Diodes AL5811 60v, linear 75ma adjustable current led driver Datasheet

AL5811
60V, LINEAR 75mA ADJUSTABLE CURRENT LED DRIVER
Description
Pin Assignments
The AL5811 is a Linear LED driver with an adjustable LED current up
(Top View)
to 75mA offering excellent temperature stability and output handling
capability. The AL5811 simplifies the design of linear and isolated or
VCC 1
8 LED
value resistors.
NC 2
7 NC
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 RSET pin is
NC 3
6 NC
outside of the LED current path and so accuracy is maintained while
RSET 4
NEW PRODUCT
non-isolated LED drivers by setting the LED current with standard
5 GND
minimizing the required overhead to regulate the LED current. This
MSOP-8EP
reduces its power dissipation when compared to traditional linear
LED drivers. This makes it ideal for driving LEDs up to 75mA.
(Top View)
Longer LED chains can be driven by tapping VCC from the chain,
where the chain voltage may exceed 60V.
VCC 1
The AL5811 is available in the exposed pad MSOP-8EP and
U-DFN3030-6 packages.
NC 2
RSET 3
Features
Exposed
Pad
•
Low Reference Voltage (VRSET = 0.5V)
•
-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
•
Isolated Offline LED Converters
•
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
•
Linear LED Driver
•
Halogen and Antimony Free. “Green” Device (Note 3)
•
LED Signs
•
Instrumentation Illumination
Notes:
6
LED
5
NC
4
GND
U-DFN3030-6
Applications
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.
Typical Applications Circuit
VIN
VIN
VCC
CIN 0.1µF
V CC
LED
CIN 0.1µF
RSET
GND
Document number: DS35255 Rev. 1 - 2
GND
RSET 10kΩ
RSET 10kΩ
AL5811
AL5811
RSET
AL5811
LED
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AL5811
Pin Descriptions
Pin Number
MSOP-8EP
U-DFN3030-6
NEW PRODUCT
Pin
Name
VCC
1
1
RSET
4
3
GND
LED
NC
5
8
2, 3, 6, 7
4
6
2, 5
EP
Exposed Pad
Exposed Pad
Function
Supply Input.
Connect a 0.1μF ceramic capacitor between VCC and GND as close as possible to the device.
LED Current Setting Pin.
Connect a resistor from this pin to GND:
ILED = 750/RSET
May also be used to provide PWM dimming functionality
Ground Reference Point of Device.
LED Current Sink Connection.
Unused
Exposed Pad (bottom).
Used to improve thermal impedance of package.
It must be connected to GND directly underneath the package.
Functional Block Diagram
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
Symbol
Ratings
Unit
VCC
Supply Voltage Relative to GND Pin (Note 4)
-0.3 to +66
V
VLED
LED Voltage Relative to GND Pin (Note 4)
-0.3 to +66
V
VRSET
RSET Voltage Relative to GND
-0.3 to +6
V
LED Pin Current Sink Current Range
85
mA
Human Body Model ESD Protection
Charged Device Model ESD protection
1
1.2
kV
kV
ILED
ESD HBM
ESD CDM
Parameters
TJ
Operating Junction Temperature
-40 to +150
°C
TST
Storage Temperature
-55 to +150
°C
Notes:
4. VCC pin can be greater or smaller than VLED; neither should go below GND.
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
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AL5811
Package Thermal Data
Package
NEW PRODUCT
MSOP-8EP
U-DFN3030-6
Notes:
θJC
Thermal Resistance
Junction-to-case
(Note 5)
37
13
θJA
Thermal Resistance
Junction-to-Ambient
(Note 5)
PDIS
TA = +25°C,
TJ = +125°C
85°C/W (Note 6)
71°C/W (Note 7)
1.2W
1.40W
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 (@TA = +25°C, unless otherwise specified.)
Symbol
Parameter
Min
Max
Unit
VCC
Supply Voltage Range Relative to GND Pin
3.5
60
VLED
OUT Voltage Range Relative to GND Pin
1.0
60
ILED
LED Pin Current (Note 8)
10
75
mA
Operating Ambient Temperature Range
-40
+125
°C
TA
Note:
V
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.
Electrical Characteristics (@TA = +25°C, VCC = 3.5V, VLED = 1.0 (Note 9), RSET = 15kΩ, unless otherwise specified.)
Symbol
VRSET
Parameter
Conditions
RSET Voltage
RSET = 37.5kΩ
ILED
ILED Current Accuracy
Min
TA = +25°C
RSET = 10kΩ
RSET = 15kΩ
TA = -40°C to +125°C
Typ
Max
0.5
TA = -40°C to +125°C
V
18
20
22
70
75
80
47
50
53
46
Unit
mA
54
LED Current Line Regulation
VCC = 3.5V to 60V
Supply Current
3.5V ≤ VCC ≤ 60V
ILEAK
LED Pin Leakage Current
VCC = 60V; VLED = 60V
RSET = Open Circuit
TSHDN
Thermal Shutdown
155
°C
THYS
Thermal Shutdown Hysteresis
20
°C
REGLINE
ICC
Note:
TA = +25°C
0.25
TA = +25°C
200
%
300
350
TA = -40°C to +125°C
1
TA = +125°C
µA
µA
9. All voltages unless otherwise stated are measured with respect to GND pin.
AL5811
Document number: DS35255 Rev. 1 - 2
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AL5811
Typical Performance Characteristics
80
90
70
80
70
LED CURRENT (mA)
LED CURRENT (mA)
60
50
40
30
20
60
RSET = 15KΩ
50
40
30
RSET = 37.4KΩ
20
10
10
0
0
VCC = 3.5V
VLED = 1.0V
-40
25
125
AMBIENT TEMPERATURE (°C)
LED Current vs. Ambient Temperature
INPUT VOLTAGE (V)
LED Current vs. Input Voltage
80
60
RSET = 10KΩ
70
RSET = 15KΩ
50
LED CURRENT (mA)
60
LED CURRENT (mA)
NEW PRODUCT
RSET = 10KΩ
40
30
20
RSET = 15KΩ
50
40
30
RSET = 37.4KΩ
20
10
10
VIN = 3.5V
T A = +25°C
0
0
1
2
3
4
7
8
LED PIN VOLTAGE (V)
LED Current vs. LED Pin Voltage
AL5811
Document number: DS35255 Rev. 1 - 2
9
10
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0
0.5
VCC = 3.5V
TA = +25°C
1.0
1.5
2.0
2.5
3.0
3.5
INPUT VOLTAGE (V)
LED Current vs. Input Voltage
4.0
January 2013
© Diodes Incorporated
AL5811
Typical Performance Characteristics (cont.)
14
RSET = 15KΩ
0.5
10
0.4
08
Tshdn
06
VRSET (V)
NEW PRODUCT
LED CURRENT (mA)
12
0.6
RSET = 75KΩ
VIN = 9V
Thys
0.3
0.2
04
0.1
02
0
125
130
135 140
145 150
155
AMBIENT TEMPERATURE(°C)
Thermal Shutdown MSOP-8EP
0
160
0.494
VLED = 1.0V
T A = +25°C
2
300
3
20
INPUT VOLTAGE (V)
RSET Voltage vs. Input Voltage
45
0.493
250
RSET = 15k
SUPPLY CURRENT (µA)
RSET VOLTAGE (V)
0.492
0.491
0.490
0.489
0.488
RSET = 10KΩ
200
150
100
RSET = 15KΩ
RSET = 37.4KΩ
0.487
0.486
0.485
250
50
VCC = 3.5V
VLED = 1.0V
VLED = 1.0V
TA = +25°C
0
0
-40
25
125
AMBIENT TEMPERATURE (°C)
RSET Voltage vs. Ambient Temperature
5 10 15 20 25 30 35 40 45 50 55 60
INPUT VOLTAGE (V)
Supply Current vs. Input Voltage
RSET = 10KΩ
SUPPLY CURRENT (µA)
200
RSET = 15KΩ
150
RSET = 37.4KΩ
100
50
VCC = 3.5V
VLED = 1.0V
0
25
-40
125
AMBIENT TEMPERATURE (°C)
Supply Current vs. Ambient Temperature
AL5811
Document number: DS35255 Rev. 1 - 2
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AL5811
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, RSET, connected from the RSET pin to GND.
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:
NEW PRODUCT
ILED = 1500 *
0 .5
R SET
where 1500 is the current ratio between the LED pin current and RSET pin current.
With RSET = 15k
ILED = 1500 *
0 .5
= 50mA
15k
The AL5811 with its 60V capability on its supply pin, VCC, and its LED drive pin allows it to operate from supply rails up to 60V and/or directly drive
LED chains up to 60V as shown in Figures 1 and 2. The voltage applied to the VCC pin can be greater or lower than the voltage applied to the LED
string. Figure 2 shows where you might power the AL5811 from a 5V rail and power the LED string from a 12V rail.
VIN
VLED
VIN
VCC
CIN 0.1µF
LED
AL5811
RSET
VCC
CIN 0.1µF
LED
AL5811
GND
RSET
RSET 10kΩ
GND
RSET = 10kΩ
Figure 1. Low Side Current LED Setting
Figure 2. Low Side Drive – Separate Supplies
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.
VIN
VIN
VCC
CIN 0.1µF
VCC
LED
CIN 0.1µF
AL5811
RSET
AL5811
RSET
LED
GND
GND
RSET
RSET
Figure 4. High Side Current LED String
Figure 3. Low Side LED String Tapping
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:
VIN(min) = VLED_CHAIN + 3.5V.
Where
VLED_CHAIN is the LED chain voltage.
AL5811
Document number: DS35255 Rev. 1 - 2
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AL5811
Application Information (cont.)
PWM Dimming
LED current dimming can be achieved by driving the RSET pin via the current setting resistor (RSET) and series MOSFET switch to ground
(Figure 5). The RSET pin current is then effectively switched on and off causing the LED current to turn on and off.
80
LED CURRENT (mA)
NEW PRODUCT
70
60
50
40
30
20
10
0
0
10
20
30
40 50 60 70 80
DUTY CYCLE (%)
LED Current vs. Duty Cycle
90 100
Frequency = 100Hz; Duty Cycle = 0.1% to 100%;
RSET = 10K; 2LEDs in Series
Figure 5. PWM Dimming
Figure 6. PWM Dimming Linearity
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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AL5811
1.6
NEW PRODUCT
POWER DISSIPATION (W)
1.4
U-DFN3030-6
1.2
MSOP-8EP
1.0
0.8
0.6
0.4
0.2
0.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
AMBIENT TEMPERATURE (°C)
Figure 7. Power Dissipation Derating
Ordering Information
Part Number
Package Code
Packaging
AL5811MP-13
AL5811FF-7
MP
FF
MSOP-8EP
U-DFN3030-6
AL5811
Document number: DS35255 Rev. 1 - 2
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7”/13” Tape and Reel
Quantity
Part Number Suffix
2500/Tape & Reel
-13
3000/Tape & Reel
-7
January 2013
© Diodes Incorporated
AL5811
Marking Information
(1)
MSOP-8EP
( Top View )
8
7
NEW PRODUCT
Logo
5
YWXE
AL5811
Part Number
1
(2)
6
2
3
G : Green
MSOP8-EP
Y : Year : 0~9
W : Week : a~z : 1~26 week;
A~Z : 27~52 week; Z represents
52 and 53 week
4
U-DFN3030-6
( Top View )
XX
YW X
Part Number
AL5811FF-7
AL5811
Document number: DS35255 Rev. 1 - 2
XX : Identification Code
Y : Year : 0~9
W : Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
X : G : Green
Package
U-DFN3030-6
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Identification Code
A9
January 2013
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AL5811
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
NEW PRODUCT
D
4X
10
°
x
E
0.25
D1
E2
Gauge Plane
Seating Plane
a
y
1
4X
10
°
8Xb
e
Detail C
E3
A1
A3
c
A2
A
L
D
E1
See Detail C
(2)
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
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
Package Type: U-DFN3030-6
3
A
1
A
A
e
n
a
l
P
g
n
i
t
a
e
S
2
D D
D
I
1
#
n
i
P
U-DFN3030-6
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
︵
︶
5
3
.
0
*
5
3
.
0
°
5
4
︵
︶
L
2
E
E
e
AL5811
Document number: DS35255 Rev. 1 - 2
b
x
4
Z
︵ ︶
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AL5811
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
(1) MSOP-8EP
X
C
NEW PRODUCT
Dimensions
Y
G
Y2
C
G
X
X1
Y
Y1
Y2
Y1
X1
Value
(in mm)
0.650
0.450
0.450
2.000
1.350
1.700
5.300
(2) U-DFN3030-6
2 1
X X
C
Dimensions
2
Y
1
Y
C
X
X1
X2
Y
Y1
Y2
Value
(in mm)
0.950
0.500
2.400
2.550
0.600
1.780
3.300
9
0
4
.
0
C
Document number: DS35255 Rev. 1 - 2
Y
X
AL5811
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AL5811
Taping Orientation (Note 10)
NEW PRODUCT
For U-DFN3030-6
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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AL5811
IMPORTANT NOTICE
NEW PRODUCT
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
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AL5811
Document number: DS35255 Rev. 1 - 2
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