SP7618ER/TR [EXAR]

LED Driver, 1-Segment, 2 X 3 MM, LEAD FREE, MO-229VCED-2, DFN-8;


型号：	SP7618ER/TR
厂家：	EXAR CORPORATION
描述：	LED Driver, 1-Segment, 2 X 3 MM, LEAD FREE, MO-229VCED-2, DFN-8 驱动接口集成电路
文件：	总30页 (文件大小：768K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

Solved by

SP7618

Constant Current LED Driver

FEATURES

■

Very low dropout voltage (ꢀ00mV @ ꢀA)

Accurate current regulation down to dropout

voltage

No external components

Built-in current DAC

Output current adjustable with 33.3 mA/steps

Power-saving shutdown mode of ꢀµA

Fast turn-on (<50µs)

Timeout function to protect the LED

Thermal Shutdown protection

ꢀA current capability

LED

GNDP

GND

SP7618

■

8 Pin DFN

CTRL

APPLICATIONS

■

Next Generation Mobile Phones

PDA, DSC, MP3 Players

Handheld Computers

LCD Display Modules

Keyboard Backlight

RoHS compliant, Lead Free packaging:

Space saving 2mmx3mm 8pin DFN

GENERAL DESCRIPTION

The SP76ꢀ8 is a linear, low-side constant-current driver designed to drive high power LEDs

from an input voltage rail. The driver acts as a current source, ensuring constant LED current

for a range of input voltages. The SP76ꢀ8 allows implementing the lowest cost LED driver

for a variety of applications. Internal circuitry maintains the preset constant current output

for a wide voltage range at the LED input. The LED current can be adjusted up to ꢀ033mA

with an external clock applied to the CTRL pin. The built-in thermal protection automatically

stops LED current to prevent overheating. A timeout function serves as a failsafe, shutting

down the output for currents greater than 266mA after 4 seconds of continuous operation if

the enable input is not cycled. The part can be shut down by using the EN pin, or sent into

Sleep Mode holding the CTRL pin low for more than ꢀ00µS.

TYPICAL APPLICATION CIRCUIT

Date: Dec 5-06 Rev E

Constant Current LED Driver

ꢀ

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (Vcc) .………………………..6.0V

Input Voltage at any input .….-0.6V to Vcc +0.5V

8-pin DFN Package

These are stress ratings only and

functional operation of the device at

these ratings or any other above those

indicated in the operation sections of

the speciﬁcations below is not implied.

Exposure to absolute maximum rating

conditions for extended periods of time

may affect reliability.

Thermal Resistance................................ 59 C/W

Junction Temperature .......... -40 C to +ꢀ70 C

Storage Temperature ..………...-65°C to +ꢀ50°C

Soldering Temperature ...………………+240°C**

*) Internally limited

**) Duration ꢀ0s maximum

ELECTRICAL CHARACTERISTICS

Ambient temperature Ta = 25°C, 3.0V < Vcc < 5.5V, ꢀ.0V < VLED < 3.0V, ꢀ00mA < ILED <ꢀ033A. Bold denotes

speciﬁcations which apply over the full operating temperature range, -40°C to +85°C.

PARAMETER

MIN

2.5

TYP

MAX UNITS CONDITIONS

ꢀ

Vcc Voltage Operating Range

Quiescent Current

5.5

420

ꢀ

350

µA

Iled = 35mA

Shutdown Mode

Sleep Mode

EN = GND, CTRL = DC

EN = Vcc, CTRL = GND

EN = Vcc, CTRL = DC

Vled = ꢀ.0V, Vcc = 5.5V

Supply

Current

350

µA

After Time Duration

LED

0 pulses on CTRL

ꢀ25

Output

Current

after

ꢀ pulse on CTRL

3 pulses on CTRL

ꢀ02

ꢀ033

3ꢀ pulses on CTRL

LED Current Accuracy

-8

35mA < Iled < ꢀ033 mA

LED Current Line Regulation

0.ꢀ

ꢀ.5

0.5

%/V

3.0 < Vcc < 5.5V,Vled =ꢀV

ꢀ < Vled < 2.5V, Vcc =

5.5V

LED Current Load Regulation

LED Current Thermal Regulation

0.0ꢀ

%/°C

Iled = ꢀ00 mA

ꢀ00

ꢀ85

2ꢀ0

Iled = ꢀ00mA @ 25°C

Iled = 700mA @ 25°C

Iled = ꢀ033mA @ 25°C

V_LEDDropout Voltage

ꢀ00

Thermal Shutdown Die Tempera-

ture

ꢀ60

°C

Iled = 35mA

Thermal Shutdown Hysteresis

°C

µs

Setup Time after last count

CTRL input Data Rate

MHz

EN = LOW to HIGH,

CTRL = DC

EN = HIGH to LOW,

CTRL = DC

EN = HIGH, CTRL =

HIGH to LOW

Iled > 266 mA, EN =

HIGH, CTRL = HIGH

Driver in Shutdown Mode

Wake-up Time from Shutdown

µs

Turn-off Time into Shutdown

Turn-off Time into Sleep Mode

Time Duration before Sleep Mode

ꢀ25

450

LOW

HIGH

0.4

EN and CTRL pin

Logic Voltage

1.4

Vcc

2.5V ≤ Vcc ≤ 5.5V

ꢀꢀ

Power-on-Reset

See notes on next page

Date: Dec 5-06 Rev E

Constant Current LED Driver

Notes (Continued from previous page)

ꢀ. Vcc must be always higher than LED pin voltage (Vled)

2. After 4s at current higher than 266 mA

3. Power MOSFET leakage current

4. Three initial Iled current steps are higher than other 28

5. Iled Variations from speciﬁed Iled value

6. Iled Variations per volt Vcc change

7. Iled Variations at Vled change from ꢀ to 2.5V

8. 5% change of I_LEDcompared with ILED value at Vled = ꢀV

9. Iled = ꢀ00 mA settles 50µs later after 3rd pulse

ꢀ0. Logic HIGH level should never exceed Vcc voltage

ꢀꢀ. Delay between applying Vcc voltage and operating condition

PIN ASSIGNMENTS

Name

Pin Function

ꢀ - 2

LED LED Current Sink. Connect LED cathode to this pin. Voltage at this pin

should be above ꢀ00 mV to maintain regulation.

Vcc

Power Supply Input. Place ꢀµF decoupling capacitor next to this pin.

Enable/Shutdown pin used to enable/disable driver and reset DAC: Logic

High – enable, Logic Low – disable/reset.

CTRL DAC Serial Input pin is used to control LED current. Positive pulse edges

sequentially increase LED current with 33.33mA steps up to ꢀ033 mA (3ꢀ

steps). When this pin is held LOW for longer than ꢀ00µs the part enters

Sleep Mode.

GND Ground pin for control and bias blocks.

7 - 8 GNDP Ground pin. LED current ﬂows through this pin to ground.

BLOCK DIAGRAM

Date: Dec 5-06 Rev E

Constant Current LED Driver

APPLICATION INFORMATION

ꢀ200

ꢀ000

800

600

400

200

0.5

ꢀ

ꢀ.5

Vled, V

2.5

3.5

3 pulses

7 pulses

ꢀ5 pulses

3ꢀ pulses

Load regulation at Vcc = 5.5V @ 25°C

ꢀ200

ꢀ000

800

600

400

200

0.2

0.4

0.6

0.8

ꢀ

Vled, V

3 pulses

7 pulses

ꢀ5 pulses

3ꢀ pulses

Load regulation at Vcc = 5.5V @ 25°C

ꢀꢀ00

ꢀ050

ꢀ000

950

900

850

800

750

700

ꢀ00

200

300

25C

400

85C

500

600

700

Load regulation vs. temperature at Iled = ꢀA and Vcc = 5.5V

Date: Dec 5-06 Rev E

Constant Current LED Driver

APPLICATION INFORMATION

ꢀ200

ꢀ000

800

600

400

200

ꢀ0

ꢀ5

Number of pulses

DAC linearity at Vled = 500mV

0.3

0.2

0.ꢀ

2.5

3.5

4.5

5.5

-0.ꢀ

-0.2

-0.3

-0.4

-0.5

Vcc, V

Line regulation at Vled = ꢀ00mA

Setup Time at Iled = ꢀ033A

Date: Dec 5-06 Rev E

Constant Current LED Driver

THEORY OF OPERATION

Introduction

The SP76ꢀ8 is a linear low-side, constant-

current driver designed to drive high power

LEDs from an input voltage rail. The design

consists of a regulator reference voltage

source, DAC, voltage-to-current converter,

thermal shutdown, timeout shutdown, and

outputdriver.Theprecisionreferencevoltage

ensuresgoodperformanceovervoltageand

temperature. The built-in thermal protection

automatically stops LED current to prevent

overheating. A timeout function serves as

a failsafe, shutting down the output for cur-

rents greater than 266mA after 4 seconds

of continuous operation if the enable input

is not cycled.

If the pulse number exceeds 3ꢀ, all other

pulses are ignored and ꢀ033 mA current

is set.

The SP76ꢀ8 can be placed into Sleep Mode

by applying a logic LOW on the CTRLpin for

longerthanꢀ00µsafteranypulsesequence.

IntheSleepMode, thedriverisdisabledand

Iled current is zero, but blocks associated

with the DAC remain active, and Icc Sleep

Mode Current is always higher than Icc

current in Shutdown Mode. This function is

used to output the Iled current for a speci-

ﬁed duration.

IftheIledcurrentexceeds266mA(8pulses)

the maximum Time Duration is 4s. After

that, the device is automatically sent into

Sleep Mode. This function is intended to

protect the LED if, for example, the device

was left on in a high current condition for a

long period of time.

Current Setting DAC

The LED output current is deﬁned by a cur-

rentcontrolDAC.TheinputtotheDACisthe

CTRL pin. The DAC outputs a unit current

of 33.33mA with each applied pulse at the

CTRL pin. The DAC has 5 bits, so the total

numberofstepsthatcanbeachievedis2⁵or

32. The initial step of the DAC corresponds

tozero, sothemaximumcurrentoutputis3ꢀ

times the unit current. Any multiple of the

33.33mA output current can be achieved

from ꢀ to 3ꢀ sequentially.

AppylinganewpulsesequencetotheCTRL

pinatSleepModewillwakeupthedevicebut

increasetheIledcurrentat33.3mAmultiplied

bythenumberofpulses.Toreturnthedevice

to the previous or lower Iled current value,

use Shutdown (EN =HIGH to LOW/LOW to

HIGH) and apply a new pulse sequence to

the CTRL pin.

The DAC CTRL input is positive-edge trig-

gered and may be either at high or low logic

state when the part is powered up. The EN-

ABLE pin logic HIGH level may be applied

with Vcc voltage.

ThecurrentcontrolDACacceptsclockrates

up to 4MHz. The code for the DAC loads

whiletheoutputdrivertakes50µstorespond.

This implies that the LED output current will

reachitsﬁnalvalue50µsaftertheﬁnalpulse

is applied to the CTRL pin.

The CTRL input allows an increase in LED

current only. If a lower Iled current value

is required, the device should be sent into

shutdown mode (EN =HIGH to LOW/LOW

to HIGH) and a new pulse sequence should

be applied to the CTRL pin.

Date: Dec 5-06 Rev E

Constant Current LED Driver

THEORY OF OPERATION

Output Driver

theinternaltemperaturedropsby25°C. Ifthe

part remains in a high ambient temperature

environment or if a high power dissipation

condition exists, the output stage will cycle

on and off to maintain a preset internal

junction temperature to avoid catastrophic

damage. In that case,the LED will appear to

be blinking. Lower the LED voltage to avoid

excess power dissipation in the IC.

The SP76ꢀ8 features a low-side regulated

outputcurrentdriver. AlargeMOSFETdevice

is connected between the LED and GNDP

pins. The MOSFET drain is connected to

the LED pins and the MOSFET source is

connected to the GNDP pins. There are

two pins on each terminal of the MOSFET

inordertominimizepowerdissipationinside

thepackage.EventhoughtherearetwoLED

and GNDP pins, there is actually only one

output intended to drive one LED.

Shutdown

The light emitting diode connects from VCC

to the LED pins. The Iled current regulation

is guaranteed at dropout at the LED pins to

be less than ꢀ00mV. The output current is

regulated to within ﬁve percent of nominal

value even if the voltage between the LED

and GNDP pins varies over a wide range.

Thenominaloutputisguaranteedwithin±8%

of the deﬁned current.

The SP76ꢀ8 has a low current shutdown

function. In shutdown mode, the part draws

less than 0.ꢀµAcurrent maximum. The part

can be placed into shutdown using the EN

pin.

ENABLEandCTRLpinscannotbetri-stated

or left ﬂoating. There are no predeﬁned in-

ternalstates, soleavingthesepinsopenwill

cause the part to operate incorrectly.

Thermal Protection

Timeout

The SP76ꢀ8 has built-in thermal protection.

Aninternalp-n junctioniscomparedtothein-

ternal temperature compensated reference.

Whenthep-n junctionreachesatemperature

speciﬁc voltage, it trips a comparator which

shutsdownthedriverstageofthepartplacing

thedeviceintosleepmodewhileDACcircuit

remains active. The shutdown temperature

is deﬁned to be 160°C.

A Time Duration Before Shutdown feature

actsasafailsafetoprotecttheLEDfromlong

ON times. The nominal timeout is deﬁned

as 4 seconds.

Power-on-Reset

This function is used to set DAC and Time

Duration counters into their initial state after

power up. No signal applied to the CTRL

pin can be accepted during this time, even

iftheinputvoltageisappliedsimultaneously

to Vcc and ENABLE pins.

Thecomparatorcircuithasbuilt-inhysteresis

correspondingto25°C.Theoutputstagewill

resume operation and start sinking the cur-

rentthatwasdeﬁnedpriortoshutdownwhen

Date: Dec 5-06 Rev E

Constant Current LED Driver

BOARD LAYOUT AND GROUNDING

To obtain the best performance from the

SP76ꢀ8, a printed circuit board with ground

plane is required. High quality, low series

resistance ceramic ꢀµF bypass capacitors

should be used at the Vcc pin (pin 3). These

capacitors must be located as close to pins

3 – 6 as possible. The traces connecting the

pins and the bypassing capacitors must be

kept short and should be made as wide as

possible. Pins ꢀ – 2 are connected together

internally but we recommend connecting the

LED cathode to both pins to avoid additional

power losses at high current. Pins 6, 7 and

8 should be connected to the ground plane.

BoardlayoutshouldpreventhighLEDground

current from ﬂowing through signal ground

connected to pin 6. This pin is a separate

ground for the reference and logic sections

oftheSP76ꢀ8.Thequiescentcurrentforthe

partﬂowsintotheVCCpinandoutoftheGND

pin. This current is proportional to the Iled

current divided by approximately ꢀ500.

TIMING DIAGRAM

Date: Dec 5-06 Rev E

Constant Current LED Driver

PACKAGE: 8 PIN DFN

Date: Dec 5-06 Rev E

Constant Current LED Driver

ORDERING INFORMATION

Package Type

Part Number

Operating Temperature Range

SP76ꢀ8ER-L...................................-40°C to +85°C ............................Lead Free 8 Pin DFN

(2mm x 3mm)

SP76ꢀ8ER-L/TR ...... ......................-40°C to +85°C ............................Lead Free 8Pin DFN

(2mm x 3mm)

/TR = Tape and Reel

Pack quantity is 3,000 for DFN.

Solved by

Sipex Corporation

Headquarters and

Sales Ofﬁce

233 South Hillview Drive

Milpitas, CA 95035

TEL: (408) 934-7500

FAX: (408) 935-7600

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume

any liability arising out of the application or use of any product or circuit described herein; neither does it convey

any license under its patent rights nor the rights of others.

Date: Dec 5-06 Rev E

Constant Current LED Driver

ꢀ0

Solved by

Appendix and Web Link Information

For further assistance:

Email:

Sipexsupport@sipex.com

WWW Support page:

Sipex Application Notes:

Product Change Notices:

http://www.sipex.com/content.aspx?p=support

http://www.sipex.com/applicationNotes.aspx

http://www.sipex.com/content.aspx?p=pcn

Sipex Corporation

Solved by

Headquarters and

Sales Office

233 South Hillview Drive

Milpitas, CA95035

tel: (408) 934-7500

faX: (408) 935-7600

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of

any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.

The following sections contain information which is more

changeable in nature and is therefore generated as appendices.

1) Package Outline Drawings

2) Ordering Information

If Available:

3) Frequently Asked Questions

4) Evaluation Board Manuals

5) Reliability Reports

6) Product Characterization Reports

7) Application Notes for this product

8) Design Solutions for this product

Datasheet Appendix & Web Link Information

Solved by

APPLICATION NOTE ANP11

Powering Flash LEDs with a Supercap

INTRODUCTION

New cellular phones have incorporated high resolution cameras, which require high brightness

illumination of the ambient area in order to achieve high quality pictures. Traditional xenon-filled photo

flash cannot be used in the very tight space available to photo cameras in cellular phones. Instead,

design engineers use a white LED with high pulsed current. It occupies small PCB space when

compared with a traditional photo flash, however, it also provides significantly lower light. Additionally,

this high current can overload the phone battery during flash. A possible solution to this problem is to use

two or three LEDs instead of one in order to improve the light output and use a super capacitor to avoid

battery overload. An example of this solution is shown below in Figures 1 and 2. The circuit uses three

SP7618 LED driver ICs with one photo flash LED connected to each driver and 0.5F super capacitor that

acts as an energy storage element during the flash pulse.

DESCRIPTION AND BOARD SCHEMATIC

The SP7618 is a linear low-side constant-current driver designed to drive high power LEDs from an input

voltage rail. The driver acts as a high current source, ensuring constant LED current for the full range of

input voltage. The SP7618 allows implementing the lowest cost LED driver for a variety of applications.

Internal circuitry maintains the preset constant current output for a wide voltage range at the LED input.

The LED current can be adjusted up to 1033mA with an external clock applied to the CTRL pin. Dimming

can be achieved by using the sequencing CTRL pin or feeding a PWM signal to the EN pin. The built-in

thermal protection automatically stops LED current to prevent overheating. A timeout function serves as

a fail safe, shutting down the output for currents greater than 266mA after 4 seconds of continuous

operation. The part can be shut down by using the EN pin or holding the CTRL pin low for more than

100µS.

Figure 1. SP7618 Evaluation Board Schematic Diagram (charge pump and drivers)

Nov29, 2006

App Note: Powering Flash LEDs with a Supercap

Page 1 of 7

The schematic in Figure 1 contains three SP7618 drivers (U3, U4, and U6), each of which has one

Luxeon Flash LED as a load (D12, D13, and D15) with preset current of 1033mA at flash mode and

33mA at torch mode. The charge pump SP6682 (U1) with capacitors (C2, C3, C6, and C10) provides

current to charge super capacitor C1 up to 5.5V in flash mode. To avoid the battery overstress, the

maximum for the charge pump’s input current is limited to 300mA both at torch and flash mode. In the

flash mode, the super capacitor provides 3A pulse current during 200ms. In the torch mode, current

consumption is limited by the charge pump and linear drivers and should not exceed 100mA. The charge

pump is used in the current regulation mode when the super capacitor is discharged and in the voltage

regulation mode if the super capacitor’s voltage exceeds 5.5V.

Figure 2. SP7618 Evaluation Board Schematic Diagram (pulse generator)

Figure 2 shows the implementation of the pulse generator. This circuit is used to program the SP7618

drivers. It is designed specifically for evaluation purpose and is NOT required in a real system, as the

programming is handled by a uP through its GPIO output. This pulse generator (U2, U5, and U7) is used

to provide a pulse sequence to the driver’s CTRL and EN pins to set LED current and turn the driver

on/off. The number of pulses that determines LED current may be set separately both at flash and torch

modes by diodes U2 – U11 using binary code. Preset value is 1 pulse at torch and 31 pulses at flash

mode; that is equal 33mA and 1033mA LED current respectively.

In flash mode every push of the button S3 generates 31 positive pulses at the driver’s control pin and

200ms later, one negative pulse at the enable pin to turn drivers off and reset internal counters. Because

the super capacitor charge current is limited at 300mA, allow 3 – 5s to completely charge it after every

flash.

In torch mode every push of the button S3 generates only 1 pulse, turning on LEDs for an unlimited time.

To turn LEDs off, turn power off (switch S1) or set the flash mode using the switch S2. If you continue to

press S3, the LED current will increase gradually by 33mA for every pulse, up to three pulses. After three

pulses, the LED current remains constant because the charge pump current is limited at 300mA. After 8

pulses drivers, turn off with the typical time duration 4s.

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 2 of 7

Selecting the LED current

LED current can be adjusted up to 1033mA with a series of pulses applied to the CTRL pin. Each pulse

increases the output current at 33.33mA steps. The maximum number of the pulses is 31. The 32^ndand

following pulses are ignored. The number of pulses depend on diode position is shown in Table 1.

Number

of pulses

Torch Mode

Flash Mode

D3 D5 D7 D9 D11 D2 D4 D6 D8 D10

Table 1. Code table

Note: “+” means this diode should be installed

If the LED current is set higher than 100mA per LED in torch mode it will be limited by the charge pump.

If the LED current is set higher than 266mA per LED (8 or more CTRL pulses), the device will go into

shutdown after 4 seconds (typ).

Powering Up the SP7618 Circuit

The SP7618 Evaluation Board can be powered from a 4.5V power supply or from 3 alkaline cells, or from

a single cell Li-Io battery. Connect the 4.5V source pin with a short lead directly to the “Vin” and -4.5V

/GND pin to the “GND” posts.

Torch Mode

Set switch S2 in Torch Mode. Turn the power on using switch S1. Push the button S3. The device will

generate continuous light. To turn the light off turn the power off using switch S1 or set Flash mode using

switch S2 (in this case the device still running).

Flash Mode

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 3 of 7

Set switch S2 in Flash Mode. Turn the power on using switch S1. Let 5 – 10s to charge the super

capacitor. Push the button S3. The device will generate a 200ms light pulse. Allow 3 – 5s to charge the

super capacitor before repeating the pulse. Turn the power off.

Note:

1. We recommend powering up the device at torch mode to avoid overstressing the battery if the super capacitor is

completely discharged.

2. In torch mode, light generation has unlimited time duration. If you continue to push S3 without resetting drivers, the

LED current will increase gradually by 33mA at every pulse provided but three first pulses only. After that, the LED

current remains stable because the charge pump current is limited at 300mA. After 8 pulses, drivers turn off with time

duration 2 – 7s typical.

Figure 3. SP7618 Input Current During Power-up in Torch Mode

With Discharged Super Capacitor (CH1: 50mA/DIV)

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 4 of 7

Figure 4. SP7618 Input Current During Switching From Torch Mode to Flash Mode (CH1: 50mA/DIV)

Figure 5. SP7618 Input Current During Flash Pulse and After Flash Pulse (CH1: 50mA/DIV)

Figure 6. SP7618 Super Capacitor Discharge Current (green) during the flash pulse (black)

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 5 of 7

CH1: Flash Control Input; CH2: LED Current, 2A/DIV

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 6 of 7

EVALUATION BOARD LAYOUT

Figure 7. SP7618 Evaluation Board Layout top and bottom side (not to scale)

Table 2. SP7618EB List of Materials

Item

Quantity

Reference

Part

GS2 06F Cap-XX

2.2uF

0.1uF

C2,C3,C6,C10,C12

C4,C5,C7,C15

C8,C9,C11,C14

D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D14

D12,D13,D15

R1,R2,R3,R4,R5

R6,R8, R11,R12,R13, R16, R17

1000pF

MMBZ5232BW Diodes Inc.

BAT42WS Diodes Inc.

LXCL-PWF1 Lumileds

100k

10k

402 ohms

2 ohms

47 ohms

150k

EG2209 E-Switch

7914G-1-000E Switch Key

SP6682

CD74HC40103M

SP7618

R10

R14

R15

S1,S2

U3,U4,U6

U5,U7

74VHC00MTC Fairchild

ORDERING INFORMATION

Model

Temperature Range

Package Type

SP7618EB.................................... -40°C to +85°C....................... SP7618 Evaluation Board

SP7618ER/TR...............................-40°C to +85°C........................ 8-pin DFN (2 x 3 mm)

/TR = Tape and Reel

Pack quantity is 3000 for DFN.

Available in lead free packaging. To order add "-L" suffix to part number.

Example: SP7618ER/TR = standard; SP7618ER-L/TR = lead free

May31, 2006

App Note: Powering Flash LEDs with a Supercap

Page 7 of 7

Solved by

SP7618

Evaluation Board Manual

•

Very low dropout voltage, 100mV

Accurate current regulation down to

dropout voltage

•

No external components

Output current adjustable with

33.33mA/steps

•

Power-saving shutdown mode of

12nA typical

•

Fast turn-on (<50µS)

Time Out function to protect the LED

Thermal Shutdown Protection

Space saving 2mm x 3mm 8 pin DFN

package

DESCRIPTION AND BOARD SCHEMATIC

Figure 1. SP7618 Evaluation Board Schematic Diagram

Dec 7-06

SP7618 Evaluation Board Manual

Page 1 of 6

The SP7618 Evaluation Board is designed to help the user evaluate the performance of the SP7618 for use as a

single photo flash Luxeon LED Driver. The evaluation board is a completely assembled and tested surface mount

board which provides easy probe access points to all SP7618 inputs and outputs so that the user can quickly

connect and measure electrical characteristics and waveforms. The Evaluation Board schematic diagram is shown

at Figure 1.

The SP7618 is a linear low side constant current driver designed to drive high power LEDs from an input voltage

rail. The driver acts as a high current source ensuring constant LED current for a range of input voltage. The

SP7618 allows implementing the lowest cost LED driver for a variety of applications. Internal circuitry maintains the

preset constant current output for a wide voltage range at the LED input.

The LED current can be adjusted up to 1033mA with an external clock applied to the CTRL pin. The built-in thermal

protection automatically stops LED current to prevent overheating. A timeout function serves as a fail safe, shutting

down the output for currents greater than 266mA after 4 seconds of continuous operation if the enable input is not

cycled. The part can be shutdown by using the EN pin or holding the CTRL pin low for more than 100µS.

The evaluation board contains SP7618 driver (U2) with one Luxeon Flash LED as a load (D1) and pulse generator.

The pulse generator (U1, U4, and U5) is used to provide a pulse sequence to the driver’s CTRL and EN pins to set

LED current and turn the driver on/off. The number of pulses that determines LED current may be set by 5-bit dip-

switch (U3) using binary code. The number of pulses depend on switch position is shown on Table 1.

USING THE EVALUATION BOARD

1) Selecting the LED current

LED current can be adjusted up to 1033mA with a series of pulses applied to the CTRL pin. Each pulse increases

the output current in steps of 33.33mA. The maximum number of the pulses is 31. The 32^ndand following pulses

are ignored. The number of pulses depends on the switch position as shown on Table 1, which is on the next page.

Dec 7-06

SP7618 Evaluation Board Manual

Page 2 of 6

Number Position of DIP-Switches

of pulses

Table 1. Code Table

Note:

“+”- this switch is in ON position

If all switches are in ON position the number of pulses is 256.

2) Powering Up the SP7618 Circuit

The SP7618 Evaluation Board can be powered from a 4.5V power supply or from 3 alkaline cells.

Connect 4.5V source pin with short lead directly to the “Vin” and -4.5V/GND pin to the “GND” posts.

Install shunt S1 to short pins 2-3 (The Evaluation board is delivered by default with shunt in this position. If shunt S1

isn’t installed or short pins 1-2 the driver SP7618 is disabled).

Push the button S2. Driver (U2) will provide to the LED current in respect to dip-switch (U3) position. If the output

current is higher than 266mA (8 pulses), the driver will turn off after 4s to prevent LED damage. Every push on

button S2 turns the driver off/on and sends the CTRL pin a new pulse sequence depending on the dip-switch

position.

Disconnect Evaluation board from power supply to turn it off.

Dec 7-06

SP7618 Evaluation Board Manual

Page 3 of 6

1200

1000

800

600

400

200

Pulses #

Measured Value

Calculated Value

Graph 1. LED Current vs. number of input pulses

Pulses #

Graph 2. LED Current Relative Error vs. number of input pulses

1200

1000

800

600

400

200

0.5

1.5

Vled, V

2.5

3.5

3 pulses

7 pulses

15 pulses

31 pulses

Graph 3. Load regulation at Vin = 5.5V

1200

1000

800

600

400

200

100

200

300

400

500

600

700

Vled, V

25C

85C

Graph 4. Load regulation at 25⁰C and 85⁰C

Dec 7-06

SP7618 Evaluation Board Manual

Page 4 of 6

EVALUATION BOARD LAYOUT

Figure 2. SP7618 Evaluation Board Layout top and bottom side

Count Reference Designator

Value

Description

C1, C2

C4, C5, C6, C7, C9

R1, R2, R3, R4, R5, R13, R14

R6, R8, R9, R10, R12

R11

0.1uF

0603ZC104MAT AVX

0.01uF

1000pF

4700pF

06033C103MAT2A AVX

06033C102MAT2A AVX

06033C472MAT2A AVX

LXCL-PWF1 Lumileds

BAT42WS Diodes Inc

GND

Vin

100k

10k

1001-0-15-01-30-02-04-0 Mill-Max

CRCW0603104J Vishay

CRCW0603102J Vishay

CRCW0603105J Vishay

CRCW060347RJ Vishay

Header 42375-22-28-4033 Molex

7914 G-002-000E Bourns

CD74HC40103M

U4, U5

SP7618 Sipex

5-bit DIP Switch

74VHC00MTC Fairchild

Table 2. SP7618EB List of Materials

Dec 7-06

SP7618 Evaluation Board Manual

Page 5 of 6

ORDERING INFORMATION

Temperature Range

Model

Package Type

SP7618EB................................................... -40°C to +85°C........................................ SP7618 Evaluation Board

SP7618ER-L/TR...........................................-40°C to +85°C..............................Lead Free 8-pin DFN (2 x 3 mm)

/TR = Tape and Reel

Pack quantity is 3000 for DFN.

For further assistance:

Email:

Sipexsupport@sipex.com

WWW Support page:

Live Technical Chat:

Sipex Application Notes:

http://www.sipex.com/content.aspx?p=support

http://www.geolink-group.com/sipex/

http://www.sipex.com/applicationNotes.aspx

Sipex Corporation

Headquarters and

Sales Office

Solved by

233 South Hillview Drive

Milpitas, CA95035

tel: (408) 934-7500

fax: (408) 935-7600

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume

any liability arising out of the application or use of any product or circuit described herein; neither does it convey

any license under its patent rights nor the rights of others.

Dec 7-06

SP7618 Evaluation Board Manual

Page 6 of 6

Reliability and Qualification Report

SP7618/SP7619

Prepared by: G. West

Quality Manager

Date: 12/04/06

Reviewed by: Fred Claussen

VP Quality & Reliability

Date: 12/04/06

SP7618/SP7619

December 4, 2006

Page 1 of 5

Table Of Contents

Title Page…………………………………………………………..………I

Table Of Contents………………………………………………….………II

Device Description…………………………………………..……….….…II

Pin Out……………………………………………………………………..II

Manufacturing Information……………………….……………………….II

Reliability Test Summary.………………..……………….…………….…III

Life Test Data……………………………………………………………...III

FIT Data Calculations……………………………………………….……..IV

MTBF Data Calculations……………………………………...…………...IV

ESD Results ………………………………………………………………..V

Latch-up Results …………………………………………………………...V

Device Description:

The SP7618/9 is a linear low side constant current driver designed to source two preset

currrents of 200mA/500mA (SP7619), 200mA/700mA (SP7619A)*. The preset currents can

be set by driving the CTRL pin high or low. Dimming or shutdown can be done by feeding

a PWM signal to the EN pin. Fast EN turn-on and turn-off time allows for very fast PWM

dimming frequencies, completely eliminating flicker. The driver acts as a current source

ensuring constant LED current for a range of input voltage. The SP7619 is useful for

implementing the lowest cost LED driver for a variety of applications. Internal circuitry

maintains the preset constant current output for a wide voltage range at the LED input. The

built-in thermal protection automatically stops LED current to prevent overheating. A timeout

function serves as a fail safe, shutting down the output for currents greater than 266mA after

4 seconds of continuous operation if the enable input is not cycled.

Pin Out:

Manufacturing Information:

Products:

Description:

Mask Set(s):

Lot Number:

Package:

SP7618/SP7619

Constant Current LED Driver

MS1473

DA10028, DA10229

8L DFN

Mold Compound:

Die Attach Material:

Bond Diagram:

Sumitomo G770HT

Ablebond 8290

501-4091

SP7618/SP7619

December 4, 2006

Page 2 of 5

Reliability Qualification Test Summary:

Stress Level Device Mask Set Lot Number Burn-In Temp Sample Size No. Fail

1000Hrs

SP7619

MS1473 DA10028

MS1473 DA10229

125 °C

Life Test

Life testing is conducted to determine if there are any fundamental reliability related

failure mechanism(s) present in the device.

These failure mechanisms can be divided roughly into four groups:

1. Process or die related failures, such as oxide-related defects, metalization-related

defects and diffusion-related defects.

2. Assembly-related defects such as chip mount wire bond or package-related

failures.

3. Design related defects.

4. Miscellaneous, undetermined or application-induced failures.

Life Test Results

As part of the Sipex design qualification program, the Engineering group had subjected

154 units of SP7619 for a 1000 Hour reliability life test at 125° C.

168 hour Life test

154 units of the SP7619 parts were subjected to the life test profile and completed

168hr the test without any part failures.

500 hour Life test

154 units of the SP7619 parts were reintroduced to the second phase of the test,

where the parts again successfully completing the 500-hour life test without any

failures.

SP7618/SP7619

December 4, 2006

Page 3 of 5

1000 hour Life test

154 units of the SP7619 parts were reintroduced to the final phase of the test,

where the parts again successfully completed 1000-hour life test without any shift

on the process parameters.

FIT Rate Calculations

The FIT (failures in time) rate is the predicted number of failures per billion device-

hours. This predicted value is based upon the:

1. Life Test conditions (time and temperature, device quantity and number of failures)

are summarized under HTOL test table.

2. Activation Energy (E_a) of the potential failure modes.

The weighted Activation Energy, E_a, of observed failure mechanisms of Sipex products

has been determined to be 0.8 eV.

Based on the above criteria, the FIT rates at 25°, 55° and 70°C operation at both 60% and

90% confidence levels for the SP508 have been calculated and are listed below.

FIT Failure Rates SP7619 Product

Confidence Level

+25°C

3.1

+55°C

47.3

+70°C

156.0

403.3

60%

90%

7.9

122.3

1 FIT = 1 Failure per Billion Device-Hours

MTBF Calculation for SP7619 Product

Confidence Level

+25°C

3.27E+08

1.26E+08

+55°C

2.11E+07

8.17E+06

+70°C

6.41E+06

2.48E+06

60%

90%

SP7618/SP7619

December 4, 2006

Page 4 of 5

ESD Testing

HBM ESD Testing - 3 units from each of two lots were subjected to +2000V Human

Body Model (HBM) ESD stress and 3 units from each of two lots were subjected to

-2000V Human Body Model (HBM) ESD stress. Each pin was subjected to three pulses

with respect to ground. All units passed testing after ESD stress.

Latch-up Testing

Latch-up Testing - 5 units from each of two lots were subjected to latch-up testing at

+/-100mA and 85C. All units passed.

SP7618/SP7619

December 4, 2006

Page 5 of 5

SP7618ER/TR [EXAR]

相关型号：

SP7618_06

SP7619

SP7619A

SP7619AER-L

SP7619AER-L/TR

SP7619AER-LTR

SP7619AERL

SP7619AERL/TR

SP7619EB

SP7619ER-L

SP7619ER-L/TR

SP7619ER-LTR