General Description
The MAX6971 serial-interfaced LED driver provides 16
open-drain, constant-current-sinking LED driver outputs
rated at 36V. The MAX6971 operates from a 3V to 5.5V
supply. The MAX6971 supply and the LEDs' supply or
supplies can power up in any order. The constant-cur-
rent outputs are programmed together to up to 55mA
using a single external resistor. The MAX6971 operates
with a 25Mb, industry-standard, 4-wire serial interface.
The MAX6971 uses the industry-standard, shift-register-
plus-latch-type serial interface. The driver accepts data
shifted into a 16-bit shift register using data input DIN
and clock input CLK. Input data appears at the DOUT
output 16 clock cycles later to allow cascading of multi-
ple MAX6971s. The latch-enable input, LE, loads the 16
bits of shift register data into a 16-bit output latch to set
which LEDs are on and which are off. The output-
enable, OE, gates all 16 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 MAX6983*, which automatically detects open-circuit
LEDs.
For safety-related applications requiring a watchdog
timer, refer to the MAX6983, which includes a fail-safe
feature that blanks the display if the serial interface
becomes inactive for more than 1s.
The MAX6971 is one of a family of 12 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
25Mb, Industry-Standard, 4-Wire Serial Interface
3V to 5.5V Logic Supply
16 Constant-Current LED Outputs Rated at 36V
Up to 55mA Continuous Current per Output
Output Current Programmed by Single Resistor
3% Current Matching Between Outputs
6% Current Matching Between ICs
High-Dissipation, 24-Pin Packages
-40C to +125C Temperature Range
MAX6971
16-Port, 36V Constant-Current LED Driver
________________________________________________________________ Maxim Integrated Products
1
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
V+
SET
DOUT
OE
LE
CLK
DIN
GND
TOP VIEW
OUT15
OUT14
OUT13
OUT12
OUT3
OUT2
OUT1
OUT0
16
15
14
13
9
10
11
12
OUT11
OUT10
OUT9
OUT8
OUT7
OUT6
OUT5
OUT4
TSSOP/PDIP
MAX6971AUG
MAX6971ANG
Pin Configuration
Ordering Information
19-3808; Rev 0; 7/05
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
MAX6971AUG
-40C to +125C
24 TSSOP
MAX6971ANG
-40C to +125C
24 Narrow PDIP
*Future product--contact factory for availability.
MAX6971
16-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 ...........................................................960mA
Continuous Power Dissipation (T
A
= +70C)
24-Pin TSSOP (derate 12.2mW/C over +70C) ..........975mW
24-Pin PDIP (derate 13.3mW/C over +70C)............1067mW
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
5.7
8
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
6
8.5
mA
Supply Current
(Interface Idle, All Output Ports
Active Low, R
SET
= 360
)
I
+
All logic inputs at V+ or GND,
DOUT unloaded
18
25
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
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+ = 3V to 5.5V, V
OUT
= 0.8V to 2.5V,
R
SET
= 360
37
50
61
mA
Output Leakage Current OUT_
I
LEAK
OE = V+
1
A
Note 1: All parameters tested at T
A
= +25C. Specifications over temperature are guaranteed by design.
MAX6971
16-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, 3)
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
10
ns
LE Rising to OUT_ Rising Delay
t
LRR
(Note 3)
100
ns
LE Rising to OUT_ Falling Delay
t
LRF
(Note 3)
300
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)
320
ns
LED Output OUT_ Turn-On Fall
Time
t
f
80% to 20%, pullup resistor = 65
120
ns
LED Output OUT_ Turn-Off Rise
Time
t
r
20% to 80%, pullup resistor = 65
120
ns
Note 1: All parameters tested at T
A
= +25C. Specifications over temperature are guaranteed by design.
Note 2: See Figure 3.
Note 3: A 65
pullup resistor connected from OUT_ to 5.5V.
MAX6971
16-Port, 36V Constant-Current LED Driver
4
_______________________________________________________________________________________
Typical Operating Characteristics
(T
A
= +25C, unless otherwise noted.)
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
50
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)
120
ns
LE Rising to OUT_ Falling Delay
t
LRF
(Note 3)
310
ns
CLK Rising to OUT_ Rising Delay
t
CRR
(Note 3)
120
ns
CLK Rising to OUT_ Falling Delay
t
CRF
(Note 3)
330
ns
OE Rising to OUT_ Rising Delay
t
OEH
(Note 3)
120
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)
120
ns
LED Output OUT_ Turn-Off Rise
Time
t
r
20% to 80% (Note 3)
120
ns
Note 1: All parameters tested at T
A
= +25C. Specifications over temperature are guaranteed by design.
Note 2: See Figure 3.
Note 3: A 65
pullup resistor connected from OUT_ to 5.5V.
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF,
R
SET
= 720
)
MAX6971 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.0
4.5
3.5
4.0
1.85
1.90
1.95
2.00
1.80
3.0
5.5
T
A
= +125
C
T
A
= +85
C
T
A
= -40
C
T
A
= +25
C
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF,
R
SET
= 360
)
MAX6971 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.0
4.5
3.5
4.0
3.55
3.60
3.65
3.70
3.50
3.0
5.5
T
A
= +125
C
T
A
= +85
C
T
A
= -40
C
T
A
= +25
C
10
30
25
20
15
35
40
3.0
4.0
3.5
4.5
5.0
5.5
MAX6971 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, R
SET
= 720
)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
MAX6971
16-Port, 36V Constant-Current LED Driver
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(T
A
= +25C, unless otherwise noted.)
15
20
30
25
45
40
35
3.0
4.0
3.5
4.5
5.0
5.5
MAX6971 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, R
SET
= 360
)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
0
10
5
20
15
25
30
0
1.0
1.5
0.5
2.0
2.5
3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 720
, V+ = 3.3V)
MAX6971 toc05
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
0
20
10
40
30
50
60
0
1.0
1.5
0.5
2.0
2.5
3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 360
, V+ = 3.3V)
MAX6971 toc06
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= +85
C
T
A
= -40
C
T
A
= +25
C
0
10
5
20
15
25
30
0
1.0
1.5
0.5
2.0
2.5
3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 720
, V+ = 5.0V)
MAX6971 toc07
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
0
20
10
40
30
50
60
0
1.0
1.5
0.5
2.0
2.5
3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 360
, V+ = 5.0V)
MAX6971 toc08
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
25.0
24.5
24.0
23.5
23.0
3.0
4.0
3.5
4.5
5.0
5.5
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (R
SET
= 720
, V
OUT
= 2V)
MAX6971 toc09
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +25
C
T
A
= -40
C
T
A
= +85
C
T
A
= +125
C
49
48
47
46
3.0
4.0
3.5
4.5
5.0
5.5
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (R
SET
= 360
, V
OUT
= 2V)
MAX6971 toc10
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125
C
T
A
= +85
C
T
A
= +25
C
T
A
= -40
C
0
10
30
20
40
50
0
2
1
3
4
5
PORT OUTPUT CURRENT
vs. R
SET
RESISTANCE (V+ = 5.0V)
MAX6971 toc11
R
SET
RESISTANCE (k
)
PORT OUTPUT CURRENT (mA)
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