CAT4008
8-Channel Constant Current LED Driver
FEATURES
8 Constant current-sink channels
Serial interface up to 25MHz clock frequency
3V to 5.5V logic supply
LED current range from 2mA to 100mA
LED current set by external RSET resistor
300mV LED dropout at 30mA
Thermal shutdown protection
Available in RoHS-compliant 16-lead SOIC (150
and 300mil wide), and TSSOP packages
DESCRIPTION
The CAT4008 is an 8 channel constant current driver
for LED billboard and other general display
applications. LED channel currents are programmed
together via an external RSET resistor. Low output
voltage operation on the LED channels as low as 0.4V
(for 2 to 100mA LED current) allows for more power
efficient designs.
A high-speed 4-wire serial interface of up to 25MHz
clock frequency controls each individual channel using
a shift register and latch configuration. A serial output
data pin (SOUT) allows multiple devices to be
cascaded and programmed via one serial interface.
The device also includes a blanking control pin
(BLANK) that can be used to disable all channels
independently of the interface.
Thermal shutdown protection is incorporated in the
device to disable the LED outputs if the die
temperature exceeds a set limit.
The device is available in the 16-lead SOIC (narrow
and wide), and TSSOP packages.
APPLICATIONS
Billboard Display
Marquee Display
Instrument Display
General Purpose Display
For Ordering Information details, see page 13.
TYPICAL APPLICATION CIRCUIT
VIN
3V to
5.5V
1µF
VDD
CONTROLLER
20mA
LED1 LED2
LED8
BLANK
LATCH
SIN
CLK
GND
CAT4008
SOUT
RSET
to next
device
3.09kΩ
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5034 Rev. A
CAT4008
ORDERING INFORMATION
Part Number
CAT4008W-T2
CAT4008V-T1
CAT4008Y-T2
Package
SOIC16 (N)
(1)
SOIC16 (W)
(1)(2)
TSSOP16
(1)(2)
Quantity per Reel
2000
1000
2000
Package Marking
CAT4008W
CAT4008V
CAT4008Y
PIN CONFIGURATION
16-Lead SOIC (W, V), TSSOP (Y)
GND
SIN
SCLK
XLAT
LED1
LED2
LED3
LED4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VDD
RSET
SOUT
BLANK
LED8
LED7
LED6
LED5
Notes:
(1)
(2)
Matte-Tin Plated Finish (RoHS-compliant).
Contact factory for package availability.
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc. No. MD-5034 Rev. A
CAT4008
ABSOLUTE MAXIMUM RATINGS
Parameter
V
DD
Supply Voltage
Logic input/output voltage (SIN, SOUT, CLK, BLANK, LATCH)
LEDn voltage
DC output current on LED1 to LED8
Storage Temperature Range
Junction Temperature Range
Lead Soldering Temperature (10sec.)
Rating
6
-0.3V to V
DD
+0.3V
6
150
-55 to +160
-40 to +150
300
Units
V
V
V
mA
°C
°C
°C
RECOMMENDED OPERATING CONDITIONS
Parameter
V
DD
Voltage applied to LED1 to LED8
LED current RSET control range
Ambient Temperature Range
Range
3.0 to 5.5
0.4 to 5.5
up to 100
-40 to +85
Units
V
V
mA
°C
ELECTRICAL OPERATING CHARACTERISTICS
DC CHARACTERISTICS
V
DD
= 5.0V, T
AMB
= 25 ºC, over recommended operating conditions unless specified otherwise.
Symbol
I
LED-ACC
Name
LED Current (any channel)
Conditions
V
LED
= 1V, R
SET
= 3.08kΩ
V
LED
= 1V, R
SET
= 1.54kΩ
V
LED
= 1V, R
SET
= 769Ω
V
LED
= 1V, R
SET
= 3.08kΩ
V
LED
= 1V, R
SET
= 1.54kΩ
V
LED
= 1V, R
SET
= 769Ω
V
DD
within 4.5V and 5.5V
LED current 30mA
V
LED
within 1V and 3V
LED current 30mA
R
SET
= 3.08kΩ
R
SET
= 769Ω
R
SET
= 3.08kΩ
R
SET
= 769Ω
V
LED
= 5V, outputs off
Min
18
36
Typ
20
40
80
±1.5
±1.5
±2.0
±0.1
±0.05
2
5.5
2.5
6.2
Max
22
44
Units
mA
I
LED-MAT
ΔI
VDD
ΔI
VLED
I
DDOFF
I
DDON
I
LKG
R
LATCH
R
BLANK
V
IH
V
IL
V
HYS
I
IL
V
OH
V
OL
V
RSET
T
SD
T
HYST
LED Current Matching
(I
LED
- I
LEDAVR
) / I
LEDAVR
LED current regulation vs. V
DD
LED current regulation vs. V
LED
Supply Current (all outputs off)
Supply Current (all outputs on)
LEDn output Leakage
LATCH Pull-down Resistance
BLANK Pull-up Resistance
Logic high input voltage
Logic low input voltage
Logic input hysteresis voltage
Logic Input leakage current
(CLK, SIN)
SOUT logic high output voltage
SOUT logic low output voltage
RSET Regulated Voltage
Thermal Shutdown
Thermal Hysteresis
-6.0
+6.0
%
%/V
%/V
8
9
1
300
300
0.3xV
DD
mA
mA
mA
mA
µA
kΩ
kΩ
V
V
V
-1
100
100
0.7xV
DD
180
180
0.1xV
DD
V
I
= V
DD
or GND
I
OH
= -1mA
I
OL
= 1mA
BLANK high, outputs off
-5
V
CC
-0.3V
1.17
1.20
160
20
0
5
0.3
1.23
µA
V
V
ºC
ºC
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. MD-5034 Rev. A
CAT4008
TIMING CHARACTERISTICS
For 3.0V
≤
V
DD
≤
5.5V, T
AMB
= 25 ºC, unless specified otherwise.
Symbol
CLK
f
clk
t
cwh
t
cwl
SIN
t
ssu
t
sh
LATCH
t
lwh
T
lh
T
lsu
LEDn
t
ld
t
ls
t
lst
t
bd
t
lr
t
lf
SOUT
t
or
t
of
t
od
SOUT rise time (10% to 90%)
SOUT fall time (90% to 10%)
Propagation delay time SOUT
C
L
= 15pF
C
L
= 15pF
CLK to SOUT
8
5
5
15
25
ns
ns
ns
LED1 Propagation delay
LED Propagation delay stagger
LED Propagation delay stagger
total
BLANK Propagation delay
LED rise time (10% to 90%)
LED fall time (90% to 10%)
LATCH to LED1 off/on
LED(n) to LED(n+1)
LED1 to LED8
BLANK to LED(n) off/on
Pull-up resistor = 50Ω to 3.0V
Pull-up resistor = 50Ω to 3.0V
40
17
120
60
40
30
300
200
250
300
40
ns
ns
ns
ns
ns
ns
LATCH Pulse width
Hold time LATCH to CLK
Setup time LATCH to CLK
Channel Stagger Delay
20
4
400
ns
ns
ns
Setup time SIN to CLK
Hold time SIN to CLK
4
4
ns
ns
CLK Clock Frequency
CLK Pulse Width High
CLK Pulse Width Low
20
20
25
MHz
ns
ns
Name
Conditions
Min
(1)
Typ
(2)
Max
(1)
Units
TEST CIRCUIT FOR AC CHARACTERISTICS
1µF
VDD
VDD
LED1
Rp
50Ω
CONTROLLER
BLANK
LATCH
SIN
CLK
RSET
RSET
GND
SOUT
Cl
15pF
CAT4008
LED8
Rp
50Ω
V1
3V
Notes:
(1) All min and max values are guaranteed by design.
(2) V
DD
= 5V, LED current 30mA.
Doc. No. MD-5034 Rev. A
4
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT4008
1/f
clk
CLK
t
ssu
SIN
t
od
SOUT
t
lh
LATCH
t
lwh
t
lsu
t
sh
t
cwl
t
cwh
Figure 1. Serial Input Timing Diagram
t
ld
LATCH
t
bd
BLANK
t
ls
LED1
LED2
t
lst
= 7 t
ls
LED8
Figure 2. LED Output Timing Diagram
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. MD-5034 Rev. A
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