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SCT2167 V01_02; Jul/12
8-bit Serial-In/Parallel-Out Constant Current Driver
Product Description
The SCT2167 serial interfaced LED driver sinks 8 LED clusters with constant current to keep the
uniform intensity of LED displays. In applications, an external resistor is used to set the full scale
constant output current from 5mA up to 45mA. The SCT2167 guarantees each output can endure
maximum 17V DC voltage stress. The built in shift registers and data latches making the SCT2167
effective solution in driving LED display. The output enable function gates all 8 outputs on and off, and is
fast enough to be used as PWM input for LED intensity control. Since the serial data input rate can be
reached up to 25MHz, the SCT2167 will satisfy system which needs high volume data transmission to
control the LED
Features
8 constant current sinkers with output voltage sustainable to 17V
Constant output current : 5 – 30/[email protected]/5V
Excellent regulation to load, supply voltage and temperature
Temperature regulation: ±0.005%/°C
load regulation: ±0.1%/V
line regulation: ±0.5%/V
High current matching accuracy: ±1% between outputs, ±2% between ICs
Fine grayscale response with 180ns PWM pulse width
Dropout voltage 0.5V@20mA, VDD=5V
CMOS Schmitt trigger inputs with clock rate up to 25MHz @ cascade connection
The constant current value of 8 outputs is set by a single external resistor
Interlaced 30ns delay of output, preventing instant current surge and output bouncing overstress
Built in power on reset(POR) circuit forces all the outputs off while power on
Package: SSOP16 and SOP16
Applications: LED Displays, Variable Message Signs, Illumination, LED Traffic Signs
8-bit Serial-In/Parallel-Out Constant Current Driver
Pin Configurations
SCT2167
GND
SDI
CLK
LA/
OUT0
OUT1
OUT2
OUT3
1
2
3
4
5
6
7
8
16 VDD
15 REXT
14 SDO
SCT2167 13 OE/
CSSG
CSOG
12 OUT7
11 OUT6
10 OUT5
9 OUT4
Terminal Description
Pin Name Pin No. I/O
Function
GND
SDI
1 Ground terminal
2 I Serial input terminal of data shift register
CLK
3
I
Clock input terminal of shift register, data is sampled at the rising edge
of CLK.
LA/
4
I
Data is latched when LA/ is low. Data on shift register goes through
when LA/ is high.
OUT[0:7] 5 12 O Open drain, constant current outputs.
OE/
13
I
Input terminal of output enable signal. Output is enabled when OE/ is
low.
SDO
REXT
VDD
14 O Output terminal of serial data output to the SDI of next SCT2167.
15 I/O Synchronous signal, daisy chain output terminal.
16 Supply voltage terminal
Block Diagram
REXT
Current
Regulator
POR
OE/
LA/
SDI
CLK
OUT0 OUT1 OUT2
OUT6 OUT7
Output Sink Driver
O
ST D
O
ST D
O
ST D
O
ST D
O
ST D
DO
C
DO
C
DO
C
SCT2167
DO
C
DO
C
SDO
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