LTM4604EV#PBF_技术文档

LTM4604

Low Voltage, 4A DC/DC

µModule Regulator

with Tracking

FeaTures

DescripTion

n

Complete Standalone Power Supply

The LTM^®4604 is a complete 4A switch mode step-down

µModule^®(micromodule) regulator. Included in the pack-

age are the switching controller, power FETs, inductor and

all support components. Operating over an input voltage

range of 2.375V to 5.5V, the LTM4604 supports an output

voltage range of 0.8V to 5V, set by a single resistor. This

high efﬁciency design delivers up to 4A continuous cur-

rent (5A peak). Only bulk input and output capacitors are

needed to complete the design.

n

Wide Input Voltage Range: 2.375V to 5.5V

n

4A DC, 5A Peak Output Current

n

0.8V to 5V Output

Output Voltage Tracking

n

2% Maximum Total DC Output Error

UltraFast^TMTransient Response

n

Current Mode Control

n

Current Foldback Protection, Parallel/Current Sharing

Small and Very Low Proﬁle Package:

15mm × 9mm × 2.32mm LGA

The low proﬁle package (2.32mm) enables utilization of

unused space on the bottom of PC boards for high density

point of load regulation. High switching frequency and

a current mode architecture enable a very fast transient

response to line and load changes without sacriﬁcing

stability. The device supports output voltage tracking for

supply rail sequencing.

applicaTions

n

Telecom and Networking Equipment

n

Servers, ATCA Cards

n

Industrial Equipment

Fault protection features include foldback current protec-

tion, thermal shutdown and a programmable soft-start

function. The LTM4604 is offered in a RoHS compliant

15mm × 9mm × 2.32mm LGA package.

L, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks

and LTpowerCAD, LTspice and UltraFast are trademarks of Linear Technology Corporation. All

other trademarks are the property of their respective owners.

Please refer to the LTM4604A for easier PC board layout

and assembly due to increased spacing between land

grid pads.

Typical applicaTion

Efﬁciency vs Output Current

3.3V to 2.5V/4A µModule Regulator

100

V

IN

V

= 3.3V

IN

OUT

3.3V

= 2.5V

95

90

10µF

6.3V

V

IN

V

2.5V

4A

OUT

85

80

75

PGOOD

LTM4604

COMP

V

OUT

FB

22µF

6.3V

V

IN

RUN/SS TRACK

GND

×2

2.37k

70

65

4604 TA01a

1

2

4

0

3

OUTPUT CURRENT (A)

4604 G02

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LTM4604

absoluTe MaxiMuM raTings

pin conFiguraTion

(Note 1)

TOP VIEW

V , PGOOD ................................................. –0.3V to 6V

IN

TRACK

PGOOD

A

B

C

D

E

F

G

COMP, RUN/SS, FB, TRACK........................ –0.3V to V

IN

V

IN

SW, V

...................................... –0.3V to (V + 0.3V)

OUT

IN

COMP

FB

1

2

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

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

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

Reﬂow (Peak Body) Temperature.......................... 245°C

RUN/

SS

SW

3

GND

4

5

6

7

8

9

10

11

GND

V

OUT

LGA PACKAGE

66-PIN (15mm × 9mm × 2.32mm)

For easier PC board layout and assembly due to in-

creased spacing between land grid pads, please refer

to the LTM4604A.

T

= 125°C, θ = 25°C/W, θ

= 7°C/W,

JMAX

JA

JC(BOT)

θ

= 50°C/W, WEIGHT = 1.0g

JC(TOP)

orDer inForMaTion

LEAD FREE FINISH

LTM4604EV#PBF

LTM4604IV#PBF

TRAY

PART MARKING*

LTM4604V

PACKAGE DESCRIPTION

TEMPERATURE RANGE (NOTE 2)

–40°C to 85°C

LTM4604EV#PBF

LTM4604IV#PBF

15mm × 9mm × 2.32mm LGA

LTM4604V

–40°C to 85°C

Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges. *The temperature grade is identiﬁed by a label on the shipping container.

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

This product is only offered in trays. For more information go to: http://www.linear.com/packaging/

elecTrical characTerisTics ^Thel denotes the speciﬁcations which apply over the full operating

temperature range (Note 2), otherwise speciﬁcations are at T_A= 25°C. V_IN= 5V unless otherwise noted. See Figure 15.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

l

V

Input DC Voltage

Output Voltage, Total Variation

with Line and Load

2.375

5.5

V

IN(DC)

C

= 10µF, C

IN

= 22µF ×3, R = 5.69k (Note 3)

OUT(DC)

IN

V

OUT FB

= 2.375V to 5.5V, I

1.478

1.470

1.5

1.522

V

= 0A to 4A, 0°C ≤ T ≤ 85°C

OUT

A

l

= 0A to 4A

Input Speciﬁcations

V

Undervoltage Lockout

Threshold

Peak Input Inrush Current at

Start-Up

I

= 0A

1.75

2

2.3

V

IN(UVLO)

OUT

I

= 0A, C = 10µF, C

= 22µF ×3,

INRUSH(VIN)

OUT

IN

OUT

RUN/SS = 0.01µF, V

= 1.5V

OUT

0.7

A

V

IN

V

IN

= 3.3V

= 5V

I

Input Supply Bias Current

V

= 3.3V, No Switching

60

28

100

35

7

µA

mA

µA

mA

µA

Q(VIN NOLOAD)

IN

V

= 3.3V, V

= 1.5V, Switching Continuous

OUT

= 5V, No Switching

= 5V, V

= 1.5V, Switching Continuous

OUT

Shutdown, RUN = 0, V = 5V

IN

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LTM4604

elecTrical characTerisTics ^Thel denotes the speciﬁcations which apply over the full operating

temperature range (Note 2), otherwise speciﬁcations are at T_A= 25°C. V_IN= 5V unless otherwise noted. See Figure 15.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

I

Input Supply Current

V

IN

V

IN

V

IN

= 2.5V, V

= 3.3V, V

= 1.5V, I

= 4A

2.9

2.2

1.45

A

S(VIN)

OUT

= 5V, V

= 1.5V, I

= 4A

OUT

Output Speciﬁcations

I

Output Continuous Current

Range

Line Regulation Accuracy

V

= 3.3V, V = 1.5V (Note 3)

OUT

4

A

OUT(DC)

IN

l

= 1.5V, V from 2.375V to 5.5V, I

= 0A

0.1

0.2

%

ΔV

OUT

IN

OUT

OUT(LINE)

V

OUT

Load Regulation Accuracy

V

= 1.5V, 0A to 4A (Note 3)

= 3.3V

= 5V

ΔV

OUT

OUT(LOAD)

l

V

IN

V

IN

0.3

0.6

%

V

OUT

V

Output Ripple Voltage

I

= 0A, C

= 22µF X5R Ceramic ×3

OUT(AC)

OUT

= 3.3V, V

= 5V, V

10

12

1.25

mV

V

= 1.5V

OUT

P-P

IN

mV

V

= 1.5V

OUT

f

S

Output Ripple Voltage

Frequency

= 4A, V = 5V, V = 1.5V

OUT

MHz

OUT

IN

Turn-On Overshoot

ΔV

C

= 22µF ×3, V

= 0A

= 1.5V, RUN/SS = 10nF,

OUT(START)

OUT

IN

OUT

I

20

mV

V

= 3.3V

= 5V

t

Turn-on Time

C

= 22µF ×3, V

= 1.5V, I

= 1A Resistive Load,

OUT

START

OUT

TRACK = V and RUN/SS = Float

IN

= 3.3V

= 5V

1.5

1.0

ms

V

IN

Peak Deviation for Dynamic

Load Step

Load: 0% to 50% to 0% of Full Load,

= 22µF ×3 Ceramic

IN

ΔV

OUT(LS)

C

OUT

V

= 5V, V

= 1.5V

OUT

25

10

mV

µs

t

I

Settling Time for Dynamic

Load Step

Load: 0% to 50% to 0% of Full Load

= 5V, V = 1.5V

SETTLE

OUT(PK)

V

IN

OUT

Output Current Limit

Voltage at FB Pin

C

= 22µF ×3

OUT

8

A

V

= 3.3V, V

= 1.5V

IN

OUT

= 5V, V

= 1.5V

OUT

Control Section

V

FB

I

= 0A, V

= 1.5V, 0°C ≤ T ≤ 85°C

0.792

0.788

0.8

0.808

0.812

V

OUT

A

l

= 1.5V

I

V

I

V

0.2

0.65

0.2

µA

V

µA

mV

V

FB

RUN/SS Pin On/Off Threshold

TRACK Pin Current

Offset Voltage

0.5

0.8

RUN/SS

TRACK

TRACK = 0.4V

30

TRACK(OFFSET)

TRACK(RANGE)

Tracking Input Range

0

0.8

R

Resistor Between V

and

OUT

4.965

4.99

5.015

kΩ

FBHI

FB Pins

PGOOD

PGOOD Range

PGOOD Resistance

7.5

90

%

Ω

ΔV

PGOOD

R

Open-Drain Pull-Down

150

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.

with statistical process controls. The LTM4604I is guaranteed over the full

–40°C to 85°C operating temperature range.

Note 3: See output current derating curves for different V , V

and T .

A

IN OUT

Note 2: The LTM4604E 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

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LTM4604

Typical perForMance characTerisTics

Efﬁciency vs Output Current

V_IN= 2.5V

Efﬁciency vs Output Current

V_IN= 3.3V

Efﬁciency vs Output Current

V_IN= 5V

100

95

90

100

95

90

85

80

85

80

75

70

65

85

80

75

V

= 3.3V

= 2.5V

= 1.8V

= 1.5V

= 1.2V

= 0.8V

OUT

75

70

65

V

= 2.5V

= 1.8V

= 1.5V

= 1.2V

= 0.8V

OUT

V

= 1.8V

= 1.5V

= 1.2V

= 0.8V

V

OUT

V

70

65

V

OUT

1

2

4

0

3

0

1

2

3

4

1

2

4

0

3

OUTPUT CURRENT (A)

4604 G01

4604 G03

4604 G02

Minimum Input Voltage

at 4A Load

Load Transient Response

3.5

3.0

V

= 3.3V

= 2.5V

= 1.8V

= 1.5V

= 1.2V

= 0.8V

OUT

I

LOAD

2.5

LOAD

2A/DIV

V

2.0

1.5

1.0

0.5

OUT

V

OUT

20mV/DIV

4604 G06

V

C

= 5V

20µs/DIV

IN

4604 G05

V

C

= 5V

20µs/DIV

IN

= 1.5V

OUT

= 1.2V

OUT

= 4 × 22µF, 6.3V CERAMICS

= 0A to 2A

= 4 × 22µF, 6.3V CERAMICS

= 0A to 2A

I

0

1.5

2.5

2

3

3.5

4 4.5

5 5.5

0.5

1

V

(V)

IN

4604 G04

Load Transient Response

I

LOAD

2A/DIV

I

LOAD

2A/DIV

V

OUT

V

OUT

20mV/DIV

OUT

20mV/DIV

4604 G07

4604 G08

4604 G09

V

C

I

= 5V

20µs/DIV

V

C

I

= 5V

20µs/DIV

V

C

I

= 5V

20µs/DIV

IN

= 1.8V

= 2.5V

= 3.3V

OUT

= 3 × 22µF, 6.3V CERAMICS

= 0A to 2A

= 3 × 22µF, 6.3V CERAMICS

= 0A to 2A

= 2 × 22µF, 6.3V CERAMICS

= 0A to 2A

OUT

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LTM4604

Typical perForMance characTerisTics

Start-Up

V

IN

2V/DIV

I

IN

I

IN

1A/DIV

4604 G10

4604 G11

V

C

= 5V

200µs/DIV

V

C

= 5V

200µs/DIV

IN

= 2.5V

OUT

= 4 × 22µF

NO LOAD

4A LOAD

(0.01µF SOFT-START CAPACITOR)

V_FBvs Temperature

Current Limit Foldback

806

804

1.6

1.4

1.2

1.0

802

800

0.8

0.6

798

796

794

V

OUT

= 1.5V

0.4

0.2

0

V

= 5V

= 3.3V

= 2.5V

IN

4

5

7

3

8

-50

-25

0

25

50

75

100

6

TEMPERATURE (°C)

OUTPUT CURRENT (A)

4604 G13

4604 G12

Short-Circuit Protection

1.5V Short, No Load

Short-Circuit Protection

1.5V Short, 4A Load

V

OUT

0.5V/DIV

I

IN

I

IN

1A/DIV

4604 G15

4604 G14

100µs/DIV

20µs/DIV

V

IN

= 5V

V

IN

= 5V

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LTM4604

pin FuncTions

V

(B1, C1, C3-C7, D7, E6 and E7): Power Input Pins.

COMP(G1):CurrentControlThresholdandErrorAmpliﬁer

Compensation Point. The current comparator threshold

increases with this control voltage. Two power modules

can current share when this pin is connected in parallel

with the adjacent module’s COMP pin.

IN

Apply input voltage between these pins and GND pins.

Recommendplacinginputdecouplingcapacitancedirectly

between V pins and GND pins.

IN

V

OUT

(D8-D11, E8-E11, F6-F11, G6-G11): Power Output

Pins. Apply output load between these pins and GND

pins. Recommend placing output decoupling capacitance

directlybetweenthesepinsandGNDpins. ReviewTable 4.

PGOOD(F1):OutputVoltagePowerGoodIndicator. Open-

drain logic output that is pulled to ground when the output

voltage is not within 7.5% of the regulation point.

GND (G3-G5, F3-F5, E4-E5, A1-A11, B6-B11, C8-C11):

RUN/SS (D1): Run Control and Soft-Start Pin. A voltage

Power Ground Pins for Both Input and Output Returns.

above 0.8V will turn on the module, and below 0.5V will

turn off the module. This pin has a 1M resistor to V and

IN

TRACK(E1):OutputVoltageTrackingPin.Whenthemodule

is conﬁgured as a master output, then a soft-start capaci-

tor is placed on the RUN/SS pin to ground to control the

master ramp rate. Slave operation is performed by putting

a resistor divider from the master output to ground, and

connecting the center point of the divider to this pin on

the slave regulator. If tracking is not desired, then connect

a 1000pF capacitor to GND. The voltage on the RUN/SS

pin clamps the control loop’s current comparator thresh-

old. A RUN/SS pin voltage of 2.375V upon completion of

soft-start guarantees the regulator can deliver full output

current.ToturnoffthemodulewhileV remainsactive,the

IN

RUN/SS pin should be pulled low with a falling edge ≤ 1µs

toensurethedevicedoesnottransitionslowlythroughthe

internal undervoltage lockout threshold. See Applications

Information section for soft-start information.

the TRACK pin to V . Load current must be present for

IN

tracking. See Applications Information section.

FB(G2):TheNegativeInputoftheErrorAmpliﬁer.Internally,

SW (B3 and B4): Switching Node of the circuit is used for

testing purposes. This can be connected to copper on the

board to improve thermal performance. Make sure not to

connect it to other output pins.

this pin is connected to V

with a 4.99k precision resis-

OUT

tor. Different output voltages can be programmed with an

externally connected resistor between FB and GND pins.

Two power modules can current share when this pin is

connected in parallel with the adjacent module’s FB pin.

See Applications Information section.

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LTM4604

block DiagraM

V

PGOOD

IN

V

IN

2.375V TO 5.5V

10µF

6.3V

×2

10µF

6.3V

R

SS

1M

RUN/SS

C

SS

C

SSEXT

1000pF

M1

M2

L

V

OUT

CONTROL,

DRIVE

4.99k

1.5V

4A

TRACK

COMP

TRACK

SUPPLY

22µF

6.3V

×3

R1

4.99k

0.5%

C2

470pF

10µF

6.3V

5.76k

INTERNAL

COMP

GND

4604 BD

FB

SW

R

FB

5.76k

Figure 1. Simpliﬁed LTM4604 Block Diagram

Decoupling reQuireMenTs _{T = 25°C. Use Figure 1 Conﬁguration.}

A

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

C

IN

External Input Capacitor Requirement

IN

I

= 4A

10

µF

OUT

(V = 2.375V to 5.5V, V

= 1.5V)

OUT

C

External Output Capacitor Requirement

(V = 2.375V to 5.5V, V = 1.5V)

I

= 4A

66

µF

OUT

IN

OUT

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LTM4604

operaTion

Power Module Description

PGOOD output low if the output feedback voltage exits a

7.5% window around the regulation point. Furthermore,

in an overvoltage condition, internal top FET M1 is turned

off and bottom FET M2 is turned on and held on until the

overvoltage condition clears.

The LTM4604 is a standalone non-isolated switch mode

DC/DC power supply. It can deliver up to 4A of DC output

current with few external input and output capacitors.

This module provides a precise regulated output voltage

programmable via one external resistor from 0.8V DC to

5.0V DC over a 2.375V to 5.5V input voltage. A typical

application schematic is shown in Figure 15.

Pulling the RUN/SS pin below 0.5V forces the controller

into its shutdown state, turning off both M1 and M2. At

low load current, the module works in continuous current

modebydefaulttoachieveminimumoutputvoltageripple.

The LTM4604 has an integrated constant frequency cur-

rent mode regulator with built-in power MOSFETs with

fast switching speed. The typical switching frequency is

1.25MHz.Withcurrentmodecontrolandinternalfeedback

loop compensation, the LTM4604 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.

The TRACK pin is used for power supply tracking. See the

Applications Information section.

The LTM4604 is internally compensated to be stable over

a wide operating range. Table 4 provides a guideline for

input and output capacitance for several operating con-

ditions. The LTpowerCAD™ GUI is available for transient

and stability analysis.

Currentmodecontrolprovidescycle-by-cyclefastcurrent

limit. In addition, foldback current limiting is provided in

The FB pin is used to program the output voltage with a

single external resistor connected to ground.

an overcurrent condition while V

drops. Internal over-

OUT

voltageandundervoltagecomparatorspulltheopen-drain

4604fb

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LTM4604

applicaTions inForMaTion

Without considering the inductor current ripple, the RMS

current of the input capacitor can be estimated as:

AtypicalLTM4604applicationcircuitisshowninFigure 15.

External component selection is primarily determined by

the maximum load current and output voltage. Refer to

Table 4 for speciﬁc external capacitor requirements for a

particular application.

I_OUT(MAX)

I_CIN(RMS)

=

• D• 1–D

(

)

h%

In the above equation, η% is the estimated efﬁciency of

the power module. The bulk capacitor can be a switcher-

ratedaluminumelectrolyticcapacitor, OS-CONorpolymer

capacitor. If a low inductance plane is used to power the

device, then no input capacitance is required. The two

internal 10µF ceramics are typically rated for 2A to 3A of

RMS ripple current. The worst-case ripple current for the

4A maximum current is 2A or less.

V to V

Step-Down Ratios

IN

OUT

There are restrictions in the maximum V and V

step-

IN

OUT

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

The LTM4604 is 100% duty cycle capable, but the V to

IN

V

OUT

minimum dropout is a function of the load current.

A typical 0.5V minimum is sufﬁcient (see Typical Perfor-

mance Characteristics).

Output Voltage Programming

Output Capacitors

ThePWMcontrollerhasaninternal0.8Vreferencevoltage.

As shown in the Block Diagram, a 4.99k, 0.5% internal

The LTM4604 is designed for low output voltage ripple.

The bulk output capacitors deﬁned as C

are chosen

OUT

feedback resistor connects the V

and FB pins together.

OUT

with low enough effective series resistance (ESR) to meet

theoutputvoltagerippleandtransientrequirements. C

The output voltage will default to 0.8V with no externally

OUT

applied feedback resistor. Adding a resistor R from the

FB

can be a low ESR tantalum capacitor, a low ESR polymer

capacitor or an X5R/X7R ceramic capacitor. The typical

output capacitance range is 22µF to 100µF. Additional

output ﬁltering may be required by the system designer

if further reduction of output ripple or dynamic transient

spikes is required. Table 4 shows a matrix of different

output voltages and output capacitors to minimize the

voltage droop and overshoot during a 2A/µs transient.

The table optimizes the total equivalent ESR and total

bulk capacitance to maximize transient performance. The

LTpowerCAD GUI is available for further optimization.

FB pin to GND programs the output voltage:

4.99k +R_FB

V_OUT= 0.8V •

R_FB

Table 1. FB Resistor vs Output Voltage

V

0.8V

1.0V

20k

1.2V

10k

1.5V

1.8V

2.5V

3.3V

OUT

R

Open

5.76k

4.02k

2.37k

1.62k

FB

Input Capacitors

The LTM4604 module should be connected to a low ac-

impedance DC source. Two 10µF ceramic capacitors are

included inside the module. Additional input capacitors

are only needed if a large load step is required up to a

full 4A level. An input 47µF bulk capacitor is only needed

if the input source impedance is compromised by long

inductive leads or traces.

Fault Conditions: Current Limit and Overcurrent

Foldback

The LTM4604 has current mode control, which inher-

ently limits the cycle-by-cycle inductor current not only

in steady-state operation, but also in transient.

To further limit current in the event of an overload condi-

tion, the LTM4604 provides foldback current limiting as

the output voltage falls. The LTM4604 device has over-

temperature shutdown protection that inhibits switching

operation around 150°C.

For a buck converter, the switching duty cycle can be

estimated as:

V_OUT

D =

V

IN

4604fb

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LTM4604

applicaTions inForMaTion

Run Enable and Soft-Start

V

IN

5V

The RUN/SS pin provides dual functions of enable and

soft-start control. The RUN/SS pin is used to control

turn on of the LTM4604. While this pin is below 0.5V, the

LTM4604 will be in a 7µA low quiescent current state. A

0.8V threshold will enable the LTM4604. This pin can be

used to sequence LTM4604 devices. The voltage on the

RUN/SS pin clamps the control loop’s current comparator

threshold.ARUN/SSpinvoltageof2.375Vuponcompletion

ofsoft-startguaranteestheregulatorcandeliverfulloutput

current. The soft-start control is provided by a 1M pull-up

C

10µF

6.3V

IN1

X5R OR X7R

V

IN

V

3.3V

4A

MASTER

PGOOD

LTM4604

COMP

V

OUT

C

OUT1

22µF

FB

6.3V ×3

X5R OR

X7R

RAMP

RUN/SS TRACK

GND

CONTROL

R

FB3

OR V

C

IN

1.62k

SSEXT

resistor (R ) and a 1000pF capacitor (C ) as shown in

SS

V

IN

the Block Diagram. An external capacitor can be applied

to the RUN/SS pin to increase the soft-start time. A typical

value is 0.01µF. Soft-start time is approximately given by:

5V

C

10µF

6.3V

IN2

X5R OR X7R





V

IN

V

IN

V

1.5V

4A

t_SOFTSTART= ln

•R_SSC +C

(

)

SLAVE

SS

SSEXT









PGOOD

LTM4604

COMP

V

V – 1.8V

OUT

FB

IN

C

OUT2

22µF

where R and C are shown in the Block Diagram of

6.3V ×3

X5R OR

X7R

SS

RUN/SS TRACK

GND

Figure 1, 1.8V is the soft-start upper range, and C

is

R

FB

SSEXT

R

FB2

5.76k

theadditionalcapacitanceforfurthersoft-startcontrol.The

soft-start function can also be used to control the output

ramp-up time, so that another regulator can be easily

tracked.Anindependentrampcontrolsignalcanbeapplied

to the master ramp, otherwise, connect the TRACK pin to

R

FB1

4.99k

4604 F02

Figure 2. Dual Outputs (3.3V and 1.5V) with Tracking

V to disable tracking. To turn off the module while V

IN

remains active, the RUN/SS pin should be pulled low with

afallingedge≤1µstoensurethedevicedoesnottransition

slowlythroughtheinternalundervoltagelockoutthreshold.

MASTER OUTPUT

SLAVE OUTPUT

Output Voltage Tracking

Output voltage tracking can be programmed externally

using the TRACK pin. The output can be tracked up and

downwithanotherregulator.Themasterregulator’soutput

is divided down with an external resistor divider that is the

sameastheslaveregulator’sfeedbackdividertoimplement

coincident tracking. The LTM4604 uses a very accurate

4.99k resistor for the top feedback resistor. Figures 2 and

3 show an example of coincident tracking.

TIME

4604 F03

Figure 3. Output Voltage Coincident Tracking

R_FB2

4.99k +R_FB2

V_TRACK

=

• V_MASTER

4604fb

10

For more information www.linear.com/LTM4604

LTM4604

applicaTions inForMaTion

V

is the track ramp applied to the slave’s TRACK pin.

applies the track reference for the slave output up

Parallel Operation

TRACK

The LTM4604 device is an inherently current mode con-

trolled device. Parallel modules will have very good cur-

rent sharing. This will balance the thermals on the design.

Figure 16 shows a schematic of the parallel design. The

voltage feedback changes with the variable N as more

modules are paralleled. The equation:

to the point of the programmed value at which V

proceeds beyond the 0.8V reference value. The V

pin must go beyond 0.8V to ensure the slave output has

reached its ﬁnal value. Load current must be present for

proper tracking.

TRACK

Ratiometric modes of tracking can be achieved by select-

ing different resistor values to change the output tracking

ratio. The master output must be greater than the slave

output for ratiometric tracking to work. LTspice™ can be

usedtoimplementdifferenttrackingscenarios.TheMaster

and Slave data inputs can be used to implement the cor-

rect resistor values for coincident or ratiometric tracking.

The master and slave regulators require load current for

tracking down.

4.99k

+R_FB

N

V_OUT= 0.8V •

R_FB

N is the number of paralleled modules.

Thermal Considerations and Output Current Derating

The power loss curves in Figures 4 and 5 can be used in

coordination with the load derating curves in Figures 6

Power Good

through 13 for calculating an approximate θ for the

JA

module with and without heat sinking methods with vari-

ous airﬂow conditions. Thermal models are derived from

several temperature measurements at the bench, and are

correlated with thermal analysis software. Tables 2 and 3

The PGOOD pin is an open-drain pin that can be used to

monitor valid output voltage regulation. This pin monitors

a 7.5% window around the regulation point.

provide a summary of the equivalent θ for the noted

JA

COMP Pin

conditions.Theseequivalentθ parametersarecorrelated

JA

The COMP pin is the external compensation pin. The

LTM4604 has already been internally compensated for all

output voltages. Table 4 is provided for most application

requirements. The LTpowerCAD GUI is available for other

control loop optimizations.

to the measured values and improve with air ﬂow. The

maximum junction temperature is monitored while the

derating curves are derived.

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

5V TO 2.5V

POWER LOSS

0.4

3.3V TO 2.5V

POWER LOSS

0.2

0

5V TO 1.2V

POWER LOSS

0.4

3.3V TO 1.2V

POWER LOSS

0.2

0

2

3

4

5

1

LOAD CURRENT (A)

0

3

4

5

1

2

4604 F05

LOAD CURRENT (A)

4604 F04

Figure 5. 2.5V Power Loss

Figure 4. 1.2V Power Loss

4604fb

11

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LTM4604

applicaTions inForMaTion

4.0

3.5

3.0

2.5

2.0

1.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

1.0

0LFM

200LFM

400LFM

0.5

200LFM

400LFM

0

90 95

70 75 80 85

100 105 110 115

90 95

70 75 80 85

100 105 110 115

AMBIENT TEMPERATURE (°C)

4606 F06

4606 F07

Figure 6. 5V_INto 1.2V_OUTNo Heat Sink

Figure 7. 5V_INto 1.2V_OUTwith Heat Sink

4.0

3.5

3.0

2.5

2.0

1.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0LFM

0.5

200LFM

400LFM

0

90 95

100 105 110 115

90 95

70 75 80 85

100 105 110 115

AMBIENT TEMPERATURE (°C)

4606 F09

4606 F08

Figure 8. 3.3V_INto 1.2V_OUTNo Heat Sink

Figure 9. 3.3V_INto 1.2V_OUTwith Heat Sink

4.0

3.5

3.0

2.5

2.0

1.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0LFM

0.5

200LFM

400LFM

0

90 95

70 75 80 85

100 105 110

90 95

70 75 80 85

100 105 110 115

AMBIENT TEMPERATURE (°C)

4606 F10

4606 F11

Figure 10. 5V_INto 2.5V_OUTNo Heat Sink

Figure 11. 5V_INto 2.5V_OUTwith Heat Sink

4604fb

12

For more information www.linear.com/LTM4604

LTM4604

applicaTions inForMaTion

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0LFM

200LFM

400LFM

0LFM

0.5

200LFM

400LFM

0

90 95

100 105 110 115

90 95

70 75 80 85

100 105 110 115

AMBIENT TEMPERATURE (°C)

4606 F13

4606 F12

Figure 12. 3.3V_INto 2.5V_OUTNo Heat Sink

Figure 13. 3.3V_INto 2.5V_OUTwith Heat Sink

4604fb

13

For more information www.linear.com/LTM4604

LTM4604

applicaTions inForMaTion

Table 2. 1.2V Output

DERATING CURVE

Figures 6, 8

Figures 7, 9

V

(V)

POWER LOSS CURVE

Figure 4

AIR FLOW (LFM)

HEAT SINK

None

θ

JA

(°C/W)

IN

3.3, 5

0

25

Figure 4

200

400

0

None

22.5

21

Figure 4

None

Figure 4

BGA Heat Sink

21

Figure 4

200

400

20

Figure 4

18

Table 3. 2.5V Output

DERATING CURVE

Figures 10, 12

V

(V)

POWER LOSS CURVE

Figure 5

AIR FLOW (LFM)

HEAT SINK

None

θ

(°C/W)

IN

JA

3.3, 5

0

25

21

18

16

Figures 10, 12

Figure 5

200

400

0

None

Figures 10, 12

Figure 5

None

Figures 11, 13

Figure 5

BGA Heat Sink

Figures 11, 13

Figure 5

200

400

Figures 11, 13

Figure 5

Table 4. Output Voltage Response Versus Component Matrix (Refer to Figure 17), 0A to 2A Load Step Typical Measured Values

C

DROOP

(mV)

PEAK-TO- RECOVERY LOAD STEP

R

FB

IN

OUT

(CERAMIC)

V

(V) (CERAMIC)

C

(Bulk)

C

V (V)

IN

PEAK(mV)

(µs)

10

12

15

(A/µs)

(kΩ)

OUT

IN

COMP

1.2

10µF

56µF Aluminum 100µF 6.3V

None

2.5

21

23

24

19

21

25

30

22

25

22

25

43

2

10

56µF Aluminum

3.3

5

45

10

22µF ×4

1.2

1.5

1.8

2.5

3.3

46

10

56µF Aluminum 100µF 6.3V

2.5

3.3

5

41

5.76

4.02

2.37

1.62

56µF Aluminum

43

22µF ×4

43

56µF Aluminum 100µF 6.3V

2.5

3.3

5

50

56µF Aluminum

60

22µF ×3

60

56µF Aluminum 100µF 6.3V

2.5

3.3

5

45

56µF Aluminum

55

22µF ×3

55

56µF Aluminum 100µF 6.3V

2.5

3.3

5

50

56µF Aluminum

56

22µF ×3

56

4604fb

14

For more information www.linear.com/LTM4604

LTM4604

applicaTions inForMaTion

Safety Considerations

•ꢀDoꢀnotꢀputꢀviasꢀdirectlyꢀonꢀtheꢀpadsꢀunlessꢀtheyꢀareꢀ

capped.

TheLTM4604µModuleregulatordoesnotprovidegalvanic

isolation from V to V . There is no internal fuse. If re-

•ꢀSWꢀpadsꢀcanꢀbeꢀsolderedꢀtoꢀboardꢀtoꢀimproveꢀthermalꢀ

performance.

IN

OUT

quired, a slow blow fuse with a rating twice the maximum

input current needs to be provided to protect each unit

from catastrophic failure.

Figure 14 gives a good example of the recommended

layout. For easier PC board layout and assembly due

to increased spacing between land grid pads, please

refer to the LTM4604A.

Layout Checklist/Example

The high integration of LTM4604 makes the PCB board

layoutverysimpleandeasy.However,tooptimizeitselectri-

cal and thermal performance, some layout considerations

are still necessary.

GND

V

OUT

C

OUT

•ꢀUseꢀ largeꢀ PCBꢀ copperꢀ areasꢀ forꢀ highꢀ currentꢀ path,ꢀ

including V , GND and V . It helps to minimize the

IN

OUT

PCB conduction loss and thermal stress.

•

•ꢀPlaceꢀhighꢀfrequencyꢀceramicꢀinputꢀandꢀoutputꢀcapacitorsꢀ

•

next to the V , GND and V

pins to minimize high

IN

OUT

•

frequency noise.

•

• •

•

V

IN

•

•ꢀPlaceꢀaꢀdedicatedꢀpowerꢀgroundꢀlayerꢀunderneathꢀtheꢀ

unit.

• •

•

SW

•

•ꢀToꢀminimizeꢀtheꢀviaꢀconductionꢀlossꢀandꢀreduceꢀmoduleꢀ

thermal stress, use multiple vias for interconnection

between top layer and other power layers.

•

C

IN

GND

•

4604 F14

Figure 14. Recommended PCB Layout

V

IN

2.375V TO 5.5V

C

IN

10µF

6.3V

X5R OR X7R

V

IN

V

1.5V

4A

OUT

OPEN-DRAIN

PGOOD

LTM4604

COMP

V

OUT

FB

PULL UP

C

OUT

22µF ×3

6.3V

X5R OR X7R

REFER TO

TABLE 4

RUN/SS TRACK

GND

R

5.69k

0.5%

FB

C

SSEXT

0.01µF

4604 F15

Figure 15. Typical 2.375V to 5.5V Input, 1.5V at 4A Design

4604fb

15

For more information www.linear.com/LTM4604

LTM4604

Typical applicaTions

V

IN

2.375V TO 5V

C

10µF

6.3V

IN1

X5R OR X7R

V

= 0.8V × ((4.99k/N) + R )/R

FB FB

OUT

WHERE N IS THE NUMBER OF PARALLEL DEVICES

V

IN

OPEN-DRAIN PULL UP

PGOOD

LTM4604

COMP

V

OUT

FB

C

OUT1

22µF ×3

6.3V

X5R OR X7R

REFER TO

TABLE 4

RUN/SS TRACK

GND

R

FB

C

SSEXT

2.87k

0.01µF

V

1.5V

8A

OUT

C

10µF

6.3V

IN2

X5R OR X7R

V

IN

PGOOD

LTM4604

COMP

V

OUT

FB

C

OUT2

22µF ×3

6.3V

X5R OR X7R

REFER TO

TABLE 4

RUN/SS TRACK

GND

4604 F16

Figure 16. Two LTM4604s in Parallel, 1.5V at 8A Design.

Also See the 8A LTM4608A or Dual 4A per Channel LTM4614

V

IN

3.3V TO 5V

C

10µF

6.3V

IN

50k

X5R OR X7R

V

IN

V

2.5V

4A

OUT

OPEN-DRAIN

PULL UP

PGOOD

LTM4604

COMP

V

OUT

FB

C

OUT

22µF ×3

6.3V

X5R OR X7R

REFER TO

TABLE 4

RUN/SS TRACK

GND

R

FB

C

SSEXT

2.37k

0.01µF

4604 F17

Figure 17. 3.3V to 5V Input, 2.5V at 4A Design

4604fb

16

For more information www.linear.com/LTM4604

LTM4604

package DescripTion

Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.

Z

b b b

Z

6 . 3 5 0

5 . 0 8 0

3 . 8 1 0

2 . 5 4 0

1 . 2 7 0

0 . 4 4 4 5

0 . 0 0 0

0 . 4 4 4 5

1 . 2 7 0

2 . 5 4 0

3 . 8 1 0

5 . 0 8 0

6 . 3 5 0

a a a

Z

4604fb

17

For more information www.linear.com/LTM4604

LTM4604

package DescripTion

Pin Assignment Table

(Arranged by Pin Number)

PIN ID

A1

FUNCTION

GND

PIN ID

B1

FUNCTION

PIN ID

C1

FUNCTION

PIN ID

D1

FUNCTION

V

IN

RUN/SS

IN

–

A2

GND

B2

C2

D2

A3

GND

B3

SW

–

C3

V

IN

V

IN

V

IN

V

IN

V

IN

D3

A4

GND

B4

C4

D4

A5

GND

B5

C5

D5

A6

GND

B6

GND

C6

D6

A7

GND

B7

C7

D7

V

IN

A8

GND

B8

C8

GND

D8

V

OUT

A9

GND

B9

C9

D9

A10

A11

GND

B10

B11

C10

C11

D10

D11

GND

PIN ID

E1

FUNCTION

PIN ID

F1

FUNCTION

PGOOD

–

PIN ID

G1

FUNCTION

COMP

FB

TRACK

–

E2

F2

G2

E3

F3

GND

G3

GND

E4

GND

F4

G4

GND

E5

F5

G5

GND

E6

V

F6

V

G6

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

IN

OUT

E7

F7

G7

E8

V

OUT

V

OUT

V

OUT

V

OUT

F8

G8

E9

F9

G9

E10

E11

F10

F11

G10

G11

4604fb

18

For more information www.linear.com/LTM4604

LTM4604

revision hisTory

REV

DATE

DESCRIPTION

PAGE NUMBER

A

5/10

Updated Front Page Text

1

2

Updated Absolute Maximum Ratings and Pin Conﬁguration Section

Updated Callouts on Graphs

5

Added text to Layout Checklist/Example Section

Updated Figure 16 Title

15

2

B

5/14

Updated thermal resistance and weight

Updated Minimum Input Voltage graph

Added output current information to Load Transient Response curves

Updated RUN/SS Pin Description

4

6

Updated Run Enable and Soft-Start section

10

4604fb

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.

For more information www.linear.com/LTM4604

19

LTM4604

relaTeD parTs

PART NUMBER

DESCRIPTION

COMMENTS

LTC2900

Quad Supply Monitor with Adjustable Reset Timer

Power Supply Tracking Controller

10A DC/DC µModule Regulator

Monitors Four Supplies; Adjustable Reset Timer

Tracks Both Up and Down; Power Supply Sequencing

Basic 10A DC/DC µModule Regulator

LTC2923

LTM4600

LTM4601

12A DC/DC µModule Regulator with PLL, Output

Tracking/ Margining and Remote Sensing

Synchronizable, PolyPhase Operation, LTM4601-1 Version has no Remote

Sensing

LTM4602

LTM4603

6A DC/DC µModule Regulator

Pin Compatible with the LTM4600

6A DC/DC µModule Regulator with PLL and Output Synchronizable, PolyPhase Operation, LTM4603-1 Version has no Remote

Tracking/Margining and Remote Sensing

Sensing, Pin Compatible with the LTM4601

LTM4608A

8A Low Voltage µModule Regulator

2.375V ≤ V ≤ 5V, Parallel for Higher Output Current, 9mm × 15mm × 2.82mm

IN

4604fb

LT 0514 REV B • PRINTED IN USA

20 ^{LinearTechnology Corporation}

1630 McCarthy Blvd., Milpitas, CA 95035-7417

For more information www.linear.com/LTM4604

●

 LINEAR TECHNOLOGY CORPORATION 2007

(408)432-1900 FAX: (408) 434-0507 www.linear.com/LTM4604


型号：	LTM4604EV#PBF
厂家：	Linear
描述：	LTM4604 - Low Voltage, 4A DC/DC µModule (Power Module) Regulator with Tracking; Package: LGA; Pins: 66; Temperature Range: -40°C to 85°C 开关
文件：	总20页 (文件大小：606K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LTM4604EV#PBF [Linear]

相关型号：

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LTM4605EV#PBF

LTM4605EV-PBF

LTM4605IV#PBF

LTM4605IV-PBF

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LTM4606EV#PBF