LM3509SDEV National Semiconductor, LM3509SDEV Datasheet - Page 5

• 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

Table 2. General Purpose Register Bit Function
Table 3. Operational Truth Table
* ENM ,ENS, or OLED high enables analog circuitry.
0
1
2
3
4
5
6
7
Bit
UNI
X
X
X
1
1
0
0
0
Don’t Care
Name
RMP0
RMP1
OLED
ENM
ENS
UNI
OLED
0
0
0
0
0
0
1
1
Enable MAIN. Writing a 1 to this bit enables the main current sink (MAIN).
Writing a 0 to this bit disables the main current sink and forces MAIN high
impedance.
Enable SUB/FB. Writing a 1 to this bit enables the secondary current sink (SUB/
FB). Writing a 0 to this bit disables the secondary current sink and forces SUB/
FB high impedance.
Unison Mode Select. Writing a 1 to this bit disables the BSUB register and
causes the contents of BMAIN to set the current in both the MAIN and SUB/
FB current sinks. Writing a 0 to this bit allows the current into MAIN and SUB/
FB to be independently controlled via the BMAIN and BSUB registers
respectively.
Brightness Rate of Change. Bits RMP0 and RMP1 set the rate of change of
the LED current into MAIN and SUB/FB in response to changes in the contents
of registers BMAIN and BSUB (see brightness rate of change description).
OLED = 0 places the LM3509 in White LED mode. In this mode both the MAIN
and SUB/FB current sinks are active. The boost converter ensures there is at
least 500mV at V
OLED = 1 places the LM3509 in OLED mode. In this mode the boost converter
regulates V
MAIN current sink to maintain current regulation.
These are non-functional read only bits. They will always read back as a 1.
ENM
0
1
0
0
1
1
1
0
SUB/FB
MAIN
to 1.21V. V
and V
ENS
X
X
X
X
0
1
0
1
SUB/FB
MAIN
is unregulated and must be > 300mV for the
.
Function
SUB/FB current sink disabled (SUB/FB configured as a feedback
SUB/FB current sink disabled (SUB/FB configured as a feedback
MAIN and SUB/FB current sinks enabled. Current levels set by
MAIN and SUB/FB current sinks enabled. Current levels set by
5
pin). MAIN current sink enabled current level set by BMAIN.
SUB/FB current sink enabled. Current level set by BSUB.
MAIN current sink enabled. Current level set by BMAIN.
contents of BMAIN and BSUB respectively.
pin). MAIN current sink disabled.
MAIN and SUB/FB Disabled
contents of BMAIN.
LM3509 Disabled
Result
Power-On-Value
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0
0
0
0
0
0
1