DIODES AP8800SG-13

AP8800
350mA LED Step-Down Converter
General Description
Features
•
•
•
•
•
•
•
•
•
LED driving current up to 350mA
Compatible with 12V & 24V standard systems
High efficiency up to 92%
High switching frequency up to 0.6MHz
PWM/DC input for dimming control
Built-in soft-start function
Built-in output open-circuit protection
SOP-8L, MSOP-8L and DFN3030-10 are available in
“Green” Molding Compound (No Br, Sb)
Lead Free Finish/RoHS Compliant (Note 1)
The AP8800 is a step-down DC/DC converter designed to drive
LEDs with a constant current. The device can drive up to seven
LEDs, depending on the forward voltage of the LEDs, in series
from a voltage source of 8V to 28V. Series connection of the
LEDs provides identical LED currents resulting in uniform
brightness and eliminates the need for ballast resistors. The
AP8800 switches at frequency up to 0.6MHz. This allows the
use of small size external components, hence minimizing the
PCB area needed.
Maximum output current of AP8800 is set via an external resistor
connected between the VIN and SET input pins. Dimming is
achieved by applying either a DC voltage or a PWM signal at the
CTRL input pin. An input voltage of 0.2V or lower at CTRL shuts
down the output at SW and puts the device into a low-current
standby state.
Applications
•
•
•
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Commercial & Industrial lighting
Small LCD panel backlight
Architecture Detail lighting
Appliances interior lighting
Ordering Information
AP 8800 XX G - X
Package
S : SOP-8L
M8 : MSOP-8L
FN : DFN3030-10
Device
AP8800SG-13
AP8800M8G-13
AP8800FNG-7
Notes:
Green
Packing
G : Green
7/ 13 : Tape & Reel
Package
Code
Packaging
(Note 2)
S
M8
FN
SOP-8L
MSOP-8L
DFN3030-10
7”/13” Tape and Reel
Quantity
Part Number Suffix
2500/Tape & Reel
2500/Tape & Reel
3000/Tape & Reel
-13
-13
-7
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Pin Assignments
(1) SOP-8L
(2) MSOP-8L
( Top View )
CTRL 1
2
RSVD
SW
AP8800
3
GND 4
( Top View )
8
SET
CTRL 1
7
NC
6
5
NC
RSVD
SW
VIN
2
3
GND 4
AP8800
8
SET
7
NC
6
5
NC
VIN
(3) DFN3030-10
( Top View )
CTRL
1
10
SET
RSVD
2
9
NC
NC
3
8
NC
SW
4
7
NC
GND
5
6
VIN
AP8800
Pin Descriptions
Pin Name
SW
Description
Switch Pin. Connect inductor/freewheeling diode here. Minimize trace area at this pin to reduce
EMI.
GND
GND pin
SET
Set Nominal Output Current Pin. To configure the output current of the device.
CTRL
VIN
RSVD
NC
AP8800 Rev. 1
Dimming and On/Off Control Input. Input voltage of 0.2V or lower forces the device into low
current standby mode and shut off the output. A PWM signal allows the output current to be
adjusted above or below the level set by the resistor connected to SET input pin.
The input impedance is about 200kΩ, and if the pin is left open VCTRL = VREF
Input Supply Pin. Must be locally bypassed.
Reserved. Normally connected to Ground
No Connection.
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AP8800
350mA LED Step-Down Converter
Block Diagram
SET
SW
VIN
Voltage
Regulator
Comparator
CTRL
5V
Sensing
Block
PWM/DC
Control
AP8800
VREF 1.25V
R
GND
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
V
VIN
VIN pin voltage
-0.3~30
VSW
SW voltage
-0.3~30
TJ
TLEAD
TST
125
C
300
o
C
-65 to +125
o
C
Maximum Junction Temperature
Maximum Lead Temperature
Storage Temperature Range
V
o
Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be
exceeded under any condition.
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
Recommended Operating Conditions
Symbol
TA
AP8800 Rev. 1
Parameter
Ambient Temperature Range
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Min
-40
Max
85
Unit
ºC
MARCH 2009
© Diodes Incorporated
AP8800
350mA LED Step-Down Converter
Electrical Characteristics
Symbol
VIN
IOUT
IQ
FOSC
VTHD
VREF
SET
Rds(on)
EN
EN
Parameter
Operating Input Voltage
Continuous switch Current
Quiescient Current
Switching Frequency
Internal Threshold Voltage
Internal Reference Voltage
SET pin input current
On Resistance of MOSFET
Switch leakage current
Voltage High
Voltage Low
θJA
Thermal Resistance
Junction-to-Ambient
θJC
Thermal Resistance
Junction-to-Case
ISW
Leakage
Notes:
(VIN =12V, TA=25oC, unless otherwise specified)
Conditions
VSET=VIN-0.1
Min
8.0
92
-
ON
OFF
SOP-8L (Note 4)
MSOP-8L (Note 4)
DFN3030-10 (Note 4)
SOP-8L (Note 4)
MSOP-8L (Note 4)
DFN3030-10 (Note 4)
1.25
-
(Note 3)
Typ.
20
0.25
100
1.25
1.3
1.7
92
120
46
60
98
32
Max
28
350
30
108
2.2
5
0.2
-
Unit
V
mA
μA
MHz
mV
V
μA
Ω
μA
V
V
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
3. Refer to figure 4 for the device derating curve.
4. Test condition for SOP-8L, MSOP-8L and DFN3030-10: Device mounted on FR-4 PCB, 2”x2”, 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.
Typical Application Circuit
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Application Information
LED Current Control
The LED current is controlled by the resistor RSET in Figure 1.
If the CTRL pin is floating and at a nominal voltage of VREF, the external current sense resistor RSET
(greater than 0.3 Ω) is connected between VIN and SET and defines the nominal average output current in
the LED(s) as:
VTHD
RSET
ILED =
If the CTRL pin is driven by an external voltage (lower than 2.5V), the average LED current in this case is:
ILED =
VCTRL VTHD
VREF RSET
The graph in figure 2 gives values of nominal average output current for several values of current setting
resistor (RSET) in the typical application circuit shown on Figure 1, for different voltages applied on the CTRL
pin.
LED current Versus RSET and VCTRL
400
0.56
350
0.3
0.33
LED Current [mA]
300
0.39
250
0.47
200
0.3
150
50
LED current @
VCTRL = 2.5V
1
0.56
0.68
0.39
0.47
0.56
100
LED current @
VCTRL = 1.25V
0.68
0.75
0.82
1.2
0.82
0.68
1
1.2
0.82
LED current @
VCTRL = 0.625V
1.5
1
1.2
2
1.5
1.5
2
3
2
3
3
0
0
0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95 2.1 2.25 2.4 2.55 2.7 2.85
3
RSET value [Ohms]
Figure 2: LED Current setting Vs RSET and VCTRL
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Application Information
(Continued)
Switching Frequency
700
600
100
47
Frequency [kHz]
500
150
400
12V - 1LED
68
24V - 3 LEDs
220
300
28V - 4LEDs
100
200
150
470
220
100
470
0
0
50
100
150
200
250
300
350
400
450
500
Inductor Value [uH]
Figure 3: Switching Frequency Vs Supply voltage, Inductor, and number of LEDs
Capacitor Selection
The small size of ceramic capacitors makes them ideal for AP8800 applications. X5R and X7R types are
recommended because they retain their capacitance over wider voltage and temperature ranges than other
types such as Z5U. A 1μF input capacitor is sufficient for most intended applications of AP8800.
Diode Selection
Schottky diode, e.g. B140, with their low forward voltage drop and fast reverse recovery, is the ideal choice for
AP8800 applications.
PWM Dimming
A Pulse Width Modulated (PWM) signal with a max resolution of 8bit can be applied to the CTRL pin to
regulate the output current to a value above or below the nominal average value set by resistor RSET.
Miscellaneous
To ensure optimal performance, RSVD pin should be connected to the GND pin with the shortest trace length.
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Application Information
(Continued)
Inductor Selection
A 100μH inductor is recommended for most AP8800 applications with input voltage at 24V.
Figure 4 displays the resulting switching frequency varying the main circuit parameters: Supply voltage,
Inductor value and number of LEDs to be driven.
Thermal Considerations
The graph below in figure 4, gives details for power derating. This assumes the device to be mounted on a
25x25mm PCB with 1oz copper standing in still air.
Maximum Power Dissipation
2
1.8
1.6
DFN3030-10
1.4
Power (W)
1.2
1
0.8
SOP8L
0.6
0.4
MSOP8L
0.2
0
0
25
50
75
100
125
150
Ambient Temperature (Deg C)
Figure 4: Derating curve
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Marking Information
(1) SOP-8L
( Top View )
5
8
Logo
Part Number
G : Green
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
X : Internal Code
AP8800
YY WW X X
1
4
(2) MSOP-8L
( Top View )
8
7
Logo
6
5
YWX
Part Number
AP8800
1
2
3
A~Z : Green
Y : Year : 0~9
W : Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
4
(3) DFN3030-10
( Top View )
XX
YW X
Part Number
AP8800FNG-7
AP8800 Rev. 1
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 : A~Z : Green
Package
DFN3030-10
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Identification Code
A4
MARCH 2009
© Diodes Incorporated
AP8800
350mA LED Step-Down Converter
Package Information
(All Dimensions in mm)
0.254
0.10/0.20
3.85/3.95
5.90/6.10
(1) Package Type: SOP-8L
Gauge Plane
Seating Plane
0.62/0.82
Detail "A"
7°~9°
7°~9°
0.15/0.25
1.75max.
1.30/1.50
0.35max. 45°
Detail "A"
0°/8°
0.3/0.5
1.27typ
4.85/4.95
5.4
8x-0.60
8x-1.55
6x-1.27
Land Pattern Recommendation
(Unit: mm)
(2) Package Type: MSOP-8L
4.4
4.7/5.1
2.9/3.1
8x-0.45
8x-1.4
6x-0.65
0.25
0.4/0.8
DETAIL "A"
AP8800 Rev. 1
0.95Ref.
°
Gauge plane
0°/8
0.75/0.95
Land Pattern Recommendation
(Unit:mm)
"A"
0.05/0.15
0.05
2.9/3.1
0/0.15
0.22/0.38
0.15Typ.
1
0.65Bsc.
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AP8800
350mA LED Step-Down Converter
Package Information
(Continued)
(3) Package Type: DFN3030-10
0.15Typ.
0/0.05
Seating Plane
Side View
2X-
0.25 A
0.08 C
0.57/0.60
TOP MARK
0.10 C
C
2.9/3.1
2.3/2.5
B
A
R0
.30
0
0.25/0.55
2.9/3.1
1.5/1.7
(Pin #1 ID)
2X-
0.25 B
0.375Typ.
0.50Typ.
0.2/0.3
0.10
C A B
Bottom View
AP8800 Rev. 1
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AP8800
350mA LED Step-Down Converter
Taping Orientation
For DFN3030-10
Notes:
5. The taping orientation of the other package type can be found on our website at http://www.diodes.com/datasheets/ap02007.pdf.
IMPORTANT NOTICE
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further
notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither
does it convey any license under its patent rights, nor the rights of others. The user of products 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 our website, harmless against all damages.
LIFE SUPPORT
Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the
President of Diodes Incorporated.
AP8800 Rev. 1
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