Datasheet
LT3745-1
4
37451f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
LED Driver
V
ISET
Trimmed I
SET
Pin Voltage
l
1.181 1.205 1.229 V
LEDxx Operating Voltage V
IN
= 48V, V
ISP
= V
ISN
= V
LEDxx
l
36 V
LEDxx Leakage Current LED Channel Off, V
IN
= 48V,
V
ISP
= V
ISN
= 36V, V
LEDxx
= 24V
0.2 µA
I
LED
LED Constant Sink Current V
ISP
= V
ISN
= 5V, V
LEDxx
= 1V
REG
DC
= 0x00
REG
DC
= 0x20
REG
DC
= 0x3F
l
l
l
23.3
47.5
70
25.3
50.5
74
27.3
53.5
78
mA
mA
mA
∆I
LEDC
Current Mismatch Between Channels V
ISP
= V
ISN
= 5V, V
LEDxx
= 1V,
REG
DC
= 0x20 (Note 6)
l
±1 ±4 %
∆I
LEDD
Current Mismatch Between Devices V
ISP
= V
ISN
= 5V, V
LEDxx
= 1V,
REG
DC
= 0x20 (Note 7)
l
±1 ±3 %
∆I
LINE
LED Current Line Regulation V
ISP
= V
ISN
= 5V, V
LEDxx
= 1V,
REG
DC
= 0x20, V
CC
= 3V to 3.6V (Note 8)
0.1 0.2 %/V
∆I
LOAD
LED Current Load Regulation V
ISP
= V
ISN
= 5V, REG
DC
= 0x20,
V
LEDxx
= 1V to 3V (Note 9)
0.1 0.2 %/V
V
OPEN
Open LED Threshold V
ISP
= V
ISN
= 5V, V
LEDxx
Falling 0.35 V
V
SHT
Short LED Threshold V
ISP
= V
ISN
= 5V, V
LEDxx
Rising 3.7 3.9 4.1 V
t
LEDON
Minimum LED On-Time V
ISP
= V
ISN
= 5V, REG
GS
= 0x001 0.5 µs
Thermal Protection
I
TSET
T
SET
Output Current V
TSET
= 1V
l
19.0 19.8 20.6 µA
T
SET
Over Temperature Threshold T
A
= 25°C 510 mV
Serial Data Interface
V
SIH
V
SIL
Single-Ended Input (Note 10)
High Level Voltage
Low Level Voltage
V
CC
= 3V to 3.6V
2.4
0
V
CC
0.6
V
V
I
SI
Single-Ended Input Current V
CC
= 3V to 3.6V, SI = V
CC
or GND –0.2 0.2 µA
V
CM
V
DTH
V
DTL
Differential Input (Note 11)
Common Mode
High
Threshold
Low Threshold
V
CC
= 3V to 3.6V
V
ID
= 200mV
V
CM
= 1.2V
V
CM
= 1.2V
0.1
–100
50
–50
2.3
100
V
mV
mV
I
DI
Differential Input Current V
CC
= 3.6V; DI
+
, DI
–
= 2.4V or 0V –0.2 0.2 µA
V
OD
Differential Output Voltage (Note 11) R
L
= 100Ω 230 330 430 mV
∆V
OD
V
OD
Magnitude Change Between
Complementary Outputs
R
L
= 100Ω 1 10 mV
V
OS
Differential Output Offset Voltage R
L
= 100Ω 1.1 1.2 1.3 V
∆V
OS
V
OS
Magnitude Change Between
Complementary Outputs
R
L
= 100Ω 1 10 mV
I
OSD
Differential Output Short-Circuit Current DO
+
= 0V or DO
–
= 0V –6 –8 mA
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
CC
= 3.3V, V
EN/UVLO
= 1.5V, V
FB
= 1.5V, V
ISP
= V
ISN
= 0V,
R
T
= 105k, R
ISET
= 60.4k, C
CAP
= 0.47µF to V
IN
, unless otherwise noted.