Datasheet

TLC5947
www.ti.com ................................................................................................................................................. SBVS114A – JULY 2008 – REVISED SEPTEMBER 2008
TERMINAL FUNCTIONS
TERMINAL
NAME DAP RHB I/O DESCRIPTION
SIN 4 32 I Serial input for grayscale data
Serial data shift clock. Schmitt buffer input. Data present on the SIN pin are shifted into the shift
register with the rising edge of the SCLK pin. Data are shifted to the MSB side by 1-bit
SCLK 3 31 I
synchronizing of the rising edge of SCLK. The MSB data appears on SOUT at the falling edge of
SCLK. A rising edge on the SCLK input is allowed 100 ns after an XLAT rising edge.
The data in the grayscale shift register are moved to the grayscale data latch with a low-to-high
transition on this pin. When the XLAT rising edge is input, all constant current outputs are forced
XLAT 30 26 I
off until the next grayscale display period. The grayscale counter is not reset to zero with a rising
edge of XLAT.
Blank (all constant current outputs off). When BLANK is high, all constant current outputs (OUT0
through OUT23) are forced off, the grayscale PWM timing controller initializes, and the grayscale
BLANK 2 30 I
counter resets to ' 0 ' . When BLANK is low, all constant current outputs are controlled by the
grayscale PWM timing controller.
This pin sets the constant current value. OUT0 through OUT23 constant sink current is set to the
IREF 31 27 I/O
desired value by connecting an external resistor between IREF and GND.
Serial data output. This output is connected to the shift register placed after the MSB of the
grayscale shift register. Therefore, the MSB data of the grayscale shift register appears at the
SOUT 29 25 O
falling edge of SCLK. This function reduces the data shifting errors caused by small timing
margins between SIN and SCLK.
Constant current output. Multiple outputs can be tied together to increase the constant current
OUT0 5 1 O
capability. Different voltages can be applied to each output.
OUT1 6 2 O Constant current output
OUT2 7 3 O Constant current output
OUT3 8 4 O Constant current output
OUT4 9 5 O Constant current output
OUT5 10 6 O Constant current output
OUT6 11 7 O Constant current output
OUT7 12 8 O Constant current output
OUT8 13 9 O Constant current output
OUT9 14 10 O Constant current output
OUT10 15 11 O Constant current output
OUT11 16 12 O Constant current output
OUT12 17 13 O Constant current output
OUT13 18 14 O Constant current output
OUT14 19 15 O Constant current output
OUT15 20 16 O Constant current output
OUT16 21 17 O Constant current output
OUT17 22 18 O Constant current output
OUT18 23 19 O Constant current output
OUT19 24 20 O Constant current output
OUT20 25 21 O Constant current output
OUT21 26 22 O Constant current output
OUT22 27 23 O Constant current output
OUT23 28 24 O Constant current output
VCC 32 28 — Power-supply voltage
GND 1 29 — Power ground
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