LTM4602HVV_技术文档

LTM4602HV

6A, 28V High Efﬁciency

IN

DC/DC µModule

U

DESCRIPTIO

FEATURES

The LTM^®4602HV is a complete 6A, 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 LTM4602HV

supports an output voltage range of 0.6V to 5V, set by

a single resistor. This high efﬁciency design delivers 6A

continuous current (8A 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

■

6A DC, Typical 8A Peak Output Current

■

0.6V to 5V Output Voltage

■

1.5% Output Voltage Regulation

■

Ultrafast Transient Response

■

Parallel µModule™ DC/DC Converters

■

Current Mode Control

■

Pin Compatible with the LTM4600 and LTM4602

■

Up to 92% Efﬁciency

Programmable Soft-Start

Output Overvoltage Protection

Optional Short-Circuit Shutdown Timer

■

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 with Gold-Pad

Finish

■

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

2.8mm) LGA Package

U

APPLICATIO S

■

Telecom and Networking Equipment

TheLTM4602HVispackagedinathermallyenhanced,com-

pact(15mm×15mm)andlowproﬁle(2.8mm)over-molded

Land Grid Array (LGA) package suitable for automated

assembly by standard surface mount equipment. For the

4.5V to 20V input range version, refer to the LTM4602.

■

Servers

■

Industrial Equipment

Point of Load Regulation

■

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

µModule is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners. Protected by U.S. Patents including 5481178,

6100678, 6580258, 5847554, 6304066.

U

TYPICAL APPLICATIO

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

90

80

70

60

50

40

6A µModule Power Supply with 4.5V to 28V Input

V

2.5V

6A

IN

OUT

4.5V TO 28V

ABS MAX

V

OUT

IN

C

OUT

IN

LTM4602HV

1.2V

1.5V

1.8V

2.5V

3.3V

OUT

30

20

10

V

OSET

PGND SGND

31.6k

(1MHz)

5

4602HV TA01a

0

1

2

3

6

4

LOAD CURRENT (A)

4602HV G03

4602hvf

1

LTM4602HV

W W U W

U

W

U

ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

(Note 1)

TOP VIEW

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

CC

OUT

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

IN

OSET

IN ADJ

COMP

V

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

V

IN

SGND

RUN/SS

FCB

Operating Temperature Range (Note 2) ... –40°C to 85°C

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

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

PGOOD

PGND

V

OUT

LGA PACKAGE

104-LEAD (15mm × 15mm × 2.8mm)

T

= 125°C, θ = 15°C/W, θ = 6°C/W,

JMAX

JA JC

θ

JA

DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS

WEIGHT = 1.7g

ORDER PART NUMBER

LGA PART MARKING*

LTM4602HVEV#PBF

LTM4602HVIV#PBF

LTM4602HVV

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

*The temperature grade is identiﬁed by a label on the shipping container.

ELECTRICAL CHARACTERISTICS ^The● denotes the speciﬁcations which apply over the –40°C to 85°C

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

OUT(DC)

V

= 5V or 12V, V

= 1.5V, I = 0A

OUT

1.478

1.470

1.50

1.522

1.530

V

IN

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

OUT

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

OUT CC

Q(VIN)

V

= 12V, V

= 24V, V

= 1.5V, FCB = 5V

1.2

42

1.8

36

50

mA

µA

IN

OUT

V

= 1.5V, FCB = 0V

= 2.5V, FCB = 5V

= 2.5V, FCB = 0V

Shutdown, RUN = 0.8V, V = 12V

100

IN

Min On Time

Min Off Time

100

ns

400

ns

I

Input Supply Current

V

= 12V, V

= 1.5V, I

= 3.3V, I

= 6A

0.88

1.50

2.08

0.98

A

S(VIN)

IN

OUT

A

= 5V, V

= 1.5V, I

= 6A

OUT

= 24V to 3.3V at 6A, EXTV = 5V

A

CC

4602hvf

2

LTM4602HV

ELECTRICAL CHARACTERISTICS ^The● denotes the speciﬁcations which apply over the –40°C to 85°C

temperature range, otherwise speciﬁcations are at T_A= 25°C, V_IN= 12V. Per typical application (front page) conﬁguration.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Output Speciﬁcations

I

Output Continuous Current Range

V

IN

V

IN

= 12V, V

= 24V, V

= 1.5V

= 2.5V (Note 3)

0

6

A

OUTDC

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

%

OUT(LINE)

OUT

IN

OUT

= 4.5V to 28V

V

OUT

Load Regulation Accuracy

V

= 1.5V. FCB = 0V, I

= 0A to 6A,

OUT(0A-6A)

OUT

IN

OUT

= 5V, V = 12V (Note 4)

0.25

0.5

1

%

IN

V

OUT

V

Output Ripple Voltage

V

IN

= 12V, V

= 1.5V, FCB = 0V, I

= 0A

10

15

mV

P-P

OUT(AC)

OUT

fs

Output Ripple Voltage Frequency

FCB = 0V, I

= 6A, V = 12V,

800

kHz

OUT

IN

V

= 1.5V

OUT

t

Turn-On Time

= 1.5V, I

= 12V

= 5V

= 1A

START

OUT

V

OUT

0.5

0.7

ms

IN

V

ΔV

OUTLS

Voltage Drop for Dynamic Load Step

V

C

= 1.5V, Load Step: 0A/µs to 3A/µs

= 22µF 6.3V, 330µF 4V Pos Cap,

30

mV

OUT

See Table 2

t

I

Settling Time for Dynamic Load Step

IN

Output Current Limit

Load: 10% to 90% to 10% of Full Load

25

µs

SETTLE

OUTPK

V

= 12V

Output Voltage in Foldback

V

= 24V, V

= 12V, V

= 2.5V

= 1.5V

9

A

IN

OUT

= 5V, V

= 1.5V

OUT

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

2

–3

3

V

RUN/SS

I

Soft-Start Charging Current

Soft-Start Discharging Current

V

= 0V

= 4V

µA

RUN(C)/SS

RUN(D)/SS

RUN/SS

µA

V

– SV

EXTV = 0V, FCB = 0V

100

16

mV

mA

IN

CC

I

Current into EXTV Pin

EXTV = 5V, FCB = 0V, V

= 1.5V,

EXTVCC

CC

= 0A

OUT

I

OUT

R

Resistor Between V

and FB Pins

OUT

100

0.6

–1

kΩ

V

FBHI

V

Forced Continuous Threshold

Forced Continuous Pin Current

0.57

0.63

–2

FCB

I

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

PGOOD Low Voltage

I

= 5mA

0.15

0.4

PGL

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 LTM4602HVE 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 LTM4602HVI 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.

Note 4: Test assumes current derating verses temperature.

4602hvf

3

LTM4602HV

U W

TYPICAL PERFOR A CE CHARACTERISTICS ^{(See Figure 22 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

80

70

60

50

40

30

20

10

0

100

90

80

70

60

50

40

30

20

10

0

90

80

70

60

50

40

30

20

10

0.8V

1.2V

1.5V

1.8V

2.5V

3.3V

OUT

0.8V

OUT

1.2V

1.5V

1.8V

2.5V

3.3V

1.2V

OUT

1.5V

1.8V

2.5V

3.3V

OUT

*

*FOR 5V TO 3.3V CONVERSION,

SEE FREQUENCY ADJUSTMENT

IN APPLICATIONS INFORMATION

(950kHz)

(1MHz)

5

0

2

4

6

8

0

2

4

6

8

0

1

2

3

6

4

LOAD CURRENT (A)

4602HV G01

4602HV G02

4602HV G03

Light Load Efﬁciency vs

Load Current with 12V_IN

(FCB > 0.7V, <5V)

Efﬁciency vs Load Current

with Different FCB Settings

1.2V Transient Response

100

90

80

70

60

50

40

30

20

100

90

80

70

60

50

40

30

20

10

0

V

= 12V

IN

OUT

= 1.5V

V

OUT

FCB > 0.7V

50mV/DIV

I

OUT

2A/DIV

FCB = GND

4602HV G05

20µs/DIV

1.2V AT 3A/µs LOAD STEP

C

= 22µF, 6.3V CERAMIC

1.2V

OUT

330µF, 4V SANYO POS CAP

1.5V

1.8V

2.5V

3.3V

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

LOAD CURRENT (A)

1

0.1

5

1

LOAD CURRENT (A)

4602HV G15

4602HV G04

1.8V Transient Response

2.5V Transient Response

1.5V Transient Response

V

OUT

50mV/DIV

V

50mV/DIV

OUT

50mV/DIV

I

OUT

I

OUT

2A/DIV

4602HV G07

4602HV G08

20µs/DIV

4602HV G06

20µs/DIV

1.8V AT 3A/µs LOAD STEP

2.5V AT 3A/µs LOAD STEP

1.5V AT 3A/µs LOAD STEP

C

OUT

= 22µF, 6.3V CERAMIC

C

= 22µF, 6.3V CERAMIC

OUT

C

= 22µF, 6.3V CERAMIC

OUT

330µF, 4V SANYO POS CAP

4602hvf

4

LTM4602HV

U W

TYPICAL PERFOR A CE CHARACTERISTICS ^{(See Figure 22 for all curves)}

Start-Up, I_OUT= 6A

(Resistive Load)

Start-Up, I_OUT= 0A

3.3V Transient Response

V

OUT

V

OUT

0.5V/DIV

50mV/DIV

OUT

0.5V/DIV

I

OUT

I

2A/DIV

IN

I

IN

0.5A/DIV

4602HV G09

0.5A/DIV

20µs/DIV

3.3V AT 3A/µs LOAD STEP

4602HV G10

4602HV G11

200µs/DIV

= 1 × 22µF, 6.3V X5R

500µs/DIV

= 1 × 22µF, 6.3V X5R

V

C

= 12V

OUT

V

C

= 12V

OUT

C

= 22µF, 6.3V CERAMIC

IN

OUT

= 1.5V

330µF, 4V SANYO POS CAP

NO EXTERNAL SOFT-START CAPACITOR

Short-Circuit Protection,

I_OUT= 0A

Short-Circuit Protection,

I_OUT= 6A

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

ADJ

5V

V

OUT

0.5V/DIV

3.3V

I

IN

I

IN

2.5V

1.8V

0.5A/DIV

4602HV G12

4602HV G13

20µs/DIV

= 1 × 22µF, 6.3V X5R

20µs/DIV

V

C

= 12V

OUT

V

C

= 12V

OUT

IN

1.5V

= 1.5V

= 1 × 22µF, 6.3V X5R

330µF, 4V SANYO POS CAP

1.2V

330µF, 4V SANYO POS CAP

NO EXTERNAL SOFT-START CAPACITOR

0.6V

10

20

25 28

0

5

15

(V)

V

IN

SEE FREQUENCY ADJUSTMENT DISCUSSION

FOR 12V TO 5V

AND 5V TO 3.3V

IN

OUT

IN OUT

CONVERSION

4602HV G14

4602hvf

5

LTM4602HV

U

PI FU CTIO S

(See Package Description for Pin Assignment)

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

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

tween these pins and PGND pins. Recommend placing

input decoupling capacitance directly between V pins

IN

and PGND pins.

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.TheLTM4602HVswitchingfrequencyistypically

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

IN

5µA pull up current.

this pin open or add additional decoupling capacitance.

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 10k 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 PGND pins. Recommend placing

High Frequency output decoupling capacitance directly

between these pins and PGND 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

4602hvf

6

LTM4602HV

W

SI PLIFIED BLOCK DIAGRA

SV

IN

RUN/SS

V

IN

1000pF

4.5V TO 28V

ABS MAX

C

1.5µF

IN

PGOOD

Q1

COMP

FCB

INT

COMP

V

2.5V

6A MAX

OUT

V

OUT

IN

4.75k

15µF

6.3V

CONTROLLER

110k

f

ADJ

PGND

Q2

10Ω

SGND

EXTV

CC

100k

0.5%

V

OSET

R

SET

31.6k

4602HV F01

Figure 1. Simpliﬁed LTM4602HV 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

= 6A, 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

= 6A, Refer to Table 2 in the

100

200

µF

OUT

Applications Information Section

IN

OUT

4602hvf

7

LTM4602HV

U

OPERATIO

µModule Description

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.

TheLTM4602HVisastandalonenon-isolatedsynchronous

switching DC/DC power supply. It can deliver up to 6A 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

typical application schematic is shown in Figure 21.

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 10k resistor to ground, so a resistor to

The LTM4602HV 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 800kHz at full load.

With current mode control and internal feedback loop

compensation, the LTM4602HV 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).

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

Current mode control provides cycle-by-cycle fast current

limit. In addition, foldback current limiting is provided

in an over-current condition while V drops. Also, the

LTM4602HV has defeatable short circuit latch off. Internal

overvoltage and undervoltage comparators pull the open-

drainPGOODoutputlowiftheoutputfeedbackvoltageexits

a 10%windowaroundtheregulationpoint. Furthermore,

off, and an internal switch connects EXTV to the gate

CC

driver voltage. This eliminates the linear regulator power

loss with high input voltage, reducing the thermal stress

FB

on the controller. The maximum voltage on EXTV pin is

CC

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.

4602hvf

8

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

The typical LTM4602HV application circuit is shown in

Figure 20. 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 LTM4602HV has an internal

0.6V 1%referencevoltage.Asshownintheblockdiagram,

= 0.6V

a100k/0.5%internalfeedbackresistorconnectsV

and

OUT

pin to SGND

R_SET•V_O•(1– M%)

R_SET+ (100kΩ R_DOWN

FB pins. Adding a resistor R from V

SET

OSET

= 0.6V

)

pin programs the output voltage:

100k +R_SET

V_O= 0.6V •

Input Capacitors

R_SET

The LTM4602HV 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 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:

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 LTM4602HV. 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.

is off, the output

UP

DOWN

V

OUT

LTM4602HV

R

DOWN

Q

100k

DOWN

2N7002

V

OSET

PGND

SGND

R

SET

UP

InFigure16,theinputcapacitorsareusedashighfrequency

inputdecouplingcapacitors.Inatypical6Aoutputapplica-

tion, 1-2piecesofverylowESRX5RorX7R, 10µFceramic

capacitors are recommended. This decoupling capacitor

should be placed directly adjacent the module input pins

Q

UP

2N7002

4602HV F02

Figure 2

4602hvf

9

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

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

LTM4602HV as well as a timer for soft-start and over-

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

the LTM4602HV into a low quiescent current shutdown

Output Capacitors

The LTM4602HV is designed for low output voltage ripple.

The bulk output capacitor C

effectiveseriesresistance(ESR)tomeettheoutputvoltage

ripple and transient requirements. C can be low ESR

is chosen with low enough

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

OUT

Q

current source to charge up the timing capacitor C .

SS

Inside LTM4602HV, there is an internal 1000pF capaci-

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 3A/µs transient with

a speciﬁc output capacitance.

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

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

LTM4602HV 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

The LTM4602HV has a current mode controller, which

inherently limits the cycle-by-cycle inductor current not

only in steady state operation, but also in transient.

There are restrictions in the maximum V to V

step

IN

OUT

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

These constraints are shown in the Typical Performance

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

tion, the LTM4602HV provides foldback current limiting.

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

maximumoutputcurrentisprogressivelyloweredtoabout

one sixth of its full current limit value.

Characteristics curves labeled “V to V

Stepdown

IN

OUT

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

See the Thermal Considerations and Output Current De-

Rating sections of this data sheet.

4602hvf

10

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

Table 2. Output Voltage Response Versus Component Matrix (Refer to Figure 17), 0A to 3A Step (Typical Values)

TYPICAL MEASURED VALUES

C

OUT1

VENDORS

PART NUMBER

C

OUT2

VENDORS

PART NUMBER

TDK

C4532X5R0J107MZ (100UF,6.3V)

JMK432BJ107MU-T ( 100µF, 6.3V)

JMK316BJ226ML-T501 ( 22µF, 6.3V)

SANYO POS CAP

6TPE330MIL (330µF, 6.3V)

2R5TPE470M9 (470µF, 2.5V)

4TPE470MCL (470µF, 4V)

TAIYO YUDEN

V

C

C3

V

IN

(V)

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

3.3

5

(CERAMIC)

2 × 10µF 25V

1 × 10µF 25V

(BULK)

(CERAMIC)

(BULK)

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

(mV)

60

54

55

60

54

56

55

50

54

59

55

54

59

54

50

60

50

60

50

54

64

60

64

58

60

64

160

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

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

NONE 100pF

NONE 220pF

NONE 100pF

5

30

25

30

25

26

25

28

26

25

29

25

29

25

27

32

30

32

38

30

32

80

25

20

25

20

25

20

25

20

30

20

30

20

30

25

30

25

30

35

25

30

35

30

25

3

5

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

12

5

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

5

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

12

5

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

5

470µF 4V

470µF 2.5V

330µF 6.3V

NONE

12

5

470µF 4V

330µF 6.3V

470µF 4V

NONE

5

470µF 4V

330µF 6.3V

NONE

12

7

330µF 6.3V

470µF 4V

NONE

7

470µF 4V

330µF 6.3V

NONE

12

15

20

NONE

5

NONE

4602hvf

11

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

After the controller has been started and given adequate

4V maximum latchoff threshold and overcome the 4µA

maximumdischargecurrent.Figure 3showsaconceptual

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

drawing of V

during startup and short circuit.

RUN

V

RUN/SS

beginsdischargingC . Ifthefaultconditionpersistsuntil

4V

SS

3.5V

the RUN/SS pin drops to 3.5V, then the controller turns

off both power MOSFETs, shutting down the converter

permanently. The RUN/SS pin must be actively pulled

down to ground in order to restart operation.

3V

1.5V

SHORT-CIRCUIT

LATCH ARMED

t

The over-current protection timer requires the soft-start

SOFT-START

CLAMPING

L

SHORT-CIRCUIT

LATCHOFF

OUTPUT

OVERLOAD

HAPPENS

timing capacitor C be made large enough to guarantee

SS

OF I RELEASED

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

SS

V

O

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:

75%V

O

t

SWITCHING

STARTS

4602HV F03

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

Figure 3. RUN/SS Pin Voltage During Startup and

Short-Circuit Protection

Generally 0.1µF is more than sufﬁcient.

V

IN

Sincetheloadcurrentisalreadylimitedbythecurrentmode

controlandcurrentfoldbackcircuitryduringashortcircuit,

overcurrent latchoff operation is NOT always needed or

desired, especially if the output has large capacitance or

the load draws high current during start-up. The latchoff

featurecanbeoverriddenbyapull-upcurrentgreaterthan

5µA but less than 80µA to the RUN/SS pin. The additional

IN

500k

LTM4602HV

RUN/SS

PGND SGND

RECOMMENDED VALUES FOR R

RUN/SS

V

R

RUN/SS

IN

current prevents the discharge of C during a fault and

4.5V TO 5.5V

10.8V TO 13.8V

24V TO 28V

50k

150k

500k

SS

also shortens the soft-start period. Using a resistor from

4602HV F04

RUN/SSpintoV isasimplesolutiontodefeatlatchoff.Any

IN

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

Resistor to V_IN

pull-up network must be able to maintain RUN/SS above

4602hvf

12

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

Enable

EXTV Connection

CC

The RUN/SS pin can be driven from logic as shown in

Figure 5. This function allows the LTM4602HV 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 LTM4602HV can be directly powered by V . The gate

IN

driver current through LDO is about 16mA. The internal

LDO power dissipation can be calculated as:

RUN/SS

P

= 16mA • (V – 5V)

IN

LTM4602HV

ON

LDO_LOSS

The LTM4602HV also provides an external gate driver

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

PGND SGND

CC

2N7002

4602HV F05

is recommended to connect EXTV pin to the external

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

Output Voltage Tracking

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

CC

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

CC

For the applications that require output voltage tracking,

several LTM4602HV 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

cident, ratiometric and offset tracking for V rising and

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

O

CC

falling can be implemented with different sets of resistor

from the internal 5V regulator.

values. See the LTC2923 data sheet for more details.

2. EXTV connected to an external supply. Internal LDO

CC

Q1

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

V

IN

DC/DC

3.3V

5V

V

IN

required that the EXTV voltage can not be higher than

CC

IN

V pin voltage.

IN

R

V

GATE

RAMP

FB1

ONB

CC

LTM4602HV

V

1.8V

ON

OSET

OUT

R

Discontinuous Operation and FCB Pin

SET

ONA

LTC2923

49.9k

The FCB pin determines whether the internal bottom

MOSFET remains on when the inductor current reverses.

There is an internal 10k 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.

STATUS

SDO

RAMPBUF

TRACK1

TRACK2

V

IN

R

TB1

TA1

V

IN

R

TB2

LTM4602HV

V

FB2

1.5V

OSET

OUT

R

GND

SET

R

TA2

66.5k

4602HV F06

Figure 6. Output Voltage Tracking with the LTC2923 Controller

4602hvf

13

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

approximate θ for the module with various heatsink-

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-

tion loss is minimized and light load efﬁcient is improved.

The penalty is that the controller may skip cycle and the

output voltage ripple increases at light load.

JA

ing methods. Thermal models are derived from several

temperature measurements at the bench, and thermal

modelinganalysis.ApplicationNote103providesadetailed

explanationoftheanalysisforthethermalmodels, andthe

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

equivalent θ for the noted conditions. These equivalent

JA

θ

parameters are correlated to the measure values, and

JA

Paralleling Operation with Load Sharing

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

Two or more LTM4602HV modules can be paralleled to

provide higher than 6A 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 LTM4602HVs in parallel is:

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

at the junction of the device. The θ values in Tables 3

JA

and 4 can be used to derive the derating curves for other

output voltages.

100k

+R_SET

Safety Considerations

N

V_OUT= 0.6V •

R_SET

The LTM4602HV modules do not provide isolation from

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

IN

OUT

where N is the number of LTM4602HVs in parallel.

blow fuse with a rating twice the maximum input current

should be provided to protect each unit from catastrophic

failure.

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

OPTI-LOOP is a trademark of Linear Technology Corporation.

V

PULLUP

100k

PGOOD

V

OUT

V

LTM4602HV

V

OUT

IN

12A MAX

PGND COMP V

SGND

OSET

R

SET

PGOOD COMP V

SGND

OSET

V

LTM4602HV

V

OUT

IN

PGND

4602HV F07

Figure 7. Parallel Two µModules with Load Sharing

4602hvf

14

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

2.0

1.8

7

6

7

6

1.6

5

4

3

2

1

0

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

5

4

3

2

1

0

12V TO 1.5V

LOSS

5V TO 1.5V

LOSS

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

0.6

1.0

3.1

4.1

5.1

6.1

2.1

60

70

80

100

50

90

60

70

80

100

50

90

CURRENT (A)

TEMPERATURE (°C)

4602HV F08

4602HV F10

4602HV F09

Figure 9. 5V to 1.5V, No Heatsink

Figure 8. 1.5V Power Loss Curves

vs Load Current

Figure 10. 5V to 1.5V, BGA Heatsink

7

6

4.0

3.5

3.0

2.5

7

6

5V TO 3.3V LOSS

12V TO 3.3V LOSS

12V TO 3.3V (950kHz) LOSS

5

4

3

2

1

0

5

4

3

2

1

0

2.0

1.5

1.0

0.5

0

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

60

70

80

100

1.0

2.1

4.1

50

90

0.5

5.1

6.1

3.1

60

70

80

100

50

90

TEMPERATURE (°C)

CURRENT (A)

TEMPERATURE (°C)

4602HV F09

4602HV F13

4602HV F11

Figure 13. 3.3V Power Loss

Figure 11. 12V to 1.5V, No Heatsink

Figure 12. 12V to 1.5V, BGA Heatsink

7

6

7

6

5

4

3

2

1

0

5

4

3

2

1

0

5

4

3

2

1

0

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

60

70

80

100

60

70

80

100

50

90

50

90

60

70

80

100

50

90

TEMPERATURE (°C)

4602HV F14

4602HV F15

4602HV F16

Figure 14. 5V to 3.3V, No Heatsink

Figure 16. 12V to 3.3V (950kHz),

No Heatsink

Figure 15. 5V to 3.3V, BGA Heatsink

4602hvf

15

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

7

6

7

6

7

6

5

4

3

2

1

0

5

4

3

2

1

0

5

4

3

2

1

0

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

0LFM

200LFM

400LFM

60

70

80

100

50

90

60

70

80

100

50

90

60

70

80

100

50

90

TEMPERATURE (°C)

4602HV F16

4602HV F18

4602HV F19

Figure 17. 12V to 3.3V (950kHz),

BGA Heatsink

Figure 19. 24V to 3.3V, BGA Heatsink

Figure 18. 24V to 3.3V, No Heatsink

Table 3. 1.5V Output

Table 4. 3.3V Output

AIR FLOW (LFM)

HEATSINK

None

θ

(°C/W)

AIR FLOW (LFM)

HEATSINK

None

θ

JA

(°C/W)

JA

0

15.2

14

0

15.2

14.6

13.4

13.9

11.1

10.5

200

400

0

None

200

400

0

None

12

None

BGA Heatsink

13.9

11.3

10.25

BGA Heatsink

200

400

200

400

Layout Checklist/Example

• Do not put via directly on pad

The high integration of the LTM4602HV makes the PCB

board layout very simple and easy. However, to optimize

its electrical and thermal performance, some layout con-

siderations are still necessary.

• Use a separated SGND ground copper area for com-

ponents connected to signal pins. Connect the SGND

to PGND underneath the unit

Figure 20 gives a good example of the recommended

layout.

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

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

IN

OUT

LTM4602 Frequency Adjustment

PCB conduction loss and thermal stress

TheLTM4602HVisdesignedtotypicallyoperateat850kHz

across most input and output conditions. The control ar-

chitectureisconstantontimevalleymodecurrentcontrol.

• Place high frequency ceramic input and output capaci-

tors next to the V , PGND and V

pins to minimize

IN

OUT

high frequency noise

The f

pin is typically left open or decoupled with an

ADJ

• Place a dedicated power ground layer underneath

the unit

optional 1000pF capacitor. The switching frequency has

beenoptimizedtomaintainconstantoutputrippleoverthe

operatingconditions.Theequationsforsettingtheoperat-

ing frequency are set around a programmable constant

• To minimize the via conduction loss and reduce module

thermal stress, use multiple vias for interconnection

between top layer and other power layers

on time. This on time is developed by a programmable

4602hvf

16

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

V

TheLTM4602hasaminimum(t )ontimeof100nanosec-

IN

ON

onds and a minimum (t ) off time of 400 nanoseconds.

OFF

The 2.4V clamp on the ramp threshold as a function of

V

will cause the switching frequency to increase by the

OUT

C

IN

ratio of V /2.4V for 3.3V and 5V outputs. This is due to

OUT

the fact the on time will not increase as V

increases

OUT

past 2.4V. Therefore, if the nominal switching frequency

is 850kHz, then the switching frequency will increase

to ~1.2MHz for 3.3V, and ~1.7MHz for 5V outputs due

PGND

to Frequency = (DC/t ) When the switching frequency

ON

increases to 1.2MHz, then the time period ts is reduced

to ~833 nanoseconds and at 1.7MHz the switching 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

V

OUT

4602HV F20

LOAD

TOP LAYER

Figure 20. Recommended PCB Layout

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

,

ON

OFF

t

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

OFF

from the f

current into an on board 10pF capacitor that establishes

a ramp that is compared to a voltage threshold that is

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.

equal to the output voltage up to a 2.4V clamp. This I

ON

current is equal to: I = (V – 0.7V)/110k, with the 110k

ON

IN

onboard resistor from V to f . The on time is equal to

IN

ADJ

t

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

ON

OUT ON OFF s ON

is equal to: Freq. = DC/t . The I current is proportional

ON

to V , and the regulator duty cycle is inversely propor-

IN

Equations for setting frequency: V

= 5V

OUT

tionaltoV , thereforethestep-downregulatorwillremain

IN

I

ON

= (V – 0.7V)/110k; for 12V input, I = 103µA

IN ON

relatively constant frequency as the duty cycle adjustment

takes place with lowering V . The on time is proportional

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

IN

ON

to V

up to a 2.4V clamp. This will hold frequency rela-

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

OUT

OUT IN

tively 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 Figure 21. The on time is

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

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

OFF

ON

OFF ON

switching period; t = 1/frequency

t

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

OFF

ON

OUT ON

OFF

s

ON

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

ON

t

= DC • t

ON

1MHz frequency or 1µs period is chosen.

t

ON

(DC) DUTY CYCLE =

t

s

t

V

OUT

ON

t

= 0.41 • 1µs ≅ 410ns

DC =

=

ON

t

V

s

IN

DC

t

= 1µs – 410ns ≅ 590ns

FREQ =

OFF

ON

t

ON

OFF

t

and t are above the minimums with adequate guard

OFF

ON

band.

4602HV F21

PERIOD t

s

Figure 21

4602hvf

17

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

Usingthefrequency=(I /[2.4V•10pF])•(DC),solvefor

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

ON

I

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

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

ON

ON ON

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

current calculated from 5V input was 39µA, so a resistor

f

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

from f

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

ADJ

57µA, sets the adequate I current for proper frequency

=16µA,setstheadequateI currentforproperfrequency

ON

range for the higher duty cycle conversion of 12V to

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

5V. Input voltage range is limited to 8V to 16V. Higher

Input voltage range is limited to 4.5V to 7V. Higher input

input voltages can be used without the 15k on f

.

voltagescanbeusedwithoutthe30.1konf . Theinduc-

ADJ

The inductor ripple current gets too high above 16V or

below 8V.

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

minimum off-time is limited below 4.5V.

Equations for setting frequency: V

= 3.3V

Therefore,at3.3Voutput,a30.1kresistorisrecommended

OUT

to add from pin f

to ground when the input voltage is

ADJ

I

= (V – 0.7V)/110k; for 5V input, I = 39µA

IN ON

ON

between 4.5V to 7V. However, this resistor needs to be

removed to avoid high inductor ripple current when the

input voltage is more than 7V. Similarly, for 5V output, a

15kresistorisrecommendedtoadjustthefrequencywhen

the input voltage is between 8V to 16V. This 15k resistor

is removed when the input voltage becomes higher than

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

ON

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

OUT IN

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

OFF

ON

OFF ON

switching period; t = 1/frequency

t

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

OFF

ON

16V. Please refer to the Typical Performance curve V to

IN

V

OUT

Step-Down Ratio.

t

= DC • t

ON

In 12V to 3.3V and 24V to 3.3V applications, if a 35k

resistor is added from the f pin to ground, then a 2%

~450kHzfrequencyor2.22µsperiodischosen.Frequency

range is about 450kHz to 650kHz from 4.5V to 7V input.

ADJ

efﬁciency gain will be achieved as shown in the 12V and

24V efﬁciency graphs shown in the Typical Characteris-

tics. This is due to lowering the transition losses in the

power MOSFETs by reducing the switching frequency

from 1.3mHz to 1mHz.

t

= 0.66 • 2.22µs ≅ 1.46µs

= 2.22µs – 1.46µs ≅ 760ns

ON

OFF

t

and t are above the minimums with adequate guard

OFF

ON

band.

5V to 3.3V at 5A

R1

30.1k

V

IN

4.5V TO 7V

C5

100pF

C3

10µF

25V

C1

10µF

25V

V

OUT

V

f

ADJ

IN

3.3V AT 5A EFFICIENCY = 92%

EXTV

FCB

V

CC

OUT

+

C4

330µF

6.3V

C2

22µF

V

OSET

R

SET

LTM4602HV

22.1k

1%

RUN/SOFT-START

RUN/SS

COMP

SV

IN

PGOOD

PGND

OPEN DRAIN

SGND

4602HV F23

5V TO 3.3V AT 5A WITH f

LTM4602HV MINIMUM ON-TIME = 100ns

LTM4602HV MINIMUM OFF-TIME = 400ns

= 30.1k

C1, C3: TDK C3216X5R1E106MT

C2: TAIYO YUDEN, JMK316BJ226ML

C4: SANYO POS CAP, 6TPE330MIL

ADJ

4602hvf

18

LTM4602HV

U

W U U

APPLICATIO S I FOR ATIO

12V to 5V at 5A

V

R1

15k

IN

8V TO 16V

C5

100pF

C3

10µF

25V

C1

10µF

25V

V

f

OUT

IN

ADJ

5V AT 5A

EFFICIENCY = 90%

EXTV

FCB

V

CC

OUT

C4

330µF

6.3V

+

C2

22µF

V

OSET

R

13.7k

1%

SET

LTM4602HV

RUN/SOFT-START

RUN/SS

COMP

SV

IN

PGOOD

PGND

OPEN DRAIN

SGND

4602HV F24

12V TO 5V AT 5A WITH f

LTM4602HV MINIMUM ON-TIME = 100ns

LTM4602HV MINIMUM OFF-TIME = 400ns

= 15k

C1, C3: TDK C3216X5R1E106MT

C2: TAIYO YUDEN, JMK316BJ226ML

C4: SANYO POS CAP, 6TPE330MIL

ADJ

V

IN

C

IN

C

+

IN

10µF

×2

150µF

5V TO 24V

GND

BULK

V

IN

CER

(MULTIPLE PINS)

EXTV

V

OUT

CC

OUT

(MULTIPLE PINS)

C3

100pF

SV

IN

C

OUT1

C

OUT2

+

22µF

f

ADJ

330µF

6.3V

REFER TO

TABLE 2

V

REFER TO

TABLE 2

V

OSET

OUT

LTM4602HV

COMP

FCB

R

SET

RUN/SS

PGOOD

0.6V TO 5V

66.5k

C4

OPT

SGND

REFER TO

TABLE 1

REFER TO STEP DOWN

RATIO GRAPH

PGND

(MULTIPLE PINS)

GND

4602HV F22

Figure 22. Typical Application, 5V to 24V Input, 0.6V to 6V Output, 6A Max

4602hvf

19

LTM4602HV

U

TYPICAL APPLICATIO

Parallel Operation and Load Sharing

V

IN

4.5V TO 24V

V

= 0.6V • ([100k/N] + R )/R

SET SET

OUT

C8

WHERE N = 2

10µF

35V

V

f

ADJ

IN

EXTV

FCB

V

CC

OUT

+

C10

330µF

4V

C9

22µF

V

OSET

R

15.8k

1%

SET

LTM4602HV

RUN

SV

IN

COMP

PGOOD

SGND

PGND

V

2.5V

12A

OUT

RUN/SOFT-START

C3

10µF

35V

C4

220pF

V

f

ADJ

IN

EXTV

V

CC

OUT

+

C5

330µF

4V

C2

22µF

FCB

V

OSET

LTM4602HV

R1

100k

RUN

SV

IN

COMP

PGOOD

PGND

SGND

C3, C8: TAIYO YUDEN, GDK316BJ106ML

C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501

C5, C10: SANYO POS CAP, 4TPE330MI

4602HV TA02

Current Sharing Between Two

LTM4602HV Modules

6

4

2

0

12V

IN

OUT

MAX

2.5V

12A

I

OUT2

I

OUT1

0

12

6

TOTAL LOAD

4602HV TA03

4602hvf

20

LTM4602HV

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

4602hvf

21

LTM4602HV

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

-

4602hvf

22

LTM4602HV

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

4602hvf

InformationfurnishedbyLinearTechnologyCorporationisbelievedtobeaccurateandreliable.However,

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.

23

LTM4602HV

U

TYPICAL APPLICATIO

1.8V, 5A Regulator

V

IN

4.5V TO 24V

C1

C5

100pF

10µF

V

f

ADJ

OUT

IN

35V

1.8V AT 6A

EXTV

FCB

V

CC

OUT

+

C4

330µF

4V

C3

22µF

V

OSET

R1

100k

LTM4602HV

RUN

SV

IN

COMP

PGOOD

PGND

PGOOD

R

49.9k

1%

SET

SGND

C1: TAIYO YUDEN, GMK316BJ106ML

C3: TAIYO YUDEN, JMK316BJ226ML-T501

C4: SANYO POS CAP, 4TPE330MI

4602HV 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

10A Basic 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, Fast Transient Response

LTM4603

6A DC/DC µModule with PLL and Output Tracking/

Margining and Remote Sensing

Synchronizable, PolyPhase Operation, LTM4603-1 Version has no Remote

Sensing, Fast Transient Response

Polyphase is a registered trademark of Linear Technology Corporation.

®

This product contains technology licensed from Silicon Semiconductor Corporation.

4602hvf

LT 0107 • PRINTED IN USA

24 ^{LinearTechnology Corporation}

1630 McCarthy Blvd., Milpitas, CA 95035-7417

●

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


型号：	LTM4602HVV
厂家：	Linear
描述：	6A, 28VIN High Effi ciency DC/DC μModule 6A ， 28VIN高艾菲效率DC / DC微型模块
文件：	总24页 (文件大小：325K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LTM4602HVV [Linear]

相关型号：

LTM4602IV-PBF

LTM4602V

LTM4603

LTM4603-1

LTM4603-1_15

LTM4603EV-1#PBF

LTM4603EV-1#TRPBF

LTM4603EV-1-PBF

LTM4603EV-PBF

LTM4603HV

LTM4603HV

LTM4603HVEV#PBF