Datasheet

LT3746
3
3746fa
For more information www.linear.com/3746
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Supply
V
IN
V
IN
Operating Voltage
l
6 55 V
I
VIN
V
IN
Supply Current V
EN/UVLO
= 0V
No Switching
0.2
0.
4
2
0.55
µA
mA
V
CC
V
CC
Operating Voltage
l
3 5.5 V
I
VCC
V
CC
Supply Current (Note 4) V
EN/UVLO
= 0V
LED Channel Off, 30MHz Data Off
LED Channel On, 30MHz Data Off
LED Channel On, 30MHz Data On
0.1
3.
3
10
19
1
4.0
µA
mA
mA
mA
Undervoltage Lockout (UVLO)
V
CC
UVLO Threshold V
CC
Rising
V
CC
Falling
2.82
2.61
2.89
2.68
2.96
2.75
V
V
EN/UVLO Shutdown Threshold
UVLO Threshold
I
VCC
<20µA
V
EN/UVLO
Rising
V
EN/UVLO
Falling
0.35
1.28
1.19
1.31
1.22
1.34
1.25
V
V
V
I
EN/UVLO
EN/UVLO Bias Current V
EN/UVLO
= V
CC
0.1 1 µA
(V
IN
– V
CAP
) UVLO Threshold (V
IN
– V
CAP
) Rising
(V
IN
– V
CAP
) Falling
4.6
4.1
4.9
4.4
5.2
4.7
V
V
Soft Start (SS)
I
SS
Soft Start Charge Current V
SS
= 1V –16 –12 –8 µA
Soft Start Discharge Current V
SS
= V
CC
, V
EN/UVLO
= 1V 330 µA
V
SS(TH)
Soft Start Reset Threshold 0.35 V
Oscillator
V
RT
RT Pin Voltage 1.186 1.205 1.224 V
I
RT
RT Pin Current Limit V
RT
= 0V –80 µA
f
OSC
Oscillator Frequency R
T
= 280k, V
IN
= 12V
R
T
= 105k, V
IN
= 12V
R
T
= 46.4k, V
IN
= 12V
185
470
950
205
510
1050
225
550
1150
kHz
kHz
kHz
f
SYNC
Sync Frequency Range (Note 5) R
T
= 348k, V
IN
= 12V 200 1000 kHz
SYNC LOGIC
High Level Voltage
Low Level Voltage
V
IN
= 12V, V
CC
= 3V to 5.5V
2.4
0
V
CC
0.6
V
V
Er
ror Amplifiers and Loop Dynamics
V
FB
FB Regulation Voltage V
ISP
= V
ISN
= 5V
l
1.186 1.210 1.234 V
I
FB
FB Input Bias Current V
ISP
= V
ISN
= 5V, V
FB
Regulated –120 nA
LED Regulation Voltage V
ISP
= V
ISN
= 5V, V
FB
= 1V 0.44 0.54 0.64 V
T
OFF(MIN)
Minimum GATE Off Time V
IN
= 12V, V
ISP
= V
ISN
= 5V, V
FB
= 1V 120 ns
T
ON(MIN)
Minimum GATE On Time V
IN
= 12V, (V
ISP
– V
ISN
) = 60mV, V
ISN
= 5V,
V
FB
= 1V
200 ns
Current Sense Amplifier
ISP/ISN Pin Common Mode V
ISP
= V
ISN
l
0 13 V
V
IN
to ISN Dropout Voltage (V
IN
– V
ISN
) V
IN
= 12V, V
ISP
= V
ISN
, V
FB
= 1V
l
1.7 2 V
Current Limit Sense Threshold (V
ISP
– V
ISN
) V
FB
= 1V 34 46.5 59 mV
I
ISP
ISP Input Bias Current –23 µA
I
ISN
ISN Input Bias Current –48 µA
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 24V, 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.