FEATURES
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LTM4639
Low V
IN
20A DC/DC
µModule Step-Down Regulator
DESCRIPTION
The
LTM
®
4639
is a complete 20A output high efficiency
switch mode step-down DC/DC µModule (micromodule)
regulator. Included in the package are the switching
controller, power FETs, inductor and compensation
components. Operating over an input voltage range from
2.375V to 7V, the LTM4639 supports an output voltage
range of 0.6V to 5.5V, set by a single external resistor.
Only a few input and output capacitors are needed.
Current mode operation allows precision current sharing of
up to four LTM4639 regulators to obtain up to 80A output.
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, multiphase/current sharing,
Burst Mode operation and output voltage tracking for
supply rail sequencing. A diode-connected PNP transistor
is included for use as an internal temperature monitor. For
up to 20V input operation, please see the LTM4637.
The LTM4639 is offered in a 15mm
×
15mm
×
4.92mm
BGA package. The LTM4639 is RoHS compliant.
L,
LT, LTC, LTM, PolyPhase, Burst Mode, µModule, Linear Technology, 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, 6580258, 6304066, 6476589, 6774611, 6677210, 8163643.
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Complete 20A Switch Mode Power Supply
2.375V to 7V Input Voltage Range (V
IN
< 4.5V,
Need C
PWR
Bias)
0.6V to 5.5V Output Voltage Range
±1.5% Maximum Total DC Output Voltage Error
(–40°C to 125°C)
Differential Remote Sense Amplifier for Precision
Regulation (V
OUT
≤ 3.3V)
Current Mode Control/Fast Transient Response
Parallel Multiphase Current Sharing (Up to 80A)
Frequency Synchronization
Selectable Pulse-Skipping or Burst Mode
®
Operation
Soft-Start/Voltage Tracking
Up to 88% Efficiency (3.3V
IN
, 1.5V
OUT
)
Overcurrent Foldback Protection
Output Overvoltage Protection
Internal Temperature Monitor
Overtemperature Protection
15mm
×
15mm
×
4.92mm BGA Package
APPLICATIONS
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Telecom Servers and Networking Equipment
Industrial Equipment
Medical Systems
High Ambient Temperature Systems
3.3V Input Systems
TYPICAL APPLICATION
3.3V
IN
, 1.5V
OUT
, 20A DC/DC µModule
®
Regulator
+5V BIAS
1µF
22µF
6.3V
×4
5k
C
COMPA
180pF
0.1µF
2.2µF
100
95
EFFICIENCY (%)
90
85
80
75
70
3.3V to 1.5V Efficiency
and Power Loss
4.5
EFFICIENCY
4.0
3.5
3.0
2.5
2.0
C
PWR
= 5V
FREQ = 400kHz
1.5
POWER LOSS
1.0
0.5
0
2
4
6 8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4639 TA01b
0
POWER LOSS
V
IN
3.3V
V
IN
C
PWR
EXTV
CC
INTV
CC
PGOOD
COMPA
COMPB
TRACK/SS
RUN
f
SET
LTM4639
V
OUT
V
OUT_LCL
DIFF_OUT
V
OSNS+
V
OSNS
–
C
FF
*
180pF
V
OUT
1.5V
20A
100µF*
+
6.3V
×2
680µF*
2.5V
×2
100k
MODE_PLLIN
TEMP
+
TEMP
–
V
FB
GND
OT_TEST
SGND
R
FB
**
40.2k
C
BOT
*
22pF
4639 TA01a
* SEE TABLE 5
** SEE TABLE 1
4639f
For more information
www.linear.com/LTM4639
1
LTM4639
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
V
IN
TOP VIEW
COMPB
MODE_PLLIN
INTV
CC
TRACK/SS COMPA
4
5
6
7
8
9
10
11
12
V
IN
, C
PWR
, OT_TEST .................................. –0.3V to 10V
V
OUT_LCL
, PGOOD, EXTV
CC
.......................... –0.3V to 6V
MODE_PLLIN, f
SET
, TRACK/SS,
V
OSNS –
, V
OSNS+
, DIFF_OUT ................... –0.3V to INTV
CC
V
FB,
COMPA, COMPB (Note 7) ................. –0.3V to 2.7V
RUN (Note 5) ............................................... –0.3V to 5V
INTV
CC
Peak Output Current (Note 6) ..................100mA
Internal Operating Temperature Range
(Note 2).................................................. –40°C to 125°C
Storage Temperature Range .................. –55°C to 125°C
Maximum Peak Body Reflow Temperature ........... 245°C
1
A
2
3
V
IN
B
C
f
SET
RUN C
PWR
OT_TEST
TEMP
–
D
E
F
G
H
J
INTV
CC
EXTV
CC
PGOOD
V
FB
PGOOD
SGND
V
OSNS+
DIFF_OUT
V
OUT_LCL
V
OSNS–
BGA PACKAGE
133-LEAD (15mm × 15mm × 4.92mm)
TEMP
+
GND
V
OUT
K
L
M
T
J(MAX)
= 125°C,
θ
JA
= 9.5°C/W,
θ
JCbottom
= 4°C/W,
θ
JCtop
= 6.7°C/W,
θ
JB
= 4.5°C/W
θ
JA
DERIVED FROM 95mm
×
76mm PCB WITH 4 LAYERS; WEIGHT = 2.8g
θ
VALUES DETERMINED PER JESD51-12
ORDER INFORMATION
PART MARKING*
PART NUMBER
LTM4639EY#PBF
LTM4639IY#PBF
LTM4639IY
PAD OR BALL FINISH
SAC305 (RoHS)
SnPb (63/37)
DEVICE
LTM4639Y
LTM4639Y
LTM4639Y
FINISH CODE
e1
e0
PACKAGE
TYPE
BGA
BGA
MSL
RATING
4
4
TEMPERATURE RANGE
(SEE NOTE 2)
–40°C to 125°C
–40°C to 125°C
• Consult Marketing for parts specified with wider operating temperature
ranges. *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
The
l
denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V, C
PWR
= 5V, per the typical application in
Figure 22.
SYMBOL
V
IN
Range
V
OUT
Range
V
OUT(DC)
PARAMETER
Input DC Voltage Range
C
PWR
Voltage
Output DC Voltage Range
Output Voltage, Total
Variation with Line and
Load
C
IN
= 22µF
×
3, C
PWR
= 5V
C
OUT
= 100µF Ceramic, 470µF POSCAP
R
FB
= 40.2k, MODE_PLLIN = GND
V
IN
= 2.375V to 7V, I
OUT
= 0A to 20A (Note 4)
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
l
TYP
5
1.50
MAX
7
6
5.5
1.523
UNITS
V
V
V
V
V
IN
< 4.5V, C
PWR
Bias
2.375
4.5
0.6
1.477
4639f
2
For more information
www.linear.com/LTM4639
LTM4639
ELECTRICAL CHARACTERISTICS
SYMBOL
V
RUN
V
RUNHYS
I
Q(VIN)
PARAMETER
RUN Pin On Threshold
RUN Pin On Hysteresis
Input Supply Bias Current
V
IN
= 7V, V
OUT
= 1.5V, Burst Mode Operation, I
OUT
= 0.1A
V
IN
= 7V, V
OUT
= 1.5V, Pulse-Skipping Mode, I
OUT
= 0.1A
V
IN
= 7V, V
OUT
= 1.5V, Switching Continuous, I
OUT
= 0.1A
Shutdown, RUN = 0, V
IN
= C
PWR
= 7V
V
IN
= 3.3V, V
OUT
= 1.5V, I
OUT
= 20A, C
PWR
= 5V
V
IN
= 7V, V
OUT
= 1.5V, I
OUT
= 20A, C
PWR
= 5V
3.3V
IN
to 1.5V
OUT
at 0A Load, C
PWR
= 5V
0
l
l
The
l
denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V, C
PWR
= 5V, per the typical application in
Figure 22.
CONDITIONS
V
RUN
Rising
MIN
1.1
TYP
1.25
130
25
35
68
45
10.35
4.93
28
20
0.02
0.1
20
15
0.6
30
0.04
0.3
MAX
1.4
UNITS
V
mV
mA
mA
mA
µA
A
A
mA
A
%/V
%
mV
P-P
mV
ms
mV
Input Specifications
I
S(VIN)
I
PWR(IN)
I
OUT(DC)
∆V
OUT
(Line)
V
OUT
∆V
OUT
(Load)
V
OUT
V
OUT(AC)
∆V
OUT(START)
t
START
∆V
OUTLS
t
SETTLE
I
OUTPK
Control Section
V
FB
I
FB
V
OVL
I
TRACK/SS
t
ON(MIN)
R
FBHI
Input Supply Current
Control Power Current
Output Specifications
Output Continuous Current V
IN
= 3.3V, V
OUT
= 1.5V (Note 4)
Range
Line Regulation Accuracy
Load Regulation Accuracy
Output Ripple Voltage
Turn-On Overshoot
Turn-On Time
Peak Deviation for
Dynamic Load
Settling Time for Dynamic
Load Step
Output Current Limit
V
OUT
= 1.5V, V
IN
from 2.375V to 7V, C
PWR
= 5V,
I
OUT
= 0A
V
OUT
= 1.5V, I
OUT
= 0A to 20A, V
IN
= 3.3V, C
PWR
= 5V
(Note 4)
I
OUT
= 0A, C
OUT
= 100µF Ceramic, 470µF POSCAP
V
IN
= 3.3V, V
OUT
= 1.5V, C
PWR
= 5V
C
OUT
= 100µF Ceramic, 470µF POSCAP,
V
OUT
= 1.5V, I
OUT
= 0A, V
IN
= 3.3V, C
PWR
= 5V
C
OUT
= 100µF Ceramic, 470µF POSCAP,
No Load, TRACK/SS = 0.001µF, V
IN
= 3.3V, C
PWR
= 5V
Load: 5A to 12.5A Load Step, 1µs Rise Time
C
OUT
= 100µF
×
2 Ceramic, C
OUT
× 2 POSCAP,
V
IN
= 3.3V, V
OUT
= 1.5V, C
PWR
= 5V
Load: 5A to 12.5A Load Step, 3.3V, V
IN
= 5V, V
OUT
= 1.5V
C
OUT
= 100µF
×
2 Ceramic, 680µF POSCAP
V
IN
= 3.3V, V
OUT
= 1.5V
V
IN
= 7V, V
OUT
= 1.5V
I
OUT
= 0A, V
OUT
= 1.5V
(Note 7)
l
l
30
30
30
0.594
0.65
1.0
0.60
–12
0.67
1.2
100
60.05
60.40
60.75
0.606
–25
0.69
1.4
µs
A
A
V
nA
V
µA
ns
kΩ
Voltage at V
FB
Pin
Current at V
FB
Pin
Feedback Overvoltage
Lockout
Track Pin Soft-Start Pull-
Up Current
Minimum On-Time
Resistor Between V
OUT_LCL
and V
FB
Pins
Common Mode Input
Range
Maximum DIFF_OUT
Voltage
Input Offset Voltage
TRACK/SS = 0V
(Note 3)
Remote Sense Amplifier
V
OSNS+
,
V
OSNS– CM RANGE
V
DIFF_OUT(MAX)
V
OS
V
IN
= 3.3V, Run > 1.4V, C
PWR
= 5V
I
DIFF_OUT
= 300µA
V
OSNS+
= V
DIFF_OUT
= 1.5V, I
DIFF_OUT
= 100µA
0
INTV
CC
– 1.4
2.5
3.6
V
V
mV
4639f
For more information
www.linear.com/LTM4639
3
LTM4639
ELECTRICAL CHARACTERISTICS
SYMBOL
A
V
SR
GBP
CMRR
I
DIFF_OUT
PSRR
R
IN
PGOOD Output
V
PGOOD
V
PGL
PGOOD Trip Level
V
FB
With Respect to Set Output
V
FB
Ramping Negative
V
FB
Ramping Positive
I
PGOOD
= 2mA
5V < V
IN
< 7V, C
PWR
Tracking V
IN
I
CC
= 0 to 40mA, C
PWR
= 5.5V
EXTV
CC
Ramping Positive, C
PWR
= 5.5V, INTV
CC
Output 5V
I
CC
= 25mA, V
EXTVCC
= 5V, C
PWR
= 5.5V
MODE_PLLIN Clock Duty Cycle = 50%
V
fSET
= 1.2V
V
fSET
= 0V
V
fSET
≥ 2.4V
250
450
210
700
9
500
250
770
10
250
2.0
0.8
I
TEMP
= 100µA
l
l
The
l
denotes the specifications which apply over the specified internal
operating temperature range (Note 2), otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V, C
PWR
= 5V, per the typical application in
Figure 22.
PARAMETER
Differential Gain
Slew Rate
Gain Bandwidth Product
Common Mode Rejection
DIFF_OUT Current
Power Supply Rejection
Ratio
Input Resistance
CONDITIONS
(Note 7)
(Note 6)
(Note 6)
(Note 7)
Sourcing
5V < V
IN
< 7V (Note 7)
C
PWR
Tracking V
IN
V
OSNS
+ to GND
2
100
80
MIN
TYP
1
2
3
60
MAX
UNITS
V/V
V/µs
MHz
dB
mA
dB
kΩ
–10
10
0.1
4.8
4.5
5
2
4.7
75
220
800
550
290
850
11
0.3
5.2
%
%
V
V
%
V
mV
kHz
kHz
kHz
kHz
µA
kΩ
V
V
V
mV/°C
PGOOD Voltage Low
V
INTVCC
Source Output
INTV
CC
Linear Regulator
V
LDOINT
V
EXTVCC
V
LDOEXT
f
SYNC
f
NOM
f
LOW
f
HIGH
I
FREQ
R
MODE_PLLIN
V
IH_MODE_PLLIN
V
IL_MODE_PLLIN
Temperature Diode
V
TEMP
TC V
TEMP
TEMP Diode Voltage
Temperature Coefficient
0.6
–2
INTV
CC
Load Regulation
External V
CC
Switchover
EXTV
CC
Voltage Drop
Frequency Sync Capture
Range
Nominal Frequency
Lowest Frequency
Highest Frequency
Frequency Set Current
MODE_PLLIN Input
Resistance
Clock Input Level High
Clock Input Level Low
Oscillator and Phase-Locked Loop
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 LTM4639 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTM4639E 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 LTM4639I is guaranteed to meet specifications over the
full –40°C to 125°C 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:
The minimum on-time condition is specified for a peak-to-peak
inductor ripple current of ~40% of I
MAX
Load. (See the Applications
Information section)
Note 4:
See output current derating curves for different V
IN
, V
OUT
and T
A
.
Note 5:
Limit current into the RUN pin to less than 2mA.
Note 6:
Guaranteed by design.
Note 7:
100% tested at wafer level.
4639f
4
For more information
www.linear.com/LTM4639
LTM4639
TYPICAL PERFORMANCE CHARACTERISTICS
2.5V Input Efficiency Graph
100
95
EFFICIENCY (%)
EFFICIENCY (%)
90
85
80
75
70
2.5V TO 1.8V
2.5V TO 1.5V
2.5V TO 1.2V
2.5V TO 1V
100
95
EFFICIENCY (%)
90
85
80
75
70
3.3V TO 2.5V
3.3V TO 1.8V
3.3V TO 1.5V
3.3V TO 1.2V
3.3V TO 1V
3.3V Efficiency Graph
100
95
90
85
80
75
70
5V Efficiency Graph
C
PWR
= 5V
FREQ = 350kHz
0
2
4
C
PWR
= 5V
FREQ = 400kHz
0
2
4
C
PWR
= V
IN
FREQ = 500kHz
0
2
4
5V TO 3.3V
5V TO 2.5V
5V TO 1.8V
5V TO 1.5V
5V TO 1.2V
5V TO 1V
6
8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4637 G01
6
8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4639 G02
6
8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4639 G03
7V Efficiency Graph
100
95
EFFICIENCY (%)
90
85
80
75
70
7V TO 5V
7V TO 3.3V
7V TO 2.5V
7V TO 1.8V
7V TO 1.5V
7V TO 1.2V
7V TO 1V
LOAD
STEP
0A TO 7.5A
V
OUT
V
P-P
= 80mV
2.5V to 1V with 7.5A/µs Load
Step, C
PWR
= 5V
V
OUT
V
P-P
= 80mV
2.5V to 1.2V with 7.5A/µs Load
Step, C
PWR
= 5V
LOAD
STEP
0A TO 7.5A
C
PWR
= V
IN
FREQ = 550kHz
0
2
4
50µs/DIV
4639 G05
50µs/DIV
4639 G06
6
8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4639 G03
COMPA CONNECTED TO COMPB
C
FF
= 180pF, C
BOT
= 22pF, C
COMPA
= 180pF
C
OUT
= 100µF CER ×2,
680µF 2.5V 6m POSCAP ×2
COMPA CONNECTED TO COMPB
C
FF
= 180pF, C
BOT
= 22pF, C
COMPA
= 180pF
C
OUT
= 100µF CER ×2,
680µF 2.5V 6m POSCAP ×2
2.5V to 1.5V with 7.5A/µs Load
Step, C
PWR
= 5V
V
OUT
V
P-P
=
80mV
V
OUT
V
P-P
= 80mV
3.3V to 1V with 7.5A/µs Load
Step, C
PWR
= 5V
V
OUT
V
P-P
= 80mV
3.3V to 1.2V with 7.5A/µs Load
Step, C
PWR
= 5V
LOAD
STEP
0A TO
7.5A
50µs/DIV
4639 G07
LOAD
STEP
0A TO 7.5A
LOAD
STEP
0A TO 7.5A
50µs/DIV
4639 G08
50µs/DIV
4639 G09
COMPA CONNECTED TO COMPB
C
FF
= 180pF, C
BOT
= 22pF, C
COMPA
= 180pF
C
OUT
= 100µF CER ×2,
680µF 2.5V 6m POSCAP ×2
COMPA CONNECTED TO COMPB
C
FF
= 180pF, C
BOT
= 22pF, C
COMPA
= 180pF
C
OUT
= 100µF CER ×2,
680µF 2.5V 6m POSCAP ×2
COMPA CONNECTED TO COMPB
C
FF
= 180pF, C
BOT
= 22pF, C
COMPA
= 180pF
C
OUT
= 100µF CER ×2,
680µF 2.5V 6m POSCAP ×2
4639f
For more information
www.linear.com/LTM4639
5