LM3509SDEV National Semiconductor, LM3509SDEV Datasheet - Page 4

• 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

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Transferring Data
Every byte on the SDA line must be eight bits long, with the
most significant bit (MSB) transferred first. Each byte of data
must be followed by an acknowledge bit (ACK). The acknowl-
edge related clock pulse (9th clock pulse) is generated by the
Register Descriptions
There are 4, 8 bit registers within the LM3509 as detailed in Table 1.
Table 1.LM3509 Register Descriptions
General Purpose Register (GP)
The General Purpose register has four functions. It controls
the on/off state of MAIN and SUB/FB, it selects between Uni-
son or Non-Unison mode, provides for control over the rate of
General Purpose (GP)
Brightness Main (BMAIN)
Brightness Sub (BSUB)
General Purpose
I/O (GPIO)
Register Name
FIGURE 7. General Purpose Register Description
FIGURE 6. Write Sequence to the LM3509
Hex Address
A0
B0
10
80
4
master. The master releases SDA (HIGH) during the 9th clock
pulse. The LM3509 pulls down SDA during the 9th clock
pulse, signifying an acknowledge. An acknowledge is gener-
ated after each byte has been received. Figure 6 is an exam-
ple of a write sequence to the General Purpose register of the
LM3509.
change of the LED current (see Brightness Rate of Change
Description), and selects between White LED and OLED
mode. Figure 7 and Table 1 describes each bit available with-
in the General Purpose Register.
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Power -On-Value
0XF8
0xC0
0xE0
0xE0
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