LED driver. BCT3661B Datasheet
White LED driver with digital pulse brightness control for up to 12 LEDs in Series
· 3.0V to 5.5V Input Voltage Range
· 42V Open LED Protection For up To 12 LEDs
· 200mV Reference Voltage
·1-Wire 32 Level Digital Pulse Brightness Control
· Built-in Soft Start
· Up to 90% Efficiency
· DFN2x2 Package
· Cellular Phones
· Portable Media Players
· Ultra Mobile Devices
· GPS Receivers
· White LED Backlighting
With 42V rated integrated switch FET, BCT3661B
is a boost converter that drives up to 12 LEDs in
series. The boost converter runs at 600kHz fixed
switching frequency to reduce output ripple,
improve conversion efficiency, and allows for the
use of small external components. The default
white LED current is set with the external sensor
resistor Rset, and the feedback voltage is
regulated to 200mV, as shown in the typical
application. During the operation, the LED current
can be controlled by using the 1-wire digital
interface through the CTRL pin. BCT3661B does
not burst LED current, therefore, it does not
generate audible noises on the output capacitor.
For maximum protection, the device integrated
open LED protection that disables the BCT3661B
to prevent the output from exceeding the absolute
maximum ratings during open LED conditions.
The BCT3661B is available in a DFN2x2 space
Figure 1. Typical Application of BCT3661B
Connection Diagram (Top View)
6-PIN 2mm x 2mm x 0.8mm DFN
NO NAME I/O
6 VIN I The input supply pin for the IC. Connect VIN to a supply voltage between 3.0V and 5.5V.
This is the switching node of the IC. Connect the inductor between the VIN and SW pin.
This pin is also used to sense the output voltage for open LED protection
1 FB I Feedback pin for current. Connect the sense resistor from FB to GND.
Output of the trans conductance error amplifier. Connect an external capacitor to this pin
to compensate the regulator.
Control pin of the boost regulator. It is a multi-functional pin which can be used for enable
control for digital dimming.
The thermal pad should be soldered to the analog ground plane. If possible, use thermal
via to connect to ground plane for ideal power dissipation.
-40°C to +85°C
3000units/Tape & Reel
ABSOLUTE MAXIMUM RATINGS(1)
VI Supply Voltages on VIN (2)
–0.3 to 6
Voltages on CTRL(2)
–0.3 to 6
Voltage on FB and COMP(2)
–0.3 to 6
Voltage on SW(2)
–0.3 to 50
PD Continuous Power Dissipation
See Dissipation Rating Table
TJ Operating Junction Temperature Range
–40 to 150
Storage Temperature Range
–65 to 150
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device.
These are stress ratings only, and functional operation of the device at these or any other conditions beyond those
indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions
for extended periods may affect device reliability.
(2) All voltage values are with respect to network ground terminal.
RECOMMENDED OPERATING CONDITIONS
VI Input voltage range, VIN
3.0 5.5 V
VO Output voltage range
VIN 42 V
10 22 µH
CIN Input capacitor 1 µF
CO Output capacitor(1)
0.47 10 µF
TA Operating ambient temperature
TJ Operating junction temperature
(1) These values are recommended values that have been successfully tested in several applications. Other values
may be acceptable in other applications but should be fully tested by the user.