LM3508TLEV National Semiconductor, LM3508TLEV Datasheet - Page 4

• Manufacturer Part Number: LM3508TLEV
• Description: BOARD EVALUATION FOR LM3508TL
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3508TLEV

• Current - Output / Channel: 20mA
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 17V
• Features: Dimmable
• Voltage - Input: 2.7 ~ 5.5V
• Utilized Ic / Part: LM3508
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Board Operation
To operate the LM3508 evaluation board, connect a 2.7V to
5.5V supply between the VIN header and PGND.
Jumper Connections
• EN is a 3-position jumper (see bottom right jumper in figure
2). The middle pin connects to EN of the device. The top pin
of the EN header connects to PGND (device disabled) and
the bottom pin connects to VIN (device enabled).
• DIM is a 3-position header (see figure 2). The middle pin
connects to DIM of the LM3508. The left pin of the DIM header
connects to PGND (current source off). The right pin connects
to VIN (current source on with max LED current of 20mA).
Drive DIM with aPWM waveform (V
to 100kHz to adjust the LED brightness.
• 2 3 4 LEDs is a 3-position header (see figure 2). Leave open
to configure the board for 4 series LEDs. Place a jumper
H
> 1.1V, V
L
< 0.5V) at up
4
across the top and middle pin to short D3 and D4 (2 LED so-
lution). Place a jumper across the bottom and middle pin to
short only D4 (3 LED solution).
• The OPEN header opens the current path from the cathode
of D4 and the input to the current source. Normally this is
shorted. This is for demonstrating OVP and/or disconnecting
the LEDs.
R1 is a short (0Ω) this can be replaced with a sense resistor
for measuring the LED current or replaced with a 5th LED for
evaluation of low VF LEDs. EN has an internal 383kΩ pull-
down resistor placing the part in shutdown by default. DIM
also has an internal 383kΩ pull-down resistor turning off the
current source by default. For more information regarding the
operation of the LM3508 please refer to the LM3508
datasheet.