Diodes AL5811 User Manual

A

60V, LINEAR 75mA ADJUSTABLE CURRENT LED DRIVER

Description

The AL5811 is a Linear LED driver with an adjustable LED current up

to 75mA offering excellent temperature stability and output handling

capability. The AL5811 simplifies the design of linear and isolated or

non-isolated LED drivers by setting the LED current with standard

value resistors.

The AL5811 has an open drain output that can swing from 1V up to

60V enabling it drive long LED chains. Its low 0.5V R

outside of the LED current path and so accuracy is maintained while

minimizing the required overhead to regulate the LED current. This

reduces its power dissipation when compared to traditional linear

LED drivers. This makes it ideal for driving LEDs up to 75mA.

Longer LED chains can be driven by tapping V

where the chain voltage may exceed 60V.

The AL5811 is available in the exposed pad MSOP-8EP and

U-DFN3030-6 packages.

NEW PRODUCT

from the chain,

CC

SET

pin is

Features

• Low Reference Voltage (V

• -40°C to +125°C Temperature Range

• ±6% Typical LED Current Tolerance

• Low Temperature Drift

• 1.0V to 60V Open-Drain Output

• High Power Supply Rejection

• MSOP-8EP and U-DFN3030-6

• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

• Halogen and Antimony Free. “Green” Device (Note 3)

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen and Antimony free, "Green" and Lead-Free.

3. Halogen and Antimony free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl)
and <1000ppm antimony compounds.

RSET

= 0.5V)

Pin Assignments

V

1

CC

2

NC

3

NC

4

SET

V

1

CC

NC

2

R

SET

3

U-DFN3030-6

Applications

• Isolated Offline LED Converters

• Linear LED Driver

• LED Signs

• Instrumentation Illumination

(Top View)

MSOP-8EP

(Top View)

Exposed

Pad

8

7

6

5

LED

6

NC

5

GND

4

Typical Applications Circuit

V

IN

V

IN

L5811

LED

NC

NC

GNDR

CIN0.1µF

R

10kΩ

SET

V

R

AL5811

Document number: DS35255 Rev. 1 - 2

CC

AL5811

SET

LED

GND

CIN0.1µF

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V

CC

AL5811

R

SET

R

SET

LED

GND

10kΩ

January 2013

© Diodes Incorporated

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Pin Descriptions

Pin Number

MSOP-8EP U-DFN3030-6

1 1

NEW PRODUCT

Pin

Name

VCC

RSET 4 3

GND 5 4 Ground Reference Point of Device.

LED 8 6 LED Current Sink Connection.

NC 2, 3, 6, 7 2, 5 Unused

EP Exposed Pad Exposed Pad

Functional Block Diagram

Function

Supply Input.
Connect a 0.1μF ceramic capacitor between V

LED Current Setting Pin.
Connect a resistor from this pin to GND:

I
May also be used to provide PWM dimming functionality

Exposed Pad (bottom).
Used to improve thermal impedance of package.

It must be connected to GND directly underneath the package.

LED

= 750/R

SET

and GND as close as possible to the device.

CC

L5811

Absolute Maximum Ratings (@T

Symbol Parameters Ratings Unit

VCC

V

LED

V

R

RSET

I

LED

ESD HBM Human Body Model ESD Protection 1 kV

ESD CDM Charged Device Model ESD protection 1.2 kV

TJ

TST

Notes: 4. VCC pin can be greater or smaller than V

Caution: Stresses greater than the 'Absolute Maximum Ratings' specified above, may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be
affected by exposure to absolute maximum rating conditions for extended periods of time.
Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when
handling and transporting these devices

AL5811

Document number: DS35255 Rev. 1 - 2

Supply Voltage Relative to GND Pin (Note 4) -0.3 to +66 V

LED Voltage Relative to GND Pin (Note 4) -0.3 to +66 V

Voltage Relative to GND

SET

LED Pin Current Sink Current Range 85 mA

Operating Junction Temperature -40 to +150 °C

Storage Temperature -55 to +150 °C

= +25°C, unless otherwise specified.)

A

; neither should go below GND.

LED

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-0.3 to +6 V

January 2013

© Diodes Incorporated

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Package Thermal Data

θ

Package

JC

Thermal Resistance

Junction-to-case

(Note 5)

Thermal Resistance

Junction-to-Ambient

θ

JA

(Note 5)

P

DIS

= +25°C,

T

A

T

= +125°C

J

MSOP-8EP 37 85°C/W (Note 6) 1.2W

U-DFN3030-6 13 71°C/W (Note 7) 1.40W

Notes: 5. Dominant conduction path via exposed pad.

6. Test condition for MSOP-8EP: Device mounted on FR-4 PCB (51mm x 51mm 2oz copper, minimum recommended pad layout on top layer and
thermal vias to bottom layer ground plane. For better thermal performance, larger copper pad for heat-sink is needed.

7. Test condition for U-DFN3030-6: Device mounted on FR-4 PCB (51mm x 51mm 2oz copper, minimum recommended pad layout on top layer and
thermal vias to bottom layer with maximum area ground plane. For better thermal performance, larger copper pad for heat-sink is needed

Recommended Operating Conditions (@T

= +25°C, unless otherwise specified.)

A

NEW PRODUCT

Symbol Parameter Min Max Unit

VCC

V

LED

I

LED

TA

Note: 8. Maximum LED current is also limited by ambient temperature and power dissipation such that junction temperature should
be kept less than or equal 125°C.

Supply Voltage Range Relative to GND Pin 3.5 60

OUT Voltage Range Relative to GND Pin 1.0 60

V

LED Pin Current (Note 8) 10 75 mA

Operating Ambient Temperature Range -40 +125 °C

Electrical Characteristics (@T

= +25°C, VCC = 3.5V, V

A

= 1.0 (Note 9), R

LED

= 15kΩ, unless otherwise specified.)

SET

Symbol Parameter Conditions Min Typ Max Unit

V

R

RSET

I

I

LED

REG

LINE

ICC

I

LEAK

T

SHDN

T

HYS

Note: 9. All voltages unless otherwise stated are measured with respect to GND pin.

Voltage

SET

R

= 37.5kΩ

SET

R

= 10kΩ

Current Accuracy

LED

LED Current Line Regulation

Supply Current

LED Pin Leakage Current

Thermal Shutdown

Thermal Shutdown Hysteresis 20 °C

SET

R

= 15kΩ

SET

VCC = 3.5V to 60V TA = +25°C

3.5V ≤ VCC ≤ 60V

V

= 60V; V

CC

RSET = Open Circuit

LED

= 60V

TA = -40°C to +125°C

T

= +25°C

A

TA = -40°C to +125°C

= +25°C

T

A

TA = -40°C to +125°C

= +125°C

T

A

155 °C

0.5 V

18 20 22

70 75 80

47 50 53

46 54

0.25 %

200 300

350

1 µA

AL5811

Document number: DS35255 Rev. 1 - 2

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L5811

mA

µA

January 2013

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CUR

RENT

CUR

RENT

CUR

RENT

CUR

REN

T

Typical Performance Characteristics

NEW PRODUCT

80

70

60

50

(mA)

40

30

LED

20

10

0

INPUT VOLTAGE (V)

LED Current vs. Input Voltage

60

50

40

(mA)

R = 15K

SET

L5811

90

80

R = 10K

70

60

(mA)

50

40

30

LED

20

V = 3.5V

CC

10

V = 1.0V

LED

0

-40 25 125
AMBIENT TEMPERATURE (°C)

LED Current vs. Ambient Temperature

80

Ω

70

60

50

(mA)

SET

Ω

R = 10K

SET

R = 37.4K

Ω

R = 15K

SET

SET

R = 15K

SET

Ω

Ω

Ω

30

40

30

20

LED

10

V = 3.5V

IN

T = +25°C

A

0

1234 78910

0

LED PIN VOLTAGE (V)

LED Current vs. LED Pin Voltage

LED

20

10

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

V = 3.5V

CC

T = +25°C

A

R = 37.4K

SET

INPUT VOLTAGE (V)

LED Current vs. Input Voltage

Ω

AL5811

Document number: DS35255 Rev. 1 - 2

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CUR

RENT

Y CUR

R

UPPLY

CUR

R

T

Typical Performance Characteristics (cont.)

14

12

R = 75K

SET

V = 9V

IN

Ω

0.6

0.5

R = 15K

SET

L5811

Ω

NEW PRODUCT

SET

R VOLTAGE (V)

0.494

0.493

0.492

0.491

0.490

0.489

0.488

0.487

0.486

0.485

250

10

(mA)

08

06

LED

04

Thys

02

0

125

AMBIENT TEMPERATURE(°C)

Thermal Shutdown MSOP-8EP

R = 15k

SET

V = 3.5V

CC

V = 1.0V

LED

-40 25 125
AMBIENT TEMPERATURE (°C)

R Voltage vs. Ambi ent Temperature

SET

Tshdn

0.4

0.3

RSET

V (V)

0.2

0.1

V = 1.0V

LED

T = +25°C

A

160130 135 140 145 150 155

0

2 3 20 45

INPUT VOLTAGE (V)

300

R Voltage vs. Input Voltage

SET

250

R = 10K

SET

Ω

200

ENT (µA)

150

100

R = 15K

SET

R = 37.4K

SET

Ω

Ω

SUPPL

50

V = 1.0V

LED

T = +25°C

A

0

600152530404555510 20 35 50

INPUT VOLTAGE (V)

Supply Current vs. Input Voltage

R = 10K

SET

Ω

200

(µA)

EN

150

100

R = 15K

R = 37.4K

SET

SET

Ω

Ω

S

50

V = 3.5V

CC

V = 1.0V

LED

0

25

125-40

AMBIENT TEMPERATURE (°C)

Supply Current vs. Ambient Temperature

AL5811

Document number: DS35255 Rev. 1 - 2

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Application Information

Description

The AL5811 is a Linear LED driver and in normal operation has the LEDs connected to the same potential as its VCC pin and regulates the LED

current by sinking current into to its LED pin. The LED current is set by the use of an external resistor, R

This resistor supplies the bias current of the AL5811 together with current regulator to set the LED current.

The LED current is determined by this equation:

5.0

With R

The AL5811 with its 60V capability on its supply pin, V

LED chains up to 60V as shown in Figures 1 and 2. The voltage applied to the V

string. Figure 2 shows where you might power the AL5811 from a 5V rail and power the LED string from a 12V rail.

NEW PRODUCT

SET

LED

= 15k

LED

V

IN

*1500I =

*1500I

where 1500 is the current ratio between the LED pin current and R

R

SET

5.0

==

k15

mA50

, and its LED drive pin allows it to operate from supply rails up to 60V and/or directly drive

CC

pin can be greater or lower than the voltage applied to the LED

CC

, connected from the R

SET

pin current.

SET

V

LED

SET

L5811

pin to GND.

V

IN

CIN0.1µF

V

CC

AL5811

LED

CIN0.1µF

V

CC

LED

AL5811

R

SET

R

10kΩ

SET

Figure 1. Low Side Current LED Setting

High Voltage Operation

An extension of Figure 2 is to derive the power for the AL5811 from the LED chain itself see Figure 3. LED chains greater than 60V can be driven in

this manner as long PWM dimming is not utilized.

V

IN

V

C

IN

0.1µF

CC

AL5811

R

SET

GND

LED

GND

R

SET

R

= 10k Ω

SET

Figure 2. Low Side Drive – Separate Supplies

V

IN

V

CC

CIN0.1µF

AL5811

R

SET

R

GND

LED

GND

SET

R

SET

The AL5811 can also be used on the high side of the LEDs, see Figure 4. This is a simple way of extending the maximum LED chain voltage,

however, it does increase the minimum system input voltage to:

V
Where

V

AL5811

Document number: DS35255 Rev. 1 - 2

Figure 3. Low Side LED String Tapping

= V

IN(min)

LED_CHAIN

LED_CHAIN

is the LED chain voltage.

+ 3.5V.

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Figure 4. High Side Current LED String

© Diodes Incorporated

January 2013

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Application Information (cont.)

PWM Dimming

LED current dimming can be achieved by driving the R
(Figure 5). The R

pin current is then effectively switched on and off causing the LED current to turn on and off.

SET

NEW PRODUCT

pin via the current setting resistor (R

SET

80

70

60

50

40

30

LED CURRENT (mA)

20

L5811

) and series MOSFET switch to ground

SET

10

Figure 5. PWM Dimming

0

0 102030405060708090100

DUTY CYCLE (%)

LED Current vs. Duty Cycle

Frequency = 100Hz; Duty Cycle = 0.1 % to 100%;

Figure 6. PWM Dimming Linearity

R = 10K; 2LEDs in Series

SET

Thermal Considerations

When designing linear LED drivers careful consideration must be given to:

1. the power dissipation within the LED driver

and

2. PCB layout/heat sinking.

A Linear LED driver has to be able to handle the large potential input voltage variations due to the supply voltage tolerance and also the variation in

LED forward voltage due to binning and temperature.

This can result in a large potential difference across the LED driver resulting in a larger than anticipated power dissipation.

For example in n 12V powered system with a 5% output voltage tolerance; the input voltage could typically vary from 12.6V down to 11.4V driving

3 LEDs with a voltage varying from 3V to 3.5V at 75mA. This means that the LED driver has to cope with a voltage drop across varying from

approximately 3.6V to 0.9V. This means that the power dissipation of the AL5811 could be as much as 270mW.

Figure 7 below shows how the AL5811’s power dissipation capability varies with package; these values will vary with PCB size and area of metal

associated with the ground plane used for heat sinking. By increasing the area on the top layer the thermal impedance of both packages could be

improved.

AL5811

Document number: DS35255 Rev. 1 - 2

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P

OWER

PATIO

N

NEW PRODUCT

Ordering Information

1.6

U-DFN3030-6

1.4

1.2

(W)

DISSI

MSOP-8EP

1.0

0.8

0.6

0.4

0.2

0.0

-40 125-25 110-10 9558020 5035 65
AMBIENT TEMPERATURE (°C)

Figure 7. Power Dissipation Derating

L5811

Part Number Package Code Packaging

AL5811MP-13 MP MSOP-8EP 2500/Tape & Reel -13

AL5811FF-7 FF U-DFN3030-6 3000/Tape & Reel -7

AL5811

Document number: DS35255 Rev. 1 - 2

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Quantity Part Number Suffix

7”/13” Tape and Reel

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Marking Information

(1) MSOP-8EP

(2) U-DFN3030-6

NEW PRODUCT

Logo

Part Number

( Top View )

87 65

W X E

Y

AL5811

234

1

G : Green
MSOP8-EP
Y : Year : 0~9

: Week : a~z : 1~26 week;

W

A~Z : 27~52 week; Z represents
52 and 53 week

L5811

AL5811

Document number: DS35255 Rev. 1 - 2

( Top View )

XX : Identification Code

Y

X X

W

XY

: Year : 0~9

W

: Week : A~Z : 1~26 week;

a~z : 27~52 week; z represents

52 and 53 week

: G : Green

X

Part Number Package Identification Code

AL5811FF-7 U-DFN3030-6 A9

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Package Outline Dimensions (All dimensions in mm.)

Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.

(1) Package type: MSOP-8EP

D

NEW PRODUCT

x

y

1

e

A1

A

D

E

8Xb

A2

E2

A3

D1

E3

E1

Gauge Plane
Seating Plane

See Detail C

4

X

c

0.25

1

0

°

4

X

Detail C

1

0

°

L

(2) Package Type: U-DFN3030-6

A

A

1

A

3

Seating Plane

L5811

MSOP-8EP

Dim Min Max Typ

A - 1.10 ­A1 0.05 0.15 0.10
A2 0.75 0.95 0.86
A3 0.29 0.49 0.39

a

b 0.22 0.38 0.30

c 0.08 0.23 0.15

D 2.90 3.10 3.00
D1 1.60 2.00 1.80

E 4.70 5.10 4.90

E1 2.90 3.10 3.00
E2 1.30 1.70 1.50
E3 2.85 3.05 2.95

e - - 0.65

L 0.40 0.80 0.60

a 0° 8° 4°

x - - 0.750

y - - 0.750

All Dimensions in mm

D

Pin #1 ID

︵

E

Z︵4

︶

2
E

x

︶

D

45°︵0.35*0.35

e

AL5811

Document number: DS35255 Rev. 1 - 2

U-DFN3030-6

2

︶

L

b

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Dim Min Max Typ

A 0.57 0.63 0.60
A1 0 0.05 0.02
A3 - - 0.15

b 0.35 0.45 0.40

D 2.95 3.05 3.00
D2 2.25 2.45 2.35

E 2.95 3.05 3.00
E2 1.48 1.68 1.58

e - - 0.95

L 0.35 0.45 0.40

Z - - 0.35

All Dimensions in mm

January 2013

© Diodes Incorporated

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Suggested Pad Layout

Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.

(1) MSOP-8EP

NEW PRODUCT

Y2

G

X C

Y

Y1

X1

(2) U-DFN3030-6

X

2

X

1

C

C-0.409

AL5811

Document number: DS35255 Rev. 1 - 2

X

Y

1

Y

2

Y

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Dimensions

C 0.650
G 0.450
X 0.450

X1 2.000

Y 1.350
Y1 1.700
Y2 5.300

Dimensions

C 0.950

X 0.500
X1 2.400
X2 2.550

Y 0.600
Y1 1.780
Y2 3.300

Value

(in mm)

Value

(in mm)

L5811

January 2013

© Diodes Incorporated

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Taping Orientation (Note 10)

For U-DFN3030-6

L5811

NEW PRODUCT

Note: 10. The taping orientation of the other package type can be found on our website at http://www.diodes.com/datasheets/ap02007.pdf.

AL5811

Document number: DS35255 Rev. 1 - 2

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DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.

Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
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indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.

Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.

NEW PRODUCT

This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.

Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:

A. Life support devices or systems are devices or systems which:

1. are intended to implant into the body, or

labeling can be reasonably expected to result in significant injury to the user.

B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.

Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
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representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.

Copyright © 2013, Diodes Incorporated

www.diodes.com

2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the

IMPORTANT NOTICE

LIFE SUPPORT

L5811

AL5811

Document number: DS35255 Rev. 1 - 2

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