Datasheet

GND
DIM
BOOT SW
VOUT
RON
LM3406
VIN
D1
L1
C
B
R
SNS
C
F
R
ON
C
IN
V
IN
VCC
CS
COMP
C
C
D2
V
O
www.ti.com Bill of Materials
If the LEDs are disconnected or one of the LEDs fails open-circuit while the LM3406 is operating, the
output voltage will experience a surge as the current in the output inductor seeks a discharge path. The
output capacitor (if present) can absorb some of this energy, however circuits with little or no output
capacitance can experience a voltage spike that exceeds the rating of the VOUT pin. The evaluation
board uses a 10 kΩ resistor in series with the VOUT pin to limit current flowing into the pin. Alternatively, a
diode connected from V
IN
to V
O
as shown in Figure 5 will clamp the spike to V
IN
plus a diode drop.
Figure 5. Schottky Diode Protection for Open-Circuit
8 Bill of Materials
Table 1. Bill of Materials
ID Part Number Type Size Parameters Qty Vendor
U1 LM3406 Buck LED TSSOP-14 42V, 1.5A 1 NSC
Driver
Q1 Si3458DV N-MOSFET SOT23-6 60V, 2.8A 1 Vishay
D1 CMSH2-60M Schottky Diode SMA 60V, 2A 1 Central Semi
L1 VLF10045T-330M2R3 Inductor 10 x 10 x 4.5mm 33 µH, 2.3A, 70 mΩ 1 TDK
Cin1 Cin2 C4532X7R1H685M Capacitor 1812 6.8 µF, 50V 2 TDK
Co C3216X7R1H474M Capacitor 1206 470 nF, 50V 1 TDK
Cf ,Cc VJ0603Y104KXXAT Capacitor 0603 100 nF 10% 2 Vishay
Cb VJ0603Y223KXXAT Capacitor 0603 22 nF 10% 1 Vishay
R3.5 ERJ6RQFR56V Resistor 0805 0.56Ω 1% 1 Panasonic
R.7 ERJ6RQFR62V Resistor 0805 0.62Ω 1% 1 Panasonic
R1 ERJ6RQFR30V Resistor 0805 0.3Ω 1% 1 Panasonic
R1.5 ERJ6RQFR16V Resistor 0805 0.16Ω 1% 1 Panasonic
Ron CRCW08051433F Resistor 0805 143kΩ 1% 1 Vishay
Rpd Rout CRCW06031002F Resistor 0603 10 kΩ 1% 2 Vishay
OFF* DIM1 160-1512 Terminal 0.062" 3 Cambion
DIM2
VIN GND 160-1026 Terminal 0.094" 2 Cambion
CS/LED-
Vo/LED+
5
SNVA300A–September 2008–Revised May 2013 AN-1750 LM3406 Evaluation Board
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