LTC3209-1 Datasheet, PDF (11/20 Pages) Linear Technology – 600mA Main/Camera LED Controller

LTC3209-1/LTC3209-2
OPERATIO
Serial Port
The microcontroller compatible I²C serial port provides all
of the command and control inputs for the LTC3209-1/
LTC3209-2. Data on the SDA input is loaded on the rising
edge of SCL. D7 is loaded first and D0 last. There are three
data registers and one address register. Once all address
bits have been clocked into the address register acknowl-
edge occurs. After the data registers have been written a
load pulse is created after the stop bit. The load pulse
transfers all of the data held in the data registers to the DAC
registers. At this point the LED current will be changed to
the new settings. The serial port uses static logic registers
so there is no minimum speed at which it can be operated.
MAIN Current Sources
LTC3209-1
There are six MAIN current sources. These current sources
have an 8-bit linear DAC for current control. For R_REF =
24.3k, the output current range is 0mA to 28mA in 256
steps.
The current sources are disabled when a block receives an
all zero data word. The supply current for that block is
reduced to zero. In addition unused LED outputs can be
connected to CPO to turn off the current source output and
reduce the operating current to typically 10µA.
LTC3209-2
There are five MAIN current sources. These current sources
have an 8-bit linear DAC for current control. For R_REF =
24.3k, the output current range is 0mA to 28mA in 256
steps.
The current sources are disabled when a block receives an
all zero data word. The supply current for that block is
reduced to zero. In addition unused LED outputs can be
connected to CPO to turn off the current source output and
reduce the operating current to typically 10µA.
Camera Current Sources
LTC3209-1
There is one CAM current source. This current source has
a 4-bit linear DAC for current control. The output current
range is 0mA to 400mA in 16 steps (R_REF = 24.3k).
The current source is disabled when the block receives an
all zero data word. The supply current for the block is
reduced to zero. In addition, the LED output can be
connected to CPO to turn off the current source output and
reduce operating current to typically 10µA. This pin cannot
be allowed to float if unused since dropout will be errone-
ously detected.
LTC3209-2
There are two CAM current sources. These current sources
have a 4-bit linear DAC for current control. The output
current range of each current source is 0mA to 200mA in
16 steps (R_REF = 24.3k).
The current sources are disabled when the block receives
an all zero data word. The supply current for the block is
reduced to zero. In addition unused LED outputs can be
connected to CPO to turn off the current source output and
reduce the operating current to typically 10µA. These pins
cannot be allowed to float if unused since dropout will be
erroneously detected.
Auxiliary Current Source
There is one AUX current source. This current source has
a 2-bit Linear DAC for current control. The output current
range is 0mA to 13.75mA in 4 steps (OFF, 33%, 67%,
100%). The AUX output does not have dropout detection
and cannot be disabled when connected to CPO.
The current source is disabled when the block receives an
all zero data word and the supply current for the block is
reduced to zero. This output can also be used as an I²C
controlled digital open-drain general purpose output.
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