1
Rev. 0
DESCRIPTION
LT3966
I
2
C Programmable Quad
Monolithic Boost LED Driver
Demonstration circuit 2630A is an I
2
C programmable
quad channel monolithic boost LED driver featuring the
. It drives four separate strings of LEDs (up
to 50V) at 125mA when V
IN
is between 9V and 18V.
DC2630A runs at 2MHz switching frequency. Its four
channels are capable of powering LED strings which can
have different currents, voltages, or dimming ratios. Each
channel can be independently controlled via I
2
C commu-
nications or analog inputs. DC2630A can be configured to
run in either mode by modifying the ADDR pin settings.
It is protected against output overcurrent, overvoltage
events, and reports open and short LED fault events by
latching an alert pin. In I
2
C mode, faults can be enabled or
disabled. A DC2026C Linduino
®
One demonstration circuit
is used to interface with the board by directly connecting
it with a QuikEval™ ribbon cable and provided command
line interface code.
The LT3966 has an input voltage range from 3V to 60V.
Each boost channel has an integrated 60V 1.6A low-side
power switch. It has adjustable switching frequency
between 300kHz and 2MHz and can be synchronized to
an external clock source. Additionally, LT3966 can be pro-
grammed to output its own master clock to sync other
devices. The high side PWMTG MOSFET drivers assist
with PWM dimming and fault protection. The LT3966
channels can be configured to operate as a ground-ref-
erenced step-up (boost) LED driver, or as a floating output
LED driver to perform step-down (buck mode) or step-up/
step-down (buck-boost mode) operation.
All registered trademarks and trademarks are the property of their respective owners.
Each channel of the LT3966 can be independently dimmed
by applying a PWM signal or CTRL voltage to the corre-
sponding channel CTRL/PWM pin while operating in non-
I
2
C mode. In I
2
C mode, each channel has a maximum of
13 bits of PWM dimming resolution and 8 bits of analog
dimming resolution.
Small ceramic input and output capacitors are used to
save space and cost. The open LED overvoltage protection
uses the IC’s constant-voltage regulation loop to regu-
late the output to approximately 57V if the LED string
is opened.
Undervoltage lockout can be adjusted on the circuit with a
few simple resistor choices. The output voltage (overvolt-
age protection) can be adjusted by changing the feedback
resistors for different string voltages. Other components
may need to be changed to accommodate the change in
output voltages as well.
The LT3966 data sheet gives a complete description of
the device, operation and applications information. The
data sheet must be read in conjunction with this demo
manual for DC2630A. The LT3966EUJ is assembled in a
40-lead plastic 6mm × 6mm QFN package with a thermally
enhanced ground.
