LM3509SDEV National Semiconductor, LM3509SDEV Datasheet - Page 3

• Manufacturer Part Number: LM3509SDEV
• Description: BOARD EVALUATION FOR LM3509SD
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3509SDEV

• Current - Output / Channel: 40mA
• Outputs And Type: 2, Non-Isolated
• Voltage - Output: 21V
• Features: Dimmable, I²C Interface
• Voltage - Input: 2.7 ~ 5.5V
• Utilized Ic / Part: LM3509
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Board Operation
To operate the LM3509 Evaluation Board, connect a 2.7V to
5.5V supply between the IN header and GND and attach an
I
TERNAL CONTROL INTERFACE section of this document.
External Control Interface
There are two mothods for controlling the LM3509 Evaluation
Board. The first option is via a National Semiconductor USB
Interface Board. The second option is by using the SDA and
SCL headers available on the upper right corner of the board.
When option 1 is used the USBL and USBR connectors plug
directly into the National Semiconductor USB Interface
Board. The connectors are keyed so they will only fit one way.
On the LM3509 Evaluation Board the VIN/VUSB jumper al-
lows for power to come from IN or from the USB Interface
board. The USB Interface Board has its own regulator that
supplies 3.3V (see documentation for the National Semicon-
ductor USB interface board). When power from the USB
Interface board is desired connect a jumper across VIN/
VUSB, if power is supplied from the IN header leave VIN/
VUSB open. DO NOT jumper VIN/VUSB while an external
source is connected to IN as this will make a conflict between
the USB Interface Board and the external power supply. This
can permanently damage the National Semiconductor USB
Interface Board. The USB interface board interfaces directly
with the LM3509.exe graphical interface via the PC (see
LM3509 I
If the National Semiconductor USB Interface Board is not
used then control of the LM3509 Evaluation Board is done by
connecting an external I
SCL and SDA headers. Both the SDA and SCL lines have
10kΩ pull-ups installed on the back side of the board.
Board Description
The following section describes the jumper settings on the
LM3509 Evaluation Board.
M_OPEN and S_OPEN are 2 position jumpers placed be-
tween the LM3509's OUT terminal and the top side of the LED
strings. Short M_OPEN to connect OUT to the MAIN LED
string and remove the jumper to open the MAIN string. The
same applys to the S_OPEN jumper and the SUB string.
These are useful for testing OVP and/or inserting a current
meter in series with the LEDs.
Both 4/3/2_M and 4/3/2_S are 4 position jumpers that allow
for different combinations of series LEDs in either the MAIN
or SUB LED strings. Both 4/3/2_S and 4/3/2_M have their
center pin (pin 2 in figure 1) connected to the bottom of the
LED string. Referring to 4/3/2_S, connecting pin 2 to pin 1 will
short D5S making the SUB string a 4 LED configuration. Con-
nect pin 2 to pin 4 to short D4S and D5S resulting in a 3 LED
configuration. Connect pin 2 to pin 3 for a 2 LED configuration
(D3S – D5S shorted). Leave 4/3/2_S open for a 5 LED con-
figuration. The operation for 4/3/2_M is the same as 4/3/2_S
only it applies to the MAIN LED string.
VIO is a 3-pin, 3-position jumper. The left pin (pin 1 in Figure
1) connects to the 3.3V supply from the USB board connector
2
C interface using one of the methods described in the EX-
2
C Compatible Interface Program section).
2
C compatible interface directly to the
3
(USBL). The right pin (pin 3) connects to IN of the LM3509.
The middle pin (pin 2) connects to VIO of the LM3509 and the
top side of the pull-up resistors (R_SDA, R_SCL, and
R_GPIO). When operating the device with the National Semi-
conductor USB Interface Board the jumper can be connected
from pin 1 to pin 2 to supply VIO with 3.3V independent of
VIN.
Resistors R4 and R5 have 0Ω’s across them. The 0Ω resis-
tors can be replaced with current sense resistors for measur-
ing LED current.
I
The LM3509 is controlled via an I
START and STOP conditions classify the beginning and the
end of the I
transitioning from HIGH to LOW while SCL is HIGH. A STOP
condition is defined as SDA transitioning from LOW to HIGH
while SCL is HIGH. The I
and STOP conditions. The I
START condition and free after a STOP condition. During da-
ta transmission the I
conditions. A START and a repeated START conditions are
equivalent function-wise. The data on SDA must be stable
during the HIGH period of the clock signal (SCL). In other
words, the state of SDA can only be changed when SCL is
LOW.
I
The chip address for the LM3509 is 0110110 (36h). After the
START condition, the I
followed by a read or write bit (R/W). R/W= 0 indicates a
WRITE and R/W = 1 indicates a READ. The second byte fol-
lowing the chip address selects the register address to which
the data will be written. The third byte contains the data for
the selected register.
2
2
C Compatible Interface
C Compatible Address
FIGURE 4. Start and Stop Sequences
2
C session. A START condition is defined as SDA
FIGURE 5. Chip Address
2
C master can generate repeated START
2
C master sends the 7-bit chip address
2
C master always generates START
2
C bus is considered busy after a
2
C compatible interface.
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