LT3745_15 Datasheet, PDF (1/28 Pages) Linear Technology – 16-Channel 50mA LED Driver with Buck Controller

LT3745
16-Channel 50mA LED
Driver with Buck Controller
Features
n _{6V to 55V Power Input Voltage Range}
n _{16 Independent LED Outputs Up to 75mA/36V}
n _{±3% LED Current Matching at 50mA (Typ ±1%)}
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
n _{40-Lead 6mm × 6mm QFN Package}
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 and
True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Description
The LT^®3745 integrates a 16-channel LED driver with a 55V
buck controller. The LED driver lights up to 75mA/36V 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. A ±3% LED cur-
rent matching and a 0.5µs minimum LED on-time can be
achieved at 50mA per channel.
The LT3745 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
16-Channel LED Driver, 1MHz Buck, 10 LEDs, 25mA to 75mA per Channel, 500Hz 12-Bit Dimming
V_IN
42V TO 55V
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
LT3745
ISN
FB
60.4k
I_SET
T_SET
32.4k
2.048MHz CLOCK
PWMCK
LED00
LED01
LED_...02
LED13
LED14
LED15
SCKI
SCKO
TTL/CMOS
SDI
SDO
3745 TA01
LDI
LDO
4.7µF
47µH 25mΩ
267k
C1
2 × 47µF
10k
.....
.....
.....
TTL/CMOS
..... ..... .....
3745f
1