LTM4600HVEV-TRPBF_技术文档

LTM4600HV

10A, 28V High Efﬁciency

IN

DC/DC µModule

U

DESCRIPTIO

FEATURES

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 efﬁciency design delivers 10A

continuous current (12A peak), needing no heat sinks or

airﬂow to meet power speciﬁcations. Only bulk input and

output capacitors are needed to ﬁnish the design.

■

Complete Switch Mode Power Supply

■

Wide Input Voltage Range: 4.5V to 28V

■

10A DC, 12A Peak Output Current

Parallel Two μModule™ DC/DC Converters for 20A

■

Output Current

0.6V to 5V Output Voltage

■

1.5% Output Voltage Regulation

■

Ultrafast Transient Response

■

Current Mode Control

■

–55°C to 125°C Operating Temperature Range

(LTM4600HVMPV)

The low proﬁle 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

adaptiveon-timecurrentmodearchitectureenablesavery

fast transient response to line and load changes without

sacriﬁcing 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.

■

Pb-Free (e4) RoHS Compliant Package Gold-Pad

Finish

Up to 92% Efﬁciency

Programmable Soft-Start

Output Overvoltage Protection

■

Optional Short-Circuit Shutdown Timer

Small Footprint, Low Proﬁle (15mm × 15mm ×

■

2.8mm) LGA Package

U

The LTM4600HV is packaged in a thermally enhanced,

compact (15mm × 15mm) and low proﬁle (2.8mm) over-

molded Land Grid Array (LGA) package suitable for auto-

mated assembly by standard surface mount equipment.

The LTM4600HV is Pb-free and RoHS compliant.

APPLICATIO S

■

Telecom and Networking Equipment

■

Military and Avionics Systems

■

Industrial Equipment

■

Point of Load Regulation

, 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.

■

Servers

U

Efﬁciency vs Load Current with 24V_IN(FCB = 0)

TYPICAL APPLICATIO

100

10A μModule Power Supply with 4.5V to 28V Input

90

V

OUT

80

70

60

50

V

IN

2.5V*

10A

V

OUT

IN

4.5V TO 28V

ABSMAX

C

OUT

IN

LTM4600HV

V

OSET

PGND SGND

31.6k

1.8V

2.5V

3.3V

OUT

4600hv TA01a

40

30

5V

OUT

*REVIEW DE-RATING CURVE AT

THE HIGHER INPUT VOLTAGE

2

4

8

0

10

6

LOAD CURRENT (A)

4600HV TA01b

4600hvfc

1

LTM4600HV

W W U W

ABSOLUTE AXI U RATI GS

PIN CONFIGURATION

(Note 1)

TOP VIEW

FCB, EXTV , PGOOD, RUN/SS, V .......... –0.3V to 6V

CC

OUT

V , SV , f ............................................ –0.3V to 28V

OSET

Operating Temperature Range (Note 2)

IN

V

IN ADJ

COMP

SGND

RUN/SS

FCB

V

IN

, COMP............................................. –0.3V to 2.7V

PGOOD

E and I Grades ..................................... –40°C to 85°C

MP Grade........................................... –55°C to 125°C

Junction Temperature ........................................... 125°C

Storage Temperature Range................... –55°C to 125°C

PGND

V

OUT

LGA PACKAGE

104-LEAD (15mm × 15mm × 2.8mm)

T

= 125°C, θ = 15°C/W, θ = 6°C/W,

JA JC

JMAX

θ

JA

DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS, WEIGHT = 1.7g

ORDER INFORMATION

LEAD FREE FINISH

TAPE AND REEL

PART MARKING

PACKAGE DESCRIPTION

TEMPERATURE RANGE

LTM4600HVEV#PBF

LTM4600HVIV#PBF

LTM4600HVMPV#PBF

LTM4600HVEV#TRPBF

LTM4600HVIV#TRPBF

LTM4600HVMPV#TRPBF LTM4600HVMPV

LTM4600HVEV

LTM4600HVIV

104-Lead (15mm × 15mm × 2.8mm)

–40°C to 85°C

–55°C to 125°C

Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges.

Consult LTC Marketing for information on non-standard lead based ﬁnish parts.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel speciﬁcations, go to: http://www.linear.com/tapeandreel/

ELECTRICAL CHARACTERISTICS ^The● denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C, V_IN= 12V. External C_IN= 120μF, C_OUT= 200μF/Ceramic per typical

application (front page) conﬁguration.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

●

V

Input DC Voltage

AbsMax 28V for Tolerance on 24V Inputs

4.5

28

V

IN(DC)

V

Output Voltage

FCB = 0V

V

OUT(DC)

V

IN

= 5V or 12V, V

= 1.5V, I = 0A

OUT

1.478

1.470

1.50

1.522

1.530

OUT

Input Speciﬁcations

V

Under Voltage Lockout Threshold

Input Inrush Current at Startup

I

= 0A

3.4

4

V

IN(UVLO)

OUT

I

= 0A, V

= 1.5V, FCB = 0

INRUSH(VIN)

OUT

V

= 5V

= 12V

= 24V

0.6

0.7

0.8

A

IN

V

I

Input Supply Bias Current

I

= 0A, EXTV Open

Q(VIN)

OUT CC

V

= 12V, V

= 24V, V

= 1.5V, FCB = 5V

1.2

42

mA

μA

IN

OUT

V

= 1.5V, FCB = 0V

= 2.5V, FCB = 5V

= 2.5V, FCB = 0V

1.8

36

Shutdown, RUN = 0.8V, V = 12V

35

75

IN

Min On Time

Min Off Time

100

400

ns

I

Input Supply Current

V

IN

V

IN

V

IN

V

IN

= 12V, V

= 1.5V, I

= 3.3V, I

= 10A

1.52

3.13

3.64

1.6

A

S(VIN)

OUT

= 5V, V

= 1.5V, I

= 10A

OUT

= 24V to 3.3V at 10A, EXTV = 5V

A

CC

4600hvfc

2

LTM4600HV

ELECTRICAL CHARACTERISTICS ^The● denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C, V_IN= 12V. External C_IN= 120μF, C_OUT= 200μF/Ceramic per typical

application (front page) conﬁguration.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Output Speciﬁcations

I

Output Continuous Current Range

V

= 12V, V

= 24V, V

= 1.5V

= 2.5V (Note 3)

0

10

A

OUTDC

IN

OUT

(See Output Current Derating Curves for

Different V , V

and T )

A

IN OUT

●

ΔV

Line Regulation Accuracy

V

= 1.5V. FCB = 0V, I

= 0A,

0.15

0.3

%

OUT(LINE)

OUT

IN

OUT

= 4.5V to 28V

V

OUT

Load Regulation Accuracy

V

OUT

= 1.5V. FCB = 0V, I

= 0A to 10A

OUT(LOAD)

OUT

V

= 5V

1

1.5

%

IN

V

OUT

= 12V (Note 4)

V

Output Ripple Voltage

Output Ripple Voltage Frequency

Turn-On Time

V

= 12V, V

= 1.5V, FCB = 0V, I

= 0A

10

15

mV

P-P

OUT(AC)

IN

OUT

fs

FCB = 0V, I

= 5A, V = 12V, V = 1.5V

OUT

850

kHz

OUT

IN

t

V

= 1.5V, I

IN

= 1A

START

OUT

V

= 12V

= 5V

0.5

0.7

ms

V

ΔV

OUTLS

Voltage Drop for Dynamic Load Step

V

C

= 1.5V, Load Step: 0A/μs to 5A/μs

= 3 • 22μF 6.3V, 470μF 4V POSCAP,

36

mV

OUT

See Table 2

t

I

Settling Time for Dynamic Load Step V = 12V Load: 10% to 90% to 10% of Full Load

IN

25

μs

SETTLE

OUTPK

Output Current Limit

Output Voltage in Foldback

V

= 24V, V

= 12V, V

= 2.5V

= 1.5V

17

A

IN

OUT

= 5V, V

= 1.5V

Control Stage

●

V

OSET

Voltage at V

I

= 0A, V = 1.5V

OUT

0.591

0.594

0.6

0.609

0.606

V

OSET

OUT

V

RUN ON/OFF Threshold

0.8

–0.5

0.8

1.5

–1.2

1.8

100

16

2

–3

3

V

μA

mV

mA

kΩ

V

RUN/SS

I

Soft-Start Charging Current

Soft-Start Discharging Current

V

= 0V

= 4V

RUN(C)/SS

RUN(D)/SS

RUN/SS

V

– SV

EXTV = 0V, FCB = 0V

CC

IN

I

Current into EXTV Pin

EXTV = 5V, FCB = 0V, V = 1.5V, I = 0A

EXTVCC

CC

OUT

R

Resistor Between V

and V Pins

OSET

100

0.6

–1

FBHI

OUT

V

Forced Continuous Threshold

0.57

0.63

–2

FCB

I

Forced Continuous Pin Current

V

= 0.6V

μA

FCB

PGOOD Output

ΔV

PGOOD Upper Threshold

PGOOD Lower Threshold

PGOOD Hysteresis

V

Rising

7.5

10

–10

2

12.5

%

V

OSETH

OSET

Falling

–7.5

–12.5

OSETL

Returning

OSET(HYS)

OSET

V

PGL

PGOOD Low Voltage

I

= 5mA

0.15

0.4

PGOOD

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 LTM4600HVE is guaranteed to meet performance

speciﬁcations from 0°C to 85°C. Speciﬁcations over the –40°C to 85°C

operating temperature range are assured by design, characterization

and correlation with statistical process controls. The LTM46000HVMP

is guaranteed and tested over the –55°C to 125°C temperature range.

For output current derating at high temperature, please refer to Thermal

Considerations and Output Current Derating discussion.

Note 3: Refer to current de-rating curves and thermal application note.

Note 4: Test assumes current derating versus temperature.

4600hvfc

3

LTM4600HV

U W

TYPICAL PERFOR A CE CHARACTERISTICS ^{(See Figure 21 for all curves)}

Efﬁciency vs Load Current

with 24V_IN(FCB = 0)

Efﬁciency vs Load Current

with 5V_IN(FCB = 0)

Efﬁciency vs Load Current

with 12V_IN(FCB = 0)

100

90

100

90

80

70

60

50

40

30

100

90

80

70

60

50

40

30

80

70

60

50

40

30

0.6V

1.2V

1.5V

2.5V

3.3V

OUT

1.8V

2.5V

3.3V

5V

0.6V

1.2V

1.5V

2.5V

OUT

2

4

8

0

10

8

10

2

4

8

6

0

2

4

6

0

10

6

LOAD CURRENT (A)

4600hv G03

4600hv G01

4600hv G02

Efﬁciency vs Load Current

with Different FCB Settings

1.2V Transient Response

1.5V Transient Response

90

80

70

60

50

40

30

20

FCB > 0.7V

V

= 50mV/DIV

OUT

FCB = GND

I

= 5A/DIV

OUT

4600hv G05

4600hv G06

25μs/DIV

1.2V AT 5A/μs LOAD STEP

C = 3 • 22μF 6.3V CERAMICS

OUT

470μF 4V SANYO POSCAP

C3 = 100pF

25μs/DIV

V

= 12V

OUT

IN

1.5V AT 5A/μs LOAD STEP

OUT

= 1.5V

C

= 3 • 22μF 6.3V CERAMICS

470μF 4V SANYO POSCAP

C3 = 100pF

0.1

10

1

LOAD CURRENT (A)

4600hv G04

1.8V Transient Response

2.5V Transient Response

3.3V Transient Response

4600hv G07

4600hv G08

4600hv G09

25μs/DIV

1.8V AT 5A/μs LOAD STEP

OUT

2.5V AT 5A/μs LOAD STEP

OUT

3.3V AT 5A/μs LOAD STEP

OUT

C

= 3 • 22μF 6.3V CERAMICS

470μF 4V SANYO POSCAP

C3 = 100pF

C

= 3 • 22μF 6.3V CERAMICS

470μF 4V SANYO POSCAP

C3 = 100pF

C

= 3 • 22μF 6.3V CERAMICS

470μF 4V SANYO POSCAP

C3 = 100pF

4600hvfc

4

LTM4600HV

U W

TYPICAL PERFOR A CE CHARACTERISTICS ^{(See Figure 21 for all curves)}

Start-Up, I_OUT= 10A

(Resistive Load)

Start-Up, I_OUT= 0A

V

OUT

(0.5V/DIV)

OUT

(0.5V/DIV)

I

IN

(0.5A/DIV)

4600hv G11

4600hv G10

200μs/DIV

V

C

= 12V

V

C

= 12V

IN

= 1.5V

OUT

= 200μF

OUT

NO EXTERNAL SOFT-START CAPACITOR

Short-Circuit Protection,

I_OUT= 0A

Short-Circuit Protection,

I_OUT= 10A

V_INto V_OUTStepdown Ratio

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

f

= OPEN

5V

ADJ

V

OUT

(0.5V/DIV)

OUT

(0.5V/DIV)

I

IN

3.3V

IN

(0.2A/DIV)

(0.5A/DIV)

2.5V

1.8V

4600hv G12

4600hv G13

20μs/DIV

1.5V

1.2V

V

C

= 12V

OUT

V

C

= 12V

OUT

IN

= 1.5V

= 2× 200μF/X5R

NO EXTERNAL SOFT-START CAPACITOR

0.6V

10

20

24

0

5

15

(V)

V

IN

SEE FREQUENCY ADJUSTMENT DISCUSSION

FOR 12V TO 5V

AND 5V TO 3.3V

IN

OUT

IN OUT

CONVERSION

4600HV G14

V_OSETvs Temperature

Start-Up Waveform, T_A= –55°C

0.610

0.605

0.600

0.595

4600HV G16

V

= 12V

400μs/DIV

IN

= 1.5V

OUT

= 10A

OUT

I

0.590

–55 –25

5

35

65

95

125

TEMPERATURE (°C)

4600HV G15

4600hvfc

5

LTM4600HV

U

PI FU CTIO S

(See Package Description for Pin Assignment)

V

(Bank 1): Power Input Pins. Apply input voltage

SGND (Pin D23): Signal Ground Pin. All small-signal

components should connect to this ground, which in turn

connects to PGND at one point.

IN

between these pins and GND pins. Recommend placing

input decoupling capacitance directly between V pins

and GND pins.

IN

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

f

(Pin A15): A 110k resistor from V to this pin sets

IN

ADJ

the one-shot timer current, thereby setting the switching

frequency.TheLTM4600HVswitchingfrequencyistypically

850kHz. An external resistor to ground can be selected to

reducetheone-shottimercurrent,thuslowertheswitching

frequency to accommodate a higher duty cycle step down

requirement. See the applications section.

pin and the V pin. This resistor must supply a minimum

IN

SV (PinA17):SupplyPinforInternalPWMController.Leave

this pin open or add additional decoupling capacitance.

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

discontinuousconductionmodetoachievehighefﬁciency

operation at light loads. There is an internal 4.75K resistor

between the FCB and SGND pins.

EXTV (Pin A19): External 5V supply pin for controller. If

CC

left open or grounded, 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 .

CC

IN

PGOOD (Pin J23): Output Voltage Power Good Indicator.

When the output voltage is within 10% of the nominal

voltage, the PGOOD is open drain output. Otherwise, this

pin is pulled to ground.

V

(Pin A21): The Negative Input of The Error Ampliﬁer.

OSET

Internally,thispinisconnectedtoV witha100kprecision

OUT

resistor.Differentoutputvoltagescanbeprogrammedwith

additional resistors between the V

and SGND pins.

OSET

PGND (Bank 2): Power ground pins for both input and

output returns.

COMP (Pin B23): Current Control Threshold and Error

Ampliﬁer 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).

V

OUT

(Bank 3): Power Output Pins. Apply output load

between these pins and GND pins. Recommend placing

High Frequency output decoupling capacitance directly

between these pins and GND pins.

TOP VIEW

2

3

4

5

6

7

16

17

18

19

A

C

E

1

20

21

22

23

24

B

D

F

COMP

SGND

RUN/SS

FCB

9

10

14

11

15

V

IN

8

BANK 1

13

12

25

32

G

J

26

33

27

34

28

35

29

36

30

37

31

38

H

K

PGOOD

48

59

39

50

61

40

51

62

41

52

63

42

53

64

43

54

65

44

55

66

45

56

67

46

57

68

47

58

69

49

60

71

PGND

BANK 2

L

M

N

70

73

84

95

74

85

96

75

86

97

76

87

98

77

88

99

78

89

79

90

80

91

81

92

72

83

94

82

93

P

R

T

V

OUT

BANK 3

100

101

102

103

104

1

3

5

7

9

11

13

15

17

19

21

23

2

4

6

8

10

12

14

16

18

20

22

4600hv PN01

4600hvfc

6

LTM4600HV

W

SI PLIFIED BLOCK DIAGRA

SV

IN

RUN/SS

LTM4600HV

V

, 4.5V TO 28V ABS MAX

IN

1000pF

C

1.5μF

IN

PGOOD

Q1

COMP

FCB

INT

COMP

, 2.5V/10A MAX

OUT

C

OUT

4.75k

15μF

6.3V

CONTROLLER

f

ADJ

PGND

Q2

10Ω

SGND

EXTV

CC

100k

0.5%

V

OSET

R6

31.6k

4600hv F01

Figure 1. Simpliﬁed LTM4600HV Block Diagram

U

W U

DECOUPLI G REQUIRE E TS

T_A= 25°C, V_IN= 12V. Use Figure 1 conﬁguration.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

C

External Input Capacitor Requirement

I

= 10A, 2x 10μF 35V Ceramic

20

μF

IN

OUT

(V = 4.5V to 28V, V

= 2.5V)

Taiyo Yuden GDK316BJ106ML

IN

OUT

C

External Output Capacitor Requirement

(V = 4.5V to 28V, V = 2.5V)

I

= 10A, Refer to Table 2 in the

100

200

μF

OUT

Applications Information Section

IN

OUT

4600hvfc

7

LTM4600HV

U

OPERATIO

μModule Description

Q1 is turned off and bottom FET Q2 is turned on and held

on until the overvoltage condition clears.

TheLTM4600HVisastandalonenon-isolatedsynchronous

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

outputvoltageprogrammableviaoneexternalresistorfrom

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.

0.6V to 5.0V . The input voltage range is 4.5V to 28V.

DC

A simpliﬁed block diagram is shown in Figure 1 and the

At low load current the module works in continuous cur-

rent mode by default to achieve minimum output voltage

ripple. It can be programmed to operate in discontinuous

current mode for improved light load efﬁciency when the

FCB pin is pulled up above 0.8V and no higher than 6V.

The FCB pin has a 4.75k resistor to ground, so a resistor

typical application schematic is shown in Figure 21.

The LTM4600HV contains an integrated LTC constant

on-time current-mode regulator, ultra-low R

FETs

DS(ON)

with fast switching speed and integrated Schottky diode.

The typical switching frequency is 850kHz at full load.

With current mode control and internal feedback loop

compensation, the LTM4600HV module has sufﬁcient

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

(X5R or X7R for extended temperature range).

to V can set the voltage on the FCB pin.

IN

When EXTV pin is grounded or open, an integrated 5V

CC

linear regulator powers the controller and MOSFET gate

drivers. If a minimum 4.7V external bias supply is ap-

plied on the EXTV pin, the internal regulator is turned

CC

off, and an internal switch connects EXTV to the gate

CC

Current mode control provides cycle-by-cycle fast current

limit. In addition, foldback current limiting is provided

in an over-current condition while V

the LTM4600HV 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 10% window around the regulation point.

Furthermore, in an overvoltage condition, internal top FET

driver voltage. This eliminates the linear regulator power

loss with high input voltage, reducing the thermal stress

drops. Also,

on the controller. The maximum voltage on EXTV pin is

CC

OSET

6V. The EXTV voltage should never be higher than the

CC

V

IN

voltage. Also EXTV must be sequenced after V .

CC IN

Recommended for 24V operation to lower temperature

in the μModule.

4600hvfc

8

LTM4600HV

U

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APPLICATIO S I FOR ATIO

The typical LTM4600HV application circuit is shown in

Figure 21. External component selection is primarily

determined by the maximum load current and output

voltage.

voltage is margined up. The output voltage is margined

down when Q

is on and Q is off. If the output

DOWN

UP

voltage V needs to be margined up/down by M%, the

O

resistor values of R and R

the following equations:

can be calculated from

UP

DOWN

Output Voltage Programming and Margining

(R_SETR_UP)•V_O•(1+ M%)

(R_SETR_UP)+100kΩ

The PWM controller of the LTM4600HV has an internal

0.6V 1%referencevoltage.Asshownintheblockdiagram,

= 0.6V

a 100k/0.5% internal feedback resistor connects V

OUT

pin to

R_SET•V_O•(1– M%)

R_SET+ (100kΩ R_DOWN

and V

pins. Adding a resistor R from V

OSET

SET

OSET

= 0.6V

)

SGND pin programs the output voltage:

100k +R_SET

V_O= 0.6V •

Input Capacitors

R_SET

The LTM4600HV μModule should be connected to a low

ac-impedance DC source. High frequency, low ESR input

capacitors are required to be placed adjacent to the mod-

Table 1 shows the standard values of 1% R

for typical output voltages:

Table 1.

resistor

SET

ule. In Figure 21, 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:

R

SET

Open 100

0.6 1.2

66.5

1.5

49.9

1.8

43.2

2

31.6

2.5

22.1

3.3

13.7

5

(kΩ)

V

(V)

O

V_O

V

IN

Voltagemarginingisthedynamicadjustmentoftheoutput

voltage to its worst case operating range in production

testing to stress the load circuitry, verify control/protec-

tion 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

D =

Without considering the inductor current ripple, the RMS

current of the input capacitor can be estimated as:

I_O(MAX)

η%

I_CIN(RMS)

=

• D•(1−D)

resistor R , several external components are added.

SET

Turn off both transistor Q and Q

margining. When Q is on and Q

to disable the

UP

DOWN

In the above equation, η% is the estimated efﬁciency 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 over temperature.

is off, the output

UP

DOWN

V

OUT

LTM4600HV

R

DOWN

Q

100k

DOWN

2N7002

V

OSET

PGND

SGND

R

SET

UP

In Figure 21, the input capacitors are used as high fre-

quency input decoupling capacitors. In a typical 10A

output application, 1-2 pieces of very low ESR X5R or

X7R (for extended temperature range), 10μF ceramic

capacitors are recommended. This decoupling capacitor

Q

UP

2N7002

4600hv F02

Figure 2. LTM4600HV Margining Implementation

4600hvfc

9

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APPLICATIO S I FOR ATIO

should be placed directly adjacent the module input pins

in the PCB layout to minimize the trace inductance and

high frequency AC noise.

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 over-

current latchoff. Pulling the RUN/SS pin below 0.8V puts

the LTM4600HV into a low quiescent current shutdown

Output Capacitors

The LTM4600HV is designed for low output voltage ripple.

(I ≤ 75μA). Releasing the pin allows an internal 1.2μA

Q

ThebulkoutputcapacitorsC ischosenwithlowenough

current source to charge up the timing capacitor C .

OUT

SS

effectiveseriesresistance(ESR)tomeettheoutputvoltage

Inside LTM4600HV, there is an internal 1000pF capaci-

ripple and transient requirements. C

can be low ESR

tor from RUN/SS pin to ground. If RUN/SS pin has an

OUT

tantalumcapacitor, lowESRpolymercapacitororceramic

capacitor (X5R or X7R). The typical capacitance is 200μF

if all ceramic output capacitors are used. The internally

optimized loop compensation provides sufﬁcient stability

margin for all ceramic capacitors applications. Additional

output ﬁltering 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 capaci-

tance matrix for each output voltage Droop, peak to peak

deviation and recovery time during a 5A/μs transient with

a speciﬁc output capacitance.

external capacitor C

starting is about:

to ground, the delay before

SS_EXT

1.5V

1.2μA

t_DELAY

=

•(C_{SS_EXT}+1000pF)

When the voltage on RUN/SS pin reaches 1.5V, the

LTM4600HV internal switches are operating with a clamp-

ing of the maximum output inductor current limited by the

RUN/SSpintotalsoft-startcapacitance.AstheRUN/SSpin

voltage rises to 3V, the soft-start clamping of the inductor

current is released.

Fault Conditions: Current Limit and Over current

Foldback

V to V

Stepdown Ratios

IN

OUT

There are restrictions in the maximum V to V

step

IN

OUT

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.

down ratio that can be achieved for a given input voltage.

These contraints are shown in the Typical Performance

Characteristics curves labeled “V to V

Stepdown

IN

OUT

To further limit current in the event of an over load condi-

tion, the LTM4600HV provides foldback current limiting.

If the output voltage falls by more than 50%, then the

maximumoutputcurrentisprogressivelyloweredtoabout

one sixth of its full current limit value.

Ratio”. Note that additional thermal de-rating may apply.

See the Thermal Considerations and Output Current De-

Rating sections of this data sheet.

4600hvfc

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Table 2. Output Voltage Response Versus Component Matrix *(Refer to Figure 21)

TYPICAL MEASURED VALUES

C

OUT1

VENDORS

PART NUMBER

C

OUT2

VENDORS

PART NUMBER

TDK

C4532X5R0J107MZ (100μF,6.3V)

JMK432BJ107MU-T ( 100μF, 6.3V)

JMK316BJ226ML-T501 ( 22μF, 6.3V)

SANYO POSCAP

6TPE330MIL (330μF, 6.3V)

2R5TPE470M9 (470μF, 2.5V)

4TPE470MCL (470μF, 4V)

6TPD470M (470μF, 6.3V)

TAIYO YUDEN

V

C

C3

V

IN

(V)

5

12

5

12

5

12

5

12

24

7

12

24

15

20

DROOP

(mV)

PEAK TO PEAK

RECOVERY TIME

(μs)

LOAD STEP

(A/μs)

OUT

IN

OUT1

OUT2

COMP

(V)

1.2

1.5

1.8

2.5

2.8

3.3

5

(CERAMIC)

2 × 10μF 35V

(BULK)

(CERAMIC)

(BULK)

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

470μF 2.5V

330μF 6.3V

NONE

470μF 4V

330μF 6.3V

470μF 4V

NONE

470μF 4V

330μF 6.3V

NONE

(mV)

68

70

80

98

68

70

80

98

75

79

84

118

75

79

89

108

81

150μF 35V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

1 × 100μF 6.3V

2 × 100μF 6.3V

3 × 22μF 6.3V

4 × 100μF 6.3V

1 × 100μF 6.3V

3 × 22μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

2 × 100μF 6.3V

1 × 100μF 6.3V

3 × 22μF 6.3V

4 × 100μF 6.3V

1 × 100μF 6.3V

3 × 22μF 6.3V

2 × 100μF 6.3V

4 × 100μF 6.3V

3 × 22μF 6.3V

4 × 100μF 6.3V

NONE 100pF

35

40

49

35

40

49

36

37

44

61

36

37

44

54

40

44

46

62

40

44

62

48

56

57

60

48

51

56

70

56

50

64

66

82

100

52

64

76

74

188

159

25

20

25

20

25

20

25

20

30

20

30

20

30

25

30

25

30

35

25

30

35

30

25

30

25

5

88

91

128

81

85

91

125

103

113

116

115

103

102

113

159

112

100

126

132

166

200

106

129

126

144

149

375

320

470μF 6.3V

330μF 6.3V

470μF 4V

NONE

470μF 4V

330μF 6.3V

NONE

470μF 6.3V

NONE

5

*X7R is recommended for extended temperature range.

4600hvfc

11

LTM4600HV

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After the controller has been started and given adequate

to defeat latchoff. Any pull-up network must be able to

maintain RUN/SS above 4V maximum latchoff threshold

andovercomethe4μAmaximumdischargecurrent.Figure

time to charge up the output capacitor, C is used as a

SS

short-circuittimer.AftertheRUN/SSpinchargesabove4V,

if the output voltage falls below 75% of its regulated value,

then a short-circuit fault is assumed. A 1.8μA current then

3 shows a conceptual drawing of V

short circuit.

during startup and

RUN

beginsdischargingC . Ifthefaultconditionpersistsuntil

SS

V

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.

RUN/SS

4V

3.5V

3V

1.5V

The over-current protection timer requires the soft-start

SHORT-CIRCUIT

LATCH ARMED

timing capacitor C be made large enough to guarantee

SS

t

SHORT-CIRCUIT

LATCHOFF

that the output is in regulation by the time C has reached

SS

SOFT-START

OUTPUT

OVERLOAD

HAPPENS

CLAMPING

OF I RELEASED

the 4V threshold. In general, this will depend upon the size

of the output capacitance, output voltage and load current

characteristic. A minimum external soft-start capacitor

can be estimated from:

L

V

O

75%V

O

C_{SS_EXT}+1000pF > C_OUT•V_OUT(10^–3[F /V_S])

t

SWITCHING

STARTS

4600hv F03

Generally 0.1μF is more than sufﬁcient.

Figure 3. RUN/SS Pin Voltage During Startup and

Short-Circuit Protection

Since the load current is already limited by the current

mode control and current foldback circuitry during a

shortcircuit,over-currentlatchoffoperationisNOTalways

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

currentgreaterthan5μAbutlessthan80μAtotheRUN/SS

V

RECOMMENDED VALUES FOR RUN/SS

IN

V

R

RUN/SS

R

LTM4600HV

IN

RUN/SS

4.5V TO 5.5V

10.8V TO 13.8V

24V TO 28V

50k

150k

500k

RUN/SS

PGND SGND

4600hv F04

pin. The additional current prevents the discharge of C

SS

during a fault and also shortens the soft-start period. Us-

Figure 4. Defeat Short-Circuit Latchoff with a Pull-Up

Resistor to V_IN

ing a resistor from RUN/SS pin to V is a simple solution

IN

4600hvfc

12

LTM4600HV

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Enable

EXTV Connection

CC

TheRUN/SSpincanbedrivenfromlogicasshowninFigure

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.

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:

RUN/SS

P

= 18mA • (V – 5V)

IN

LDO_LOSS

LTM4600HV

ON

The LTM4600HV also provides an external gate driver

voltage pin EXTV . If there is a 5V rail in the system, it

PGND SGND

CC

2N7002

is recommended to connect EXTV pin to the external

4600hv F05

CC

5V rail. Whenever the EXTV pin is above 4.7V, the in-

CC

Figure 5. Enable Circuit with External Logic

ternal 5V LDO is shut off and an internal 50mA P-channel

switch connects the EXTV to internal 5V. Internal 5V is

CC

Output Voltage Tracking

supplied from EXTV until this pin drops below 4.5V. Do

CC

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. Coin-

not apply more than 6V to the EXTV pin and ensure that

CC

EXTV < V . The following list summaries the possible

CC

IN

connections for EXTV :

CC

1. EXTV grounded. Internal 5V LDO is always powered

CC

cident, ratiometric and offset tracking for V rising and

O

from the internal 5V regulator.

falling can be implemented with different sets of resistor

values. See the LTC2923 data sheet for more details.

2. EXTV connected to an external supply. Internal LDO

CC

is shut off. A high efﬁciency supply compatible with the

MOSFET gate drive requirements (typically 5V) can im-

prove overall efﬁciency. With this connection, it is always

Q1

V

IN

DC/DC

3.3V

5V

V

IN

required that the EXTV voltage can not be higher than

CC

V pin voltage.

IN

R

V

GATE

RAMP

FB1

ONB

CC

LTM4600HV

V

3. EXTV is recommended for V > 20V

V

CC

IN

1.8V

ON

OSET

OUT

R

ONA

49.9k

LTC2923

Discontinuous Operation and FCB Pin

STATUS

SDO

RAMPBUF

TRACK1

TRACK2

V

IN

The FCB pin determines whether the internal bottom

MOSFET remains on when the current reverses. There is

an internal 4.75k pull-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.

R

TB1

TA1

IN

R

TB2

LTM4600HV

V

FB2

1.5V

OSET

OUT

GND

R

66.5k

TA2

4600hv F06

Figure 6. Output Voltage Tracking with the LTC2923 Controller

4600hvfc

13

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In the application where the light load efﬁciency is im-

portant, tying the FCB pin above 0.6V threshold enables

discontinuous operation where the bottom MOSFET turns

offwheninductorcurrentreverses.Therefore,theconduc-

tionlossisminimizedandlightloadefﬁciencyisimproved.

The penalty is that the controller may skip cycle and the

output voltage ripple increases at light load.

explanationoftheanalysisforthethermalmodels, andthe

derating curves. Tables 3 and 4 provide a summary of the

equivalent θ for the noted conditions. These equivalent

JA

θ

JA

parameters are correlated to the measure values, and

improvedwithair-ﬂow.Thecasetemperatureismaintained

at 100°C or below for the derating curves. This allows for

4W maximum power dissipation in the total module with

top and bottom heatsinking, and 2W power dissipation

Paralleling Operation with Load Sharing

through the top of the module with an approximate θ

JC

between 6°C/W to 9°C/W. This equates to a total of 124°C

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 en-

sures good current sharing among modules to balance

the thermal stress. The new feedback equation for two or

more LTM4600HVs in parallel is:

at the junction of the device.

Safety Considerations

The LTM4600HV modules do not provide isolation from

V to V . There is no internal fuse. If required, a slow

IN

OUT

blow fuse with a rating twice the maximum input current

should be provided to protect each unit from catastrophic

failure.

100k

+R_SET

N

V_OUT= 0.6V •

R_SET

Layout Checklist/Example

where N is the number of LTM4600HVs in parallel.

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 con-

siderations are still necessary.

V

OUT

IN

OUT

(20A

)

MAX

LTM4600HV

PGND COMP

V

SGND

OSET

• Use large PCB copper areas for high current path, in-

R

SET

cluding V , PGND and V . It helps to minimize the

IN

OUT

PCB conduction loss and thermal stress

COMP

V

SGND

OSET

• Place high frequency ceramic input and output capaci-

V

LTM4600HV

V

OUT

IN

tors next to the V , PGND and V

pins to minimize

IN

OUT

PGND

high frequency noise

4600hv F07

• Place a dedicated power ground layer underneath

the unit

Figure 7. Parallel Two μModules with Load Sharing

• Tominimizetheviaconductionlossandreducemodule

thermal stress, use multiple vias for interconnection

between top layer and other power layers

Thermal Considerations and Output Current Derating

The power loss curves in Figures 8 and 15 can be used

in coordination with the load current derating curves in

Figures 9 to 14, and Figures 16 to 19 for calculating an

• Do not put vias directly on pad unless they are capped.

• Use a separated SGND ground copper area for com-

ponents connected to signal pins. Connect the SGND

to PGND underneath the unit

approximate θ for the module with various heatsink-

JA

ing methods. Thermal models are derived from several

temperature measurements at the bench, and thermal

modelinganalysis.ApplicationNote103providesadetailed

Figure 20 gives a good example of the recommended

OPTI-LOOP is a trademark of Linear Technology Corporation.

layout.

4600hvfc

14

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10

9

4.5

V

= 5V

V

= 5V

IN

OUT

V

= 1.5V

IN

OUT

= 1.5V

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

9

8

7

6

5

4

18V LOSS

8

7

12V LOSS

6

5V LOSS

0 LFM

200 LFM

400 LFM

5

0 LFM

200 LFM

400 LFM

4

50

60

70

80

90

50

60

70

80

90

100

0

2

4

6

8

10

AMBIENT TEMPERATURE (°C)

OUTPUT CURRENT (A)

4600hv F09

4600hv F10

4600hv F08

Figure 8. 1.5V Power Loss Curves

vs Load Current

Figure 9. No Heatsink

Figure 10. BGA Heatsink

10

9

8

7

6

5

4

3

2

1

0

10

9

10

9

V

= 18V

OUT

V

= 12V

V

= 12V

IN

OUT

= 1.5V

V

= 1.5V

OUT

8

7

6

5

0 LFM

200 LFM

400 LFM

5

0 LFM

200 LFM

400 LFM

0 LFM

200 LFM

400 LFM

4

3

40

50

60

70

80

90

50 55 60 65 70 75 80 85 90

AMBIENT TEMPERATURE (°C)

4600hv F11

50

60

70

80

90

100

AMBIENT TEMPERATURE (°C)

4600hv F13

4600hv F12

Figure 13. No Heatsink

Figure 11. No Heatsink

Figure 12. BGA Heatsink

10

8

10

9

8

7

6

5

4

3

2

1

0

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

V

= 18V

V

= 12V

OUT

IN

OUT

IN

= 1.5V

= 3.3V

6

24V LOSS

4

12V LOSS

2

0 LFM

200 LFM

400 LFM

0 LFM

200 LFM

400 LFM

0

50

60

70

80

90

100

40

50

60

70

80

90

0

2

4

6

8

10

AMBIENT TEMPERATURE (°C)

OUTPUT CURRENT (A)

4600hv F14

4600hv F16

4600hv F15

Figure 14. BGA Heatsink

Figure 16. No Heatsink

Figure 15. 3.3V Power Loss

Curves vs Load Current

4600hvfc

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10

9

10

8

10

9

0 LFM

200 LFM

400 LFM

V

= 12V

V

= 24V

IN

OUT

IN

OUT

= 3.3V

= 3.3V TEMPERATURE

DE-RATING

8

6

7

4

6

2

5

0 LFM

200 LFM

400 LFM

0 LFM

200 LFM

400 LFM

5

V

= 24V

OUT

DE-RATING

IN

= 3.3V TEMPERATURE

4

0

4

40

50

60

70

80

90

100

50

60

70

80

90

50

60

70

80

90

AMBIENT TEMPERATURE (°C)

4600hv F17

4600hv F18.eps

4600hv F19.eps

Figure 17. BGA Heatsink

Figure 18. No Heatsink

Figure 19. BGA Heatsink

Table 3. 1.5V Output

DERATING CURVE

Figures 9, 11, 13

Figures 10, 12, 14

V

(V)

POWER LOSS CURVE

Figure 8

AIR FLOW (LFM)

HEATSINK

None

θ

JA

(°C/W)

IN

5, 12, 18

0

15.2

14

Figure 8

200

400

0

None

Figure 8

None

12

Figure 8

BGA Heatsink

13.9

11.3

10.25

Figure 8

200

400

Figure 8

Table 4. 3.3V Output

DERATING CURVE

Figures 16, 18

V

(V)

POWER LOSS CURVE

Figure 15

AIR FLOW (LFM)

HEATSINK

None

θ

(°C/W)

JA

IN

12, 24

0

15.2

14.6

13.4

13.9

11.1

10.5

Figures 16, 18

Figure 15

200

400

0

None

Figures 16, 18

Figure 15

None

Figures 17, 19

Figure 15

BGA Heatsink

Figures 17, 19

Figure 15

200

400

Figures 17, 19

Figure 15

4600hvfc

16

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V

t

IN

ON

(DC) DUTY CYCLE =

t

s

t

ON

V

OUT

DC =

=

t

V

s

IN

DC

FREQ =

t

ON

t

ON

C

OFF

IN

4602 F25

PERIOD t

s

The LTM4600HV has a minimum (t ) on time of 100

PGND

ON

nanoseconds and a minimum (t ) off time of 400

OFF

nanoseconds. The 2.4V clamp on the ramp threshold as

V

a function of V

will cause the switching frequency to

OUT

4600hv F20

increasebytheratioofV /2.4Vfor3.3Vand5Voutputs.

OUT

LOAD

This is due to the fact the on time will not increase as V

OUT

TOP LAYER

increases past 2.4V. Therefore, if the nominal switch-

ing frequency is 850kHz, then the switching frequency

will increase to ~1.2MHz for 3.3V, and ~1.7MHz for 5V

Figure 20. Recommended PCB Layout

LTM4600HV Frequency Adjustment

outputs due to Frequency = (DC/t ) When the switching

ON

frequency increases to 1.2MHz, then the time period t is

TheLTM4600HVisdesignedtotypicallyoperateat850kHz

across most input and output conditions. The control ar-

chitectureisconstantontimevalleymodecurrentcontrol.

S

reducedto~833nanosecondsandat1.7MHztheswitching

period reduces to ~588 nanoseconds. When higher duty

cycle conversions like 5V to 3.3V and 12V to 5V need to

be accommodated, then the switching frequency can be

lowered to alleviate the violation of the 400ns minimum

The f

pin is typically left open or decoupled with an

ADJ

optional 1000pF capacitor. The switching frequency has

beenoptimizedtomaintainconstantoutputrippleoverthe

operatingconditions.Theequationsforsettingtheoperat-

ing frequency are set around a programmable constant on

time.Thisontimeisdevelopedbyaprogrammablecurrent

into an on board 10pF capacitor that establishes a ramp

that is compared to a voltage threshold equal to the output

off time. Since the total switching period is t = t + t

,

S

ON OFF

t

will be below the 400ns minimum off time. A resistor

OFF

from the f

pin to ground can shunt current away from

ADJ

the on time generator, thus allowing for a longer on time

and a lower switching frequency. 12V to 5V and 5V to

3.3V derivations are explained in the data sheet to lower

switching frequency and accommodate these step-down

conversions.

voltage up to a 2.4V clamp. This I current is equal to:

ON

I

ON

= (V – 0.7V)/110k, with the 110k onboard resistor

IN

from V to f . The on time is equal to t = (V /I )

ADJ

ON

OUT ON

• 10pF and t = t – t . The frequency is equal to: Freq.

OFF

s

ON

Equations for setting frequency for 12V to 5V:

= DC/t . The I current is proportional to V , and the

ON

IN

I

= (V – 0.7V)/110k; I = 103μA

IN ON

ON

regulator duty cycle is inversely proportional to V , there-

IN

forethestep-downregulatorwillremainrelativelyconstant

frequency = (I /[2.4V • 10pF]) • DC = 1.79MHz;

ON

frequency as the duty cycle adjustment takes place with

DC = duty cycle, duty cycle is (V /V )

OUT IN

lowering V . The on time is proportional to V

up to a

IN

OUT

t = t + t , t = on-time, t = off-time of the

OFF

S

ON

OFF ON

2.4V clamp. This will hold frequency relatively constant

with different output voltages up to 2.4V. The regulator

switching period is comprised of the on time and off time

as depicted in the following waveform. The on time is

switching period; t = 1/frequency

S

t

must be greater than 400ns, or t – t > 400ns.

S ON

OFF

t

= DC • t

S

ON

equal to t = (V /I ) • 10pF and t = t – t . The

ON

OUT ON

OFF

s

ON

1MHz frequency or 1μs period is chosen for 12V to 5V.

frequency is equal to: Frequency = DC/t ).

ON

4600hvfc

17

LTM4600HV

U

W U U

APPLICATIO S I FOR ATIO

t

must be greater than 400ns, or t – t > 400ns.

S ON

t

= 0.41 • 1μs ≅ 410ns

OFF

ON

t

= DC • t

S

t

= 1μs – 410ns ≅ 590ns

ON

OFF

~450kHz frequency or 2.22μs period is chosen for 5V to

3.3V. Frequency range is about 450kHz to 650kHz from

4.5V to 7V input.

t

and t are above the minimums with adequate guard

OFF

ON

band.

Using the frequency = (I /[2.4V • 10pF]) • DC, solve for

ON

t

= 0.66 • 2.22μs ≅ 1.46μs

= 2.22μs – 1.46μs ≅ 760ns

I

ON

= (1MHz • 2.4V • 10pF) • (1/0.41) ≅ 58μA. I current

ON

calculated from 12V input was 103μA, so a resistor from

OFF

f

to ground = (0.7V/15k) = 46μA. 103μA – 46μA =

ADJ

t

and t are above the minimums with adequate guard

OFF

ON

band.

57μA, sets the adequate I current for proper frequency

ON

range for the higher duty cycle conversion of 12V to

5V. Input voltage range is limited to 9V to 16V. Higher

Using the frequency = (I /[2.4V • 10pF]) • DC, solve for

ON

input voltages can be used without the 15k on f . The

ADJ

I

ON

= (450kHz • 2.4V • 10pF) • (1/0.66) ≅ 16μA. I current

ON

inductor ripple current gets too high above 16V, and the

calculated from5V input was39μA, so a resistorfrom f

ADJ

400ns minimum off-time is limited below 9V.

to ground = (0.7V/30.1k) = 23μA. 39μA – 23μA = 16μA,

sets the adequate I current for proper frequency range

ON

Equations for setting frequency for 5V to 3.3V:

for the higher duty cycle conversion of 5V to 3.3V. Input

I

= (V – 0.7V)/110k; I = 39μA

IN ON

ON

voltagerangeislimitedto4.5Vto7V.Higherinputvoltages

can be used without the 30.1k on f . The inductor ripple

frequency = (I /[2.4V • 10pF]) • DC = 1.07MHz;

ADJ

ON

current gets too high above 7V, and the 400ns minimum

DC = duty cycle, duty cycle is (V /V )

OUT IN

off-time is limited below 4.5V.

t = t + t , t = on-time, t = off-time of the

OFF

S

ON

OFF ON

switching period; t = 1/frequency

S

5V to 3.3V at 8A

R1

30.1k

4.5V TO 7V

C5

100pF

C3

10μF

25V

C1

10μF

25V

V

f

ADJ

IN

3.3V AT 8A EFFICIENCY = 94%

EXTV

FCB

V

CC

OUT

+

C2

22μF

C4

330μF

6.3V

V

OSET

R2

22.1k

1%

LTM4600HV

RUN/SOFT-START

RUN/SS

COMP

SV

IN

PGOOD

PGND

OPEN DRAIN

SGND

4600 F22

5V TO 3.3V AT 8A WITH f

LTM4600HV MINIMUM ON-TIME = 100ns

LTM4600HV MINIMUM OFF-TIME = 400ns

= 30.1k

C1, C3: TDK C3216X5R1E106MT

C2: TAIYO YUDEN, JMK316BJ226ML

C4: SANYO POSCAP, 6TPE330MIL

ADJ

4600hvfc

18

LTM4600HV

U

W U U

APPLICATIO S I FOR ATIO

12V to 5V at 8A

V_INto V_OUTStepdown Ratio for

12V to 5V and 5V to 3.3V

R1

15k

5.0

9V TO 16V

3.3V: f

= 30.1k

ADJ

= 15k

4.5 5V: f

ADJ

C5

100pF

C3

10μF

25V

C1

10μF

25V

4.0

V

f

ADJ

IN

5V AT 8A

EFFICIENCY = 94%

3.5

EXTV

FCB

V

CC

OUT

+

C2

22μF

C4

330μF

6.3V

3.0

V

OSET

R2

2.5

LTM4600HV

13.7k

1%

RUN/SOFT-START

RUN/SS

COMP

SV

IN

2.0

PGOOD

PGND

OPEN DRAIN

1.5

SGND

1.0

4600 F23

3.3V AT 8A

5V AT 8A

0.5

0

12V TO 5V AT 8A WITH f

= 15k

C1, C3: TDK C3216X5R1E106MT

C2: TAIYO YUDEN, JMK316BJ226ML

C4: SANYO POSCAP, 6TPE330MIL

ADJ

1

3

5

7

9

11 13 15 17

LTM4600HV MINIMUM ON-TIME = 100ns

LTM4600HV MINIMUM OFF-TIME = 400ns

V

(V)

IN

4600 F24

U

TYPICAL APPLICATIO

V

IN

+

C

(BULK)

C

(CER)

IN

5V TO 24V

GND

150μF

10μF

V

IN

2x

(MULTIPLE PINS)

EXTV

V

OUT

CC

OUT

(MULTIPLE PINS)

C3

100pF

SV

IN

C

+

OUT1

C

OUT2

22μF

6.3V

×3

f

ADJ

470μF

V

REFER TO

TABLE 2

V

OSET

OUT

LTM4600HV

COMP

FCB

REFER TO

TABLE 2

RUN/SS

PGOOD

0.6V TO 5V

SGND

REFER TO STEP DOWN

RATIO GRAPH

PGND

(MULTIPLE PINS)

C4

OPT

R1

66.5k

REFER TO

TABLE 1

GND

4600HV F21

Figure 21. Typical Application, 5V to 24V Input, 0.6V to 5V Output, 10A Max

4600hvfc

19

LTM4600HV

U

TYPICAL APPLICATIO

Parallel Operation and Load Sharing

4.5V TO 24V

V

= 0.6V • ([100k/N] + R )/R

SET SET

OUT

WHERE N = 2

C8

10μF

35V

C7

10μF

35V

V

f

ADJ

IN

EXTV

FCB

V

CC

OUT

+

C9

C10

470μF

4V

V

22μF

OSET

x3

LTM4600HV

R4

15.8k

1%

RUN

SV

IN

COMP

PGOOD

SGND

PGND

2.5V AT 20A

RUN/SOFT-START

C4

220pF

C3

10μF

35V

C1

10μF

V

f

ADJ

IN

35V

2.5V

EXTV

V

CC

OUT

+

C2

22μF

x3

C5

470μF

4V

FCB

V

OSET

LTM4600HV

R1

100k

RUN

SV

IN

COMP

PGOOD

PGND

SGND

C1, C3, C7, C8: TAIYO YUDEN, GDK316BJ106ML

C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501

C5, C10: SANYO POSCAP, 4TPE470MCL

4600hv TA02

Current Sharing Between Two

LTM4600HV Modules

12

10

8

12V

IN

OUT

MAX

2.5V

20A

I

OUT2

I

OUT1

6

4

2

0

10

TOTAL LOAD

15

20

5

4600hv TA03

4600hvfc

20

LTM4600HV

U

PACKAGE DESCRIPTIO

Z

b b b

Z

6 . 9 8 6 5

5 . 7 1 4 2

6 . 3 5 0 0

3 . 8 1 0 0

1 . 2 7 0 0

5 . 0 8 0 0

4 . 4 4 4 2

3 . 1 7 4 2

1 . 9 0 4 2

2 . 5 4 0 0

0 . 0 0 0 0

0 . 6 3 4 2

0 . 0 0 0 0

0 . 3 1 7 5

0 . 6 3 5 8

1 . 2 7 0 0

3 . 8 1 0 0

6 . 3 5 0 0

1 . 9 0 5 8

3 . 1 7 5 8

2 . 5 4 0 0

5 . 0 8 0 0

4 . 4 4 5 8

5 . 7 1 5 8

6 . 9 4 2 1

4600hvfc

21

LTM4600HV

U

PACKAGE DESCRIPTIO

Pin Assignment Tables

(Arranged by Pin Number)

PIN NAME

E1

PIN NAME

A1

-

B1

V

-

C1

-

V

-

V

-

V

-

D1

V

-

V

-

V

-

V

-

F1

V

-

G1 PGND

H1

-

IN

A2

-

B2

C2

D2

E2

F2

G2

-

H2

H3

H4

H5

H6

A3

V

-

B3

C3

D3

E3

F3

G3

IN

A4

B4

C4

D4

E4

F4

G4

A5

V

-

B5

C5

D5

E5

F5

G5

IN

A6

B6

C6

D6

E6

F6

G6

A7

V

-

B7

C7

D7

E7

F7

G7

H7 PGND

H8

H9 PGND

H10

H11 PGND

H12

H13 PGND

H14

H15 PGND

H16

H17 PGND

IN

A8

B8

C8

D8

E8

F8

G8

-

A9

V

-

B9

C9

D9

E9

F9

G9

IN

A10

A11

A12

A13

A14

A15

A16

B10

B11

B12

B13

B14

B15

B16

B17

B18

B19

B20

B21

B22

C10

C11

C12

C13

C14

C15

C16

C17

C18

C19

C20

C21

C22

C23

D10

D11

D12

D13

D14

D15

D16

D17

D18

D19

D20

D21

D22

E10

E11

E12

E13

E14

E15

E16

E17

E18

E19

E20

E21

E22

E23

F10

F11

F12

F13

F14

F15

F16

F17

F18

F19

F20

F21

F22

G10

G11

G12

G13

G14

G15

G16

G17

G18

G19

G20

G21

G22

-

IN

V

-

IN

-

V

-

IN

-

f

ADJ

-

A17 SV

IN

A18

-

H18

H19

H20

H21

H22

H23

-

A19 EXTV

CC

A20

A21

A22

A23

-

V

-

OSET

-

B23 COMP

D23 SGND

F23 RUN/SS G23 FCB

PIN NAME

PIN NAME PIN NAME

PIN NAME

J1 PGND

K1

K2

K3

K4

K5

K6

-

L1

-

M1

M2 PGND

M3

M4 PGND

M5

M6 PGND

M7

M8 PGND

M9

-

N1

-

P1

-

R1

-

T1

-

J2

-

L2 PGND

N2 PGND

P2

V

-

R2

V

-

T2

V

-

OUT

J3

L3

L4 PGND

L5

L6 PGND

L7

L8 PGND

L9

L10 PGND

L11

L12 PGND

L13

L14 PGND

L15

L16 PGND

L17

L18 PGND

L19

L20 PGND

L21

L22 PGND

L23

-

N3

N4 PGND

N5

N6 PGND

N7

N8 PGND

N9

N10 PGND

N11

N12 PGND

N13

N14 PGND

N15

N16 PGND

N17

N18 PGND

N19

N20 PGND

N21

N22 PGND

N23

-

P3

R3

T3

J4

P4

V

-

R4

V

-

T4

V

-

J5

-

P5

R5

T5

J6

P6

V

-

R6

V

-

T6

V

-

J7

K7 PGND

K8

-

P7

R7

T7

J8

P8

V

-

R8

V

-

T8

V

-

J9

K9 PGND

K10

-

P9

R9

T9

J10

J11

J12

J13

J14

J15

J16

J17

J18

J19

J20

J21

J22

M10 PGND

M11 -

P10

P11

P12

P13

P14

P15

P16

P17

P18

P19

P20

P21

P22

P23

V

-

R10

R11

R12

R13

R14

R15

R16

R17

R18

R19

R20

R21

R22

R23

V

-

T10

T11

T12

T13

T14

T15

T16

T17

T18

T19

T20

T21

T22

T23

V

-

K11 PGND

-

K12

K13 PGND

K14

K15 PGND

K16

K17 PGND

-

M12 PGND

M13 -

V

-

V

-

V

-

M14 PGND

M15 -

V

-

V

-

V

-

M16 PGND

M17 -

V

-

V

-

V

-

K18

K19

K20

K21

K22

-

M18 PGND

M19 -

V

-

V

-

V

-

M20 PGND

M21 -

V

-

V

-

V

-

M22 PGND

M23 -

V

-

V

-

V

-

J23 PGOOD K23

-

4600hvfc

22

LTM4600HV

U

PACKAGE DESCRIPTIO

Pin Assignment Tables

(Arranged by Pin Number)

PIN NAME

G1

PGND

P2

V

A3

V

A15

A17

A19

A21

B23

D23

F23

G23

J23

f

ADJ

OUT

IN

P4

V

A5

H7

H9

H11

H13

H15

H17

PGND

SV

IN

P6

P8

A7

A9

A11

A13

EXTV

V

CC

P10

P12

P14

P16

P18

P20

P22

OSET

COMP

B1

V

IN

SGND

RUN/SS

FCB

J1

PGND

C10

C12

C14

V

IN

V

IN

V

IN

K7

K9

K11

K13

K15

K17

PGND

D1

V

R2

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

IN

PGOOD

R4

E10

E12

E14

V

IN

V

IN

V

IN

R6

R8

R10

R12

R14

R16

R18

R20

R22

L2

PGND

F1

V

IN

L4

L6

L8

L10

L12

L14

L16

L18

L20

L22

T2

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

T4

T6

T8

T10

T12

T14

T16

T18

T20

T22

M2

PGND

M4

M6

M8

M10

M12

M14

M16

M18

M20

M22

N2

PGND

N4

N6

N8

N10

N12

N14

N16

N18

N20

N22

4600hvfc

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

23

LTM4600HV

U

TYPICAL APPLICATIO

1.8V, 10A Regulator

4.5V TO 22V

C5

100pF

C2

10μF

35V

C1

10μF

35V

V

f

ADJ

IN

1.8V AT 10A

EXTV

FCB

V

CC

OUT

+

C3

22μF

x3

C4

470μF

4V

V

OSET

R1

100k

LTM4600HV

RUN

SV

IN

COMP

PGOOD

PGND

PGOOD

R2

49.9k

1%

SGND

C1, C2: TAIYO YUDEN, GDK316BJ106ML

C3: TAIYO YUDEN, JMK316BJ226ML-T501

C4: SANYO POSCAP, 4TPE470MCL

4600hv TA04

RELATED PARTS

PART NUMBER

LTC2900

DESCRIPTION

COMMENTS

Quad Supply Monitor with Adjustable Reset Timer

Power Supply Tracking Controller

Synchronous Isolated Flyback Controllers

10A DC/DC μModule

Monitors Four Supplies; Adjustable Reset Timer

Tracks Both Up and Down; Power Supply Sequencing

No Optocoupler Required; 3.3V, 12A Output; Simple Design

Basic 10A DC/DC μModule

LTC2923

LT3825/LT3837

LTM4600

LTM4601

12A DC/DC μModule with PLL, Output Tracking/

Margining and Remote Sensing

Synchronizable, PolyPhase Operation to 48A, LTM4601-1 Version has no

Remote Sensing

LTM4602

LTM4603

6A DC/DC μModule

Pin Compatible with the LTM4600

6A DC/DC μModule with PLL and Outpupt Tracking/ Synchronizable, PolyPhase Operation to 48A, LTM4601-1 Version has no

Margining and Remote Sensing

Remote Sensing, Pin Compatible with the LTM4601

®

This product contains technology licensed from Silicon Semiconductor Corporation.

4600hvfc

LT 0707 REV C • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

24

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LTM4600HVEV-TRPBF
厂家：	Linear
描述：	10A, 28VIN High Effi ciency DC/DC μModule 10A ， 28VIN高艾菲效率DC / DC微型模块
文件：	总24页 (文件大小：356K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LTM4600HVEV-TRPBF [Linear]

相关型号：

LTM4600HVIV

LTM4600HVIV#PBF

LTM4600HVIV-PBF

LTM4600HVIV-TRPBF

LTM4600HVMP

LTM4600HVMPV

LTM4600HVMPV#PBF

LTM4600HVMPV-PBF

LTM4600HVMPV-TRPBF

LTM4600IV

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LTM4600IV#TRPBF