Diodes AP8800 - Manual

AP8800
Document number: DS31764 Rev. 7 - 2
1 of 13
www.diodes.com
August 2012
© Diodes Incorporated
AP8800
350mA LED STEP-DOWN CONVERTER
Description
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 V
IN
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.
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
•
SO-8, MSOP-8 and U-DFN3030-10: Available in “Green”
Molding Compound (No Br, Sb) with lead Free Finish/ RoHS
Compliant
ƒ
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
ƒ Halogen and Antimony Free. “Green” Device (Note 3)
Applications
• Commercial & Industrial Lighting
•
Small LCD Panel Backlight
•
Architecture Detail Lighting
• Appliances Interior Lighting
Pin Assignments
SO-8
1
2
3
4 5
6
7
8
( Top View )
RSVD
GND
SW
NC
CTRL SET
NC
V
IN
AP8800
MSOP-8
1
2
3
4 5
6
7
8
( Top View )
RSVD
GND
SW
NC
CTRL SET
NC
V
IN
AP8800
U-DFN3030-10
( Top View )
1
2
5
3
6
8
7
10
9
GND
RSVD
NC
CTRL
SW NC
V
IN
NC
SET
NC AP8800
4
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.
Typical Applications Circuit