Page 1
Electrical Specifications Subject to Change
LTM4600HV
FEATURES
■
Complete Switch Mode Power Supply
■
Wide Input Voltage Range: 4.5V to 28V
■
10A DC, 12A Peak Output Current
■
Parallel Two µModules™ for 20A Output Current
■
0.6V to 5V Output Voltage
■
1.5% Regulation of Output Voltage
■
Ultrafast Transient Response
■
Current Mode Control
■
Up to 92% Effi ciency
■
Programmable Soft-Start
■
Output Overvoltage Protection
■
Optional Short-Circuit Shutdown Timer
■
Pb-Free (e4) RoHS Compliant Package
■
Small Footprint, Low Profi le (15mm × 15mm ×
2.8mm) 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.
10A, 28V
High Effi ciency
IN
DC/DC µModule
U
DESCRIPTIO
The LTM®4600HV is a complete 10A, DC/DC step down
power supply with up to 28V input operation. 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 28V, the LTM4600HV
supports an output voltage range of 0.6V to 5V, set by a
single resistor. This high effi ciency design delivers 10A
continuous current (12A 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 LTM4600HV is packaged in a thermally enhanced,
compact (15mm × 15mm) and low profi le (2.8mm) overmolded Land Grid Array (LGA) package suitable for automated assembly by standard surface mount equipment.
The LTM4600HV is Pb-free and RoHS compliant.
U
TYPICAL APPLICATIO
10A µModule Power Supply with 4.5V to 28V Input
V
4.5V TO 28V
ABSMAX
IN
C
IN
*REVIEW DE-RATING CURVE AT
THE HIGHER INPUT VOLTAGE
V
V
IN
LTM4600HV
V
OSET
PGND SGND
OUT
C
OUT
66.5k
4600hv TA01a
V
OUT
2.5V*
10A
PRERELEASE
Effi ciency vs Load Current
100
90
80
70
60
EFFICIENCY (%)
50
40
30
0
with 24VIN (FCB = 0)
1.5V
OUT
1.8V
OUT
2.5V
OUT
3.3V
OUT
5V
OUT
24 8
LOAD CURRENT (A)
6
4600HV TA01b
10
4600hvp
1
Page 2
LTM4600HV
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 28V
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
LTM4600HVEV
LTM4600HVIV
LGA PART
MARKING
V
OUT
LTM4600HVEV
LTM4600HVIV
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
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)
Min On Time 50 100 ns
Min Off Time 250 400 ns
I
S(VIN)
Input DC Voltage AbsMax 28V for Tolerance on 24V Inputs
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
V
= 24V
IN
Input Supply Bias Current
V
= 12V, V
IN
V
= 12V, V
IN
V
= 24V, V
IN
V
= 24V, V
IN
Shutdown, RUN = 0, V
Shutdown, RUN = 0, V
Input Supply Current
V
= 12V, V
IN
V
= 12V, V
IN
V
= 5V, V
IN
V
= 24V to 3.3V at 10A, EXTVCC = 5V
IN
= 1.5V, I
OUT
= 1.5V, I
OUT
= 1.5V, I
OUT
= 1.5V, FCB = 5V
OUT
= 1.5V, FCB = 0V
OUT
= 2.5V, FCB = 5V
OUT
= 2.5V, FCB = 0V
OUT
= 1.5V, I
OUT
= 3.3V, I
OUT
= 1.5V, I
OUT
OUT
OUT
OUT
= 12V
IN
= 28V
IN
OUT
OUT
OUT
= 0A
= 10A
= 0A
= 10A
= 10A
= 10A
FCB = 0
= 0A 3.4 4 V
OUT
= 0A. V
I
OUT
I
= 0A, EXTVCC Open
OUT
= 1.5V, FCB = 0
OUT
LGA PACKAGE
T
= 125°C, θJA = 15°C/W
JMAX
= 200µF/Ceramic per typical
OUT
●
4.5 28 V
●
1.478 1.50 1.522 V
0.6
0.7
1.2
42
1.8
36
15
40
1.52
3.13
3.64
0.8
mA
mA
mA
mA
A
A
A
µA
µA
A
A
A
A
2
4600hvp
PRERELEASE
Page 3
LTM4600HV
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
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
V
IN
= 24V, V
= 12V, V
= 5V, V
= 1.5V, FCB = 0V
OUT
= 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
= 24V, V
IN
V
= 12V, V
IN
V
= 5V, V
IN
Voltage at V
= 1.5V
OUT
= 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
V
= 24V, V
IN
= 1.5V. FCB = 0V
V
OUT
= 1.5V. FCB = 0V
V
OUT
0A to 10A
= 1.5V
OUT
= 1.5V (Note 3)
OUT
0
TBD
● 0.15 0.3 %
10
10
±1
●
±1
25
I
OUT
= 0A
= 5A, VIN = 12V, V
OUT
OUT
●
=
20
15
800 kHz
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
Output Voltage in Foldback
17
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
mV
mV
mV
P-P
P-P
P-P
ms
ms
A
A
%
%
A
A
A
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTM4600HVE is guaranteed to meet performance
specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C
PRERELEASE
operating temperature range are assured by design, characterization
and correlation with statistical process controls. The LTM4600HVI is
guaranteed and tested over the –40°C to 85°C temperature range.
Note 3: Refer to current de-rating curves and thermal application note.
4600hvp
3
Page 4
LTM4600HV
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
V
> 0.7V
80
70
60
50
EFFICIENCY (%)
40
30
20
0.1
OUT
FCB = GND
LOAD CURRENT (A)
0.6V
OUT
1.2V
OUT
1.5V
OUT
2.5V
OUT
812
610
4600hv G01
1
10
4600hv 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 21)
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
4600hv G02
4600hv G05
Effi ciency vs Load Current
with 24V
100
90
80
70
60
EFFICIENCY (%)
50
40
30
12
0
(FCB = 0)
IN
1.5V
OUT
1.8V
OUT
2.5V
OUT
3.3V
OUT
5V
OUT
24 8
LOAD CURRENT (A)
6
4600hv G03
10
1.5V Transient Response
(See Figure 21)
25µs/DIV
1.5V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600hv G06
1.8V Transient Response
See Figure 21
25µs/DIV
1.8V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600hv G07
4
2.5V Transient Response
See Figure 21
25µs/DIV
2.5V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600hv G08
PRERELEASE
3.3V Transient Response
See Figure 21
25µs/DIV
3.3V AT 5A/µs LOAD STEP
= 3 • 22µF 6.3V CERAMICS
C
OUT
470µF 4V SANYO POS CAP
C3 = 100pF
4600hv G09
4600hvp
Page 5
UW
(
)
)
)
TYPICAL PERFOR A CE CHARACTERISTICS
LTM4600HV
Start-Up, I
OUT
(See Figure 21)
200µs/DIV
VIN = 12V
= 1.5V
V
OUT
= 200µF
C
OUT
NO EXTERNAL SOFT-START CAPACITOR
Short-Circuit Protection,
I
= 0A (See Figure 21
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
4600hv G12
= 0A
V
OUT
(0.5V/DIV)
I
IN
(0.5A/DIV)
4600hv G10
Short-Circuit Protection,
I
= 10A (See Figure 21
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
Start-Up, I
OUT
= 10A
Resistive Load) (See Figure 21
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
V
5.5
5.0
4.5
4.0
3.5
3.0
(V)
OUT
2.5
4600hv G13
V
2.0
1.5
1.0
0.5
0
0
4600hv G11
to V
Stepdown Ratio
0.6V
10 2420
515
5V
3.3V
2.5V
1.8V
1.5V
1.2V
VIN (V)
4600HV G17
Current Limit with 12V
18
16
14
12
10
8
6
CURRENT LIMIT (A)
4
2
0
0
OUTPUT VOLTAGE (V)
654321
4600hv G14
Current Limit with 9V
18
16
14
12
10
8
6
CURRENT LIMIT (A)
4
2
0
0
OUTPUT VOLTAGE (V)
PRERELEASE
4600hv G15
Current Limit with 5V
18
16
14
12
10
8
6
OUTPUT CURRENT (A)
4
2
0
654321
0
OUTPUT VOLTAGE (V)
IN
4.03.53.02.52.01.00.5 1.5
4600hv G16
4600hvp
5
Page 6
LTM4600HV
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
48
59
70
81
92
19 21
18 20 22
OSET
1918171676543
A
20
B
COMP
C
21
D
SGND
E
22
F
RUN/SS
23
G
FCB
H
24
J
PGOOD
K
49
L
60
M
71
N
82
P
93
R
104
S
4600hv PN01
4600hvp
Page 7
SI PLIFIEDWBLOCK DIAGRA
W
LTM4600HV
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
LTM4600HV
100k
0.5%
4600hv F01
V
, 4.5V TO 28V ABS MAX
IN
C
IN
V
, 1.5V/10A MAX
OUT
C
OUT
PGND
Figure 1. Simplifi ed LTM4600HV 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 28V, V
IN
OUT
= 1.5V)
External Output Capacitor Requirement
(V
= 4.5V to 28V, V
IN
OUT
= 1.5V)
WU
= 25°C, VIN = 12V. Use Figure 1 confi guration.
A
= 10A, 2x 10µF 35V Ceramic 20 µF
I
OUT
= 10A, Refer to Table 2 in the
I
OUT
Applications Information Section
100 200 µF
PRERELEASE
4600hvp
7
Page 8
LTM4600HV
U
OPERATIO
µModule Description
The LTM4600HV 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
A simplifi ed block diagram is shown in Figure 1 and the
typical application schematic is shown in Figure 21.
The LTM4600HV contains an integrated LTC constant
on-time current-mode regulator, ultra-low R
with fast 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 LTM4600HV 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
LTM4600HV has defeatable short circuit latch off. Internal
overvoltage and undervoltage comparators pull the opendrain PGOOD output low if the output feedback voltage exits
a ±10% window around the regulation point. Furthermore,
to 5.0VDC. The input voltage range is 4.5V to 28V.
DC
DS(ON)
drops. Also, the
FB
FETs
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
CC
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
CC
24V operation to lower temperature in the µModule.
pin is grounded, an integrated 5V linear
CC
pin, the internal regulator is turned off, and an
to the gate driver voltage.
CC
pin is 6V. The EXTVCC
CC
voltage. Also
IN
must be sequenced after VIN. Recommended for
8
4600hvp
PRERELEASE
Page 9
LTM4600HV
U
WUU
APPLICATIO S I FOR ATIO
The typical LTM4600HV application circuit is shown in
Figure 20. External component selection is primarily
determined by the maximum load current and output
voltage.
Output Voltage Programming and Margining
The PWM controller of the LTM4600HV has an internal
0.6V±1% reference voltage. As shown in the block diagram,
a 100k/0.5% internal feedback resistor connects V
FB pins. Adding a resistor R
SET
from V
pin to SGND
OSET
pin programs the output voltage:
kR
VV
=+06
O
100
.•
Table 1 shows the standard vaules of 1% R
R
SET
SET
SET
for typical output voltages:
Table 1.
R
SET
Open 100 66.5 49.9 43.2 31.6 22.1 13.7
(kΩ)
V
O
0.6 1.2 1.5 1.8 2 2.5 3.3 5
(V)
Voltage margining is the dynamic adjustment of the output
voltage to its worst case operating range in production
testing to stress the load circuitry, verify control/protection functionality of the board and improve the system
reliability. Figure 2 shows how to implement margining
function with the LTM4600HV. In addition to the feedback
resistor R
Turn off both transistor Q
margining. When Q
, several external components are added.
SET
UP
LTM4600HV
100k
PGND SGND
and Q
UP
is on and Q
V
OUT
V
OSET
DOWN
R
SET
to disable the
DOWN
is off, the output
R
DOWN
Q
2N7002
R
UP
OUT
resistor
DOWN
and
voltage is margined up. The output voltage is margined
down when Q
voltage V
DOWN
needs to be margined up/down by ±M%, the
O
resistor values of R
is on and Q
and R
UP
DOWN
is off. If the output
UP
can be calculated from
the following equations:
()••(%)
RR V M
SET UP O
()
RR k
SET UP
RV M
••(–%)
SET O
RkR
()
100
+Ω
SET DOWN
1
+
100
+Ω
1
=
=
.
06
.
06
V
V
Input Capacitors
The LTM4600HV µModule should be connected to a low
ac-impedance AC source. High frequency, low ESR input
capacitors are required to be placed adjacent to the module. In Figure 20, the bulk input capacitor C
is selected
IN
for its ability to handle the large RMS current into the
converter. For a buck converter, the switching duty-cycle
can be estimated as:
V
O
D
=
V
IN
Without considering the inductor current ripple, the RMS
current of the input capacitor can be estimated as:
I
OMAX
()
%
η
DD
••()=−
1
I
CIN RMS
()
In the above equation, η% is the estimated effi ciency of
the power module. C1 can be a switcher-rated electrolytic
aluminum capacitor, OS-CON capacitor or high volume
ceramic capacitors. Note the capacitor ripple current
ratings are often based on only 2000 hours of life. This
makes it advisable to properly derate the input capacitor,
or choose a capacitor rated at a higher temperature than
required. Always contact the capacitor manufacturer for
derating requirements.
Figure 2.
Q
2N7002
4600hv F02
UP
quency input decoupling capacitors. In a typical 10A
output application, 1-2 pieces of very low ESR X5R or
X7R, 10µF ceramic capacitors are recommended. This
decoupling capacitor should be placed directly adjacent
PRERELEASE
In Figure 16, the input capacitors are used as high fre-
4600hvp
9
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LTM4600HV
U
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APPLICATIO S I FOR ATIO
the module input pins in the PCB layout to minimize the
trace inductance and high frequency AC noise.
Output Capacitors
The LTM4600HV is designed for low output voltage ripple.
The bulk output capacitors C
effective series resistance (ESR) to meet the output voltage
ripple and transient requirements. C
tantalum capacitor, low ESR polymer capacitor or ceramic
capacitor. The typical capacitance is 200µF if all ceramic
output capacitors are used. The internally optimized loop
compensation provides suffi cient stability margin for all
ceramic capacitors applications. Additional output fi ltering may be required by the system designer, if further
reduction of output ripple or dynamic transient spike is
required. Refer to Table 2 for an output capacitance matrix
for each output voltage Droop, peak to peak deviation and
recovery time during a 5A/µs transient with a specifi c
output capacitance.
Fault Conditions: Current Limit and Over current
Foldback
The LTM4600HV has a current mode controller, which
inherently limits the cycle-by-cycle inductor current not
only in steady state operation, but also in transient.
To further limit current in the event of an over load condition, the LTM4600HV provides foldback current limiting.
If the output voltage falls by more than 50%, then the
maximum output current is progressively lowered to about
one sixth of its full current limit value.
is chosen with low enough
OUT
can be low ESR
OUT
Soft-Start and Latchoff with the RUN/SS pin
The RUN/SS pin provides a means to shut down the
LTM4600HV as well as a timer for soft-start and overcurrent latchoff. Pulling the RUN/SS pin below 0.8V puts
the LTM4600HV into a low quiescent current shutdown
≤ 40µA). Releasing the pin allows an internal 1.2µA
(I
Q
current source to charge up the timing capacitor CSS.
Inside LTM4600HV, there is an internal 1000pF capacitor from RUN/SS pin to ground. If RUN/SS pin has an
external capacitor CSS_EXT to ground, the delay before
starting is about:
V
15
t
DELAY SS EXT
When the voltage on RUN/SS pin reaches 1.5V, the
LTM4600HV internal switches are operating with a clamping of the maximum output inductor current limited by the
RUN/SS pin total soft-start capacitance. As the RUN/SS pin
voltage rises to 3V, the soft-start clamping of the inductor
current is released.
to V
V
IN
OUT
There are restrictions in the maximum V
down ratio that can be achieved for a given input voltage.
These contraints are shown in the Typical Performance
Characteristics curves labeled “V
Ratio”. Note that additional thermal de-rating may apply.
See the Thermal Considerations and Output Current DeRating sections of this data sheet.
.
=
12
.
Stepdown Ratios
CpF
•( )
A
µ
_
+
1000
to V
IN
to V
IN
OUT
Stepdown
OUT
step
10
4600hvp
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APPLICATIO S I FOR ATIO
Table 2. Output Voltage Response Versus Component Matrix
TYPICAL MEASURED VALUES
C
VENDORS PART NUMBER C
OUT1
TDK C4532X5R0J107MZ (100UF,6.3V) SANYO POS CAP 6TPE330MIL (330µF, 6.3V)
TAIYO YUDEN JMK432BJ107MU-T ( 100µF, 6.3V) SANYO POS CAP 2R5TPE470M9 (470µF, 2.5V)
TAIYO YUDEN JMK316BJ226ML-T501 ( 22µF, 6.3V) SANYO POS CAP 4TPE470MCL (470µF, 4V)
TAIYO YUDEN JMK316BJ226ML-T501 ( 22µF, 6.3V) SANYO POS CAP 6TPD470M (470µF, 6.3V)
V
OUT
(V)
1.2 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 35 68 25 5
1.2 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 35 68 25 5
1.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 36 75 25 5
1.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 36 75 25 5
1.8 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 40 81 30 5
1.8 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 40 81 30 5
2.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 51 102 30 5
2.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 57 116 30 5
3.3 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 64 129 35 5
3.3 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 7 82 166 35 5
1.2 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 35 70 20 5
1.2 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 35 70 20 5
1.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 37 79 20 5
1.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 37 79 20 5
1.8 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 44 85 20 5
1.8 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 44 88 20 5
2.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 100pF 12 48 103 30 5
2.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 100pF 5 48 103 30 5
3.3 2
3.3 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 100pF 7 66 132 30 5
1.2 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 40 80 20 5
1.2 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 40 80 20 5
1.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 44 89 20 5
1.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 44 84 20 5
1.8 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 44 91 20 5
1.8 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 46 91 20 5
2.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 56 113 30 5
2.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 56 113 30 5
3.3 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 64 126 30 5
3.3 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 7 64 126 30 5
1.2 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 49 98 20 5
1.2 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 49 98 20 5
1.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 54 108 20 5
1.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 61 118 20 5
1.8 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 62 125 20 5
1.8 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 62 128 20 5
2.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 70 159 25 5
2.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 60 115 25 5
3.3 2 ×
3.3 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 7 100 200 25 5
52 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 15 188 375 25 5
52 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 20 159 320 25 5
1.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 6.3V NONE 100pF 24 45 89 25 5
2.8 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 6.3V NONE 100pF 24 50 100 30 5
2.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 6.3V NONE 100pF 24 56 112 30 5
3.3 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 6.3V NONE 100pF 24 74 149 30 5
CIN
(CERAMIC)
× 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 100pF 12 52 106 30 5
10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 76 144 25 5
CIN
(BULK)
C
OUT1
(CERAMIC)
C
OUT2
(BULK)
C
COMP
VENDORS PART NUMBER
OUT2
C3 VIN
(V)
DROOP
(mV)
PEAK TO PEAK
(mV)
RECOVERY TIME
(µs)
LOAD STEP
(A/µs)
4600hvp
PRERELEASE
11
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After the controller has been started and given adequate
time to charge up the output capacitor, CSS is used as a
short-circuit timer. After the RUN/SS pin charges above 4V,
if the output voltage falls below 75% of its regulated value,
then a short-circuit fault is assumed. A 1.8µA current then
begins discharging CSS. If the fault condition persists until
the RUN/SS pin drops to 3.5V, then the controller turns
off both power MOSFETs, shuting down the converter
permanently. The RUN/SS pin must be actively pulled
down to ground in order to restart operation.
The over-current protection timer requires the soft-start
timing capacitor CSS be made large enough to guarantee
that the output is in regulation by the time CSS has reached
the 4V threshold. In general, this will depends upon the
size of the output capacitance, output voltage and load
current characteristic. A minimum external soft-start
capacitor can be estimated from:
3
CpFCVFV
SS EXT OUT OUT S_
•([/])+>1000 10
Generally 0.1µF is more than suffi cient.
Since the load current is already limited by the current
mode control and current foldback circuitry during a
shortcircuit, over-current latchoff operation is NOT always
needed or desired, especially the output has large amount
of capacitance or the load draw huge current during start
up. The latchoff feature can be overridden by a pull-up
current greater than 5µA but less than 80µA to the RUN/SS
pin. The additional current prevents the discharge of CSS
during a fault and also shortens the soft-start period. Using a resistor from RUN/SS pin to V
–
is a simple solution
IN
to defeat latchoff. Any pull-up network must be able to
maintain RUN/SS above 4V maximum latchoff threshold
and overcome the 4µA maximum discharge current. Figure
3 shows a conceptual drawing of V
during startup and
RUN
short circuit.
V
RUN/SS
4V
3V
1.5V
SOFT-START
CLAMPING
RELEASED
OF I
L
SWITCHING
STARTS
Figure 3. RUN/SS Pin Voltage During Startup and
Short-Circuit Protection
Figure 4. Defeat Short-Circuit Latchoff with a Pull-Up
Resistor to V
SHORT-CIRCUIT
LATCH ARMED
V
IN
500k
IN
V
O
V
IN
LTM4600HV
RUN/SS
PGND SGND
OUTPUT
OVERLOAD
HAPPENS
4600hv F04
SHORT-CIRCUIT
LATCHOFF
75%V
O
3.5V
t
t
4600hv F03
12
4600hvp
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APPLICATIO S I FOR ATIO
Enable
The RUN/SS pin can be driven from logic as shown in Figure
5. This function allows the LTM4600HV to be turned on or
off remotely. The ON signal can also control the sequence
of the output voltage.
RUN/SS
ON
2N7002
Figure 5. Enable Circuit with External Logic
Output Voltage Tracking
For the applications that require output voltage tracking,
several LTM4600HV modules can be programmed by the
power supply tracking controller such as the LTC2923.
Figure 6 shows a typical schematic with LTC2923. Coincident, ratiometric and offset tracking for V
V
IN
DC/DC
5V
Q1
LTM4600HV
PGND
SGND
3.3V
4600hv F05
rising and
O
V
IN
falling can be implemented with different sets of resistor
values. See the LTC2923 data sheet for more details.
EXTV
Connection
CC
An internal low dropout regulator produces an internal 5V
supply that powers the control circuitry and FET drivers.
Therefore, if the system does not have a 5V power rail,
the LTM4600HV can be directly powered by V
. The gate
IN
driver current through LDO is about 18mA. The internal
LDO power dissipation can be calculated as:
P
LDO_LOSS
= 18mA • (VIN – 5V)
The LTM4600HV also provides an external gate driver
voltage pin EXTV
is recommended to connect EXTV
5V rail. Whenever the EXTV
. If there is a 5V rail in the system, it
CC
pin to the external
CC
pin is above 4.7V, the in-
CC
ternal 5V LDO is shut off and an internal 50mA P-channel
switch connects the EXTV
supplied from EXTV
CC
not apply more than 6V to the EXTV
EXTV
< VIN. The following list summaries the possible
CC
connections for EXTV
1. EXTV
grounded. Internal 5V LDO is always powered
CC
to internal 5V. Internal 5V is
CC
until this pin drops below 4.5V. Do
pin and ensure that
CC
:
CC
from the internal 5V regulator.
V
R
ONB
R
ONA
R
TB1
R
TA1
TB2
R
TA2
R
V
GATE
CC
ON
LTC2923
RAMPBUF
TRACK1
TRACK2
RAMP
FB1
STATUS
SDO
FB2
GND
LTM4600HV
V
OSET
49.9k
LTM4600HV
V
OSET
66.5k
4600hv F06
IN
V
1.8V
OUT
V
IN
V
IN
V
1.5V
OUT
Figure 6. Output Voltage Tracking with the LTC2923 Controller
2. EXTV
connected to an external supply. Internal LDO
CC
is shut off. A high effi ciency supply compatible with the
MOSFET gate drive requirements (typically 5V) can improve overall effi ciency. With this connection, it is always
required that the EXTV
pin voltage.
V
IN
3. EXTV
is recommended for VIN > 20V
CC
voltage can not be higher than
CC
Discontinuous Operation and FCB Pin
The FCB pin determines whether the internal bottom
MOSFET remains on when the inductor current reverses.
There is an internal 4.75k pulling down resistor connecting
this pin to ground. The default light load operation mode
is forced continuous (PWM) current mode. This mode
provides minimum output voltage ripple.
4600hvp
PRERELEASE
13
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LTM4600HV
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APPLICATIO S I FOR ATIO
In the application where the light load effi ciency is important, tying the FCB pin above 0.6V threshold enables
discontinuous operation where the bottom MOSFET turns
off when inductor current reverses. Therefore, the conduction loss is minimized and light load effi cient is improved.
The penalty is that the controller may skip cycle and the
output voltage ripple increases at light load.
Paralleling Operation with Load Sharing
Two or more LTM4600HV modules can be paralleled to
provide higher than 10A output current. Figure 7 shows
the necessary interconnection between two paralleled
modules. The OPTI-LOOP™ current mode control ensures good current sharing among modules to balance
the thermal stress. The new feedback equation for two or
more LTM4600HVs in parallel is:
k
100
VV
=+06
OUT
.•
where N is the number of LTM4600HVs in parallel.
V
IN
Figure 7. Parallel Two µModules with Load Sharing
OPTI-LOOP is a trademark of Linear Technology Corporation.
V
IN
PGND SGNDCOMP
V
IN
PGND
N
R
R
SET
SET
LTM4600HV
V
OSET
OSET
LTM4600HV
V
OUT
R
SET
SGNDCOMP V
V
OUT
4600hv F07
V
OUT
(20A
MAX
)
Thermal Considerations and Output Current Derating
The power loss curves in Figures 8 and 15 can be used
in coordination with the load current de-rating curves in
Figures 9 to 14 and Figures 16 to 19 for calculating an
approximate θ
for the module. Each of the load current
JA
de-rating curves will lower the maximum load current
as a function of the increased ambient temperature to
keep the maximum junction temperature of the power
module at 100°C maximum. This 100°C maximum is to
allow for an increased rise of about 15°C to 20°C inside
the module. This will maintain the maximum operating
temperature to below 125°C. Each of the de-rating curves
and the power loss curve that corresponds to the correct
output voltage can be used to solve for the approximate
of the condition. Each Figure has three curves that are
θ
JA
taken at three different air fl ow conditions. For example
in Figure 9, the 10A load current can be achieved up to
60°C ambient temperature with no air fl ow. If this 60°C
is subtracted from the maximum module temperature
of 100°C, then 40°C is the maximum temperature rise.
Now Figure 8 records the power loss for this 5V to 1.5V
at the 10A output. If we take the 40°C rise and divided it
by the 3 watts of loss, then we get an approximate θ
JA
of 13.5°C/W with no heatsink. If we take the next air fl ow
curve in Figure 9 at 200LFM of air fl ow, then the maximum
ambient temperature allowed at 10A load current is 65°C.
This calculates to a 35°C rise, and an approximate θ
JA
of
11.6°C/W with no heatsink. In the next air fl ow curve at
400LFM in Figure 9, the maximum ambient temperature
allowed at 10A load current is 73°C. This calculates to
a 27°C rise, and an approximate θ
of 9°C/W with no
JA
heatsink. Each of the de-rating curves in Figures 9 to
14 or Figures 16 to 19 can be used with the appropriate
power loss curve in either fi gure 8 or fi gure 15 to derive an
approximate θ
for Figures 9 to 14, and Figures 16 to 19. A complete
θ
JA
. Tables 3 and 4 provide the approximate
JA
explanation of the thermal characteristics is provided in
the thermal application note for the LTM4600.
14
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PRERELEASE
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APPLICATIO S I FOR ATIO
4.5
4.0
3.5
3.0
2.5
12V LOSS
2.0
1.5
POWER LOSS (W)
1.0
0.5
0
24 10
086
OUTPUT CURRENT (A)
24V LOSS
Figure 8. 1.5V Power Loss Curves
vs Load Current
10
9
8
7
6
MAXIMUM LOAD CURRENT (A)
5
0 LFM
200 LFM
400 LFM
4
50 55 70
60 65 75 80 85 90
AMBIENT TEMPERATURE (°C)
5V LOSS
4600hv F08
10
9
8
7
6
MAXIMUM LOAD CURRENT (A)
5
4
VIN = 12V
= 1.5V
V
O
4600hv F11
0 LFM
200 LFM
400 LFM
50 70
60 80 90
AMBIENT TEMPERATURE (°C)
Figure 9. No Heatsink
VIN = 5V
= 1.5V
V
O
4600hv F09
10
VIN = 12V
= 1.5V
V
O
9
8
7
6
5
MAXIMUM LOAD CURRENT (A)
0 LFM
4
200 LFM
400 LFM
3
60
50
10
9
8
7
6
MAXIMUM LOAD CURRENT (A)
5
4
50
70
AMBIENT TEMPERATURE (°C)
VIN = 5V
= 1.5V
V
O
0 LFM
200 LFM
400 LFM
70
60 80 90 100
AMBIENT TEMPERATURE (°C)
Figure 10. BGA Heatsink
80 90 100
4600hv F12
4600hv F10
Figure 11. No Heatsink
10
9
8
7
6
5
4
3
2
MAXIMUM LOAD CURRENT (A)
0 LFM
200 LFM
1
400 LFM
0
40 50 70
60 80 90
AMBIENT TEMPERATURE (°C)
Figure 13. No Heatsink
VIN = 24V
= 1.5V
V
O
4600hv F13
PRERELEASE
Figure 12. BGA Heatsink
10
VIN = 24V
= 1.5V
V
O
8
6
4
2
MAXIMUM LOAD CURRENT (A)
0 LFM
200 LFM
400 LFM
0
50
70
60
AMBIENT TEMPERATURE (°C)
Figure 14. BGA Heatsink
80 90 100
4600hv F14
4600hvp
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APPLICATIO S I FOR ATIO
5.0
4.5
4.0
3.5
3.0
2.5
2.0
POWER LOSS (W)
1.5
1.0
0.5
0
086
Figure 15. 3.3V Power Loss Curves vs Load Current
10
9
8
7
6
5
4
3
2
MAXIMUM LOAD CURRENT (A)
0 LFM
200 LFM
1
400 LFM
0
40 70
6050 80 90
AMBIENT TEMPERATURE (°C)
VIN = 12V
= 3.3V
V
O
4600hv F16
24V LOSS
12V LOSS
24 10
OUTPUT CURRENT (A)
4600hv F15
10
VIN = 12V
= 3.3V
V
O
9
8
7
6
MAXIMUM LOAD CURRENT (A)
5
0 LFM
200 LFM
400 LFM
4
40 50
70
60 80 90 100
AMBIENT TEMPERATURE (°C)
4600hv F17
16
10
8
6
4
2
MAXIMUM LOAD CURRENT (A)
0
50 70
VIN = 24V
= 3.3V TEMPERATURE
V
OUT
DE-RATING
0 LFM
200 LFM
400 LFM
60 80 90
AMBIENT TEMPERATURE (°C)
Figure 18. No Heatsink
4600hv F18.eps
PRERELEASE
Figure 17. BGA HeatsinkFigure 16. No Heatsink
10
MAXIMUM LOAD CURRENT (A)
0 LFM
200 LFM
400 LFM
9
8
7
6
5
VIN = 24V
= 3.3V TEMPERATURE
V
OUT
DE-RATING
4
50
AMBIENT TEMPERATURE (°C)
60 80 90
70
Figure 19. BGA Heatsink
4600hv F19.eps
4600hvp
Page 17
LTM4600HV
U
WUU
APPLICATIO S I FOR ATIO
Table 3. 1.5V Output
DE-RATING CURVE VIN (V) POWER LOSS CURVE AIR FLOW (LFM) HEATSINK θJA (°C/W)
Figures 9, 11, 13 5, 12, 24 Figure 8 0 None 13.5
Figures 9, 11, 13 5, 12, 24 Figure 8 200 None 11
Figures 9, 11, 13 5, 12, 24 Figure 8 400 None 9
Figures 10, 12, 14 5, 12, 24 Figure 8 0 BGA Heatsink 9.5
Figures 10, 12, 14 5, 12, 24 Figure 8 200 BGA Heatsink 6.25
Figures 10, 12, 14 5, 12, 24 Figure 8 400 BGA Heatsink 4.5
Table 4. 3.3V Output
DE-RATING CURVE VIN (V) POWER LOSS CURVE AIR FLOW (LFM) HEATSINK θJA (°C/W)
Figures 16, 18 12, 24 Figure 15 0 None 13.5
Figures 16, 18 12, 24 Figure 15 200 None 11.6
Figures 16, 18 12, 24 Figure 15 400 None 10.4
Figures 16, 18 12, 24 Figure 15 0 BGA Heatsink 9.5
Figures 16, 18 12, 24 Figure 15 200 BGA Heatsink 6
Figures 16, 18 12, 24 Figure 15 400 BGA Heatsink 4.77
PRERELEASE
4600hvp
17
Page 18
LTM4600HV
U
WUU
APPLICATIO S I FOR ATIO
Safety Considerations
The LTM4600HV modules do not provide isolation from
to V
V
IN
blow fuse with a rating twice the maximum input current
should be provided to protect each unit from catastrophic
failure.
Layout Checklist/Example
The high integration of the LTM4600HV makes the PCB
board layout very simple and easy. However, to optimize
its electrical and thermal performance, some layout considerations are still necessary.
• Use large PCB copper areas for high current path, including V
PCB conduction loss and thermal stress
• Place high frequency ceramic input and output capacitors next to the V
high frequency noise
. There is no internal fuse. If required, a slow
OUT
, PGND and V
IN
, PGND and V
IN
. It helps to minimize the
OUT
pins to minimize
OUT
• Do not put via directly on pad
• Use a separated SGND ground copper area for components connected to signal pins. Connect the SGND
to PGND underneath the unit
Figure 20 gives a good example of the recommended
layout.
V
IN
C
IN
PGND
V
OUT
SGND
• Place a dedicated power ground layer underneath the
unit
• To minimize the via conduction loss and reduce module
thermal stress, use multiple vias for interconnection
between top layer and other power layers
LOAD
TOP LAYER
Figure 20. Recommended PCB Layout
4600hv F20
18
4600hvp
PRERELEASE
Page 19
TYPICAL APPLICATIO
LTM4600HV
U
5V TO 24V
V
REFER TO
TABLE 2
OUT
66.5k
+
C1
150µF
C3
100pF
R1
C4
OPT
C
IN
10µF
2x
EXTV
SV
IN
F
ADJ
V
OSET
COMP
FCB
PGOOD
SGND
CC
V
IN
(MULTIPLE PINS)
(MULTIPLE PINS)
LTM4600HV
PGND
(MULTIPLE PINS)
V
OUT
RUN/SS
C2
22µF
6.3V
×3
REFER TO
TABLE 2
4600hv F21
Figure 21. Typical Application, 5V to 24V Input, 0.6V to 5V Output, 10A Max
0.6V TO 5V
C
OUT
470µF
REFER TO
TABLE 2
PRERELEASE
4600hvp
19
Page 20
LTM4600HV
P
TYPICAL APPLICATIO
U
arallel Operation and Load Sharing
C8
10µF
35V
RUN/SOFT-START
C3
10µF
35V
C7
10µF
35V
C1
10µF
35V
4.5V TO 24V
EXTV
FCB
RUN
COMP
EXTV
FCB
RUN
COMP
V
IN
CC
LTM4600HV
V
IN
CC
LTM4600HV
V
= 0.6V • ([100k/N] + R
OUT
WHERE N = 2
F
SET
V
OUT
FB
R4
SV
IN
PGOOD
PGNDSGND
F
SET
V
OUT
FB
SV
IN
PGOOD
PGNDSGND
4600hv F22
15.8k
1%
C4
220pF
2.5V
R1
100k
C1, C3, C7, C8: TBD
C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501
C5, C10: SANYO POS CAP, 4TPE470MCL
C9
22µF
x3
C2
22µF
x3
SET
)/R
SET
C10
470µF
4V
C5
470µF
4V
2.5V AT 20A
Current Sharing Between Two
LTM4600HV Modules
12
12V
IN
2.5V
OUT
20A
10
MAX
8
6
4
INDIVIDUAL SHARE
2
0
0
5
I
OUT2
10 15 20
TOTAL LOAD
I
OUT1
25
4600hv F23
4600hvp
20
PRERELEASE
Page 21
PACKAGE DESCRIPTIO
LTM4600HV
U
aaa Z
LGA Package
104-Lead (15mm × 15mm)
(Reference LTM DWG # 05-05-1800)
6.9865
4.4442
1.9042
0.0000
1.9058
4.4458
5.7142
3.1742
0.6342
0.6358
3.1758
5.7158
6.9421
Y
X
15
BSC
15
BSC
TOP VIEW
aaa Z
PAD 1
CORNER
4
0.15
0.10
0.15
TOLERANCE
2.72 – 2.92
0.27 – 0.37
SUBSTRATE
CAP
MOLD
20
21
19
1817
16
11
7
10
6
9
13 14 15
5
4
5.7650
4.4950
3
2
1
8
24
23
22
28 29 30 31
27
26
2.3600
32
12
25
38
37
36
35
33 34
1.0900
60
49
59
48
58
47
57
46
56
45
55
44
54
53
42 43
52
41
40
51
39
50
82
71
81
70
68 69
78 79 80
67
77
66
65
64
74 75 76
63
62
73
61
72
Z
DETAIL B
bbb Z
2.45 – 2.55
93
92
89 90 91
88
84 85 86 87
83
6.3500
104
3.8100
1.2700
0.3175
0.3175
99 100 101 102 103
1.2700
3.8100
95 96 97 98
6.3500
94
DETAIL B
3
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994
2. ALL DIMENSIONS ARE IN MILLIMETERS
3
R
T
93
104
92
99 100 101 102 103
5.0800
2.5400
0.0000
PADS
12.70
NOTES:
SEE NOTES
BSC
TOP VIEW
2.5400
SUGGESTED SOLDER PAD LAYOUT
5.0800
84 85 86 87 88 89 90 91
95 96 97 98
94
83
DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL,
BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.
THE PAD #1 IDENTIFIER IS A MARKED FEATURE OR A
NOTCHED BEVELED PAD
4
LAND DESIGNATION PER JESD MO-222, SPP-010
P
82
81
74 75 76 77 78 79 80
73
72
5. PRIMARY DATUM -Z- IS SEATING PLANE
L
M
N
71
60
49
70
59
48
42 43 44 45 46 47
63 64 65 66 67 68 69
52 53 54 55 56 57 58
41
40
51
62
39
50
61
aaa
eee
bbb
SYMBOL
6. THE TOTAL NUMBER OF PADS: 104
K
33 34 35 36 37 38
FGH
J
24
23
22
26 27 28 29 30 31
32
12
25
ABCDE
20
21
1918171676543
11109
13 14 15
2
1
8
YXeee
4600 02-18
M
23
19 21
18 20 22
15 17
14 16
13.93
11 13
10 12
79
68
35
24
1
BSC
BOTTOM VIEW
6.9888
6.5475
5.2775
4.0075
2.7375
1.4675
0.3175
0.0000
0.3175
1.2700
2.5400
5.7150
4.4450
6.9850
PRERELEASE
0.11 – 0.27
13.97
BSC
PAD 1
C(0.30)
4600hvp
21
Page 22
LTM4600HV
PACKAGE DESCRIPTIO
PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME
A1 - B1 V
A2 - B2 - C2 - D2 - E2 - F2 - G2 - H2 A3 V
IN
A4 - B4 - C4 - D4 - E4 - F4 - G4 - H4 A5 V
IN
A6 - B6 - C6 - D6 - E6 - F6 - G6 - H6 A7 V
IN
A8 - B8 - C8 - D8 - E8 - F8 - G8 - H8 A9 V
IN
A10 - B10 - C10 V
A11 V
IN
A12 - B12 - C12 V
A13 V
IN
A14 - B14 - C14 V
A15 FADJ B15 - C15 - D15 - E15 - F15 - G15 - H15 PGND
A16 - B16 - C16 - D16 - E16 - F16 - G16 - H16 A17 SV
IN
A18 - B18 - C18 - D18 - E18 - F18 - G18 - H18 A19 EXTVCCB19 - C19 - D19 - E19 - F19 - G19 - H19 A20 - B20 - C20 - D20 - E20 - F20 - G20 - H20 A21 V
OSET
A22 - B22 - C22 - D22 - E22 - F22 - G22 - H22 A23 - B23 COMP C23 - D23 SGND E23 - F23 RUN/SS G23 FCB H23 -
IN
B3 - C3 - D3 - E3 - F3 - G3 - H3 -
B5 - C5 - D5 - E5 - F5 - G5 - H5 -
B7 - C7 - D7 - E7 - F7 - G7 - H7 PGND
B9 - C9 - D9 - E9 - F9 - G9 - H9 PGND
B11 - C11 - D11 - E11 - F11 - G11 - H11 PGND
B13 - C13 - D13 - E13 - F13 - G13 - H13 PGND
B17 - C17 - D17 - E17 - F17 - G17 - H17 PGND
B21 - C21 - D21 - E21 - F21 - G21 - H21 -
U
Pin Assignment Tables
(Arranged by Pin Number)
C1 - D1 V
D10 - E10 V
IN
D12 - E12 V
IN
D14 - E14 V
IN
E1 - F1 V
IN
G1 PGND H1 -
IN
F10 - G10 - H10 -
IN
F12 - G12 - H12 -
IN
F14 - G14 - H14 -
IN
PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME
J1 PGND K1 - L1 - M1 - N1 - P1 - R1 - T1 J2 - K2 - L2 PGND M2 PGND N2 PGND P2 V
OUT
R2 V
OUT
T2 V
J3 - K3 - L3 - M3 - N3 - P3 - R3 - T3 J4 - K4 - L4 PGND M4 PGND N4 PGND P4 V
OUT
R4 V
OUT
T4 V
J5 - K5 - L5 - M5 - N5 - P5 - R5 - T5 J6 - K6 - L6 PGND M6 PGND N6 PGND P6 V
OUT
R6 V
OUT
T6 V
J7 - K7 PGND L7 - M7 - N7 - P7 - R7 - T7 J8 - K8 L8 PGND M8 PGND N8 PGND P8 V
OUT
R8 V
OUT
T8 V
J9 - K9 PGND L9 - M9 - N9 - P9 - R9 - T9 J10 - K10 L10 PGND M10 PGND N10 PGND P10 V
OUT
R10 V
OUT
T10 V
J11 - K11 PGND L11 - M11 - N11 - P11 - R11 - T11 J12 - K12 - L12 PGND M12 PGND N12 PGND P12 V
OUT
R12 V
OUT
T12 V
J13 - K13 PGND L13 - M13 - N13 - P13 - R13 - T13 J14 - K14 - L14 PGND M14 PGND N14 PGND P14 V
OUT
R14 V
OUT
T14 V
J15 - K15 PGND L15 - M15 - N15 - P15 - R15 - T15 J16 - K16 - L16 PGND M16 PGND N16 PGND P16 V
OUT
R16 V
OUT
T16 V
J17 - K17 PGND L17 - M17 - N17 - P17 - R17 - T17 J18 - K18 - L18 PGND M18 PGND N18 PGND P18 V
OUT
R18 V
OUT
T18 V
J19 - K19 - L19 - M19 - N19 - P19 - R19 - T19 J20 - K20 - L20 PGND M20 PGND N20 PGND P20 V
OUT
R20 V
OUT
T20 V
J21 - K21 - L21 - M21 - N21 - P21 - R21 - T21 J22 - K22 - L22 PGND M22 PGND N22 PGND P22 V
OUT
R22 V
OUT
T22 V
J23 PGOOD K23 - L23 - M23 - N23 - P23 - R23 - T23 -
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
22
4600hvp
PRERELEASE
Page 23
PACKAGE DESCRIPTIO
LTM4600HV
U
Pin Assignment Tables
(Arranged by Pin Number)
PIN NAME
G1 PGND
H7
H9
H11
H13
H15
H17
PGND
PGND
PGND
PGND
PGND
PGND
J1 PGND
K7
K9
K11
K13
K15
K17
L2
L4
L6
L8
L10
L12
L14
L16
L18
L20
L22
M2
M4
M6
M8
M10
M12
M14
M16
M18
M20
M22
N2
N4
N6
N8
N10
N12
N14
N16
N18
N20
N22
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
P2
P4
P6
P8
P10
P12
P14
P16
P18
P20
P22
R2
R4
R6
R8
R10
R12
R14
R16
R18
R20
R22
T2
T4
T6
T8
T10
T12
T14
T16
T18
T20
T22
PIN NAME
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
PIN NAME
A3
A5
A7
A9
A11
A13
B1 V
C10
C12
C14
D1 V
E10
E12
E14
F1 V
PIN NAME
V
IN
V
IN
V
IN
V
IN
V
IN
V
IN
IN
V
IN
V
IN
V
IN
IN
V
IN
V
IN
V
IN
IN
A15 FADJ
A17 SV
A19 EXTV
A21 V
IN
CC
OSET
B23 COMP
D23 SGND
F23 RUN/SS
G23 FCB
J23 PGOOD
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
no responsibility is assumed for its use. Linear Technology Corporation makes no representation that
the interconnection of its circuits as described herein will not infringe on existing patent rights.
PRERELEASE
However,
4600hvp
23
Page 24
LTM4600HV
1.8V, 10A R
TYPICAL APPLICATIO
C2
10µF
35V
U
4.5V TO 24V
C1
10µF
35V
EXTV
FCB
RUN
COMP
V
IN
CC
LTM4600HV
egulator
C5
F
SET
V
OUT
FB
SV
IN
PGOOD
PGNDSGND
4600hv F24
100pF
R2
49.9k
1%
1.8V AT 10A
C3
R1
100k
C1, C2: TBD
C3: TAIYO YUDEN, JMK316BJ226ML-T501
C4: SANYO POS CAP, 4TPE470MCL
22µF
x3
PGOOD
C4
470µF
4V
24
PRERELEASE
This product contains technology licensed from Silicon Semiconductor Corporation.
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
PRERELEASE
®
4600hvp
LT 1105 • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2005
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