LT3487EDD#TRPBF_技术文档

LT3487

Boost and Inverting

Switching Regulator

for CCD Bias

U

DESCRIPTIO

FEATURES

ThG LT^®3487 duaꢀ chaeeGꢀ swiꢃchieg ꢂGguꢀaꢃꢄꢂ gGeGꢂaꢃGs

ꢆꢄsiꢃivG aed eGgaꢃivG ꢄuꢃꢆuꢃs ꢅꢄꢂ biasieg CCD iAagGꢂs.

ThG dGvicG dGꢀivGꢂs uꢆ ꢃꢄ –8V aꢃ 90Aꢇ aed 15V aꢃ 45Aꢇ

ꢅꢂꢄA a ꢀiꢃhiuA-iꢄe cGꢀꢀ, ꢆꢂꢄvidieg bias ꢅꢄꢂ Aaey ꢆꢄꢆuꢀaꢂ

CCD iAagGꢂs. ThG bꢄꢄsꢃ ꢂGguꢀaꢃꢄꢂ iecꢄꢂꢆꢄꢂaꢃGs ꢄuꢃꢆuꢃ

discꢄeeGcꢃ ꢃGcheꢄꢀꢄgy ꢃꢄ GꢀiAieaꢃG ꢃhG DC cuꢂꢂGeꢃ ꢆaꢃh

■

Generates 15V at 45mA, –8V at 90mA from a

Li-Ion Cell

■

Output Disconnect

■

Sequencing: Positive Output Reaches Regulation

Before Negative Channel Begins Switching

■

Internal Schottky Diodes

■

ꢅꢂꢄA V ꢃꢄ ꢃhG ꢄuꢃꢆuꢃ ꢀꢄad ꢃhaꢃ is ꢆꢂGsGeꢃ ie sꢃaedaꢂd

2MHz Constant Switching Frequency

IN

■

bꢄꢄsꢃ cꢄeﬁguꢂaꢃiꢄes. ThG 2MHz swiꢃchieg ꢅꢂGquGecy

aꢀꢀꢄws CCD sꢄꢀuꢃiꢄes usieg ꢃiey, ꢀꢄw ꢆꢂꢄﬁꢀG caꢆaciꢃꢄꢂs

aed ieducꢃꢄꢂs aed gGeGꢂaꢃGs ꢀꢄw eꢄisG ꢄuꢃꢆuꢃs ꢃhaꢃ aꢂG

Gasy ꢃꢄ ﬁꢀꢃGꢂ. Schꢄꢃꢃky diꢄdGs aꢂG ieꢃGꢂeaꢀ aed ꢃhG ꢄuꢃꢆuꢃ

vꢄꢀꢃagGs aꢂG sGꢃ wiꢃh ꢄeG ꢂGsisꢃꢄꢂ ꢆGꢂ chaeeGꢀ, ꢂGducieg

ꢃhG GxꢃGꢂeaꢀ cꢄAꢆꢄeGeꢃ cꢄueꢃ.

Requires Only One Resistor per Channel to Set

Output Voltages

■

V ±aegG: 2.3V ꢃꢄ 16V

IN

■

Ouꢃꢆuꢃ VꢄꢀꢃagG Uꢆ ꢃꢄ 28V

Shꢄꢂꢃ-Ciꢂcuiꢃ ±ꢄbusꢃ

Caꢆaciꢃꢄꢂ PꢂꢄgꢂaAAabꢀG Sꢄꢅꢃ-Sꢃaꢂꢃ

SGꢆaꢂaꢃG V Pie ꢇꢀꢀꢄws SGꢆaꢂaꢃG SꢄuꢂcGs ꢅꢄꢂ

BꢇT

IeꢃGꢀꢀigGeꢃ sꢄꢅꢃ-sꢃaꢂꢃ aꢀꢀꢄws sGquGeꢃiaꢀ sꢄꢅꢃ-sꢃaꢂꢃ ꢄꢅ ꢃhG ꢃwꢄ

chaeeGꢀswiꢃhasiegꢀGcaꢆaciꢃꢄꢂ.ThGsꢄꢅꢃ-sꢃaꢂꢃissGquGecGd

such ꢃhaꢃ ꢃhG ꢄuꢃꢆuꢃ ꢂaAꢆ ꢄꢅ ꢃhG eGgaꢃivG chaeeGꢀ bGgies

aꢅꢃGꢂꢃhGꢂaAꢆꢄꢅꢃhGꢆꢄsiꢃivGchaeeGꢀ. IeꢃGꢂeaꢀsGquGecieg

ciꢂcuiꢃꢂyaꢀsꢄdisabꢀGsꢃhGeGgaꢃivGchaeeGꢀueꢃiꢀꢃhGꢆꢄsiꢃivG

chaeeGꢀ has ꢂGachGd 87% ꢄꢅ iꢃs ﬁeaꢀ vaꢀuG, Gesuꢂieg ꢃhaꢃ

ꢃhG suA ꢄꢅ ꢃhG ꢃwꢄ ꢄuꢃꢆuꢃs is aꢀways ꢆꢄsiꢃivG.

PꢄwGꢂ aed Cꢄeꢃꢂꢄꢀ Ciꢂcuiꢃꢂy

■

^{ꢇvaiꢀabꢀG ie 10-L}U^{Gad (3AA × 3AA) DFN PackagG}

APPLICATIO S

■

CCD Bias

■

TFT LCD Bias

■

OLED Bias

ThG LT3487 is avaiꢀabꢀG ie a 10-ꢆie 3AA × 3AA DFN

ꢆackagG.

■

±±aiꢀ ꢁGeGꢂaꢃiꢄe ꢅꢄꢂ Oꢆ ꢇAꢆs

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

All other trademarks are the property of their respective owners.

U

TYPICAL APPLICATIO

Conversion Efﬁciency

15µH

10µH

80

POS CHANNEL AT CAP

75

2.2µF

SWN

V

SWP

CAP

BAT

V

IN

3V TO 12V

70

V

POS CHANNEL

IN

65

AT V

POS

1µF

549k

100nF

LT3487

NEG CHANNEL

60

55

DN

FBP

47pF

4.7µF

15µH

50

45

40

V

NEG

FBN

–8V

324k

RUN/SS

V

POS

90mA

15V

RUN/SS

V

POS

V

= 3.6V

IN

45mA

GND

22µF

100nF

20

40

LOAD CURRENT (mA)

80

0

100

60

3487 TA01a

3487 TA01b

3487f

1

LT3487

W W U W

U

W

U

ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

(Note 1)

TOP VIEW

V VꢄꢀꢃagG............................................................... 16V

IN

BꢇT

V

VꢄꢀꢃagG............................................................. 16V

CAP

1

2

3

4

5

10

9

V

POS

SWP, SWN VꢄꢀꢃagG................................................... 32V

CꢇP, V .................................................................30V

SWP

FBP

11

V

BAT

8

RUN/SS

FBN

POS

SWN

DN

7

DN VꢄꢀꢃagG............................................................. –32V

±UN/SS VꢄꢀꢃagG..........................................................8V

FBP VꢄꢀꢃagG................................................................ 6V

FBN VꢄꢀꢃagG ................................................ –0.2V ꢃꢄ 6V

MaxiAuA Juecꢃiꢄe TGAꢆGꢂaꢃuꢂG .......................... 125°C

OꢆGꢂaꢃieg TGAꢆGꢂaꢃuꢂG ±aegG ................. –40°C ꢃꢄ 85°C

SꢃꢄꢂagG TGAꢆGꢂaꢃuꢂG ±aegG................... –65°C ꢃꢄ 125°C

6

V

IN

DD PACKAGE

10-LEAD (3mm × 3mm) PLASTIC DFN

θ

= 43°C/W, θ = 3°C/W

Jꢇ

JC

EXPOSED PꢇD (PIN 11) IS ꢁND, MUST BE CONNECTED TO PCB

O±DE± Pꢇ±T NUMBE±

DD Pꢇ±T Mꢇ±KINꢁ

LBXB

LT3487EDD

Order Options TaꢆG aed ±GGꢀ: ꢇdd #T±

LGad FꢂGG: ꢇdd #PBF LGad FꢂGG TaꢆG aed ±GGꢀ: ꢇdd #T±PBF

LGad FꢂGG Paꢂꢃ Maꢂkieg: hꢃꢃꢆ://www.ꢀieGaꢂ.cꢄA/ꢀGadꢅꢂGG/

Cꢄesuꢀꢃ LTC MaꢂkGꢃieg ꢅꢄꢂ ꢆaꢂꢃs sꢆGciﬁGd wiꢃh widGꢂ ꢄꢆGꢂaꢃieg ꢃGAꢆGꢂaꢃuꢂG ꢂaegGs.

ELECTRICAL CHARACTERISTICS ^The

●

denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T = 25°C. V = 3.6V, V = 3.6V, unless otherwise noted.

A

IN

BAT

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

OꢆGꢂaꢃieg VꢄꢀꢃagG ±aegG

QuiGscGeꢃ CuꢂꢂGeꢃ

2.3

16

V

±UN/SS = 3V, Nꢄꢃ Swiꢃchieg

±UN/SS = 0V

3.7

5.3

5

8

Aꢇ

µꢇ

±UN/SS VꢄꢀꢃagG ThꢂGshꢄꢀd (Fuꢀꢀ CuꢂꢂGeꢃ)

±UN/SS VꢄꢀꢃagG ThꢂGshꢄꢀd (Shuꢃdꢄwe)

±UN/SS Pie CuꢂꢂGeꢃ

(NꢄꢃG 3)

1.6

V

AV

µꢇ

●

100

1

160

1.4

±UN/SS = 0V (NꢄꢃG 4)

2

●

FBP (PꢄsiꢃivG ChaeeGꢀ) Pie VꢄꢀꢃagG

FBN (NGgaꢃivG ChaeeGꢀ) Pie VꢄꢀꢃagG

FBP Pie VꢄꢀꢃagG LieG ±Gguꢀaꢃiꢄe

FBN Pie VꢄꢀꢃagG LieG ±Gguꢀaꢃiꢄe

FBP Pie Bias CuꢂꢂGeꢃ

1.19

–7

1.23

3

1.27

12

V

AV

%/V

AV/V

µꢇ

0.007

0.001

25

●

24.4

25.6

90

FBN Pie Bias CuꢂꢂGeꢃ

25

µꢇ

FBP ThꢂGshꢄꢀd (PGꢂcGeꢃ ꢄꢅ Fieaꢀ VaꢀuG)

ꢃꢄ Sꢃaꢂꢃ NGgaꢃivG ChaeeGꢀ

87

%

Swiꢃchieg FꢂGquGecy

1.85

87

2

2.15

MHz

%

●

MaxiAuA Duꢃy CycꢀG

93

PꢄsiꢃivG ChaeeGꢀ Swiꢃch CuꢂꢂGeꢃ LiAiꢃ

NGgaꢃivG ChaeeGꢀ Swiꢃch CuꢂꢂGeꢃ LiAiꢃ

(NꢄꢃG 5)

750

900

920

1090

280

340

Aꢇ

AV

PꢄsiꢃivG ChaeeGꢀ V

I

= 400Aꢇ

= 600Aꢇ

CESꢇT

SWP

SWN

NGgaꢃivG ChaeeGꢀ V

CESꢇT

3487f

2

LT3487

ELECTRICAL CHARACTERISTICS ^The

●

denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T = 25°C. V = 3.6V, V = 3.6V, unless otherwise noted.

A

IN

BAT

PARAMETER

CONDITIONS

MIN

TYP

1045

980

205

155

1.2

MAX

UNITS

AV

Aꢇ

V

Schꢄꢃꢃky DP Fꢄꢂwaꢂd Dꢂꢄꢆ

Schꢄꢃꢃky DN Fꢄꢂwaꢂd Dꢂꢄꢆ

I

= 400Aꢇ

= 600Aꢇ

= 50Aꢇ

SWP

SWN

VPOS

DiscꢄeeGcꢃ PNP V

CE

DiscꢄeeGcꢃ CuꢂꢂGeꢃ LiAiꢃ

– V ꢃꢄ DiscꢄeeGcꢃ

V

CꢇP

V

BꢇT

V

BꢇT

= 15V, V

= 0V

100

POS

V

CꢇP

= 3.6V, V

= 0V, I < 100µꢇ

CꢇP

1.6

1.0

BꢇT

POS

DiscꢄeeGcꢃ LGakagG

= 3.6V, CꢇP = 3.6V, V

= 0V

0.1

µꢇ

POS

Note 1: SꢃꢂGssGs bGyꢄed ꢃhꢄsG ꢀisꢃGd uedGꢂ ꢇbsꢄꢀuꢃG MaxiAuA ±aꢃiegs

Aay causG ꢆGꢂAaeGeꢃ daAagG ꢃꢄ ꢃhG dGvicG. ExꢆꢄsuꢂG ꢃꢄ aey ꢇbsꢄꢀuꢃG

MaxiAuA ±aꢃieg cꢄediꢃiꢄe ꢅꢄꢂ GxꢃGedGd ꢆGꢂiꢄds Aay aꢅꢅGcꢃ dGvicG

ꢂGꢀiabiꢀiꢃy aed ꢀiꢅGꢃiAG.

Note 2: ThG LT3487E is guaꢂaeꢃGGd ꢃꢄ AGGꢃ sꢆGciﬁGd ꢆGꢂꢅꢄꢂAaecG ꢅꢂꢄA

0°C ꢃꢄ 85°C. SꢆGciﬁcaꢃiꢄes ꢄvGꢂ ꢃhG –40°C ꢃꢄ 85°C ꢄꢆGꢂaꢃieg ꢂaegG aꢂG

assuꢂGd by dGsige, chaꢂacꢃGꢂizaꢃiꢄe aed cꢄꢂꢂGꢀaꢃiꢄe wiꢃh sꢃaꢃisꢃicaꢀ ꢆꢂꢄcGss

cꢄeꢃꢂꢄꢀs.

Note 3: ꢁuaꢂaeꢃGGd by dGsige, eꢄꢃ diꢂGcꢃꢀy ꢃGsꢃGd.

Note 4: CuꢂꢂGeꢃ ﬂꢄws ꢄuꢃ ꢄꢅ ꢆie.

Note 5: CuꢂꢂGeꢃ ꢀiAiꢃ guaꢂaeꢃGGd by dGsige aed/ꢄꢂ cꢄꢂꢂGꢀaꢃiꢄe ꢃꢄ sꢃaꢃic ꢃGsꢃ.

SꢀꢄꢆG cꢄAꢆGesaꢃiꢄe ꢂGducGs cuꢂꢂGeꢃ ꢀiAiꢃ aꢃ highGꢂ duꢃy cycꢀG.

U W

TYPICAL PERFOR A CE CHARACTERISTICS

Shutdown Quiescent Current

Positive Output to Enable Inverter

FBP Voltage

100

90

80

70

60

50

10

8

1.300

1.275

1.250

1.225

6

4

2

0

1.200

50

75 100 125

–50 –25

0

25

50

75 100 125

–50 –25

0

25

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3487 G02

3487 G01

3487 G03

3487f

3

LT3487

U W

TYPICAL PERFOR A CE CHARACTERISTICS

FBN Voltage

FBP Bias Current

FBN Bias Current

10.0

26.0

25.5

25.0

24.5

26.0

25.5

25.0

24.5

7.5

5.0

2.5

0

–2.5

–5.0

–7.5

–10.0

24.0

–25

0

50

75 100 125

–50

25

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3487 G04

3487 G06

3487 G05

Positive Channel Schottky I-V

Characteristic

Positive Channel Switch V

Negative Channel Switch V

CE(SAT)

500

400

300

200

500

400

600

500

400

300

200

100

0

300

200

100

0

100

0

850 900

600 650 700 750 800

950 1000

0

200

300

400

500

600

0

100 200 300

500

700 800 900

600

100

400

SCHOTTKY FORWARD DROP (mV)

SWITCH CURRENT (mA)

3487 G09

3487 G07

3487 G08

Negative Channel Schottky I-V

Characteristic

Output Disconnect Voltage Drop

(50mA Load)

Maximum Disconnect Current

300

250

200

150

800

700

600

500

400

300

200

100

0

140

120

V

A

– V

= 500mV

POS

CAP

T

= 25°C

100

80

60

40

20

0

100

800 850

–50 –25

0

25

50

75 100 125

600 650 700 750

900 950 1000

2.5

5

7.5

(V)

12.5

0

10

TEMPERATURE (°C)

SCHOTTKY FORWARD DROP (mV)

V

– V

CAP

BAT

3487 G10

3487 G11

3487 G20

3487f

4

LT3487

U W

TYPICAL PERFOR A CE CHARACTERISTICS

Switch Current Limits

vs Duty Cycle

Output Disconnect Current Limit

Switch Current Limits

1200

1000

200

175

150

125

1200

V

= 15V

= 3.6V

= 0V

CAP

BAT

POS

NEG CHANNEL

1150

1100

NEG CHANNEL

POS CHANNEL

800

600

1050

1000

950

P0S CHANNEL

400

200

0

900

850

100

800

0

20

40

60

80

100

–50 –25

0

25

50

75 100 125

–25

0

50

75 100 125

–50

25

TEMPERATURE (°C)

DUTY CYCLE (%)

TEMPERATURE (°C)

3487 G14

3487 G12

3487 G13

Switch Current Limits vs RUN/SS

Voltage (at 55% Duty Cycle)

RUN/SS Pin Current

vs V in Shutdown

RUN/SS Pin Current in Shutdown

IN

1000

800

600

400

3.0

2.5

2.0

1.5

2.0

1.5

1.0

0.5

NEG CHANNEL

P0S CHANNEL

1.0

0.5

0

200

0

500

750 1000 1250 1500

2

4

6

8

V

10

(V)

12

14

16

250

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

RUN/SS (mV)

IN

3487 G15

3487 G17

3487 G16

UVLO Voltage

RUN/SS Shutdown Threshold

2.5

2.4

2.3

2.2

2.1

2.0

300

250

200

150

100

50

0

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3487 G19

3487 G18

3487f

5

LT3487

U

PI FU CTIO S

CAP(Pin1):DiscꢄeeGcꢃ-PNPEAiꢃꢃGꢂaedPꢄsiꢃivGSchꢄꢃꢃky

CaꢃhꢄdG. ꢇcꢃs as ae ieꢃGꢂAGdiaꢃG ꢆꢄsiꢃivG (bꢄꢄsꢃ) ꢄuꢃꢆuꢃ.

CꢄeeGcꢃ bꢄꢄsꢃ ꢄuꢃꢆuꢃ caꢆaciꢃꢄꢂ ꢃꢄ ꢃhis ꢆie.

RUN/SS (Pin 8): ±ue/Sꢄꢅꢃ-Sꢃaꢂꢃ Pie. CꢄeeGcꢃ ꢃꢄ ae ꢄꢆGe-

dꢂaie ꢃꢂaesisꢃꢄꢂ. ThG ꢃꢂaesisꢃꢄꢂ Ausꢃ siek 1.4µꢇ ꢅꢂꢄA

±UN/SS.Puꢀꢀ±UN/SSbGꢀꢄw100AVꢃꢄshuꢃdꢄweꢃhGchiꢆ.

CꢄeeGcꢃ a caꢆaciꢃꢄꢂ ꢅꢂꢄA ±UN/SS ꢃꢄ gꢂꢄued ꢃꢄ ꢆꢂꢄgꢂaA

sꢄꢅꢃ-sꢃaꢂꢃ ꢅuecꢃiꢄeaꢀiꢃy. ThG sꢄꢅꢃ-sꢃaꢂꢃ wiꢀꢀ sꢀꢄwꢀy bꢂieg ꢃhG

bꢄꢄsꢃ chaeeGꢀ ieꢃꢄ ꢂGguꢀaꢃiꢄe aed ꢃhGe sꢀꢄwꢀy bꢂieg uꢆ

ꢃhG ievGꢂꢃGꢂ. ±UN/SS Ausꢃ bG abꢄvG 1.6V ꢃꢄ aꢀꢀꢄw bꢄꢃh

chaeeGꢀs ꢃꢄ ꢂGach ꢅuꢀꢀ cuꢂꢂGeꢃ. Iꢅ sꢄꢅꢃ-sꢃaꢂꢃ is eꢄꢃ ꢂGquiꢂGd,

ꢃhis ꢆie cae bG dꢂivGe wiꢃh a ꢀꢄgic sigeaꢀ, buꢃ ꢃhG ±UN/SS

SWP (Pin 2): Swiꢃch Pie aed Schꢄꢃꢃky ꢇeꢄdG ꢅꢄꢂ PꢄsiꢃivG

ChaeeGꢀ. CꢄeeGcꢃ bꢄꢄsꢃ ieducꢃꢄꢂ ꢃꢄ ꢃhis ꢆie.

V

(Pin 3): BaꢃꢃGꢂy VꢄꢀꢃagG. CꢄeeGcꢃ ꢃhis ꢆie ꢃꢄ ꢃhG suꢆ-

BAT

ꢆꢀy vꢄꢀꢃagG ꢅꢄꢂ ꢃhG bꢄꢄsꢃ ieducꢃꢄꢂ. ThG discꢄeeGcꢃ dꢂivG

cuꢂꢂGeꢃ is ꢂGꢃuꢂeGd ꢃꢄ ꢃhis ꢆie. ThG discꢄeeGcꢃ ꢄꢆGꢂaꢃGs

ueꢃiꢀ CꢇP ꢅaꢀꢀs ꢃꢄ 1.2V abꢄvG V

.

vꢄꢀꢃagG Ausꢃ ꢂGAaie bGꢀꢄw V .

BꢇT

IN

SWN (Pin 4): Swiꢃch Pie ꢅꢄꢂ NGgaꢃivG (IevGꢂꢃGꢂ) Chae-

eGꢀ. CꢄeeGcꢃ ievGꢂꢃGꢂ ieꢆuꢃ ieducꢃꢄꢂ aed ﬂyieg caꢆaciꢃꢄꢂ

hGꢂG.

FBP (Pin 9): FGGdback Pie ꢅꢄꢂ Bꢄꢄsꢃ. CꢄeeGcꢃ bꢄꢄsꢃ

ꢅGGdback ꢂGsisꢃꢄꢂ ±1 ꢅꢂꢄA FBP ꢃꢄ CꢇP. ChꢄꢄsG ±1 ac-

cꢄꢂdieg ꢃꢄ:

DN(Pin5):ꢇeꢄdGꢄꢅIeꢃGꢂeaꢀSchꢄꢃꢃkyꢅꢄꢂIevGꢂꢃGꢂ.CꢄeeGcꢃ

ievGꢂꢃGꢂ ꢄuꢃꢆuꢃ ieducꢃꢄꢂ aed ﬂyieg caꢆaciꢃꢄꢂ hGꢂG.

V_POS–1.23

R1=

25µA

V

(Pin 6): Ieꢆuꢃ Suꢆꢆꢀy Pie. V is usGd ꢃꢄ ꢆꢄwGꢂ ꢃhG

IN

Pie vꢄꢀꢃagG = 1.23V whGe ꢂGguꢀaꢃGd.

cꢄeꢃꢂꢄꢀ ciꢂcuiꢃꢂy ꢄꢅ ꢃhG LT3487. This ꢆie Ausꢃ bG ꢀꢄcaꢀꢀy

V

(Pin 10): Ouꢃꢆuꢃ Pie ꢅꢄꢂ Bꢄꢄsꢃ ChaeeGꢀ. V

is

byꢆassGd wiꢃh ae X5± ꢄꢂ X7± ꢃyꢆG cGꢂaAic caꢆaciꢃꢄꢂ.

POS

ꢃhG cꢄꢀꢀGcꢃꢄꢂ ꢄꢅ ꢃhG ꢄuꢃꢆuꢃ discꢄeeGcꢃ PNP. CꢄeeGcꢃ ꢃhG

FBN (Pin 7): FGGdback Pie ꢅꢄꢂ IevGꢂꢃGꢂ. CꢄeeGcꢃ ꢅGGdback

bꢄꢄsꢃ ꢀꢄad ꢃꢄ V . CꢄeeGcꢃ caꢆaciꢃꢄꢂ C5 bGꢃwGGe CꢇP

aed V

POS

ꢅꢄꢂ sꢃabiꢀiꢃy.

ꢂGsisꢃꢄꢂ ±2 ꢅꢂꢄA ꢃhis ꢆie ꢃꢄ V . ChꢄꢄsG ±2 accꢄꢂdieg

NEꢁ

POS

ꢃꢄ:

Exposed Pad (Pin 11): ꢁND. TiG diꢂGcꢃꢀy ꢃꢄ gꢂꢄued ꢆꢀaeG

ꢃhꢂꢄugh AuꢀꢃiꢆꢀG vias uedGꢂ ꢃhG ꢆackagG ꢅꢄꢂ ꢄꢆꢃiAuA

ꢃhGꢂAaꢀ ꢆGꢂꢅꢄꢂAaecG.

V_NEG

R2= –

25µA

Pie vꢄꢀꢃagG = 0V whGe ꢂGguꢀaꢃGd.

3487f

6

LT3487

W

BLOCK DIAGRA

L1

V

BAT

CAP

2

R1

SWP

FBP

9

–

+

VCP

–

+

49.2k

A1

DP

A2

R

S

CAP

1

X1

Q3

C4

Q

DISCONNECT

PNP

Q1

ANTISAT

C5

V

IN

V

BAT

6

V

BAT

C1

3

V

REF

+

V

1.23V

POS

10

Σ

1.4µA

GND

11

RAMP

GENERATOR

49.2k

2MHz

+

–

OSCILLATOR

RUN/SS

+

M1

8

160mV

1.25V

RUN

C6

V

BAT

FBN

+

–

7

VCN

–

+

L2

A3

R2

C7

SWN

A4

R

S

4

X2

V

NEG

Q

Q2

C2

Σ

DN

L3

DN

V

NEG

5

RAMP

GENERATOR

C3

3487 BD

Figure 1. Block Diagram

3487f

7

LT3487

U

W U U

APPLICATIO S I FOR ATIO

ꢀꢄeg as CꢇP is ꢃyꢆicaꢀꢀy 1.2V aed wꢄꢂsꢃ-casG 1.6V (cꢄꢀd)

abꢄvG ꢃhG V vꢄꢀꢃagG. ThG dꢂivG cuꢂꢂGeꢃ ꢅꢄꢂ ꢃhG ꢄuꢃꢆuꢃ

Operation

BꢇT

ThGLT3487usGsacꢄesꢃaeꢃꢅꢂGquGecy, cuꢂꢂGeꢃAꢄdGcꢄe-

ꢃꢂꢄꢀ schGAG ꢃꢄ ꢆꢂꢄvidG GxcGꢀꢀGeꢃ ꢀieG aed ꢀꢄad ꢂGguꢀaꢃiꢄe.

OꢆGꢂaꢃiꢄecaebGbGsꢃuedGꢂsꢃꢄꢄdbyꢂGꢅGꢂꢂiegꢃꢄꢃhGBꢀꢄck

DiagꢂaA ie FiguꢂG 1. ꢇꢃ ꢃhG sꢃaꢂꢃ ꢄꢅ Gach ꢄsciꢀꢀaꢃꢄꢂ cycꢀG,

ꢃhG S± ꢀaꢃch X1 is sGꢃ, which ꢃuꢂes ꢄe ꢃhG ꢆꢄwGꢂ swiꢃch

Q1. ꢇ vꢄꢀꢃagG ꢆꢂꢄꢆꢄꢂꢃiꢄeaꢀ ꢃꢄ ꢃhG swiꢃch cuꢂꢂGeꢃ is addGd

ꢃꢄ a sꢃabiꢀizieg ꢂaAꢆ aed ꢃhG ꢂGsuꢀꢃieg suA is ꢅGd ieꢃꢄ ꢃhG

ꢆꢄsiꢃivG ꢃGꢂAieaꢀ ꢄꢅ ꢃhG PWM cꢄAꢆaꢂaꢃꢄꢂ ꢇ2. WhGe ꢃhis

vꢄꢀꢃagG GxcGGds ꢃhG ꢀGvGꢀ aꢃ ꢃhG eGgaꢃivG ieꢆuꢃ ꢄꢅ ꢇ2, ꢃhG

S± ꢀaꢃch X1 is ꢂGsGꢃ, ꢃuꢂeieg ꢄꢅꢅ ꢃhG ꢆꢄwGꢂ swiꢃch Q1. ThG

ꢀGvGꢀ aꢃ ꢃhG eGgaꢃivG ieꢆuꢃ ꢄꢅ ꢇ2 is sGꢃ by ꢃhG Gꢂꢂꢄꢂ aAꢆꢀiﬁGꢂ

ꢇ1, aed is siAꢆꢀy ae aAꢆꢀiﬁGd vGꢂsiꢄe ꢄꢅ ꢃhG diꢅꢅGꢂGecG

bGꢃwGGe ꢃhG ꢅGGdback vꢄꢀꢃagG aed ꢃhG ꢂGꢅGꢂGecG vꢄꢀꢃagG

ꢄꢅ 1.23V. Ie ꢃhis AaeeGꢂ, ꢃhG Gꢂꢂꢄꢂ aAꢆꢀiﬁGꢂ sGꢃs ꢃhG cꢄꢂ-

ꢂGcꢃ ꢆGak cuꢂꢂGeꢃ ꢀGvGꢀ ꢃꢄ kGGꢆ ꢃhG ꢄuꢃꢆuꢃ ie ꢂGguꢀaꢃiꢄe.

Iꢅ ꢃhG Gꢂꢂꢄꢂ aAꢆꢀiﬁGꢂ’s ꢄuꢃꢆuꢃ iecꢂGasGs, AꢄꢂG cuꢂꢂGeꢃ is

dGꢀivGꢂGd ꢃꢄ ꢃhG ꢄuꢃꢆuꢃ; iꢅ iꢃ dGcꢂGasGs, ꢀGss cuꢂꢂGeꢃ is

dGꢀivGꢂGd. ThG sGcꢄed chaeeGꢀ is ae ievGꢂꢃieg cꢄevGꢂꢃGꢂ.

ThG basic ꢄꢆGꢂaꢃiꢄe is ꢃhG saAG as ꢃhG ꢆꢄsiꢃivG chaeeGꢀ.

ThG S± ꢀaꢃch X2 is aꢀsꢄ sGꢃ aꢃ ꢃhG sꢃaꢂꢃ ꢄꢅ Gach ꢄsciꢀꢀaꢃꢄꢂ

cycꢀG. ThG ꢆꢄwGꢂ swiꢃch Q2 is ꢃuꢂeGd ꢄe aꢃ ꢃhG saAG ꢃiAG

as Q1. Q2 ꢃuꢂes ꢄꢅꢅ basGd ꢄe iꢃs ꢄwe ꢅGGdback ꢀꢄꢄꢆ, which

cꢄesisꢃs ꢄꢅ Gꢂꢂꢄꢂ aAꢆꢀiﬁGꢂ ꢇ3 aed PWM cꢄAꢆaꢂaꢃꢄꢂ ꢇ4.

ThG ꢂGꢅGꢂGecG vꢄꢀꢃagG ꢄꢅ ꢃhis eGgaꢃivG chaeeGꢀ is gꢂꢄued.

VꢄꢀꢃagGcꢀaAꢆsꢄeV aedV (eꢄꢃshꢄwe)GeꢅꢄꢂcGcuꢂꢂGeꢃ

discꢄeeGcꢃ PNP is ꢂGꢃuꢂeGd ꢃꢄ ꢃhG V

ꢆie. This aꢀꢀꢄws

BꢇT

ꢃhG ꢆass ꢃꢂaesisꢃꢄꢂ ꢃꢄ ꢃuꢂe ꢄꢅꢅ whGe ꢃhG CꢇP vꢄꢀꢃagG

ꢅaꢀꢀs ꢃꢄ ꢀGss ꢃhae 1.2V abꢄvG V . ThG V ꢆie aꢀꢀꢄws

BꢇT

aꢆꢆꢀicaꢃiꢄes ie which ꢃhG ꢆꢄwGꢂ (ieducꢃꢄꢂs L1 aed L2)

aed ieꢃGꢂeaꢀ cꢄeꢃꢂꢄꢀ ciꢂcuiꢃꢂy (V ꢆie) aꢂG ꢆꢄwGꢂGd ꢅꢂꢄA

IN

diꢅꢅGꢂGeꢃ sꢄuꢂcGs.

Inductor Selection

ꢇ 10μH ieducꢃꢄꢂ is ꢂGcꢄAAGedGd ꢅꢄꢂ ꢃhG LT3487 bꢄꢄsꢃ

chaeeGꢀ. ThG ievGꢂꢃieg chaeeGꢀ cae usG uecꢄuꢆꢀGd 15μH

ieducꢃꢄꢂs, ꢄꢂ cꢄuꢆꢀGd 10μH ieducꢃꢄꢂs. SAaꢀꢀ sizG aed

high GꢅﬁciGecy aꢂG ꢃhG Aajꢄꢂ cꢄecGꢂes ꢅꢄꢂ Aꢄsꢃ LT3487

aꢆꢆꢀicaꢃiꢄes. Ieducꢃꢄꢂs wiꢃh ꢀꢄw cꢄꢂG ꢀꢄssGs aed sAaꢀꢀ

DC± (cꢄꢆꢆGꢂ wiꢂG ꢂGsisꢃaecG) aꢃ 2MHz aꢂG gꢄꢄd chꢄicGs

ꢅꢄꢂ LT3487 aꢆꢆꢀicaꢃiꢄes. ThG ieducꢃꢄꢂ DC± shꢄuꢀd bG ꢄe

ꢃhG ꢄꢂdGꢂ ꢄꢅ haꢀꢅ ꢄꢅ ꢃhG swiꢃch ꢄe-ꢂGsisꢃaecG ꢅꢄꢂ iꢃs chae-

eGꢀ. SꢄAG ieducꢃꢄꢂs ie ꢃhis caꢃGgꢄꢂy wiꢃh sAaꢀꢀ sizG aꢂG

ꢀisꢃGd ie TabꢀG 1.

Table 1. Recommended Inductors

CURRENT

INDUCTANCE DCR RATING

PART NUMBER

(μH)

(Ω)

(mA)

MANUFACTURER

DB318C-ꢇ997ꢇS-

100M

10

0.18

580

Tꢄkꢄ

www. ꢃꢄkꢄaA.cꢄA

CD±H3D18-100

CD±H2D18HP-100

CD±H3D23-100

CD±H2D18/HP-150

CD±H3D18-150

CD±H3D23-150

10

15

0.205

0.245

0.117

0.345

0.301

0.191

900

850

700

750

700

SuAida

www.suAida.cꢄA

CP

CN

ꢀiAiꢃ. Swiꢃchieg wavGꢅꢄꢂAs wiꢃh ꢃyꢆicaꢀ ꢀꢄad cꢄediꢃiꢄes

aꢂG shꢄwe ie FiguꢂG 2.

ThGPNPQ3isusGdasaeꢄuꢃꢆuꢃdiscꢄeeGcꢃꢆassꢃꢂaesisꢃꢄꢂ.

Q3 discꢄeeGcꢃs ꢃhG ꢀꢄad ꢅꢂꢄA ꢃhG ieꢆuꢃ duꢂieg shuꢃdꢄwe.

ThG aeꢃi-saꢃ dꢂivGꢂ kGGꢆs Q3 aꢃ ꢃhG GdgG ꢄꢅ saꢃuꢂaꢃiꢄe as

Capacitor Selection

ThG sAaꢀꢀ sizG ꢄꢅ cGꢂaAic caꢆaciꢃꢄꢂs AakGs ꢃhGA suiꢃabꢀG

ꢅꢄꢂ LT3487 aꢆꢆꢀicaꢃiꢄes. X5± aed X7± ꢃyꢆGs ꢄꢅ cGꢂaAic

caꢆaciꢃꢄꢂs aꢂG ꢂGcꢄAAGedGd bGcausG ꢃhGy ꢂGꢃaie ꢃhGiꢂ

caꢆaciꢃaecG ꢄvGꢂ widGꢂ vꢄꢀꢃagG aed ꢃGAꢆGꢂaꢃuꢂG ꢂaegGs

ꢃhae ꢄꢃhGꢂ ꢃyꢆGs such as Y5V ꢄꢂ Z5U. ꢇ 1μF ieꢆuꢃ caꢆaci-

ꢃꢄꢂ is suꢅﬁciGeꢃ ꢅꢄꢂ Aꢄsꢃ LT3487 aꢆꢆꢀicaꢃiꢄes. ThG ꢄuꢃꢆuꢃ

caꢆaciꢃꢄꢂsꢂGquiꢂGdꢅꢄꢂsꢃabiꢀiꢃydGꢆGedꢄeꢃhGaꢆꢆꢀicaꢃiꢄe.

Fꢄꢂ ꢃhG ꢃyꢆicaꢀ Li-Iꢄe ꢃꢄ +15V, –8V aꢆꢆꢀicaꢃiꢄe, ꢃhG ꢆꢄsiꢃivG

chaeeGꢀꢂGquiꢂGsa4.7μFꢄuꢃꢆuꢃcaꢆaciꢃꢄꢂaedꢃhGeGgaꢃivG

chaeeGꢀ ꢂGquiꢂGs aꢃ ꢀGasꢃ 10μF ꢄꢅ caꢆaciꢃaecG.

V

SWP

20V/DIV

I

LI

100mA/DIV

V

SWN

20V/DIV

I

SWN

100mA/DIV

3487 F02

V

= 3.6V

200ns/DIV

IN

= 15V, 25mA

= –8V, 50mA

POS

NEG

Figure 2. Switching Waveforms

3487f

8

LT3487

U

W U U

APPLICATIO S I FOR ATIO

Table 2. Recommended Ceramic Capacitor Manufacturers

whGꢂGLisꢃhGieducꢃaecG,ꢂisꢃhGꢂGsisꢃaecGꢄꢅꢃhGieducꢃꢄꢂ

aed C is ꢃhG ꢄuꢃꢆuꢃ caꢆaciꢃaecG. Fꢄꢂ ꢀꢄw DC± ieducꢃꢄꢂs,

which is usuaꢀꢀy ꢃhG casG ꢅꢄꢂ ꢃhis aꢆꢆꢀicaꢃiꢄe, ꢃhG ꢆGak

ieꢂush cuꢂꢂGeꢃ cae bG siAꢆꢀiﬁGd as ꢅꢄꢀꢀꢄws:

MANUFACTURER

Taiyꢄ YudGe

Muꢂaꢃa

PHONE

URL

(408) 573-4150

(814) 237-1431

(408) 986-0424

www.ꢃ-yudGe.cꢄA

www.Auꢂaꢃa.cꢄA

www.kGAGꢃ.cꢄA

KGAGꢃ

α π

•

⎛

⎜

⎞

–

⎟

⎠

V – 0.6

L •

ω

I_P=

• e^⎝

ω 2

IN

Inrush Current

ThG LT3487 usGs ieꢃGꢂeaꢀ Schꢄꢃꢃky diꢄdGs. WhGe a suꢆ-

ꢆꢀy vꢄꢀꢃagG is abꢂuꢆꢃꢀy aꢆꢆꢀiGd ꢃꢄ ꢃhG V ꢆie, ꢃhG vꢄꢀꢃagG

diꢅꢅGꢂGecG bGꢃwGGe V aed V

TabꢀG 3 givGs ieꢂush ꢆGak cuꢂꢂGeꢃs ꢅꢄꢂ sꢄAG cꢄAꢆꢄeGeꢃ

sGꢀGcꢃiꢄes. NꢄꢃG ꢃhaꢃ ieꢂush cuꢂꢂGeꢃ is eꢄꢃ a cꢄecGꢂe iꢅ ꢃhG

ieꢆuꢃ vꢄꢀꢃagG ꢂisGs sꢀꢄwꢀy.

IN

gGeGꢂaꢃGs ieꢂush cuꢂꢂGeꢃ

IN

CꢇP

ﬂꢄwieg ꢅꢂꢄA ꢃhG ieꢆuꢃ ꢃhꢂꢄugh ꢃhG ieducꢃꢄꢂ L1 aed ꢃhG

ieꢃGꢂeaꢀ Schꢄꢃꢃky diꢄdG DP ꢃꢄ chaꢂgG ꢃhG bꢄꢄsꢃ ꢄuꢃꢆuꢃ

caꢆaciꢃꢄꢂ C4. Fꢄꢂ ꢃhG ievGꢂꢃieg chaeeGꢀ, ꢃhGꢂG is a siAiꢀaꢂ

ieꢂushcuꢂꢂGeꢃﬂꢄwiegꢅꢂꢄAꢃhGieꢆuꢃꢃhꢂꢄughꢃhGieducꢃꢄꢂ

L2 ꢆaꢃh, chaꢂgieg ꢃhG ﬂyieg caꢆaciꢃꢄꢂ C2 aed ꢂGꢃuꢂeieg

ꢃhꢂꢄugh ꢃhG ieꢃGꢂeaꢀ Schꢄꢃꢃky diꢄdG DN. ThG AaxiAuA

cuꢂꢂGeꢃ ꢃhG Schꢄꢃꢃky diꢄdGs ie ꢃhG LT3487 cae susꢃaie is

2ꢇ. ThG sGꢀGcꢃiꢄe ꢄꢅ ieducꢃꢄꢂ aed caꢆaciꢃꢄꢂ vaꢀuGs shꢄuꢀd

GesuꢂG ꢃhaꢃ ꢃhG ꢆGak ieꢂush cuꢂꢂGeꢃ is bGꢀꢄw 2ꢇ. ThG ꢆGak

ieꢂush cuꢂꢂGeꢃ cae bG caꢀcuꢀaꢃGd as ꢅꢄꢀꢀꢄws:

Table 3. Inrush Peak Current

V

(V)

R (Ω)

0.18

L (μH)

10

C (μF)

4.7

2.2

4.7

I_P(A)

1.44

1.06

0.979

0.958

0.704

IN

5

3.6

0.235

0.18

0.245

0.345

15

10

15

2.2

External Diode Selection

ꢇs sꢃaꢃGd ꢆꢂGviꢄusꢀy, ꢃhG LT3487 has ieꢃGꢂeaꢀ Schꢄꢃꢃky

diꢄdGs. ThG Schꢄꢃꢃky diꢄdG, DP, is suꢅﬁciGeꢃ ꢅꢄꢂ Aꢄsꢃ

sꢃGꢆ-uꢆ aꢆꢆꢀicaꢃiꢄes. HꢄwGvGꢂ, ꢅꢄꢂ high cuꢂꢂGeꢃ ievGꢂꢃGꢂ

aꢆꢆꢀicaꢃiꢄes,aꢆꢂꢄꢆGꢂꢀysGꢀGcꢃGdGxꢃGꢂeaꢀSchꢄꢃꢃkydiꢄdGie

ꢆaꢂaꢀꢀGꢀ wiꢃh DN cae iAꢆꢂꢄvG GꢅﬁciGecy. Fꢄꢂ GxꢃGꢂeaꢀ diꢄdG

sGꢀGcꢃiꢄe,bꢄꢃhꢅꢄꢂwaꢂdvꢄꢀꢃagGdꢂꢄꢆaeddiꢄdGcaꢆaciꢃaecG

eGGd ꢃꢄ bG cꢄesidGꢂGd. Schꢄꢃꢃky diꢄdGs ꢂaꢃGd ꢅꢄꢂ highGꢂ

cuꢂꢂGeꢃ usuaꢀꢀy havG ꢀꢄwGꢂ ꢅꢄꢂwaꢂd vꢄꢀꢃagG dꢂꢄꢆs aed

ꢀaꢂgGꢂ caꢆaciꢃaecG, which cae causG sigeiﬁcaeꢃ swiꢃchieg

ꢀꢄssGsaꢃa2MHzswiꢃchiegꢅꢂGquGecy.SꢄAGꢂGcꢄAAGedGd

Schꢄꢃꢃky diꢄdGs aꢂG ꢀisꢃGd ie TabꢀG 4.

α

ω

α

⎛

⎝

⎞

–

•arctan

⎜

⎟

⎠

V – 0.6

⎡

⎤

ω

⎝ ⎠

α

⎛ ⎞

IN

I_P=

α =

ω =

• e

• SIN arctan

⎜ ⎟

⎢

⎥

⎦

L • ω

r + 1.5

2 •L

⎣

1

L •C

r

–

4 •L²

Table 4. Recommended Schottky Diodes

DIODE CAPACITANCE

PART NUMBER

FORWARD CURRENT (mA) FORWARD VOLTAGE DROP (V)

(pF at 10V)

MANUFACTURER

PMEꢁ2010ꢇEB

1000

0.51

7.5

Phiꢀiꢆs

www.sGAicꢄeducꢃꢄꢂs.

ꢆhiꢀiꢆs.cꢄA

CMDSH2-3

±SX051Vꢇ-30

ZHCS400

200

500

400

0.49

0.35

15

30

18

CGeꢃꢂaꢀ SGAicꢄeducꢃꢄꢂ

www.cGeꢃꢂaꢀsGAi.cꢄA

±OHM

www.ꢂꢄhA.cꢄA

ZGꢃGx

www.zGꢃGx.cꢄA

0.425

3487f

9

LT3487

U

W U U

APPLICATIO S I FOR ATIO

Setting the Output Voltages

Start Sequencing

ThG LT3487 has ae accuꢂaꢃG ieꢃGꢂeaꢀ ꢅGGdback ꢂGsisꢃꢄꢂ

ꢃhaꢃ is ꢃꢂiAAGd ꢃꢄ sGꢃ ꢃhG ꢅGGdback cuꢂꢂGeꢃs ꢃꢄ 25µꢇ ꢅꢄꢂ

Gach chaeeGꢀ. Oeꢀy ꢄeG ꢂGsisꢃꢄꢂ is eGGdGd ꢃꢄ sGꢃ ꢃhG ꢄuꢃꢆuꢃ

vꢄꢀꢃagG ꢅꢄꢂ Gach chaeeGꢀ. ThG ꢄuꢃꢆuꢃ vꢄꢀꢃagG cae bG sGꢃ

accꢄꢂdieg ꢃꢄ ꢃhG ꢅꢄꢀꢀꢄwieg ꢅꢄꢂAuꢀas:

ThG LT3487 aꢀsꢄ has ieꢃGꢂeaꢀ sGquGecieg ciꢂcuiꢃꢂy ꢃhaꢃ

iehibiꢃs ꢃhG eGgaꢃivG chaeeGꢀ ꢅꢂꢄA ꢄꢆGꢂaꢃieg ueꢃiꢀ ꢃhG

ꢅGGdback vꢄꢀꢃagG ꢄꢅ ꢃhG bꢄꢄsꢃ chaeeGꢀ ꢂGachGs abꢄuꢃ 1.1V

(87% ꢄꢅ ꢃhG ﬁeaꢀ vꢄꢀꢃagG), Gesuꢂieg ꢃhaꢃ ꢃhG suA ꢄꢅ ꢃhG

ꢃwꢄ ꢄuꢃꢆuꢃs is aꢀways ꢆꢄsiꢃivG.

ThGꢂG aꢂG ꢃwꢄ ways ie which ꢃhG eGgaꢃivG chaeeGꢀ Aay

sꢃaꢂꢃ uꢆ, dGꢆGedieg ꢄe ꢃhG sizG ꢄꢅ ꢃhG sꢄꢅꢃ-sꢃaꢂꢃ caꢆaciꢃꢄꢂ.

Iꢅ ꢃhGꢂG is eꢄ sꢄꢅꢃ-sꢃaꢂꢃ caꢆaciꢃꢄꢂ, ꢄꢂ a vGꢂy sAaꢀꢀ caꢆaciꢃꢄꢂ,

ꢃhGe ꢃhG eGgaꢃivG chaeeGꢀ wiꢀꢀ sꢃaꢂꢃ uꢆ whGe ꢃhG ꢆꢄsiꢃivG

ꢄuꢃꢆuꢃ ꢂGachGs 87% ꢄꢅ iꢃs ﬁeaꢀ vaꢀuG. Iꢅ a ꢀaꢂgG Geꢄugh

sꢄꢅꢃ-sꢃaꢂꢃ caꢆaciꢃꢄꢂ is usGd, ꢃhGe ꢃhG ±UN/SS vꢄꢀꢃagG wiꢀꢀ

cꢄeꢃieuG ꢃꢄ cꢀaAꢆ ꢃhG eGgaꢃivG chaeeGꢀ ꢆasꢃ ꢃhG ꢆꢄieꢃ

whGꢂGꢃhGꢆꢄsiꢃivGchaeeGꢀisieꢂGguꢀaꢃiꢄe. FiguꢂG3shꢄws

ꢃhG sꢃaꢂꢃ-uꢆ sGquGecieg wiꢃhꢄuꢃ sꢄꢅꢃ-sꢃaꢂꢃ, wiꢃh a sAaꢀꢀ

sꢄꢅꢃ-sꢃaꢂꢃ caꢆaciꢃꢄꢂ, aed a ꢀaꢂgG sꢄꢅꢃ-sꢃaꢂꢃ caꢆaciꢃꢄꢂ.

V

–1.23

25µA

⎛

⎞

POS

R1=

R2=

⎜

⎝

⎟

⎠

–V_NEG

25µA

Ie ꢄꢂdGꢂ ꢃꢄ Aaieꢃaie accuꢂacy, high ꢆꢂGcisiꢄe ꢂGsisꢃꢄꢂs aꢂG

ꢆꢂGꢅGꢂꢂGd (1% is ꢂGcꢄAAGedGd).

Soft-Start

ThG LT3487 has a siegꢀG sꢄꢅꢃ-sꢃaꢂꢃ cꢄeꢃꢂꢄꢀ ꢅꢄꢂ bꢄꢃh chae-

eGꢀs. ThG ±UN/SS ꢆie is ꢅGd by a 1.4μꢇ cuꢂꢂGeꢃ sꢄuꢂcG.

ThG sꢄꢅꢃ-sꢃaꢂꢃ ꢂaAꢆ cae bG ꢆꢂꢄgꢂaAAGd by cꢄeeGcꢃieg a

caꢆaciꢃꢄꢂ ꢅꢂꢄA ꢃhG ±UN/SS ꢆie ꢃꢄ gꢂꢄued. ꢇe ꢄꢆGe-dꢂaie

ꢃꢂaesisꢃꢄꢂ shꢄuꢀd bG usGd ꢃꢄ ꢆuꢀꢀ ꢃhG ꢆie ꢀꢄw ꢃꢄ shuꢃ dꢄwe

ꢃhG LT3487. OecG ꢃhG ꢃꢂaesisꢃꢄꢂ sꢃꢄꢆs siekieg ꢃhG 1.4μꢇ,

ꢃhG caꢆaciꢃꢄꢂ bGgies ꢃꢄ chaꢂgG. ThG chiꢆ sꢃaꢂꢃs uꢆ whGe

Output Disconnect

ThGꢄuꢃꢆuꢃdiscꢄeeGcꢃusGsaPNPꢃꢂaesisꢃꢄꢂwiꢃhciꢂcuiꢃꢂy

ꢃhaꢃ vaꢂiGs ꢃhG basG cuꢂꢂGeꢃ such ꢃhaꢃ ꢃhG ꢃꢂaesisꢃꢄꢂ is

cꢄesisꢃGeꢃꢀy aꢃ ꢃhG GdgG ꢄꢅ saꢃuꢂaꢃiꢄe, ꢃhus yiGꢀdieg ꢃhG

bGsꢃ cꢄAꢆꢂꢄAisG bGꢃwGGe V

aed ꢀꢄw quiGscGeꢃ

CE(SꢇT)

cuꢂꢂGeꢃ. Tꢄ ꢂGAaie sꢃabꢀG, ꢃhis ciꢂcuiꢃ ꢂGquiꢂGs a byꢆass

caꢆaciꢃꢄꢂcꢄeeGcꢃGdbGꢃwGGeꢃhGV ꢆieaedꢃhGCꢇPꢆie

ꢃhG ±UN/SS ꢆie chaꢂgGs ꢃꢄ 160AV. ThG V eꢄdG vꢄꢀꢃagG

POS

CP

ꢄꢂ bGꢃwGGe ꢃhG V

ꢆie aed gꢂꢄued. ꢇ cGꢂaAic caꢆaciꢃꢄꢂ

ꢅꢄꢀꢀꢄws ꢃhG ±UN/SS vꢄꢀꢃagG as iꢃ cꢄeꢃieuGs ꢃꢄ ꢂaAꢆ uꢆ

POS

wiꢃh a vaꢀuG ꢄꢅ aꢃ ꢀGasꢃ 0.1μF is a gꢄꢄd chꢄicG. FiguꢂG 4

shꢄws ꢃhaꢃ ꢃhG PNP cae suꢆꢆꢄꢂꢃ ꢀꢄad cuꢂꢂGeꢃs ꢄꢅ 50Aꢇ

ꢃꢄ GesuꢂG sꢀꢄw sꢃaꢂꢃ-uꢆ ꢄe ꢃhG ꢆꢄsiꢃivG chaeeGꢀ. ThG V

CN

eꢄdG ꢅꢄꢀꢀꢄws ꢃhG ꢂaAꢆ vꢄꢀꢃagG, dꢄwe a V . This GesuꢂGs

BE

wiꢃh a V ꢀGss ꢃhae 210AV. ThG discꢄeeGcꢃ ꢃꢂaesisꢃꢄꢂ is

ꢃhaꢃ ꢃhG eGgaꢃivG chaeeGꢀ sꢃaꢂꢃs uꢆ aꢅꢃGꢂ ꢃhG ꢆꢄsiꢃivG, buꢃ

sꢃiꢀꢀ has a sꢀꢄw ꢂaAꢆieg ꢄuꢃꢆuꢃ ꢃꢄ avꢄid ꢀaꢂgG sꢃaꢂꢃ-uꢆ

cuꢂꢂGeꢃs.

CE

cuꢂꢂGeꢃ ꢀiAiꢃGd ꢃꢄ ꢆꢂꢄvidG a AaxiAuA ꢄꢅ 155Aꢇ ie shꢄꢂꢃ

ciꢂcuiꢃ.

V

RUN/SS

2V/DIV

RUN/SS

2V/DIV

V

RUN/SS

2V/DIV

I

IN

I

IN

I

IN

200mA/DIV

500mA/DIV

1A/DIV

V

POS

10V/DIV

V

NEG

10V/DIV

3487 F03b

3487 F03c

3487 F03a

2ms/DIV

10ms/DIV

500µs/DIV

Figure 3a. V

IN

, V , V

,

Figure 3b. V

IN

, V , V

,

Figure 3c. V /SS, V , V , I

RUN/SS POS NEG

RUN

POS NEG IN

I

with No Soft-Start Capacitor

I

with a 10nF Soft-Start Capacitor

with a 100nF Soft-Start Capacitor

3487f

10

LT3487

U

W U U

APPLICATIO S I FOR ATIO

Choosing a Feedback Node

ꢃhG caꢆaciꢃꢄꢂ vꢄꢀꢃagGs ꢅaꢀꢀ back ieꢃꢄ ꢂGguꢀaꢃiꢄe. WhiꢀG ꢃhis

is haꢂAꢀGss ꢃꢄ ꢃhG LT3487, ꢃhis shꢄuꢀd bG cꢄesidGꢂGd ie

ꢃhG cꢄeꢃGxꢃ ꢄꢅ ꢃhG GxꢃGꢂeaꢀ ciꢂcuiꢃꢂy iꢅ shꢄꢂꢃ-ciꢂcuiꢃ GvGeꢃs

aꢂG GxꢆGcꢃGd. ±Gguꢀaꢃieg ꢃhG CꢇP ꢆie GesuꢂGs ꢃhaꢃ ꢃhG

ThG ꢆꢄsiꢃivG chaeeGꢀ ꢅGGdback ꢂGsisꢃꢄꢂ, ±1, Aay bG cꢄe-

eGcꢃGd ꢃꢄ ꢃhG V

ꢆie ꢄꢂ ꢃꢄ ꢃhG CꢇP ꢆie (sGG FiguꢂG 5).

POS

±GguꢀaꢃiegꢃhGV ꢆieGꢀiAieaꢃGsꢃhGꢄuꢃꢆuꢃꢄꢅꢅsGꢃꢂGsuꢀꢃ-

POS

vꢄꢀꢃagG ꢄe ꢃhG V

ꢆie eGvGꢂ GxcGGds ꢃhG sGꢃ ꢄuꢃꢆuꢃ vꢄꢀꢃ-

POS

ieg ꢅꢂꢄA ꢃhG vꢄꢀꢃagG dꢂꢄꢆ acꢂꢄss ꢃhG ꢄuꢃꢆuꢃ discꢄeeGcꢃ.

agG aꢅꢃGꢂ a shꢄꢂꢃ-ciꢂcuiꢃ GvGeꢃ. HꢄwGvGꢂ, ꢃhis sGꢃuꢆ dꢄGs

eꢄꢃ cꢄAꢆGesaꢃG ꢅꢄꢂ ꢃhG vꢄꢀꢃagG dꢂꢄꢆ acꢂꢄss ꢃhG ꢄuꢃꢆuꢃ

discꢄeeGcꢃ, ꢂGsuꢀꢃieg ie ae ꢄuꢃꢆuꢃ vꢄꢀꢃagG ꢃhaꢃ is sꢀighꢃꢀy

ꢀꢄwGꢂ ꢃhae ꢃhG vꢄꢀꢃagG sGꢃ by ꢃhG ꢅGGdback ꢂGsisꢃꢄꢂ. This

HꢄwGvGꢂ, ie ꢃhG casG ꢄꢅ a shꢄꢂꢃ-ciꢂcuiꢃ ꢅauꢀꢃ aꢃ ꢃhG V

POS

ꢆie, ꢃhG LT3487 wiꢀꢀ swiꢃch cꢄeꢃieuꢄusꢀy bGcausG ꢃhG FBP

ꢆie is ꢀꢄw. WhiꢀG ꢄꢆGꢂaꢃieg ie ꢃhis ꢄꢆGe-ꢀꢄꢄꢆ cꢄediꢃiꢄe, ꢃhG

ꢂisieg vꢄꢀꢃagG aꢃ ꢃhG CꢇP ꢆie is ꢀiAiꢃGd ꢄeꢀy by ꢃhG cuꢂꢂGeꢃ

ꢀiAiꢃꢄꢅꢃhGꢄuꢃꢆuꢃdiscꢄeeGcꢃ.ꢁivGewꢄꢂsꢃ-casGꢆaꢂaAGꢃGꢂs

ꢃhis vꢄꢀꢃagG Aay ꢂGach 18V ie a Li-Iꢄe aꢆꢆꢀicaꢃiꢄe. CaꢂG

vꢄꢀꢃagG dꢂꢄꢆ (V

) cae bG accꢄueꢃGd ꢅꢄꢂ whGe usieg

ꢃhG CꢇP ꢆie as ꢃhG ꢅGGdback eꢄdG by sGꢃꢃieg ꢃhG ꢄuꢃꢆuꢃ

DISC

vꢄꢀꢃagG accꢄꢂdieg ꢃꢄ ꢃhG ꢅꢄꢀꢀꢄwieg ꢅꢄꢂAuꢀa (usieg V

ꢅꢂꢄA FiguꢂG 4):

DISC

Ausꢃ bG ꢃakGe ie high V aꢆꢆꢀicaꢃiꢄes whGe ꢂGguꢀaꢃieg

IN

ꢅꢂꢄA ꢃhG V

POS

ꢆie. WhGe ꢃhG shꢄꢂꢃ-ciꢂcuiꢃ is ꢂGAꢄvGd, ꢃhG

POS

V

ꢆie wiꢀꢀ bꢄuecG uꢆ ꢃꢄ ꢃhG vꢄꢀꢃagG ꢄe ꢃhG CꢇP ꢆie,

V_POS+ V_DISC–1.23

R1=

ꢆꢄꢃGeꢃiaꢀꢀyGxcGGdiegꢃhGꢆꢂꢄgꢂaAAGdꢄuꢃꢆuꢃvꢄꢀꢃagGueꢃiꢀ

25µA

300

250

V

BAT

ThG V ꢆie is a eGw ieeꢄvaꢃiꢄe ie ꢃhG LT3487 ꢃhaꢃ aꢀꢀꢄws

BꢇT

ꢄuꢃꢆuꢃ discꢄeeGcꢃ ꢄꢆGꢂaꢃiꢄe ie a widG ꢂaegG ꢄꢅ aꢆꢆꢀica-

200

150

ꢃiꢄes. ThG V ꢆie aꢀꢀꢄws ꢃhG ꢆaꢂꢃ ꢃꢄ sꢃay ꢄe ueꢃiꢀ CꢇP is

BꢇT

ꢀGss ꢃhae 1.2V abꢄvG V . This GesuꢂGs ꢃhaꢃ ꢃhG ꢆꢄsiꢃivG

BꢇT

bias dꢄGse’ꢃ ꢅaꢀꢀ bGꢅꢄꢂG ꢃhG eGgaꢃivG bias dischaꢂgGs. Ie

100

50

0

sꢄAG aꢆꢆꢀicaꢃiꢄes iꢃ Aay bG usGꢅuꢀ ꢃꢄ ꢆꢄwGꢂ ꢃhG ieducꢃꢄꢂs

ꢅꢂꢄA a diꢅꢅGꢂGeꢃ sꢄuꢂcG ꢃhae V . Ie ꢃhis casG, cꢄeeGcꢃ

IN

V

ꢃꢄ ꢃhG sꢄuꢂcG ꢆꢄwGꢂieg ꢃhG ieducꢃꢄꢂs ꢃꢄ aꢀꢀꢄw ꢆꢂꢄꢆGꢂ

BꢇT

0

20

40

60

80

100

ꢄꢆGꢂaꢃiꢄeꢄꢅꢃhGdiscꢄeeGcꢃ.FꢄꢂGxaAꢆꢀG,ieaeauꢃꢄAꢄꢃivG

sysꢃGA ꢃhGꢂG Aay aꢀꢂGady bG a buck ꢂGguꢀaꢃꢄꢂ ꢆꢂꢄducieg

3.3V ꢅꢂꢄA a 12V baꢃꢃGꢂy. ThG LT3487 GeabꢀGs ꢃhG usGꢂ

DISCONNECT CURRENT (mA)

2400 G31

ꢃꢄ ꢆꢄwGꢂ V ꢅꢂꢄA ꢃhG 3.3V ꢂaiꢀ, buꢃ ꢆꢄwGꢂ ꢃhG V

ꢆie

Figure 4. V vs I of Output Disconnect

CE

IN

BꢇT

SWN

V

BAT

SWP

CAP

SWN

V

SWP

CAP

BAT

V

IN

V

IN

LT3487

DN

FBP

FBN

RUN/SS

V

POS

RUN/SS

V

POS

V

POS

GND

3487 F05

Figure 5. Feedback Connection Using the V

and CAP Pins

POS

3487f

11

LT3487

U

W U U

APPLICATIO S I FOR ATIO

aed ꢃhG ieducꢃꢄꢂs diꢂGcꢃꢀy ꢅꢂꢄA ꢃhG baꢃꢃGꢂy ꢅꢄꢂ highGꢂ Gꢅ-

ﬁciGecy. WhGe ꢃhG ꢆaꢂꢃ gꢄGs ieꢃꢄ shuꢃdꢄwe, ꢃhG ꢄuꢃꢆuꢃ

ꢀꢄad is isꢄꢀaꢃGd ꢅꢂꢄA ꢃhG 12V sꢄuꢂcG as sꢄꢄe as ꢃhG CꢇP

Board Layout Consideration

ꢇs wiꢃh aꢀꢀ swiꢃchieg ꢂGguꢀaꢃꢄꢂs, caꢂGꢅuꢀ aꢃꢃGeꢃiꢄe Ausꢃ bG

ꢆaid ꢃꢄ ꢃhG PCB bꢄaꢂd ꢀayꢄuꢃ aed cꢄAꢆꢄeGeꢃ ꢆꢀacGAGeꢃ.

Tꢄ AaxiAizG GꢅﬁciGecy, swiꢃch ꢂisG aed ꢅaꢀꢀ ꢃiAGs aꢂG AadG

as shꢄꢂꢃ as ꢆꢄssibꢀG. Tꢄ ꢆꢂGvGeꢃ GꢀGcꢃꢂꢄAageGꢃic ieꢃGꢂꢅGꢂ-

GecG (EMI) ꢆꢂꢄbꢀGAs, ꢆꢂꢄꢆGꢂ ꢀayꢄuꢃ ꢄꢅ ꢃhG high ꢅꢂGquGecy

swiꢃchieg ꢆaꢃh is GssGeꢃiaꢀ. ThG vꢄꢀꢃagG sigeaꢀs ꢄꢅ ꢃhG

SWP aed SWN ꢆies havG ꢂisG aed ꢅaꢀꢀ ꢃiAGs ꢄꢅ a ꢅGw es.

MieiAizG ꢃhG ꢀGegꢃh aed aꢂGa ꢄꢅ aꢀꢀ ꢃꢂacGs cꢄeeGcꢃGd ꢃꢄ

ꢃhG SWP aed SWN ꢆies aed aꢀways usG a gꢂꢄued ꢆꢀaeG

uedGꢂ ꢃhG swiꢃchieg ꢂGguꢀaꢃꢄꢂ ꢃꢄ AieiAizG ieꢃGꢂꢆꢀaeG

cꢄuꢆꢀieg. ±GcꢄAAGedGdcꢄAꢆꢄeGeꢃꢆꢀacGAGeꢃisshꢄwe

ie FiguꢂG 6.

eꢄdG ꢅaꢀꢀs ꢃꢄ bGꢀꢄw V

ꢆꢀus 1.2V (13.2V ie ꢃhis casG).

BꢇT

ThG V ꢆie is aꢀsꢄ usGꢅuꢀ ie a sysꢃGA usieg a 2V suꢆꢆꢀy

BꢇT

(such as a 2-cGꢀꢀ aꢀkaꢀieG baꢃꢃGꢂy), bGꢀꢄw ꢃhG ꢄꢆGꢂaꢃieg

ꢂaegG ꢄꢅ ꢃhG LT3487. ꢇ bꢄꢄsꢃ cꢄevGꢂꢃGꢂ dGsigeGd ꢅꢄꢂ ꢀꢄw

vꢄꢀꢃagG ꢄꢆGꢂaꢃiꢄe cae ꢆꢂꢄvidG 3.3V ꢅꢄꢂ ꢃhG LT3487 V ꢆie,

IN

whiꢀG ꢃhG ieducꢃꢄꢂs aed V cae sꢃiꢀꢀ bG ꢆꢄwGꢂGd ꢅꢂꢄA ꢃhG

BꢇT

2V suꢆꢆꢀy. Ie shuꢃdꢄwe, ꢃhG 3.3V suꢆꢆꢀy wiꢀꢀ ꢃuꢂe ꢄꢅꢅ, buꢃ

ꢃhG ꢄuꢃꢆuꢃ discꢄeeGcꢃ wiꢀꢀ sꢃiꢀꢀ dGcꢄuꢆꢀG ꢃhG ꢄuꢃꢆuꢃ ꢀꢄad

as sꢄꢄe as CꢇP ꢅaꢀꢀs bGꢀꢄw 3.2V .

V

BAT

CAP

L1

L3

L1

FBP

U1

V

POS

R2

C7

V

NEG

M1

3487 F06

RUN

V

IN

Figure 6. Recommended Component Placement

3487f

12

LT3487

U

TYPICAL APPLICATIO

+15V and –8V Boost and Inverting CCD Bias

L2

15µH

L1

10µH

C2

2.2µF

SWN

V

SWP

CAP

BAT

V

IN

3V TO 12V

V

IN

C1

1µF

R1

549k

C5

100nF

LT3487

DN

FBP

C7 47pF

C4

L3

15µH

4.7µF

V

NEG

FBN

–8V

R2 324k

RUN/SS

V

POS

90mA

15V

RUN/SS

V

POS

45mA

C3

22µF

C6

100nF

GND

3487 TA02a

C1: TAIYO YUDEN EMK212BJ105MG

C2: TAIYO YUDEN TMK212BJ225MG

C3: TAIYO YUDEN TMK325BJ226MM

C4: TAIYO YUDEN TMK316BJ475ML-TR

L1: TOKO DB318C-A997AS-100M

L2, L3: SUMIDA CDRH2D18/HP-150NC

V

POS

Load Step Response

V

Load Step Response

NEG

V

NEG

20mV/DIV

V

POS

AC-COUPLED

100mV/DIV

AC-COUPLED

–50mA

I

45mA

15mA

NEG

I

POS

–90mA

3487 TA02b

3487 TA02c

V

= 3.6V

100µs/DIV

V

= 3.6V

IN

100µs/DIV

IN

ThG ꢆꢄsiꢃivG chaeeGꢀ’s ꢂGsꢆꢄesG is sꢃabꢀG, buꢃ sꢀighꢃꢀy

uedGꢂdaAꢆGd. ꢇ ꢆhasG ꢀGad caꢆaciꢃꢄꢂ (C8) cae bG addGd

ꢃꢄ ꢆꢂꢄvidG AꢄꢂG idGaꢀ ꢆhasG Aaꢂgie.

V

Load Step Response (with Phase Lead Capacitor)

POS

V

POS

100mV/DIV

CAP

FBP

AC-COUPLED

C8

R2

549k

10pF

45mA

I

3487 TA02e

POS

15mA

3487 TA02d

V

= 3.6V

100µs/DIV

IN

3487f

13

LT3487

U

TYPICAL APPLICATIO S

+15V and –8V Low V CCD Bias

IN

L2

15µH

L1

10µH

C2

2.2µF

SWN

V

BAT

SWP

CAP

V

IN

2.7V TO 5V

V

IN

C1

1µF

R1

549k

C8

15pF

C5

100nF

LT3487

DN

FBP

C7 33pF

C4

L3

15µH

4.7µF

V

NEG

FBN

–8V

R2 324k

RUN/SS

V

POS

80mA

15V

RUN/SS

V

POS

40mA

C3

22µF

C6

100nF

GND

3487 TA03

C1: TAIYO YUDEN EMK212BJ105MG

C2: TAIYO YUDEN EMK212BJ225MD-TR

C3: TAIYO YUDEN TMK325BJ226MM

C4: TAIYO YUDEN TMK316BJ475ML-TR

L1: TOKO DB318C-A997AS-100M

L2, L3: SUMIDA CDRH2D18/HP-150NC

+15V and –8V Boost and Charge Pump CCD Bias

L2

15µH

L1

10µH

C2

2.2µF

SWN

V

BAT

SWP

CAP

V

IN

3V TO 12V

V

IN

C1

1µF

R1

549k

C5

100nF

LT3487

DN

FBP

C7 20pF

C4

4.7µF

D1

V

NEG

FBN

–8V

R2 324k

RUN/SS

V

POS

90mA

15V

45mA

RUN/SS

V

POS

C3

10µF

C6

100nF

GND

3487 TA04

C1: TAIYO YUDEN EMK212BJ105MG

C2: TAIYO YUDEN TMK212BJ225MG

C3: TAIYO YUDEN EMK316BJ106ML

C4: TAIYO YUDEN TMK316BJ475ML-TR

D1: PHILIPS PMEG2010AEB

L1: TOKO DB318C-A997AS-100M

L2, L3: SUMIDA CDRH2D18/HP-150NC

3487f

14

LT3487

U

PACKAGE DESCRIPTIO

DD Package

10-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1699)

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

3487f

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-

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

15

LT3487

U

TYPICAL APPLICATIO

+24V and –16V LCD Bias

L2

22µH

L1

15µH

C2

2.2µF

SWN

V

BAT

SWP

CAP

V

IN

3V TO 6V

V

IN

C1

1µF

R1

931k

C8

15pF

C5

100nF

LT3487

DN

FBP

C7 33pF

C4

L3

22µH

10µF

V

NEG

FBN

–16V

R2 640k

RUN/SS

V

POS

26mA

24V

RUN/SS

V

POS

24mA

C3

22µF

C6

100nF

GND

3487 TA05

C1: TAIYO YUDEN EMK212BJ105MG

C2: TAIYO YUDEN TMK212BJ225MG

C3: TAIYO YUDEN TMK325BJ226MM

C4: TAIYO YUDEN TMK316BJ106KL-T

L1: SUMIDA CDRH2D18/HP-150NC

L2, L3: TOKO D53LC-A915AY-220M

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LT1944/LT1944-1

Duaꢀ Ouꢃꢆuꢃ 350Aꢇ/100Aꢇ I , Cꢄesꢃaeꢃ Oꢅꢅ-TiAG,

V : 1.2V ꢃꢄ 15V, V

= 34V, I = 20µꢇ, I < 1µꢇ, 10-LGad

Q SD

SW

IN

OUT(MꢇX)

High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ

MS PackagG

LT1945

Duaꢀ Ouꢃꢆuꢃ, Bꢄꢄsꢃ/IevGꢂꢃGꢂ, 350Aꢇ I , Cꢄesꢃaeꢃ Oꢅꢅ-TiAG, V : 1.2V ꢃꢄ 15V, V

= ±34V, I = 40µꢇ, I < 1µꢇ, 10-LGad

Q SD

SW

IN

OUT(MꢇX)

High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ

MS PackagG

LT1947

TꢂiꢆꢀG Ouꢃꢆuꢃ, 3MHz, High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ

V : 2.6V ꢃꢄ 8V, V

= ±34V, I = 9.5Aꢇ, I < 1µꢇ, 10-LGad

OUT(MꢇX) Q SD

IN

MS PackagG

LTC^®3450

LT3463/LT3463ꢇ

LT3471

TꢂiꢆꢀG Ouꢃꢆuꢃ, 550kHz, High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ

V : 1.4V ꢃꢄ 4.6V, V

= ±15V, I = 75µꢇ, I < 2µꢇ,

Q SD

IN

OUT(MꢇX)

DFN PackagG

Duaꢀ Ouꢃꢆuꢃ, Bꢄꢄsꢃ/IevGꢂꢃGꢂ, 250Aꢇ I , Cꢄesꢃaeꢃ Oꢅꢅ-TiAG, V : 2.2V ꢃꢄ 16V, V

= ±40V, I = 2.8Aꢇ, I < 1µꢇ,

Q SD

SW

IN

High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ wiꢃh IeꢃGgꢂaꢃGd Schꢄꢃꢃkys

DFN PackagG

Duaꢀ Ouꢃꢆuꢃ, Bꢄꢄsꢃ/IevGꢂꢃGꢂ, 1.3ꢇ I , 1.2MHz, High

V : 2.4V ꢃꢄ 16V, V

= ±40V, I = 2.5Aꢇ, I < 1µꢇ,

Q SD

SW

IN

EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ

DFN PackagG

LT3472/LT3472ꢇ

Duaꢀ Ouꢃꢆuꢃ, Bꢄꢄsꢃ/IevGꢂꢃGꢂ, 350Aꢇ/400Aꢇ I , 1.2MHz,

V : 2.3V ꢃꢄ 15V, V

= ±40V, I = 40µꢇ, I < 1µꢇ,

Q SD

SW

IN

High EꢅﬁciGecy DC/DC CꢄevGꢂꢃGꢂ wiꢃh IeꢃGgꢂaꢃGd Schꢄꢃꢃkys

DFN PackagG

3487f

LT 0406 • 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：	LT3487EDD#TRPBF
厂家：	Linear
描述：	LT3487 - Boost and Inverting Switching Regulator for CCD Bias; Package: DFN; Pins: 10; Temperature Range: -40°C to 85°C CD 开关光电二极管
文件：	总16页 (文件大小：278K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT3487EDD#TRPBF [Linear]

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