LT1618EMS#TRPBF_技术文档

LT1618

Constant-Current/

Constant-Voltage 1.4MHz

Step-Up DC/DC Converter

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FEATURES

DESCRIPTIO

■

Accurate Input/Output Current Control: ±5% Over

The LT^®1618 step-up DC/DC converter combines a tradi-

tionalvoltagefeedbackloopandauniquecurrentfeedback

loop to operate as a constant-current, constant-voltage

source. Thisfixedfrequency, currentmodeswitcheroper-

ates from a wide input voltage range of 1.6V to 18V, and

thehighswitchingfrequencyof1.4MHzpermitstheuseof

tiny, low profile inductors and capacitors. The current

sensevoltageissetat50mVandcanbeadjustedusingthe

Temperature

■

Accurate Output Voltage Control: ±1%

■

Wide V_INRange: 1.6V to 18V

■

1.4MHz Switching Frequency

■

High Output Voltage: Up to 35V

■

Low V_CESATSwitch: 200mV at 1A

■

Available in (3mm × 3mm × 0.8mm) 10-Pin DFN and

I_ADJpin.

^{10-Pin MSOP Pa}U^ckages

Available in the 10-Pin (3mm × 3mm) Exposed Pad DFN

and 10-pin MSOP packages, the LT1618 provides a com-

plete solution for constant-current applications.

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

APPLICATIO S

■

LED Backlight Drivers

USB Powered Boost/SEPIC Converters

Input Current Limited Boost/SEPIC Converters

Battery Chargers

■

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TYPICAL APPLICATIO

USB to 12V Boost Converter

(with Selectable 100mA/500mA Input Current Limit)

L1

10µH

D1

0.1Ω

Efficiency Curve

V

IN

5V

V

OUT

12V

90

85

80

75

70

65

60

2

7

ISN

ISP

SW

C1

4.7µF

R1

3

909k

LT1618

1

8

9

C2

4.7µF

V

FB

IN

3.3V

ON

R2

107k

SHDN

OFF

0V

I

V

GND

5

ADJ

C

20k

4

10

2k

10nF

3.3V

500mA

100mA

0V

13k

100 160

120 140

0

80

20 40 60

LOAD CURRENT (mA)

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN EMK316BJ475

D1: ON SEMICONDUCTOR MBR0520

L1: SUMIDA CR43-100

1618 TA01a

1618 TA01b

sn1618 1618fas

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LT1618

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ABSOLUTE AXI U RATI GS ^{(Note 1)}

V_IN, SHDN Voltage ................................................... 18V

SW Voltage .............................................................. 36V

ISP, ISN Voltage ...................................................... 36V

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

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

Storage Temperature Range

MSOP ............................................... –65°C to 150°C

DFN ................................................. –65°C to 125°C

Lead Temperature (Soldering, 10 sec) (MSOP) .... 300°C

I

_ADJVoltage ............................................................... 6V

FB Voltage .............................................................. 1.5V

V_CVoltage .............................................................. 1.5V

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W

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PACKAGE/ORDER I FOR ATIO

TOP VIEW

ORDER PART

NUMBER

ORDER PART

NUMBER

TOP VIEW

FB

ISN

ISP

1

2

3

4

5

10

9

V

C

FB

ISN

ISP

ADJ

GND

1

2

3

4

5

10

9

V

C

SHDN

LT1618EDD

LT1618EMS

11

8

V

IN

8

V

SW

NC

IN

I

7

SW

I

7

6

ADJ

GND

6

DD PART

MARKING

MS PART

MARKING

MS PACKAGE

10-LEAD PLASTIC MSOP

DD PACKAGE

10-LEAD (3mm × 3mm) PLASTIC DFN

T_JMAX= 125°C, θ_JA= 160°C/W

T_JMAX= 125°C, θ_JA= 43°C/W, θ_JC= 3°C/W

LAFQ

LTNH

EXPOSED PAD (PIN 11) IS GND AND

MUST BE SOLDERED TO PCB

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

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating

temperature range, otherwise specifications are at T_A= 25°C. V_IN= 1.6V, V_SHDN= 1.6V, unless otherwise noted.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Voltage

1.6

18

V

Quiescent Current

V

SHDN

V

SHDN

= 1.6V, Not Switching

= 0V

1.8

0.1

2.7

1

mA

µA

Reference Voltage

Measured at FB Pin

1.250

1.243

1.263

1.276

1.283

V

●

Reference Voltage Line Regulation

FB Pin Bias Current

1.6V < V < 18V

0.01

±2

0.03

%/V

nA

IN

V

FB

= 1.263V, V = 1.8V

±12

IN

Error Amplifier Voltage Gain

180

160

15

V/V

µmho

µA

Error Amplifier Transconductance

Error Amplifier Sink Current

∆I = ± 5µA

C

V

FB

V

FB

V

FB

V

ISP

= 1.35V, V = 1V

C

Error Amplifier Source Current

Current Sense Voltage (ISP, ISN)

ISP, ISN Pin Bias Currents (Note 3)

(ISP, ISN) Common Mode Minimum Voltage

Switching Frequency

= 1.10V, V = 1V

30

µA

C

= 0V, V

= 0V

●

47.5

1.25

50

52.5

80

mV

µA

IADJ

= 1.85V, V = 1.80V, V

= 0V

IADJ

50

ISN

1.8

1.6

V

FB

V

FB

= 1V

= 0V

1.4

550

MHz

kHz

Maximum Switch Duty Cycle

Switch Current Limit

●

88

92

%

A

(Note 4)

1.5

2.1

2.8

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LT1618

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating

temperature range, otherwise specifications are at T_A= 25°C. V_IN= 1.6V, V_SHDN= 1.6V, unless otherwise noted.

PARAMETER

Switch V

CONDITIONS

= 1A (Note 4)

MIN

TYP

200

0.01

5

MAX

260

5

UNITS

mV

µA

I

CESAT

SW

Switch Leakage Current

Switch Off, V = 5V

SW

SHDN Pin Current

V

= 1.6V

20

µA

SHDN

Shutdown Threshold (SHDN Pin)

Start-Up Threshold (SHDN Pin)

0.3

V

1

V

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

temperature range are assured by design, characterization, and correlation

with statistical process controls.

Note 2: The LT1618 is guaranteed to meet performance specifications

from 0°C to 70°C. Specifications over the –40°C to 85°C operating

Note 3: Bias currents flow into the ISP and ISN pins.

Note 4: Switch current limit and switch V

for the DD package is

CESAT

guaranteed by design and/or correlation to static test.

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TYPICAL PERFOR A CE CHARACTERISTICS

Switch Saturation Voltage

(V_{CE, SAT}

)

FB Pin Voltage and Bias Current

Switch Current Limit

1.270

1.265

1.260

1.255

1.250

4

500

400

300

200

100

0

2.5

2.0

1.5

1.0

0.5

0

2

T = 125°C

VOLTAGE

CURRENT

J

T = 25°C

J

0

T = –50°C

–2

J

–4

–50 –25

25

50

75

125

0

100

–50 –25

25

50

75

125

1.0

1.5

0

100

0

0.5

2.0

TEMPERATURE (°C)

SWITCH CURRENT (A)

1618 G02

1618 G03

1618 G01

Current Sense Voltage

(I_ADJPin = 0V)

Current Sense Voltage

(V_{ISP, ISN}

Quiescent Current

)

2.5

2.0

1.5

1.0

0.5

0

52

51

50

49

48

60

50

40

30

20

10

0

V

= 18V

IN

V

= 1.6V

IN

–50 –25

25

50

75

125

0

100

–50 –25

25

50

75

125

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

PIN VOLTAGE (V)

0

100

TEMPERATURE (°C)

I

ADJ

1618 G06

1618 G04

1618 G05

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LT1618

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TYPICAL PERFOR A CE CHARACTERISTICS

Switching Frequency

Frequency Foldback

SHDN Pin Current

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

50

45

40

35

30

25

20

15

10

5

T = 25°C

J

T = –50°C

J

V

= 18V

IN

T = 25°C

J

V

= 1.6V

IN

T = 125°C

J

0

–50 –25

25

50

75

125

0.4

0.6

0.8

1.2

0

100

0

0.2

1.0

5

15

0

10

20

TEMPERATURE (°C)

FEEDBACK PIN VOLTAGE (V)

SHUTDOWN PIN VOLTAGE (V)

1618 G07

1618 G08

1618 G09

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PIN FUNCTIONS _(MS/DD)

FB (Pin 1/Pin 1): Feedback Pin. Set the output voltage by

selecting values for R1 and R2 (see Figure 1):

SW (NA/Pin 6): Switch Pin for DD Package. Connect this

pin to Pin 7.

SW (Pin 7/Pin 7): Switch Pin. This is the collector of the

internal NPN power switch. Minimize the metal trace area

connected to this pin to minimize EMI.

⎛

⎞

V_OUT

R1= R2

– 1

⎟

⎜

1.263V

⎝

⎠

V_IN(Pin 8/Pin 8): Input Supply Pin. Bypass this pin with

a capacitor to ground as close to the device as possible.

ISN (Pin 2/Pin 2): Current Sense (–) Pin. The inverting

input to the current sense amplifier.

SHDN (Pin 9/Pin 9): Shutdown Pin. Tie this pin higher

than 1V to turn on the LT1618; tie below 0.3V to turn it off.

ISP (Pin3/Pin3):CurrentSense(+)Pin. Thenoninverting

input to the current sense amplifier.

V_C(Pin 10/Pin 10): Compensation Pin for Error Amplifier.

ConnectaseriesRCfromthispintoground.Typicalvalues

are 2kΩ and 10nF.

I_ADJ(Pin 4/Pin 4): Current Sense Adjust Pin. A DC voltage

applied to this pin will reduce the current sense voltage. If

this adjustment is not needed, tie this pin to ground.

Exposed Pad (NA/Pin 11): The Exposed Pad on the DD

package is GND and must be soldered to the PCB GND for

optimum thermal performance.

GND(Pin5/Pin5):GroundPin. Tiethispindirectlytolocal

ground plane.

NC (Pin 6/NA): No Connection for MS Package.

sn1618 1618fas

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LT1618

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BLOCK DIAGRA

D1

R

L1

SENSE

V

OUT

IN

C1

C2

SHDN

V

SW

IN

9

7

8

Q1

DRIVER

ISP

ISN

+

–

+

–

3

2

4

A1

×25

0.02Ω

×5

I

ADJ

+

1.4MHz

OSCILLATOR

Σ

+

S

R

+

–

Q

R1

R2

A3

–

+

FB

1

A2

1.263V

5

10

V

GND

C

R

C

Figure 1. LT1618 Block Diagram

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OPERATIO

The LT1618 uses a constant frequency, current mode

control scheme to provide excellent line and load regula-

tion. Operation can be best understood by referring to the

Block Diagram in Figure 1. At the start of each oscillator

cycle, the SR latch is set, turning on power switch Q1. The

signal at the noninverting input of PWM comparator A3 is

a scaled-down version of the switch current (summed

together with a portion of the oscillator ramp). When this

signal reaches the level set by the output of error amplifier

A2, comparatorA3resetsthelatchandturnsoffthepower

switch. In this manner, A2 sets the correct peak current

leveltokeeptheoutputinregulation.Iftheerroramplifier’s

output increases, more current is delivered to the output;

if it decreases, less current is delivered. A2 has two

inverting inputs, one from the voltage feedback loop, and

one from the current feedback loop. Whichever inverting

input is higher takes precedence, forcing the converter

into either a constant-current or a constant-voltage mode.

The LT1618 is designed to transition cleanly between the

twomodesofoperation.CurrentsenseamplifierA1senses

the voltage between the ISP and ISN pins and provides a

25× level-shifted version to error amplifier A2. When the

voltage between ISP and ISN reaches 50mV, the output of

A1provides1.263VtooneofthenoninvertinginputsofA2

and the converter is in constant-current mode. If the

current sense voltage exceeds 50mV, the output of A1 will

increase causing the output of A2 to decrease, thus

reducing the amount of current delivered to the output. In

this manner the current sense voltage is regulated to

50mV. Similarly, if the FB pin increases above 1.263V, the

output of A2 will decrease to reduce the peak current level

and regulate the output (constant-voltage mode).

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LT1618

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APPLICATIONS INFORMATION

the same footprint device. Always use a capacitor with a

sufficient voltage rating.

Inductor Selection

SeveralinductorsthatworkwellwiththeLT1618arelisted

in Table 1, although there are many other manufacturers

and devices that can be used. Consult each manufacturer

for more detailed information and for their entire selection

of related parts. Many different sizes and shapes are

available. Ferrite core inductors should be used to obtain

the best efficiency, as core losses at 1.4MHz are much

lower for ferrite cores than for the cheaper powdered-iron

ones. Choose an inductor that can handle the necessary

peak current without saturating, and ensure that the

inductor has a low DCR (copper-wire resistance) to mini-

mize I²R power losses. A 4.7µH or 10µH inductor will be

a good choice for many LT1618 designs.

Ceramic capacitors also make a good choice for the input

decoupling capacitor, which should be placed as close as

possible to the V_INpin of the LT1618. A 1µF to 4.7µF input

capacitorissufficientformostapplications.Table2shows

a list of several ceramic capacitor manufacturers. Consult

the manufacturers for detailed information on their entire

selection of ceramic parts.

Table 2. Recommended Ceramic Capacitor Manufacturers

VENDOR

Taiyo Yuden

Murata

PHONE

URL

(408) 573-4150

(814) 237-1431

(408) 986-0424

www.t-yuden.com

www.murata.com

www.kemet.com

Kemet

Table 1. Recommended Inductors

L

(µH)

MAX

(mΩ)

HEIGHT

(mm)

Diode Selection

PART

VENDOR

CDRH5D18-4R1

CDRH5D18-100

CR43-2R2

CR43-4R7

CR43-100

4.1

10

2.2

4.7

10

57

124

71

109

182

100

2.0

3.5

4.8

Sumida

(847) 956-0666

www.sumida.com

Schottky diodes, with their low forward voltage drop and

fast switching speed, are the ideal choice for LT1618

applications. Table 3 shows several Schottky diodes that

work well with the LT1618. Many different manufacturers

make equivalent parts, but make sure that the component

chosen has a sufficient current rating and a voltage rating

greater than the output voltage. The diode conducts cur-

rent only when the power switch is turned off (typically

less than half the time), so a 0.5A or 1A diode will be

sufficient for most designs. The companies below also

offer Schottky diodes with higher voltage and current

ratings.

CR54-100

10

LQH3C1R0M24

LQH3C2R2M24

LQH3C4R7M24

1.0

2.2

4.7

78

126

260

2.0

Murata

(814) 237-1431

www.murata.com

Capacitor Selection

Low ESR (equivalent series resistance) capacitors should

beusedattheoutputtominimizetheoutputripplevoltage.

Multilayer ceramic capacitors are an excellent choice.

They have an extremely low ESR and are available in very

small packages. X5R and X7R dielectrics are preferred, as

these materials retain their capacitance over wider voltage

and temperature ranges than other dielectrics. A 4.7µF to

10µF output capacitor is sufficient for high output current

designs. Converters with lower output currents may need

only a 1µF or 2.2µF output capacitor. Solid tantalum or

OSCON capacitors can be used, but they will occupy more

board area than a ceramic and will have a higher ESR for

Table 3. Recommended Schottky Diodes

1A PART

0.5A PART

VENDOR

PHONE/URL

UPS120

UPS130

UPS140

Microsemi

(510) 353-0822

www.microsemi.com

MBRM120 MBR0520

MBRM130 MBR0530

MBRM140 MBR0540

ON Semiconductor (800) 282-9855

www.onsemi.com

B120

B130

B140

B0520

B0530

B0540

Diodes, Inc

(805) 446-4800

www.diodes.com

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LT1618

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APPLICATIONS INFORMATION

Setting Output Voltage

the output of the error amplifier (the V_Cpin) will be pulled

down and the LT1618 will stop switching.

To set the output voltage, select the values of R1 and R2

(see Figure 1) according to the following equation.

A pulse width modulated (PWM) signal can also be used

to adjust the current sense voltage; simply add an RC

filterto convert the PWM signal into a DC voltage for the

I_ADJpin. If the I_ADJpin is not used, it should be tied to

ground. Do not leave the pin floating.

⎛

⎞

V_OUT

1.263

R1= R2

– 1

⎟

⎜

⎝

⎠

For current source applications, use the FB pin for over-

voltage protection. Pick R1 and R2 so that the output

voltage will not go too high if the load is disconnected or

if the load current drops below the preset value. Typically

choose R1 and R2 so that the overvoltage value will be

about 20% to 30% higher than the normal output voltage

(when in constant-current mode). This prevents the volt-

age loop from interfering with the current loop in current

sourceapplications. Forbattery chargerapplications, pick

the values of R1 and R2 to give the desired end of charge

voltage.

For applications needing only a simple one-step current

sense adjustment, the circuit in Figure 2 works well. If a

largevalueresistor(≥2MΩ)isplacedbetweentheI_ADJpin

and ground, the current sense voltage will reduce to about

25mV, providing a 50% reduction in current. Do not leave

the I_ADJpin open. This method gives a well-regulated

current value in both states, and is controlled by a logic

signal without the need for a variable PWM or DC control

signal. When the NMOS transistor is on, the current sense

voltage will be 50mV, when it is off, the current sense

voltage will be reduced to 25mV.

Selecting R_SENSE/Current Sense Adjustment

LT1618

Use the following formula to choose the correct current

sense resistor value (for constant current operation).

I

ADJ

FULL

CURRENT

R_SENSE= 50mV/I_MAX

2M

1618 F02

For designs needing an adjustable current level, the I_ADJ

pin is provided. With the I_ADJpin tied to ground, the

nominal current sense voltage is 50mV (appearing be-

tween the ISP and ISN pins). Applying a positive DC

voltage to the I_ADJpin will decrease the current sense

voltage according to the following formula:

Figure 2

Considerations When Sensing Input Current

In addition to regulating the DC output current for current-

source applications, the constant-current loop of the

LT1618 can also be used to provide an accurate input

current limit. Boost converters cannot provide output

short-circuit protection, but the surge turn-on current can

be drastically reduced using the LT1618’s current sense

at the input. SEPICs, however, have an output that is DC-

isolated from the input, so an input current limit not only

helps soft-start the output but also provides excellent

short-circuit protection.

1.263V – (0.8)V

IADJ

V

=

ISENSE

25

For example, if 1V is applied to the I_ADJpin, the current

sense voltage will be reduced to about 18mV. This

adjustability allows the regulated current to be reduced

without changing the current sense resistor (e.g. to adjust

brightnessinanLEDdriverortoreducethechargecurrent

in a battery charger). If the I_ADJpin is taken above 1.6V,

sn1618 1618fas

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LT1618

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APPLICATIONS INFORMATION

When sensing input current, the sense resistor should be

placed in front of the inductor (between the decoupling

capacitor and the inductor) as shown in the circuits in the

TypicalApplicationssection. Thiswillregulatetheaverage

inductor current and maintain a consistent inductor ripple

current, which will, in turn, maintain a well regulated input

current. Do not place the sense resistor between the input

source and the input decoupling capacitor, as this may

allow the inductor ripple current to vary widely (even

though the average input current and the average inductor

current will still be regulated). Since the inductor current

is a triangular waveform (not a DC waveform like the

output current) some tweaking of the compensation

values(R_CandC_ContheV_Cpin)mayberequiredtoensure

a clean inductor ripple current while the constant-current

loop is in effect. For these applications, the constant-

current loop response can usually be improved by reduc-

ing the R_Cvalue, or by adding a capacitor (with a value of

approximately C_C/10) in parallel with the R_Cand C_C

compensation network.

loop transfer function of a switching regulator, so the V_C

pin pole and zero are positioned to provide the best loop

response. A thorough analysis of the switching regulator

control loop is not within the scope of this data sheet, and

will not be presented here, but values of 2kΩ and 10nF will

be a good choice for many designs. For those wishing to

optimize the compensation, use the 2kΩ and 10nF as a

starting point. For LED backlight applications where a

pulse-width modulation (PWM) signal is used to drive

the I_ADJpin, the resistor is usually not included in the

compensation network. This helps to provide additional

filtering of the PWM signal at the output of the error

amplifier (the V_Cpin).

Switch Node Considerations

Tomaximizeefficiency, switchriseandfalltimesaremade

as short as possible. To prevent radiation and high fre-

quency resonance problems, proper layout of the high

frequency switching path is essential. Keep the output

switch (SW pin), diode and output capacitor as close

together as possible. Minimize the length and area of all

traces connected to the switch pin, and always use a

ground plane under the switching regulator to minimize

interplane coupling. The high speed switching current

path is shown in Figure 3. The signal path including the

switch, output diode and output capacitor contains nano-

second rise and fall times and should be kept as short as

possible.

Frequency Compensation

TheLT1618hasanexternalcompensationpin(V_C), which

allows the loop response to be optimized for each applica-

tion. An external resistor and capacitor (or sometimes just

a capacitor) are placed at the V_Cpin to provide a pole and

azero(orjustapole)toensureproperloopcompensation.

Numerousotherpolesandzeroesarepresentintheclosed

SWITCH

NODE

L1

V

OUT

HIGH

FREQUENCY

CIRCULATING

PATH

V

IN

LOAD

1618 • F03

Figure 3

sn1618 1618fas

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LT1618

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TYPICAL APPLICATIO S

4.5W Direct Broadcast Satellite (DBS) Power Supply with Short-Circuit Protection

C2

1µF

L1

33µH

L3

2.2µH

D1

0.068Ω

V

IN

12V

R3

10k

D2

2

7

L2

33µH

MURS110

Q1

FMMT717

ZETEX

ISN

ISP

SW

R1

100k

3

13.5V/18.5V

LT1618

1

8

9

C3

3.3µF

C4

3.3µF

V

IN

FB

22kHz

NETWORK

TUNING

R5

24.9k

R2

10k

SHDN

Q1

MMBT3904

ADD 5V

3.3V

I

V

GND

5

ADJ

C

4

10

RHCP

LHCP

C1

4.7µF

R

C

R4

1k

0V

2k

C

33nF

1618 TA02a

C1: TAIYO YUDEN EMK316BJ475

C2: TAIYO YUDEN TMK316BJ105

(408) 573-4150

(800) 282-9855

(847) 956-0666

C3, C4: TAIYO YUDEN TMK325BJ335

D1: ON SEMICONDUCTOR MBRM140

L1, L2: SUMIDA CR54-330

L3: SUMIDA CR43-2R2

Efficiency

80

75

70

65

60

0

50

100

150

200

250

300

LOAD CURRENT (mA)

1618 TA02b

sn1618 1618fas

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LT1618

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TYPICAL APPLICATIONS

2-Cell White LED Driver

L1

4.7µH

20mA

D1

2.49Ω

V

IN

1.6V TO 3V

C1

8

7

4.7µF

V

SW

IN

9

4

3

2

SHDN

ISP

ISN

10kHz TO 50kHz

PWM

BRIGHTNESS

ADJUST

R3

R1

LT1618

5.1k

2M

1

I

ADJ

FB

V

C

GND

5

10

C3

0.1µF

C2

1µF

R2

160k

C

0.1µF

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN EMK316BJ105

D1: ON SEMICONDUCTOR MBR0520

L1: SUMIDA CLQ4D10-4R7

(408) 573-4150

(800) 282-9855

(847) 956-0666

1618 • TA03

2-Cell Luxeon LED Driver

L1

10µH

350mA

D1

0.15Ω

V

IN

1.8V TO 3V

8

7

V

SW

IN

9

4

3

2

SHDN

ISP

ISN

C1

1µF

D2

LT1618

100nF

332k

124k

1

I

ADJ

FB

V

C

GND

5

10

C2

1µF

C1, C2: TAIYO YUDEN JMK107BJ105KA

D1: ON SEMICONDUCTOR MBR0520

D2: LUMILEDS LXHL-BW02

L1: SUMIDA CR43-100

1618 • TA12

sn1618 1618fas

10

LT1618

U

TYPICAL APPLICATIONS

Li Ion White LED Driver

L1

10µH

20mA

D1

2.49Ω

V

IN

2.7V TO 5V

C1

8

7

4.7µF

V

SW

IN

9

4

3

2

SHDN

ISP

ISN

10kHz TO 50kHz

PWM

BRIGHTNESS

ADJUST

R1

2M

R3

5.1k

LT1618

1

I

FB

ADJ

GND

V

C

5

10

C2

1µF

C3

0.1µF

R2

100k

C

0.1µF

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN TMK316BJ105

D1: ON SEMICONDUCTOR MBR0530

L1: SUMIDA CLQ4D10-100

(408) 573-4150

(800) 282-9855

(847) 956-0666

1618 • TA04

White LED Driver for 20 LEDs

L1

10µH

80mA

D1

0.619Ω

V

IN

2.7V TO 5V

C1

8

7

4.7µF

V

SW

IN

SHDN

9

4

3

2

ISP

ISN

10kHz TO 50kHz

PWM

BRIGHTNESS

ADJUST

R3

5.1k

R1

LT1618

2M

1

I

ADJ

FB

V

C

GND

5

10

C2

1µF

C3

0.1µF

R2

121k

C

0.1µF

51Ω

51Ω 51Ω 51Ω

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN TMK316BJ105

D1: ON SEMICONDUCTOR MBR0530

L1: SUMIDA CR43-100

(408) 573-4150

(800) 282-9855

(847) 956-0666

1618 • TA05

sn1618 1618fas

11

LT1618

U

TYPICAL APPLICATIONS

USB to 5V SEPIC Converter

C3

0.47µF

L1

10µH

I

IN

D1

0.1Ω

V

OUT

IN

Efficiency

5V

80

75

70

65

60

2

7

L2

10µH

ISN

ISP

SW

C1

R1

3

4.7µF

316k

LT1618

1

8

9

C2

10µF

V

FB

IN

3.3V

ON

R2

107k

SHDN

OFF

0V

I

V

GND

5

ADJ

C

20k

4

10

2k

10nF

3.3V

100mA

0V

500mA

13k

0

50

150 200 250

350

100

300

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN JMK316BJ106

C3: TAIYO YUDEN EMK212BJ474

D1: ON SEMICONDUCTOR MBR0520

L1: SUMIDA CR43-100

(408) 573-4150

(800) 282-9855

(847) 956-0666

LOAD CURRENT (mA)

1618 F09b

1618 • TA09a

USB SEPIC During Start-Up

USB SEPIC Start-Up with Output Shorted

V

OUT

2V/DIV

V

OUT

2V/DIV

I

IN

50mA/DIV

1618 TA10

1618 TA11

1ms/DIV

sn1618 1618fas

12

LT1618

U

TYPICAL APPLICATIO S

12V Boost Converter with 500mA Input Current Limit

L1

10µH

I

D1

L1

0.1Ω

V

IN

OUT

Efficiency

1.8V TO 5V

12V

90

85

80

75

70

65

60

2

7

V

= 5V

IN

ISN

ISP

SW

R1

3

909k

LT1618

1

8

9

C2

4.7µF

V

FB

IN

V

IN

= 3.3V

R2

107k

SHDN

I

V

GND

5

ADJ

C

10

4

C1

4.7µF

2k

10nF

20 40 60 80 100

160

0

120 140

L0AD CURRENT (mA)

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN EMK316BJ475

D1: ON SEMICONDUCTOR MBR0520

L1: SUMIDA CR43-100

(408) 573-4150

(800) 282-9855

(847) 956-0666

1618 TA06b

1618 • TA06a

12V Boost Converter Start-Up with Input Current Limit

(V_IN= 1.8V, I_LOAD= 40mA)

12V Boost Converter Start-Up without Input Current Limit

(V_IN= 1.8V, I_LOAD= 40mA)

V

OUT

5V/DIV

V

OUT

5V/DIV

I

LI

200mA/DIV

I

LI

200mA/DIV

1618 TA08

1618 TA07

50µs/DIV

sn1618 1618fas

13

LT1618

U

PACKAGE DESCRIPTIO

DD Package

10-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1698)

0.675 ±0.05

3.50 ±0.05

2.15 ±0.05 (2 SIDES)

1.65 ±0.05

PACKAGE

OUTLINE

0.25 ± 0.05

0.50

BSC

2.38 ±0.05

(2 SIDES)

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

R = 0.115

TYP

6

0.38 ± 0.10

10

3.00 ±0.10

(4 SIDES)

1.65 ± 0.10

(2 SIDES)

PIN 1

TOP MARK

(SEE NOTE 6)

(DD10) DFN 1103

5

1

0.25 ± 0.05

0.50 BSC

0.75 ±0.05

0.200 REF

2.38 ±0.10

(2 SIDES)

0.00 – 0.05

BOTTOM VIEW—EXPOSED PAD

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).

CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE

TOP AND BOTTOM OF PACKAGE

sn1618 1618fas

14

LT1618

U

PACKAGE DESCRIPTIO

MS Package

10-Lead Plastic MSOP

(Reference LTC DWG # 05-08-1661)

0.889 ± 0.127

(.035 ± .005)

5.23

(.206)

MIN

3.20 – 3.45

(.126 – .136)

3.00 ± 0.102

(.118 ± .004)

(NOTE 3)

0.497 ± 0.076

(.0196 ± .003)

REF

0.50

0.305 ± 0.038

(.0120 ± .0015)

TYP

(.0197)

10 9

8

7 6

BSC

RECOMMENDED SOLDER PAD LAYOUT

3.00 ± 0.102

(.118 ± .004)

(NOTE 4)

4.90 ± 0.152

(.193 ± .006)

DETAIL “A”

0.254

(.010)

0° – 6° TYP

GAUGE PLANE

1

2

3

4 5

0.53 ± 0.152

(.021 ± .006)

0.86

(.034)

REF

1.10

(.043)

MAX

DETAIL “A”

0.18

(.007)

SEATING

PLANE

0.17 – 0.27

(.007 – .011)

TYP

0.127 ± 0.076

(.005 ± .003)

MSOP (MS) 0603

0.50

(.0197)

BSC

NOTE:

1. DIMENSIONS IN MILLIMETER/(INCH)

2. DRAWING NOT TO SCALE

3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX

sn1618 1618fas

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 represen-

tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.

15

LT1618

U

TYPICAL APPLICATIONS

Li-Ion Buck-Boost Mode Luxeon LED Driver

Buck Mode Luxeon LED Driver

D2

700mA

350mA

0.07Ω

0.15Ω

V

IN

16V

D2

L1

3.3µH

D1

V

IN

3.2V TO 5V

L1

47µH

3

7

ISP

ISN

SW

2

7

2

100k

10k

ISN

SW

LT1618

3

1

8

9

C2

4.7µF

ISP

C1

4.7µF

V

IN

FB

LT1618

1

8

9

V

FB

SHDN

IN

C1

4.7µF

I

V

C

GND

5

ADJ

SHDN

4

10

I

V

C

GND

5

ADJ

4

10

10nF

10k

2.2nF

220pF

C1: TAIYO YUDEN JMK212BJ475KG

C2: TAIYO YUDEN EMK316BJ475ML

D1: ON SEMICONDUCTOR MBRM120

D2: LUMILEDS DS25

1618 TA13

L1: NEC PLC-07453R3

C1: TAIYO YUDEN TMK325BJ475MN

D1: PHILIPS PMEG2010

D2: LUMILEDS DS45

1618 TA14

L1: TOKO D104C

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OUT(MAX)

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Q SD

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LT1961

1.5A (I ), 1.25MHz, High Efficiency Step-Up DC/DC Converter

V : 3V to 25V, V

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OUT(MAX) Q SD

SW

IN

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LTC3401/LTC3402 1A/2A (I ), 3MHz, Synchronous Step-Up DC/DC Converter

V : 0.5V to 5V, V

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OUT(MAX) Q SD

SW

IN

MS Package

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LT3463/LT3463A

LT3464

0.3A (I ), 1.3MHz/3MHz, High Efficiency Step-Up DC/DC

V : 2.5V to 16V, V

= 38V, I = 2.8mA, I < 1µA,

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Q SD

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OUT(MAX)

with Integrated Schottky Diodes

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= 34V, I = 25µA, I < 1µA,

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Integrated Schottky, Output Disconnect

ThinSOT Package

LT3465/LT3465A

LT3467/LT3467A

Constant Current, 1.2MHz/2.7MHz, High Efficiency White LED

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V : 2.7V to 16V, V

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Q SD

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V : 2.4V to 16V, V

IN

= 40V, I = 1.2mA, I < 1µA,

Q SD

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ThinSOT is a trademark of Linear Technology Corporation.

sn1618 1618fas

LT/TP 0504 1K REV A • PRINTED IN USA

16 ^{LinearTechnology Corporation}

1630 McCarthy Blvd., Milpitas, CA 95035-7417

●

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


型号：	LT1618EMS#TRPBF
厂家：	Linear
描述：	LT1618 - Constant-Current/Constant-Voltage 1.4MHz Step-Up DC/DC Converter; Package: MSOP; Pins: 10; Temperature Range: -40°C to 85°C 开关光电二极管
文件：	总16页 (文件大小：207K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT1618EMS#TRPBF [Linear]

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