Datasheet
LM3431
www.ti.com
SNVS547G –NOVEMBER 2007–REVISED MAY 2013
ELECTRICAL CHARACTERISTICS (continued)
Specifications in standard type are for T
J
= 25°C only, and limits in boldface type apply over the junction temperature (T
J
)
range of -40°C to +125°C. Unless otherwise stated, V
IN
= 12V. Minimum and Maximum limits are specified through test,
design, or statistical correlation. Typical values represent the most likely parametric norm at T
J
= 25°C, and are provided for
reference purposes only.
(1)
Parameter Test Conditions Min Typ Max Units
PROTECTION
V
SC_SHORT
SC high threshold LED short circuit fault, SC rising 5.7 6 6.2 V
V
SC_OPEN
SC open clamp voltage LED open circuit fault, SC rising 3.16 3.50 3.87 V
I
DLY_SC
DLY source current DLY = 1.0V 39 57 73 µA
I
DLY_SK
DLY sink current DLY = 1.0V 1.8 µA
V
DLY
DLY threshold voltage DLY rising 2.40 2.8 3.16 V
V
DLY_reset
DLY reset threshold voltage DLY falling 350 mV
T
DLY_BLK
DLY blank time DIM rising 1.6 µs
V
THM
THM threshold 1.19 1.23 1.27 V
I
THM
THM hysteresis current THM = 1V 9.6 µA
I
ILIM
ILIM max source current COMP = 2.0V 31 40 46 µA
V
AFB_max
AFB overvoltage threshold 1.87 2.0 2.22 V
V
AFB_UVP
AFB undervoltage threshold AFB falling 0.73 0.85 0.98 V
T
SD
Thermal shutdown threshold 160 °C
BOOST CONTROLLER
V
CFB
CFB voltage DIM high 1.60 1.71 1.82 V
I
CFB
CFB source current DIM high 35 50 65 µA
CFB
TC
CFB temperature coefficient -2.6 mV/°C
ΔV
CFB
/ ΔV
IN
CFB Line regulation 5.5V < VIN < 36V 0.001 %/V
I
SS/SH
SS/SH source current At EN going high 13 19 24 µA
V
SS_END
SS/SH voltage At end of soft-start cycle 1.80 1.85 1.90 V
V
RT
RT voltage R
RT
= 34.8 kΩ 1.22 V
F
SW
Switching Frequency R
RT
= 34.8 kΩ 651 700 749 kHz
Minimum Switching Frequency R
RT
= 130 kΩ 180 200 220
Maximum Switching Frequency R
RT
= 22.6 kΩ 900 1000 1100
T
on_min
Minimum on time 170 230 ns
D
MAX
Maximum duty cycle 80 85 %
ILIM
gm
ILIM amplifier transconductance COMP to ILIM gain 85 umho
Vslope Slope compensation Peak voltage per cycle 75 mV
I
COMP_SC
COMP source current VCOMP = 1.2V, AFB = 0.5V 155 µA
I
COMP_SK
COMP sink current VCOMP =1.2V, AFB = 1.5V 150 µA
EA
gm
Error amplifier transconductance CFB to COMP gain, DIM high 230 umho
R
LG
Gate Drive On Resistance Source Current = 200 mA, VIN = 5.5V 6.4 Ω
Sink Current = 200 mA 2.2 Ω
I
LG
Driver Output Current Source, LG = 2.5V, VIN = 5.5V 0.35 A
Sink, LG = 2.5V 0.70 A
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