACK/SS Pull-Up Current
FCB Threshold
FCB Pin Current
Minimum On-Time
Minimum Off-Time
Remote Sense Pin-Pair Differential
Mode Input Range
Remote Sense Pin-Pair Common
Mode Input Range
Input Resistance
45
mA
I
OUT
= 0A
V
TRACK/SS
= 0V
V
FCB
= 0.8V
(Note 4)
(Note 4)
Valid Differential V
OSNS+
-to- V
OSNS–
Range
(Use R
SET1A
= R
SET1B
≤ 8.2k)
Valid V
OSNS–
Common Mode Range
Valid V
OSNS+
Common Mode Range
(Use R
SET1A
= R
SET1B
≤ 8.2k)
V
OSNS+
to GND
l
591
–0.45
0.76
600
–1
0.8
0
43
220
609
mV
μA
0.84
±1
75
300
2.7
V
μA
ns
ns
V
V
V
Ω
V
l
l
l
0
–0.3
3
16400
5.3
16482
5.4
16318
5.1
–0.7
–1
4.2
3.9
3.2
4.3
4.05
3.35
±2
±3
%
%
V
4.2
3.5
V
V
11
20
0.985
0.980
1.000
1.000
18
27
1.015
1.020
mA
mA
V
V
V
1VREF(DC)
PGOOD Output
V
PGOOD(TH)
1V
REF
DC Voltage Regulation
Power Good Window, Logic State
Transition Thresholds
533
645
621
525
8
556
660
644
540
16
75
12
579
675
667
555
24
400
mV
mV
mV
mV
mV
mV
μs
V
PGOOD(HYST)
V
PGOOD(VOL)
t
PGOOD(DELAY)
Hysteresis
Logic-Low Output Voltage
PGOOD Logic-Low Blanking Time
4641fe
For more information
www.linear.com/LTM4641
5
Test/Measurement
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