4
Electrical Characteristics (continued)
SC4540
Parameter Symbol Conditions Min Typ Max Units
Boost Converter Characteristics (continued)
Switch Over-Current Protection I
OCP
425 725 mA
Switch Leakage Current I
L(LX)
V
LX
= 12V 0.01 1 µA
Switch Saturation Voltage V
SAT
I
LX
= 0.3A 250 450 mV
COMP Sourcing Current
I
COMP
V
COMP
= 0.9V, T
A
= 25ºC 5
µA
COMP Sinking Current V
COMP
= 0.9V, T
A
= 25ºC 6
OUT Over-Voltage Protection V
OVP
38 43 V
OUT Internal Pull-Down Current I
OVP
During OVP condition 1 mA
OUT Bias Current
I
OUT
V
EN
= V
IN
, V
OUT
= 20V 50 70 µA
OUT Leakage Current V
EN
= 0V, V
OUT
= V
IN
= 12V 0.01 1 µA
PWM Dimming Frequency Range
(1)(2)
f
EN
Applied to EN pin 100 50k Hz
PWM Dimming Duty Cycle Range
(1)(2)
D
EN
200Hz on EN pin 0 100 %
Current Sink Characteristics
BL Current Setting Range
(3)
I
BL
130mA
BL Current Setting Accuracy T
A
= 25°C -3.5 3.5 %
BL Leakage Current I
L(BL)
V
EN
= 0V, V
BL
= 2V 0.01 0.1 µA
BL Current Line Regulation I
BL
/V
IN
V
IN
= 3.0 to 5.5V ±0.05 mA/V
BL Voltage V
BL
0.35 V
ISET Bias Voltage V
ISET
0.5 V
ISET-to-I
BL
Gain A
ISET
230 A/A
Start-Up Time
t
start-up
1µs
Notes:
(1) Guaranteed by design.
(2) See PWM Dimming description in the Applications Information section for limitations at high PWM dimming frequencies and low PWM
dimming duty cycles.
(3) Not recommended to program below 1mA with R
ISET
due to tolerance stackup. To produce output current less than 1mA, set the current >
1mA and use PWM dimming.
