CAT3612_08 Datasheet, PDF (11/14 Pages) Catalyst Semiconductor – Programmable 300mA Camera Flash LED Driver

CAT3612
Protection Mode
If an LED becomes open-circuit, the output voltage
VOUT is internally limited to about 5.5V. This is to
prevent the output pin from exceeding its absolute
maximum rating.
The driver enters a thermal shutdown mode as soon
as the die temperature exceeds about +165ºC. When
the device temperature drops down by about 20ºC,
the device resumes normal operation.
External Components
The driver requires a total of four external 1μF
ceramic capacitors: two for decoupling input and
output, and two for the charge pump. Both capacitor
types X5R and X7R are recommended for the LED
driver application. In the 1.5x charge pump mode, the
input current ripple is kept very low by design, and an
input bypass capacitor of 1μF is sufficient. In 1x mode,
the device operating in linear mode does not introduce
switching noise back onto the supply.
Recommended Layout
In 1.5x charge pump mode, the driver switches
internally at a high frequency of 1MHz. It is
recommended to minimize trace length to all four
capacitors. A ground plane should cover the area
under the driver IC as well as the bypass capacitors.
Short connection to ground on capacitors Cin and
Cout can be implemented with the use of multiple via.
A copper area matching the TDFN exposed pad
(GND) must be connected to the ground plane
underneath. The use of multiple via improves the
package heat dissipation.
Figure 5. Recommended Layout
© Catalyst Semiconductor, Inc.
11
Characteristics subject to change without notice
Doc. No. MD-5016 Rev. B