General Description
The MAX6970 serial-interfaced LED driver provides
eight open-drain, constant-current-sinking LED driver
outputs rated at 36V. The device operates from a 3V to
5.5V supply. The MAX6970 supply and the LEDs' sup-
ply can power up in any order. The constant-current
outputs are programmed together up to 55mA using a
single external resistor. The MAX6970 operates with a
25Mbps, industry-standard, 4-wire serial interface.
The MAX6970 uses the industry-standard shift-register-
plus-latch-type serial interface. The driver accepts data
shifted into an 8-bit shift register using data input DIN
and clock input CLK. Input data appears at output
DOUT eight clock cycles later to allow cascading of
multiple MAX6970s. The latch-enable input, LE, loads
the 8 bits of shift register data into an 8-bit output latch
to set which LEDs are on and which are off. The output-
enable input, OE, gates all eight outputs on and off,
and is fast enough to be used as a PWM input for LED
intensity control.
For applications requiring LED fault detection, refer to
the MAX6981 data sheet that automatically detects
open-circuit LEDs.
For safety-related applications requiring a watchdog
timer, refer to the MAX6980 data sheet, which includes
a fail-safe feature that blanks the display if the serial
interface becomes inactive for more than 1s.
The MAX6970 is one of a family of 10 shift-register-plus-
latch-type LED drivers. The family includes 8-port and
16-port types, with 5.5V- or 36V-rated LED outputs, with
and without open-circuit LED detection and watchdog.
All versions operate from a 3V to 5.5V supply, and are
specified over the -40C to +125C temperature range.
Features
o 25Mbps Industry-Standard 4-Wire Serial Interface
at 5V
o 3V to 5.5V Logic Supply
o Eight Constant-Current LED Outputs Rated at 36V
o Up to 55mA Continuous Current per Output
o Output Current Programmed by Single Resistor
o 3% Current Matching Between Outputs
o 6% Current Matching Between ICs
o -40C to +125C Temperature Range
MAX6970
8-Port, 36V Constant-Current LED Driver
________________________________________________________________ Maxim Integrated Products
1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
GND
V+
SET
DOUT
OE
OUT7
OUT6
OUT5
OUT4
TOP VIEW
MAX6970
TSSOP/PDIP/SSOP
DIN
CLK
OUT1
LE
OUT0
OUT2
OUT3
Pin Configuration
Ordering Information
19-3890; Rev 0; 10/05
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Typical Application Circuit and Selector Guide appear at
end of data sheet.
Applications
Variable Message Signs
Marquee Displays
Point-of-Order Signs
Traffic Signs
Gaming Features
Architectural Lighting
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX6970AUE
-40C to +125C
16 TSSOP-EP*
U16E-3
MAX6970APE
-40C to +125C
16 PDIP
A16-2
MAX6970AAE
-40C to +125C
16 SSOP
P16-1
*EP = Exposed pad.
MAX6970
8-Port, 36V Constant-Current LED Driver
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
(Voltage with respect to GND.)
V+ ............................................................................-0.3V to +6V
OUT_ .....................................................................-0.3V to +40V
DIN, CLK, LE, OE, SET ................................-0.3V to (V+ + 0.3V)
DOUT Current ..................................................................10mA
OUT_ Sink Current .............................................................60mA
Total GND Current ...........................................................480mA
Continuous Power Dissipation (T
A
= +70C)
16-Pin TSSOP-EP
(derate 21.3mW/C above +70C) ..............................1702mW
16-Pin PDIP (derate 10.5mW/C above +70C)............842mW
16-Pin SSOP (derate 7.1mW/C above +70C) ............571mW
Operating Temperature Range .........................-40C to +125C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
ELECTRICAL CHARACTERISTICS
(Typical Operating Circuit, V+ = 3V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 5V, T
A
= +25C.)
(Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Operating Supply Voltage
V+
3.0
5.5
V
Output Voltage
V
OUT
36
V
Standby Current
(Interface Idle, All Output Ports
High Impedance, R
SET
= 360
)
I+
All logic inputs at V+ or GND, DOUT
unloaded
3.6
5.6
mA
Standby Current
(Interface Running, All Output
Ports High Impedance,
R
SET
= 360
)
I+
f
CLK
= 5MHz, OE = V+, DIN and LE = V+
or GND, DOUT unloaded
3.8
6
mA
Supply Current
(Interface Idle, All Output Ports
Active Low, R
SET
= 360
)
I+
All logic inputs at V+ or GND,
DOUT unloaded
17
30
mA
Input High Voltage
DIN, CLK, LE, OE
V
IH
0.7 x V+
V
Input Low Voltage
DIN, CLK, LE, OE
V
IL
0.3 x V+
V
Hysteresis Voltage
DIN, CLK, LE, OE
V
I
0.8
V
Input Leakage Current
DIN, CLK, LE, OE
I
IH
, I
IL
-1
+1
A
Pullup Resistor to V+, OE
R
OE
V+ = 5.5V
0.170
3
10.000
M
Pullup Resistor to GND, LE
R
LE
V+ = 5.5V
0.170
3
10.000
M
Output High Voltage DOUT
V
OH
I
SOURCE
= 4mA
V + - 0.5V
V
Output Low Voltage
V
OL
I
SINK
= 4mA
0.5
V
Output Current OUT_
I
OUT
V+ = 3.0V to 5.5V, V
OUT
= 0.8V to 2.5V,
R
SET
= 360
36
50
60
mA
Output Leakage Current OUT_
I
LEAK
OE = V+
1
A
MAX6970
8-Port, 36V Constant-Current LED Driver
_______________________________________________________________________________________
3
5V TIMING CHARACTERISTICS
(Typical Operating Circuit, V+ = 4.5V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
CLK Clock Period
t
CP
40
ns
CLK Pulse-Width High
t
CH
19
ns
CLK Pulse-Width Low
t
CL
19
ns
DIN Setup Time
t
DS
4
ns
DIN Hold Time
t
DH
8
ns
DOUT Propagation Delay
t
DO
12
32
ns
DOUT Rise and Fall Time
t
DR
, t
DF
C
DOUT
= 10pF, 20% to 80%
10
ns
LE Pulse-Width High
t
LW
20
ns
LE Setup Time
t
LS
15
ns
LE Rising to OUT_ Rising Delay
t
LRR
(Note 3)
100
ns
LE Rising to OUT_ Falling Delay
t
LRF
(Note 3)
280
ns
CLK Rising to OUT_ Rising Delay
t
CRR
(Note 3)
100
ns
CLK Rising to OUT_ Falling Delay
t
CRF
(Note 3)
310
ns
OE Rising to OUT_ Rising Delay
t
OEH
(Note 3)
100
ns
OE Falling to OUT_ Falling Delay
t
OEL
(Note 3)
300
ns
LED Output OUT_ Turn-On Fall
Time
t
f
80% to 20% (Note 3)
200
ns
LED Output OUT_ Turn-Off Rise
Time
t
r
20% to 80% (Note 3)
120
ns
MAX6970
8-Port, 36V Constant-Current LED Driver
4
_______________________________________________________________________________________
3.3V TIMING CHARACTERISTICS
(Typical Operating Circuit, V+ = 3V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
CLK Clock Period
t
CP
52
ns
CLK Pulse-Width High
t
CH
24
ns
CLK Pulse-Width Low
t
CL
24
ns
DIN Setup Time
t
DS
4
ns
DIN Hold Time
t
DH
8
ns
DOUT Propagation Delay
t
DO
12
48
ns
DOUT Rise and Fall Time
t
DR
, t
DF
C
DOUT
= 10pF, 20% to 80%
12
ns
LE Pulse-Width High
t
LW
20
ns
LE Setup Time
t
LS
15
ns
LE Rising to OUT_ Rising Delay
t
LRR
(Note 3)
140
ns
LE Rising to OUT_ Falling Delay
t
LRF
(Note 3)
310
ns
CLK Rising to OUT_ Rising Delay
t
CRR
(Note 3)
140
ns
CLK Rising to OUT_ Falling Delay
t
CRF
(Note 3)
340
ns
OE Rising to OUT_ Rising Delay
t
OEH
(Note 3)
140
ns
OE Falling to OUT_ Falling Delay
t
OEL
(Note 3)
330
ns
LED Output OUT_ Turn-On Fall
Time
t
f
80% to 20% (Note 3)
250
ns
LED Output OUT_ Turn-Off Rise
Time
t
r
20% to 80% (Note 3)
150
ns
Note 1: All parameters are tested at T
A
= +25C. Specifications over temperature are guaranteed by design.
Note 2: See Figure 3.
Note 3: A 65
pullup resistor is connected from OUT_ to 5.5V.
Typical Operating Characteristics
(T
A
= +25C, unless otherwise noted.)
1.3
1.6
1.5
1.4
1.7
1.8
1.9
2.0
2.1
2.2
2.3
3.0
4.0
3.5
4.5
5.0
5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF, R
SET
= 720
)
MAX6970 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
3.2
3.5
3.4
3.3
3.6
3.7
3.8
3.9
4.0
4.1
4.2
3.0
4.0
3.5
4.5
5.0
5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF, R
SET
= 360
)
MAX6970 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
5
8
11
14
17
20
3.0
4.0
3.5
4.5
5.0
5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, R
SET
= 720
)
MAX6970 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
MAX6970
8-Port, 36V Constant-Current LED Driver
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(T
A
= +25C, unless otherwise noted.)
10
13
16
19
22
25
3.0
4.0
3.5
4.5
5.0
5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, R
SET
= 360
)
MAX6970 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
0
10
5
20
15
25
30
PORT OUTPUT CURRENT vs.
PORT OUTPUT VOLTAGE (R
SET
= 720
, V+ = 3.3V)
MAX6970 toc05
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
0
1.0
1.5
0.5
2.0
2.5
3.0
T
A
= +25
C
T
A
= -40
C
T
A
= +85
C
T
A
= +125
C
0
20
10
40
30
50
60
PORT OUTPUT CURRENT vs.
PORT OUTPUT VOLTAGE (R
SET
= 360
, V+ = 3.3V)
MAX6970 toc06
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
0
1.0
1.5
0.5
2.0
2.5
3.0
T
A
= +85
C
T
A
= +25
C
T
A
= +125
C
T
A
= -40
C
0
10
5
20
15
25
30
PORT OUTPUT CURRENT vs.
PORT OUTPUT VOLTAGE (R
SET
= 720
, V+ = 5.0V)
MAX6970 toc07
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
0
1.0
1.5
0.5
2.0
2.5
3.0
T
A
= +25
C
T
A
= -40
C
T
A
= +85
C
T
A
= +125
C
0
20
10
40
30
50
60
PORT OUTPUT CURRENT vs.
PORT OUTPUT VOLTAGE (R
SET
= 360
, V+ = 5.0V)
MAX6970 toc08
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
0
1.0
1.5
0.5
2.0
2.5
3.0
T
A
= +25
C
T
A
= -40
C
T
A
= +85
C
T
A
= +125
C
24.0
24.5
25.0
25.5
26.0
3.0
4.0
3.5
4.5
5.0
5.5
PORT OUTPUT CURRENT vs. SUPPLY VOLTAGE
(R
SET
= 720
, V
OUT
= 2V)
MAX6970 toc09
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
48
49
50
51
52
3.0
4.0
3.5
4.5
5.0
5.5
PORT OUTPUT CURRENT vs. SUPPLY VOLTAGE
(R
SET
= 360
, V
OUT
= 2V)
MAX6970 toc10
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
0
10
20
30
40
50
0
4000
5000
2000
3000
1000
6000
7000
8000
9000
10,000
PORT OUTPUT CURRENT
vs. R
SET
RESISTANCE (V+ = 5.0V)
MAX6970 toc11
R
SET
RESISTANCE (
)
PORT OUTPUT CURRENT (mA)
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