EL7512CYZ-T7全新原装原理图各脚功能电路原理芯片引脚定义-中国IC网-芯三七

EL7512

®

Data Sheet

May 23, 2005

FN7290.1

High Frequency PWM Step-Up Regulator

Features

The EL7512 is a high frequency, high efficiency step-up

DC:DC regulator operated at fixed frequency PWM mode.

With an integrated 1A MOSFET, it can deliver up to 600mA

output current at up to 90% efficiency. The adjustable

switching frequency is up to 1.2MHz, making it ideal for DSL

applications.

• 90% efficiency

• Up to 600mA I

OUT

< 18V

• 5V < V

OUT

• V > 2V

IN

• Up to 1.2MHz adjustable frequency

• < 3µA shutdown current

When shut down, it draws <3µA of current. This feature,

along with the minimum starting voltage of 2V, makes it

suitable for portable equipment powered by one lithium ion

or 3 to 4 NiMH cells.

• Adjustable soft-start

• Low battery detection

The EL7512 is available in a 10-pin MSOP package, with

maximum height of 1.1mm. With proper external

components, the whole converter takes less than 0.25in

• Internal thermal protection

2

• 1.1mm max height 10-pin MSOP package

• Pb-Free available (RoHS compliant)

PCB space.

This device is specified for operation over the full -40°C to

+85°C temperature range.

Applications

• 3V to 5V, 12V, and 18V converters

• 5V to 12V and 16V converters

• TFT-LCD

Pinout

EL7512

(10-PIN MSOP)

TOP VIEW

• DSL

• Portable equipment

• Desktop equipment

L

D

1

V

OUT

V

(2V-

9V)

IN

(12V up

to

400mA)

10µH

R

1kΩ

C

5

4

C

1

47µF

10µF

Ordering Information

1

2

3

4

5

PGND

LX 10

C

4

TAPE &

0.1µF

SGND

RT

VDD

9

8

7

6

R

80.6k

2

PART NUMBER

EL7512CY

PACKAGE

10-Pin MSOP

REEL

PKG. DWG. #

MDP0043

R

3

FB

SS

R

C

10

4.7nF

1

100k

-

7”

13”

-

C

3

10kΩ

EN

EL7512CY-T7

EL7512CY-T13

20nF

LBI

LBO

EL7512CYZ

(See Note)

10-Pin MSOP

(Pb-free)

EL7512CYZ-T7

(See Note)

10-Pin MSOP

(Pb-free)

7”

MDP0043

EL7512CYZ-T13

(See Note)

10-Pin MSOP

(Pb-free)

13”

NOTE: Intersil Pb-free products employ special Pb-free material sets;

molding compounds/die attach materials and 100% matte tin plate

termination finish, which are RoHS compliant and compatible with

both SnPb and Pb-free soldering operations. Intersil Pb-free products

are MSL classified at Pb-free peak reflow temperatures that meet or

exceed the Pb-free requirements of IPC/JEDEC J STD-020.

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1

1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

EL7512

Absolute Maximum Ratings (T = 25°C)

A

EN, LBI, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+18V

LX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20V

Storage Temperature. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C

Operating Temperature . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C

Operating Junction Temperature:. . . . . . . . . . . . . . . . . . . . . . . 135°C

V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12V

DD

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the

device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests

are at the specified temperature and are pulsed tests, therefore: T = T = T

J

C

A

Electrical Specifications

V

= 5V, V

OUT

= 12V, I

= 0mA, R = 100kΩ, T = 25°C unless otherwise specified.

IN

OUT

T

A

PARAMETER

DESCRIPTION

CONDITION

MIN

TYP

MAX

3

UNIT

µA

mA

V

IQ1

IQ2

VFB

IB

Quiescent Current - Shut-down

Quiensent Current

VEN = 0

VEN = 2V

2.5

4

Feedback Voltage

1.31

1.35

1.39

0.10

Feedback Input Bias Current

Input Voltage Range

µA

V

2

IN

D

Maximum Duty Cycle

84

90

%

MAX

I

Current Limit - Max Average Input

Current

1000

1250

1500

mA

LIM

I

Shut-down Input Bias Current

LBI Threshold Voltage

LBO Output Low

1

250

0.2

1

µA

mV

V

SHDN

V

180

220

0.1

LBI

ILBO = 1mA

OL-LBO

LEAK-LBO

I

LBO Output Leakage Current

Switch On Resistance

Switch Leakage Current

Line Regulation

VLBI = 250mV, VLBO = 5V

at 12V output

0.02

300

µA

mΩ

µA

%/V

%

R

DS-ON

I

1

LEAK-SWITCH

∆V

/∆V

3V < V < 6V, V

IN OUT

= 12V, no load

0.15

OUT

IN

∆V

/∆I

Load Regulation

I

< 250mA

OUT

0.5

1200

670

OUT OUT

OSC-MAX

OSC1

F

Maximum Switching Frequency

Switching Frequency

R

= 49.9kΩ

kHz

V

T

530

1.6

800

0.5

VHI_EN

VLO_EN

EN Input High Threshold

EN Input Low Threshold

V

Pin Descriptions

PIN NUMBER

PIN NAME

PIN FUNCTION

Power ground; connected to the source of internal N-channel power MOSFET

1

2

PGND

SGND

RT

Signal ground; ground reference for all the control circuitry; needs to have only a single connection to PGND

Timing resistor to adjust the oscillation frequency of the converter

3

4

EN

Chip enable; connects to logic HI (>1.6V) for chip to function

5

LBI

Low battery input; connects to a sensing voltage, or left open if function is not used

Low battery detection output; connected to the open drain of a MOSFET; able to sink 1mA current

Soft-start; connects to a capacitor to control the start-up of the converter

6

LBO

SS

7

8

FB

Voltage feedback input; needs to connect to resistor divider to decide V

Control circuit positive supply

O

9

VDD

LX

10

Inductor drive pin; connected to the drain of internal N-channel power MOSFET

2

EL7512

Block Diagram

V

OUT

15µF

80.6k

V

IN

1kΩ

0.1µF

10kΩ

4.7nF

47µF

10µF

FB

V

LX

DD

Thermal

Shut-down

MAX_DUTY

RT

Reference

Generator

100kΩ

VREF

PWM

Logic

PWM

Comparator

0.3Ω

VRAMP

EN

LBO

12µA

LBI

-

Start-up

Oscillator

+

I

LOUT

7.2k

80mΩ

210mV

SGND

SS

PGND

20nF

3

EL7512

Typical Performance Curves

Efficiency

V =3.3V, V =5V

IN

V

=3.3V, V =12V

IN

O

100

80

60

40

20

0

100

80

60

40

20

0

F

=670kHz

F

=670kHz

110

S

10

60

110

(mA)

160

210

10

210

310

I (mA)

O

410

510

360

150

I

O

F

vs V

Efficiency

=5V, V =12V

S

DD

V

IN

O

1400

100

80

60

40

20

0

R =51.1kΩ

T

1200

1000

800

600

400

200

0

R =71.5kΩ

T

R =100kΩ

T

R =200kΩ

T

F

=670kHz

60

S

5

6

7

8

9

10

11

12

10

110

160

210

I (mA)

O

260

310

V

(V)

DD

Internal V

vs T

F vs Temperature

S

REF

J

1.4

1.35

1.3

760

740

720

700

680

660

640

V

=5V

DD

1.25

1.2

V

=10V

=12V

DD

1.15

1.1

V

DD

1.05

1

V

=12V

R =100kΩ

T

DD

-50

0

50

(°C)

100

150

-50

0

50

(°C)

100

T

J

4

EL7512

Typical Performance Curves (Continued)

V

vs V

F vs R

S T

FB

DD

1.355

1.35

1400

V

=10V

DD

1200

1000

800

600

400

200

0

1.345

1.34

1.335

1.33

1.325

1.32

5

6

7

8

9

10

11

12

50

100

150

200

V

R (kΩ)

T

DD

Steady State Operation (inductor continuous

conduction) V =5V, V =12V, I =300mA

I

vs F

S

DD

IN

O

3.6

3.4

3.2

3

V

=10V

DD

O

∆V

=12V-18V

I

V

LX

2.8

2.6

2.4

2.2

2

∆V

O

i

L

650

750

850

950

(kHz)

1050

1150

1250

F

S

Steady State Operation (inductor discontinuous

conduction) V =5V, V =12V, I =25mA

Power-Up

=5V, V =12V, I =300mA

V

IN

O

IN

O

∆V

I

V

LX

V

IN

V

O

∆V

O

i

L

Load Transient Response

V

=5V, V =12V, I =50mA-300mA

IN

O O

i

O

∆V

O

5

EL7512

where:

Applications Information

The EL7512 is a step-up regulator, operated at fixed

frequency pulse-width-modulation (PWM) control. The input

voltage is 2V-12V and output voltage is 5V-18V. The

switching frequency (up to 1.2MHz) is decided by the

resistor connected to RT pin.

∆I is the inductor peak-to-peak current ripple and is

decided by:

L

V

D

F

S

IN

--------- ------

∆I

=

×

L

D is the MOSFET turn-on ratio and is decided by:

Start-Up

V

– V

IN

V

O

After V

DD

reaches a threshold of about 2V, the start-up

O

D = -----------------------

oscillator generates fixed duty-ratio of 0.5-0.7 at a frequency

of several hundred kilohertz. This will boost the output

voltage.

F

is the switching frequency.

S

The following table gives typical values:

When V

reaches about 3.7V, the PWM comparator takes

DD

MAX CONTINUOUS OUTPUT CURRENTS

over the control. The duty ratio will be decided by the

multiple-input direct summing comparator, Max_Duty signal

(about 90% duty-ratio), and the Current Limit Comparator,

whichever is the smallest.

I

OMAX

(mA)

V

(V)

V

(V)

L (µH)

10

F (kHz)

S

IN

O

2

5

1000

360

190

140

600

310

230

470

340

260

630

470

670

510

The soft-start is provided by the current limit comparator. As

the internal 12µA current source charges the external CSS,

the peak MOSFET current is limited by the voltage on the

capacitor. This in turn controls the rising rate of the output

voltage.

2

9

10

1000

12

5

10

3.3

5

10

9

10

The regulator goes through the start-up sequence as well

after the EN signal is pulled to HI.

12

9

10

Steady-State Operation

5

12

15

12

15

18

10

When the output reaches the preset voltage, the regulator

operates at steady state. Depending on the input/output

conditions and component values, the inductor operates at

either continuous-conduction mode or discontinuous-

conduction mode.

5

10

9

10

9

10

12

10

In the continuous-conduction mode, the inductor current is a

triangular waveform and LX voltage a pulse waveform. In the

discontinuous-conduction mode, the inductor current is

completely dried out before the MOSFET is turned on again.

The input voltage source, the inductor, and the MOSFET and

output diode parasitic capacitors forms a resonant circuit.

Oscillation will occur in this period. This oscillation is normal

and will not affect the regulation.

11

Component Considerations

It is recommended that C is larger than 10µF.

IN

Theoretically, the input capacitor has ripple current of ∆I .

L

Due to high-frequency noise in the circuit, the input current

ripple may exceed the theoretical value. Larger capacitor will

reduce the ripple further.

At very low load, the MOSFET will skip pulses sometimes.

This is normal.

The inductor has peak and average current decided by:

I

O

I

= -------------

Current Limit

LAVG

1 – D

The MOSFET current limit is nominally 1.2A and guaranteed

∆I

L

1A. This restricts the maximum output current I

on the following formula:

based

I

= I

+ --------

LAVG

OMAX

LPK

2

V

∆I

IN

L



The inductor should be chosen to be able to handle this

current. Furthermore, due to the fixed internal

compensation, it is recommended that maximum inductance

of 10µH and 15µH to be used in the 5V and 12V or higher

output voltage, respectively.







---------

I

=

1 – --------

×

OMAX

V

O

2

The output diode has average current of I , and peak

O

current the same as the inductor's peak current. Schottky

6

EL7512

diode is recommended and it should be able to handle those

currents.

Layout Considerations

The layout is very important for the converter to function

properly. Power Ground ( ) and Signal Ground (- --)

should be separated to ensure that the high pulse current in

the Power Ground never interferes with the sensitive signals

connected to Signal Ground. They should only be connected

at one point.

Output voltage ripple is the product of peak inductor current

times the ESR of output capacitor. Low ESR capacitor is to

be used to reduce the output ripple. The minimum output

capacitance of 330µF, 47µF, and 33µF is recommended for

5V, 12V, and 16V for 600kHz switching frequency,

respectively. For 1MHz switching frequency, 220µF, 33µF,

and 22µF capacitor can be used for the output voltages. In

addition to the voltage rating, the output capacitor should

also be able to handle the rms current is given by:

The trace connected to pin 8 (FB) is the most sensitive trace.

It needs to be as short as possible and in a “quiet” place,

preferably between PGND or SGND traces.

In addition, the bypass capacitor connected to the V

needs to be as close to the pin as possible.

DD

2









∆I

1

12

L



------

I

=

(1 – D) × D + ------------------- ×

× I

The heat of the chip is mainly dissipated through the SGND

pin. Maximizing the copper area around it is preferable. In

addition, a solid ground plane is always helpful for the EMI

performance.

CORMS

LAVG





2

I

LAVG

Output Voltage

The demo board is a good example of layout based on these

principles. Please refer to the EL7512 Application Brief for

the layout.

An external resistor divider is required to divide the output

voltage down to the nominal reference voltage. The current

drawn by the resistor network should be limited to maintain

the overall converter efficiency. The maximum value of the

resistor network is limited by the feedback input bias current

and the potential for noise being coupled into the feedback

pin. A resistor network less than 300kΩ is recommended.

The boost converter output voltage is determined by the

relationship:

R









2

V

= V × 1 + ------



FB

OUT

R



1

where V slightly changes with V . The curve is shown in

FB

DD

this data sheet.

RC Filter

The maximum voltage rating for the V

pin is 12V and is

DD

recommended to be about 10V for maximum efficiency to

drive the internal MOSFET. The series resistor R4 in the RC

filter connected to V

can be utilized to reduce the voltage.

DD

If V is larger than 10V, then:

O

V

– 10

O

I

R

= --------------------

4

DD

where I

is shown in I vs F curve. Otherwise, R4 can

DD S

DD

be 10Ω to 51Ω with C4 = 0.1µF.

Thermal Performance

The EL7512 uses a fused-lead package, which has a

reduced θ of 100°C/W on a four-layer board and 115°C/W

JA

on a two-layer board. Maximizing copper around the ground

pins will improve the thermal performance.

This chip also has internal thermal shut-down set at around

135°C to protect the component.

7

EL7512

Package Outline Drawing

NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil website at

<http://www.intersil.com/design/packages/index.asp>

All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.

Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without

notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and

reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result

from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

8

型号:	EL7512CYZ-T7
是否无铅：	不含铅
是否Rohs认证：	符合
生命周期：	Active
IHS 制造商：	ROCHESTER ELECTRONICS INC
零件包装代码：	TSSOP
包装说明：	TSSOP,
针数：	10
Reach Compliance Code：	unknown
风险等级：	5.21
Is Samacsys：	N
模拟集成电路 - 其他类型：	SWITCHING REGULATOR
控制技术：	PULSE WIDTH MODULATION
最大输入电压：	6 V
最小输入电压：	2 V
标称输入电压：	5 V
JESD-30 代码：	S-PDSO-G10
JESD-609代码：	e3
长度：	3 mm
湿度敏感等级：	2
功能数量：	1
端子数量：	10
最高工作温度：	85 °C
最低工作温度：	-40 °C
最大输出电流：	1.2 A
封装主体材料：	PLASTIC/EPOXY
封装代码：	TSSOP
封装形状：	SQUARE
封装形式：	SMALL OUTLINE, THIN PROFILE, SHRINK PITCH
峰值回流温度（摄氏度）：	260
认证状态：	COMMERCIAL
座面最大高度：	1.1 mm
表面贴装：	YES
切换器配置：	BOOST
最大切换频率：	1200 kHz
温度等级：	INDUSTRIAL
端子面层：	MATTE TIN
端子形式：	GULL WING
端子节距：	0.5 mm
端子位置：	DUAL
处于峰值回流温度下的最长时间：	40
宽度：	3 mm
Base Number Matches：	1

电子百科

产品导航

产品型号EL7512CYZ-T7的Datasheet PDF文件预览

EL7512CYZ-T7相关产品

EL7512CYZ-T7相关文章

IC37:专业IC行业平台