ZXLD1356DACTC Diodes Inc, ZXLD1356DACTC Datasheet - Page 25

• Manufacturer Part Number: ZXLD1356DACTC
• Description: LED Drivers 550mA, 60V LED Drver, Int Swtch
• Manufacturer: Diodes Inc

Specifications of ZXLD1356DACTC

• Operating Supply Voltage: 6 V to 60 V
• Maximum Supply Current: 550 mA
• Maximum Power Dissipation: 1.8 W
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: DFN-6
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A Product Line of
Diodes Incorporated
ZXLD1356
Application information
(Continued)
Layout Considerations
LX pin
The LX pin of the device is a fast switching node, so PCB tracks should be kept as short as possible. To minimize ground
'bounce', the ground pin of the device should be soldered directly to the ground plane.
Coil and decoupling capacitors and current sense resistor
It is particularly important to mount the coil and the input decoupling capacitor as close to the device pins as possible to minimize
parasitic resistance and inductance, which will degrade efficiency. It is also important to minimize any track resistance in series
with current sense resistor R
. Its best to connect V
directly to one end of R
and Isense directly to the opposite end of R
with
S
IN
S
S
no other currents flowing in these tracks. It is important that the cathode current of the Schottky diode does not flow in a track
between R
and V
as this may give an apparent higher measure of current than is actual because of track resistance.
S
IN
ADJ pin
The ADJ pin is a high impedance input for voltages up to 1.35V so, when left floating, PCB tracks to this pin should be as short
as possible to reduce noise pickup. A 100nF capacitor from the ADJ pin to ground will reduce frequency modulation of the output
under these conditions. An additional series 3.3kΩ resistor can also be used when driving the ADJ pin from an external circuit
(see below). This resistor will provide filtering for low frequency noise and provide protection against high voltage transients.
3.3k
ZXLD1356
ADJ
GND
100nF
GND
High voltage tracks
Avoid running any high voltage tracks close to the ADJ pin, to reduce the risk of leakage currents due to board contamination.
The ADJ pin is soft-clamped for voltages above 1.35V to desensitize it to leakage that might raise the ADJ pin voltage and cause
excessive output current. However, a ground ring placed around the ADJ pin is recommended to minimize changes in output
current under these conditions.
Evaluation Boards
ZXLD1356 evaluation boards are available on request, which have connection terminals that allow customers to connect their
own LED products to the board.
25 of 29
ZXLD1356
December 2010
www.diodes.com
© Diodes Incorporated
Document number: DS33470 Rev. 3 - 2