LT3746 Datasheet, PDF (1/28 Pages) Linear Technology – 32-Channel 20mA LED Driver with Buck Controller 0.5μs Minimum LED On Time

LT3746
32-Channel 20mA LED
Driver with Buck Controller
Features
n _{6V to 55V Power Input Voltage Range}
n _{32 Independent LED Outputs up to 30mA/13V}
n _{6-Bit Dot Correction Current Adjustment}
n _{12-Bit Grayscale PWM Dimming}
n _{0.5µs Minimum LED On Time}
n _{Adaptive LED Bus Voltage for High Efficiency}
n _{Cascadable 30MHz Serial Data Interface}
n _{Full Diagnostic and Protection: Individual Open/Short}
LED and Overtemperature Fault
Applications
n _{Large Screen Display LED Backlighting}
n _{Mono-, Multi-, Full-Color LED Displays}
n _{LED Billboards and Signboards}
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Description
The LT^®3746 integrates a 32-channel LED driver with a 55V
buck controller. The LED driver lights up to 30mA/13V of
LEDs in series per channel, and the buck controller gener-
ates an adaptive bus voltage supplying the parallel LED
strings. Each channel has individual 6-bit dot correction
current adjustment and 12-bit grayscale PWM dimming.
Both dot correction and grayscale are accessible via a
serial data interface in TTL/CMOS logic.
The LT3746 performs full diagnostic and protection
against open/short LED and overtemperature fault. The
fault status is sent back through the serial data interface.
The 30MHz fully-buffered, skew-balanced, cascadable
serial data interface makes the chip extremely suitable
for large screen LCD dynamic backlighting and mono-,
multi-, full-color LED displays.
Typical Application
32-Channel LED Driver, 1MHz Buck, 3 LEDs 10mA to 30mA per Channel, 500Hz 12-Bit Dimming
V_IN
13V TO 42V
0.47µF
EN
V_CC
3V TO 5.5V
10µF
V_IN CAP
EN/UVLO
GATE
100k
V_CC
SYNC
GND
46.4k
RT
SS
10nF
ISP
LT3746
ISN
FB
60.4k
I_SET
T_SET
32.4k
2.048MHz CLOCK
PWMCK
LED00
LED01
LED_...02
LED29
LED30
LED31
TTL/CMOS
SCKI
SDI
LDI
SCKO
SDO
LDO
3746 TA01
4.7µF
22µH 33mΩ
80.6k
C1
2 × 47µF
10k
TTL/CMOS
3746f
1