LINEAR TECHNOLOGY LTM4600 Technical data
FEATURES
Electrical Specifications Subject to Change
LTM4600
10A High Effi ciency
DC/DC µModule
U
DESCRIPTIO
■
Complete Switch Mode Power Supply
■
Wide Input Voltage Range: 4.5V to 20V
■
10A DC, 14A Peak Output Current
■
Parallel Two µModules™ for 20A Output Current
■
0.6V to 5V Output Voltage
■
1.5% Regulation
■
Ultrafast Transient Response
■
Current Mode Control
■
Pb-Free (e4) RoHS Compliant Package
■
Up to 92% Effi ciency
■
Programmable Soft-Start
■
Output Overvoltage Protection
■
Optional Short-Circuit Shutdown Timer
■
Small Footprint, Low Profi le (15mm × 15mm ×
2.8mm) Surface Mount LGA Package
U
APPLICATIO S
■
Telecom and Networking Equipment
■
Servers
■
Industrial Equipment
■
Point of Load Regulation
■
Other General Purpose Step Down DC/DC
, LTC, LT and LTM are registered trademarks of Linear Technology Corporation.
µModule is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents including 5481178,
6100678, 6580258, 5847554, 6304066.
The LTM®4600 is a complete 10A, DC/DC step down 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 20V, the
LTM4600 supports an output voltage range of 0.6V to 5V,
set by a single resistor. This high effi ciency design delivers
10A continuous current (14A peak), needing no heat sinks
or airfl ow to meet power specifi cations. Only bulk input
and output capacitors are needed to fi nish the design.
The low profi le package (2.8mm) enables utilization of
unused space on the bottom of PC boards for high density
point of load regulation. High switching frequency and an
adaptive on-time current mode architecture enables a very
fast transient response to line and load changes without
sacrifi cing stability. Fault protection features include
integrated overvoltage and short circuit protection with
a defeatable shutdown timer. A built-in soft-start timer is
adjustable with a small capacitor.
The LTM4600 is packaged in a thermally enhanced, compact
(15mm × 15mm) and low profi le (2.8mm) over-molded
Land Grid Array (LGA) package suitable for automated
assembly by standard surface mount equipment. The
LTM4600 is Pb-free and RoHS certifi ed.
U
TYPICAL APPLICATIO
10A µModule Power Supply with 4.5V to 20V Input
V
4.5V TO 20V
IN
V
C
IN
V
IN
LTM4600
V
OSET
PGND SGND
OUT
C
OUT
66.5k
4600 TA01a
V
OUT
1.5V
10A
PRERELEASE
Effi ciency vs Load Current
100
90
80
70
60
50
EFFICIENCY (%)
40
30
20
0
with 12V
24 8
LOAD CURRENT (A)
(FCB = 0)
IN
6
0.6V
1.2V
1.5V
2.5V
3.3V
10
OUT
OUT
OUT
OUT
OUT
4600 TA01b
12
4600p
1
LTM4600
WW
W
ABSOLUTE AXI U RATI GS
U
UUW
PACKAGE/ORDER I FOR ATIO
(Note 1)
FCB, EXTVCC, PGOOD, RUN/SS, V
, SVIN, F
V
IN
, COMP ............................................. –0.3V to 2.7V
V
OSET
........................................... –0.3V to 20V
ADJ
.......... –0.3V to 6V
OUT
Operating Temperature Range (Note 2) ... –40°C to 85°C
Junction Temperature ........................................... 125°C
Storage Temperature Range ................... –65°C to 150°C
V
PGND
TOP VIEW
IN
ADJ
F
IN
OSET
EXTVCCV
SV
COMP
SGND
RUN/SS
FCB
PGOOD
ORDER PART
NUMBER
LTM4600EV
LTM4600IV
LGA PART
MARKING
V
OUT
104-LEAD (15mm × 15mm × 2.8mm)
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
The ● denotes the specifi cations which apply over the –40°C to 85°C
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. External CIN = 120µF, C
LGA PACKAGE
T
= 125°C, θJA = 15°C/W
JMAX
= 200µF/Ceramic per typical
OUT
application (front page) confi guration.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN(DC)
V
OUT(DC)
Input Specifi cations
V
IN(UVLO)
I
INRUSH(VIN)
I
Q(VIN)
I
S(VIN)
Input DC Voltage
Output Voltage
V
= 12V, V
IN
V
= 12V, V
IN
V
= 5V, V
IN
Under Voltage Lockout Threshold I
Input Inrush Current at Startup
V
= 5V
IN
V
= 12V
IN
Input Supply Bias Current
V
= 12V, V
IN
V
= 12V, V
IN
VIN = 5V, V
V
= 5V, V
IN
Shutdown, RUN = 0, V
Input Supply Current
V
= 12V, V
IN
V
= 12V, V
IN
V
= 5V, V
IN
= 1.5V, I
OUT
= 1.5V, I
OUT
= 1.5V, I
OUT
= 1.5V, FCB = 5V
OUT
= 1.5V, FCB = 0V
OUT
= 1.5V, FCB = 5V
OUT
= 1.5V, FCB = 0V
OUT
IN
= 1.5V, I
OUT
= 3.3V, I
OUT
= 1.5V, I
OUT
OUT
OUT
= 0A
OUT
= 12V
OUT
OUT
= 10A
OUT
= 0A
= 0A
= 10A
= 10A
FCB = 0
= 0A 3.4 4 V
OUT
= 0A. V
I
OUT
I
= 0A, EXTVCC Open
OUT
= 1.5V, FCB = 0
OUT
●
4.5 20 V
●
1.478 1.50 1.522 V
1.52
3.13
3.64
0.6
0.7
1.2
42
1.0
52
15
LTM4600EV
LTM4600IV
mA
mA
mA
mA
A
A
µA
A
A
A
2
4600p
PRERELEASE
LTM4600
The ● denotes the specifi cations which apply over the –40°C to 85°C
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Specifi cations
I
OUTDC
ΔV
/ΔVIN Line Regulation Accuracy
OUT
/ΔI
ΔV
OUT
OUT
V
OUT(AC)
Fs Output Ripple Voltage Frequency FCB = 0V, I
t
START
ΔV
OUTLS
t
SETTLE
I
OUTPK
Control Stage
V
OSET
V
RUN/SS
I
RUN(C)/SS
I
RUN(D)/SS
– SV
V
IN
IN
I
EXTVCC
R
FBHI
V
FCB
I
FCB
PGOOD Output
ΔV
OSETH
ΔV
OSETL
ΔV
OSET(HYS)
V
PGL
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTM4600E is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating
Output Continuous Current Range
(See Output Current Derating Curves for
Different V
I
OUT
IN
= 0A
, V
OUT
and TA)
Load Regulation Accuracy
V
= 5V
IN
V
= 12V
IN
Output Ripple Voltage
V
IN
V
IN
= 12V, V
= 5V, V
= 1.5V, FCB = 0V
OUT
= 1.5V, FCB = 0V
OUT
Turn-On Time
V
= 12V
IN
V
= 5V
IN
Voltage Drop for Dynamic Load Step
V
= 12V, V
IN
OUT
= 1.5V
Settling Time for Dynamic Load Step
V
= 12V
IN
Output Current Limit
V
= 12V, V
IN
V
= 5V, V
IN
Voltage at V
= 1.5V
OUT
= 1.5V
OUT
Pin I
OSET
RUN ON/OFF Threshold 0.8 1.5 2 V
Soft-Start Charging Current V
Soft-Start Discharging Current V
Current into EXTVCC Pin FCB = 0V, V
Resistor Between V
and FB Pins 100 kΩ
OUT
Forced Continuous Threshold 0.57 0.6 0.63 V
Forced Continuous Pin Current V
PGOOD Upper Threshold V
PGOOD Lower Threshold V
PGOOD Hysteresis V
PGOOD Low Voltage I
= 25°C, VIN = 12V. Per typical application (front page) confi guration.
A
= 12V, V
V
IN
= 1.5V. FCB = 0V
V
OUT
= 1.5V. FCB = 0V
V
OUT
0A to 10A
= 0A
I
OUT
= 1.5V 0 10 A
OUT
● 0.3 %
±1
●
±1
15
20 25
800 kHz
= 5A, VIN = 12V, V
OUT
OUT
●
=
1.5V
V
OUT
= 1.5V, I
OUT
= 10A
0.5
0.7
Load Step: 0A to 5A/µs
C
= 3 • 22µF 6.3V, 470µF 4V Pos Cap,
OUT
36 mV
See Table 2
Load: 10% to 90% to 10% of Full Load 25 µs
17
17
= 0A, V
OUT
RUN/SS
RUN/SS
= 1.5V
OUT
= 0V –0.5 –1.2 –3 µA
= 4V 0.8 1.8 3 µA
●
0.594 0.6 0.606 V
EXTVCC = 0, FCB = 0V 100 mV
= 1.5V, I
OUT
= 0.6V –1 –2 µA
FCB
Rising 7.5 10 12.5 %
OSET
Falling –7.5 –10 –12.5 %
OSET
Returning 1 2.5 %
OSET
= 5mA 0.15 0.4 V
PGOOD
= 0A 16 mA
OUT
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTM4600I is guaranteed and tested
over the –40°C to 85°C temperature range.
mV
mV
P-P
P-P
ms
ms
%
%
A
A
PRERELEASE
4600p
3
LTM4600
w
)
(
)
(
)
(
)
UW
TYPICAL PERFOR A CE CHARACTERISTICS
Effi ciency vs Load Current
ith 5V
100
90
80
70
60
EFFICIENCY (%)
50
40
30
0
(FCB = 0)
IN
24
LOAD CURRENT (A)
Effi ciency vs Load Current
with Different FCB Settings
90
80
70
60
50
EFFICIENCY (%)
40
30
20
0.1
FCB > 0.7V
FCB = GND
LOAD CURRENT (A)
0.6V
OUT
1.2V
OUT
1.5V
OUT
2.5V
OUT
812
610
4600 G01
1
10
4600 G04
Effi ciency vs Load Current
with 12V(FCB = 0
100
90
80
70
60
50
EFFICIENCY (%)
40
30
20
24 8
0
LOAD CURRENT (A)
6
1.2V Transient Response
(See Figure 17)
V
= 50mV/DIV
OUT
I
= 5A/DIV
OUT
25µs/DIV
1.2V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
0.6V
1.2V
1.5V
2.5V
3.3V
10
OUT
OUT
OUT
OUT
OUT
4600 G02
4600 G05
12
Effi ciency vs Load Current
with 18V
100
90
80
70
60
EFFICIENCY (%)
50
40
30
0
(FCB = 0)
IN
24 8
6
LOAD CURRENT (A)
1.5V Transient Response
(See Figure 17)
25µs/DIV
1.5V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
1.5V
1.8V
2.5V
3.3V
10
OUT
OUT
OUT
OUT
4600 G03
4600 G06
12
1.8V Transient Response
See Figure 17
25µs/DIV
1.8V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600 G07
4
2.5V Transient Response
See Figure 17
25µs/DIV
2.5V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600 G08
PRERELEASE
3.3V Transient Response
See Figure 17
25µs/DIV
3.3V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600 G09
4600p
UW
(
)
)
)
TYPICAL PERFOR A CE CHARACTERISTICS
LTM4600
Start-Up, I
OUT
= 0A
(See Figure 17)
V
OUT
(0.5V/DIV)
I
IN
(0.5A/DIV)
200µs/DIV
VIN = 12V
= 1.5V
V
OUT
= 200µF
C
OUT
NO EXTERNAL SOFT-START CAPACITOR
4600 G10
Short-Circuit Protection,
I
= 10A (See Figure 17
V
OUT
(0.5V/DIV)
I
IN
(0.5A/DIV)
20µs/DIV
VIN = 12V
= 1.5V
V
OUT
= 2× 200µF/X5R
C
OUT
NO EXTERNAL SOFT-START CAPACITOR
4600 G13
Start-Up, I
OUT
= 10A
Resistive Load) (See Figure 17
V
OUT
(0.5V/DIV)
I
IN
(0.5A/DIV)
200µs/DIV
VIN = 12V
= 1.5V
V
OUT
= 200µF
C
OUT
NO EXTERNAL SOFT-START CAPACITOR
Current Limit with 12V
18
16
14
12
10
8
6
CURRENT LIMIT (A)
4
2
0
0
OUTPUT VOLTAGE (V)
4600 G11
4600 G14
Short-Circuit Protection,
I
= 0A (See Figure 17
V
OUT
(0.5V/DIV)
I
IN
(0.2A/DIV)
20µs/DIV
VIN = 12V
= 1.5V
V
OUT
= 2× 200µF/X5R
C
OUT
NO EXTERNAL SOFT-START CAPACITOR
4600 G12
Current Limit with 9V
18
16
14
12
10
8
6
CURRENT LIMIT (A)
4
2
654321
0
0
OUTPUT VOLTAGE (V)
654321
4600 G15
Current Limit with 5V
18
16
14
12
10
8
6
OUTPUT CURRENT (A)
4
2
0
0
OUTPUT VOLTAGE (V)
IN
4.03.53.02.52.01.00.5 1.5
4600 G16
PRERELEASE
(V)
OUT
V
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
VIN to V
Stepdown Ratio
OUT
5V
3.3V
2.5V
1.8V
1.5V
1.2V
0.6V
515
10 20
VIN (V)
4600 G17
4600p
5
LTM4600
PI FU CTIO S
UUU
(See Package Description for Pin Assignment)
VIN (Bank 1): Power Input Pins. Apply input voltage
between these pins and GND pins. Recommend placing
input decoupling capacitance directly between V
pins
IN
and GND pins.
(Pin A15): An internal resistor from VIN to this pin
F
ADJ
sets the one-shot timer current, thereby setting the switching frequency.
(Pin A17): Supply Pin for Internal PWM Controller.
SV
IN
Leave this pin open or add additional decoupling capacitance.
EXTV
(Pin A19): External 5V supply pin for controller.
CC
If left open, the internal 5V linear regulator will power the
controller and MOSFET drivers. For high input voltage
applications, connecting this pin to an external 5V will
reduce the power loss in the power module. The EXTV
voltage should never be higher than V
(Pin A21): The Negative Input of The Error Am-
V
OSET
plifi er. Internally, this pin is connected to V
IN
.
with a
OUT
CC
100k precision resistor. Different output voltages can be
programmed with additional resistors between the V
OSET
and SGND pins.
COMP (Pin B23): Current Control Threshold and Error
Amplifi er Compensation Point. The current comparator
threshold increases with this control voltage. The voltage
ranges from 0V to 2.4V with 0.8V corresponding to zero
sense voltage (zero current).
SGND (Pin D23): Signal Ground Pin. All small-signal
components should connect to this ground, which in turn
connects to PGND at one point.
RUN/SS (Pin F23): Run and Soft-Start Control. Forcing
this pin below 0.8V will shut down the power supply.
Inside the power module, there is a 1000pF capacitor
which provides approximately 0.7ms soft-start time with
200µF output capacitance. Additional soft-start time can
be achieved by adding additional capacitance between
the RUN/SS and SGND pins. The internal short-circuit
latchoff can be disabled by adding a resistor between this
pin and the V
pin. This resistor must supply a minimum
IN
5µA pull up current.
FCB (Pin G23): Forced Continuous Input. Grounding this
pin enables forced continuous mode operation regardless
of load conditions. Tying this pin above 0.63V enables
discontinuous conduction mode to achieve high effi ciency
operation at light loads. There is an internal 4.75K resistor
between the FCB and SGND pins.
PGOOD (Pin J23): Output Voltage Power Good Indicator.
When the output voltage is within 10% of the nominal
voltage, the PWRGD is open drain output. Otherwise, this
pin is pulled to ground.
PGND (Bank 2): Power ground pins for both input and
output returns.
(Bank 3): Power Output Pins. Apply output load
V
OUT
between these pins and GND pins. Recommend placing
High Frequency output decoupling capacitance directly
between these pins and GND pins.
6
TOP VIEW
2
1
V
8
IN
BANK 1
12
25
32
39
PGND
BANK 2
BANK 3
50
61
72
V
83
OUT
94
1 23
24
26 27 28 29 30 31
33 34 35 36 37 38
42 43 44 45 46 47
41
40
52 53 54 55 56 57 58
51
62
63 64 65 66 67 68 69
73
74 75 76 77 78 79 80
84 85 86 87 88 89 90 91
95 96 97 98
35
79
68
11109
13 14 15
99 100 101 102 103
11 13
10 12
14 16
PRERELEASE
ADJ
F
15 17
IN
EXTVCCV
SV
1918171676543
48
59
70
81
92
19 21
18 20 22
OSET
49
60
71
82
93
104
A
20
B
COMP
C
21
D
SGND
E
22
F
RUN/SS
23
G
FCB
H
24
J
PGOOD
K
L
M
N
P
R
S
4600 PN01
4600p
SI PLIFIEDWBLOCK DIAGRA
W
LTM4600
SV
IN
R6
66.5k
RUN/SS
PGOOD
COMP
FCB
F
ADJ
SGND
EXTV
V
OSET
1000pF
Q1
INT
COMP
4.75k
10Ω
CC
CONTROLLER
Q2
1.5µF
15µF
6.3V
LTM4600
100k
0.5%
4600 F01
V
4.5V TO 20V
IN
V
1.5V/10A MAX
OUT
PGND
C
IN
C
OUT
Figure 1. Simplifi ed LTM4600 Block Diagram
U
DECOUPLI G REQUIRE E TS
T
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
C
IN
C
OUT
External Input Capacitor Requirement
(V
= 4.5V to 15V, V
IN
OUT
= 1.5V)
External Output Capacitor Requirement
(V
= 4.5V to 15V, V
IN
OUT
= 1.5V)
WU
= 25°C, VIN = 12V. Use Figure 1 confi guration.
A
= 10A 20 µF
I
OUT
= 10A, Refer to Table 2 in the
I
OUT
Applications Information Section
100 200 µF
PRERELEASE
4600p
7
LTM4600
OPERATIO
U
µModule Description
The LTM4600 is a standalone non-isolated synchronous
switching DC/DC power supply. It can deliver up to 10A of
DC output current with only bulk external input and output
capacitors. This module provides a precisely regulated
output voltage programmable via one external resistor from
0.6V
The input voltage range is 4.5V to 20V. A simplifi ed block
diagram is shown in Figure 1 and the typical application
schematic is shown in Figure 17.
The LTM4600 contains an integrated LTC constant on-time
current-mode regulator, ultra-low R
switching speed and integrated Schottky diode. The typical
switching frequency is 800kHz at full load. With current
mode control and internal feedback loop compensation,
the LTM4600 module has suffi cient stability margins and
good transient performance under a wide range of operating conditions and with a wide range of output capacitors,
even all ceramic output capacitors.
Current mode control provides cycle-by-cycle fast current
limit. In addition, foldback current limiting is provided in an
over-current condition while V
has defeatable short circuit latch off. Internal overvoltage and undervoltage comparators pull the open-drain
PGOOD output low if the output feedback voltage exits a
to 5.0VDC, not to exceed 80% of the input voltage.
DC
FETs with fast
DS(ON)
drops. Also, the LTM4600
FB
±10% window around the regulation point. Furthermore,
in an overvoltage condition, internal top FET Q1 is turned
off and bottom FET Q2 is turned on and held on until the
overvoltage condition clears.
Pulling the RUN/SS pin low forces the controller into its
shutdown state, turning off both Q1 and Q2. Releasing the
pin allows an internal 1.2µA current source to charge up
the softstart capacitor. When this voltage reaches 1.5V,
the controller turns on and begins switching.
At low load current the module works in continuous current mode by default to achieve minimum output voltage
ripple. It can be programmed to operate in discontinuous
current mode for improved light load effi ciency when the
FCB pin is pulled up above 0.8V and no higher than 5V.
The FCB pin has a 4.25k resistor to ground, so a resistor
can set the voltage on the FCB pin.
to V
IN
When EXTV
regulator powers the controller and MOSFET gate drivers.
If a minimum 4.7V external bias supply is applied on the
EXTV
internal switch connects EXTV
This eliminates the linear regulator power loss with high
input voltage, reducing the thermal stress on the controller.
The maximum voltage on EXTV
voltage should never be higher than the V
EXTV
pin, the internal regulator is turned off, and an
CC
must be sequenced after VIN.
CC
pin is grounded, an integrated 5V linear
CC
to the gate driver voltage.
CC
pin is 6V. The EXTVCC
CC
voltage. Also
IN
8
4600p
PRERELEASE
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