16-Port, 36V Constant-Current LED Driver
MAX6971
Pin Description
PIN
1
2
3
4
5鈥?0
21
22
23
24
NAME
GND
DIN
CLK
LE
OUT0鈥揙UT15
OE
DOUT
SET
V+
Ground
Serial-Data Input. Data is loaded into the internal 16-bit shift register on CLK鈥檚 rising edge.
Serial-Clock Input. Data is loaded into the internal 16-bit shift register on CLK鈥檚 rising edge.
Load-Enable Input. Data is loaded transparently from the internal shift register(s) to the output latch(es)
while LE is high. Data is latched into the output latch(es) on LE鈥檚 falling edge, and retained while LE is low.
LED Driver Outputs. OUT0 to OUT15 are open-drain, constant-current-sinking outputs rated to 28V.
Output-Enable Input. High forces outputs OUT0 to OUT15 high impedance, without altering the contents
of the output latches. Low enables outputs OUT0 to OUT15 to follow the state of the output latches.
Serial-Data Output. Data is clocked out of the 16-bit internal shift register to DOUT on CLK鈥檚 rising edge.
LED Current Setting. Connect SET to GND through a resistor (R
SET
) to set the maximum LED current.
Positive Supply Voltage. Bypass V+ to GND with a 0.1碌F ceramic capacitor.
FUNCTION
CLK
MAX6971
DIN
D0
SERIAL-TO-PARALLEL SHIFT REGISTER
D15
DOUT
LE
D0
LATCHES
D15
POWER-ON
RESET
V+
OE
V+
D0
CONSTANT-CURRENT SINKS
D15
CURRENT
REFERENCE
R
SET
OUT0
OUT1
OUT2
OUT3
OUT4
OUT15
GND
GND
Figure 1. Block Diagram
6
_______________________________________________________________________________________