MAXIM MAX6970 Technical data
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’ supply 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-registerplus-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 outputenable 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-pluslatch-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 -40°C to +125°C temperature range.
Features
♦ 25Mbps Industry-Standard 4-Wire Serial Interface
at 5V
♦ 3V to 5.5V Logic Supply
♦ Eight 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
♦ -40°C to +125°C Temperature Range
MAX6970
8-Port, 36V Constant-Current LED Driver
________________________________________________________________ Maxim Integrated Products 1
Pin Configuration
Ordering Information
19-3890; Rev 0; 10/05
For pricing, delivery, and ordering information, please contact Maxim 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.
EVALUATION KIT
AVAILABLE
Applications
Variable Message Signs
Marquee Displays
Point-of-Order Signs
Traffic Signs
Gaming Features
Architectural Lighting
*EP = Exposed pad.
PART TEMP RANGE
MAX6970AUE -40°C to +125°C 16 TSSOP-EP* U16E-3
MAX6970AAE -40°C to +125°C 16 SSOP P16-1
PINPACKAGE
PKG
CODE
TOP VIEW
GND
DIN
CLK
OUT0
OUT1
OUT2
OUT3
1
2
3
4
LE
5
6
7
8
MAX6970
TSSOP/SSOP
16
V+
15
SET
14
DOUT
13
OE
12
OUT7
OUT6
11
10
OUT5
9
OUT4
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 (TA= +70°C)
16-Pin TSSOP-EP
(derate 21.3mW/°C above +70°C)..............................1702mW
16-Pin SSOP (derate 7.1mW/°C above +70°C) ............571mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(Typical Operating Circuit, V+ = 3V to 5.5V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 5V, TA= +25°C.)
(Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Supply Voltage V+ 3.0 5.5 V
Output Voltage V
Standby Current
(Interface Idle, All Output Ports
High Impedance, R
Standby Current
(Interface Running, All Output
Ports High Impedance,
R
= 360Ω)
SET
Supply Current
(Interface Idle, All Output Ports
Active Low, R
Input High Voltage
DIN, CLK, LE, OE
Input Low Voltage
DIN, CLK, LE, OE
Hysteresis Voltage
DIN, CLK, LE, OE
Input Leakage Current
DIN, CLK, LE, OE
Pullup Resistor to V+, OE R
Pullup Resistor to GND, LE R
Output High Voltage DOUT V
Output Low Voltage V
Output Current OUT_ I
Output Leakage Current OUT_ I
SET
= 360Ω)
SET
= 360Ω)
V
V
ΔV
I
IH
OUT
LEAK
OUT
I+
I+
I+
IH
IL
, I
OE
LE
OH
OL
I
IL
All logic inputs at V+ or GND, DOUT
unloaded
f
CLK
or GND, DOUT unloaded
All logic inputs at V+ or GND,
DOUT unloaded
V+ = 5.5V 0.170 3 10.000 MΩ
V+ = 5.5V 0.170 3 10.000 MΩ
I
SOURCE
I
SINK
V+ = 3.0V to 5.5V, V
R
OE = V+ 1 µA
= 5MHz, OE = V+, DIN and LE = V+
= 4mA V + - 0.5V V
= 4mA 0.5 V
= 360Ω
SET
36 V
3.6 5.6 mA
3.8 6 mA
17 30 mA
0.7 x V+ V
0.3 x V+ V
0.8 V
-1 +1 µA
= 0.8V to 2.5V,
OUT
36 50 60 mA
MAX6970
8-Port, 36V Constant-Current LED Driver
_______________________________________________________________________________________ 3
5V TIMING CHARACTERISTICS
(Typical Operating Circuit, V+ = 4.5V to 5.5V, TA= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CLK Clock Period t
CLK Pulse-Width High t
CLK Pulse-Width Low t
DIN Setup Time t
DIN Hold Time t
DOUT Propagation Delay t
DOUT Rise and Fall Time
LE Pulse-Width High t
LE Setup Time t
LE Rising to OUT_ Rising Delay t
LE Rising to OUT_ Falling Delay t
CLK Rising to OUT_ Rising Delay t
CLK Rising to OUT_ Falling Delay t
OE Rising to OUT_ Rising Delay t
OE Falling to OUT_ Falling Delay t
LED Output OUT_ Turn-On Fall
Time
LED Output OUT_ Turn-Off Rise
Time
CP
CH
CL
DS
DH
DO
, t
t
DR
DF
LW
LS
LRR
LRF
CRR
CRF
OEH
OEL
t
f
t
r
C
DOUT
(Note 3) 100 ns
(Note 3) 280 ns
(Note 3) 100 ns
(Note 3) 310 ns
(Note 3) 100 ns
(Note 3) 300 ns
80% to 20% (Note 3) 200 ns
20% to 80% (Note 3) 120 ns
40 ns
19 ns
19 ns
4ns
8ns
12 32 ns
= 10pF, 20% to 80% 10 ns
20 ns
15 ns
MAX6970
8-Port, 36V Constant-Current LED Driver
4 _______________________________________________________________________________________
3.3V TIMING CHARACTERISTICS
(Typical Operating Circuit, V+ = 3V to 5.5V, TA= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2: See Figure 3.
Note 3: A 65Ω pullup resistor is connected from OUT_ to 5.5V.
Typical Operating Characteristics
(TA = +25°C, 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 4.03.5 4.5 5.0 5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF, R
SET
= 720Ω)
MAX6970 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +125°C
TA = -40°C
TA = +25°C
TA = +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 4.03.5 4.5 5.0 5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF, R
SET
= 360Ω)
MAX6970 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +125°C
TA = -40°C
TA = +25°C
TA = +85°C
5
8
11
14
17
20
3.0 4.03.5 4.5 5.0 5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, R
SET
= 720Ω)
MAX6970 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +125°C
TA = -40°C
TA = +25°C
TA = +85°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CLK Clock Period t
CLK Pulse-Width High t
CLK Pulse-Width Low t
DIN Setup Time t
DIN Hold Time t
DOUT Propagation Delay t
DOUT Rise and Fall Time tDR, t
LE Pulse-Width High t
LE Setup Time t
LE Rising to OUT_ Rising Delay t
LE Rising to OUT_ Falling Delay t
CLK Rising to OUT_ Rising Delay t
CLK Rising to OUT_ Falling Delay t
OE Rising to OUT_ Rising Delay t
OE Falling to OUT_ Falling Delay t
LED Output OUT_ Turn-On Fall
Time
LED Output OUT_ Turn-Off Rise
Time
CP
CH
CL
DS
DH
DO
DFCDOUT
LW
LS
LRR
LRF
CRR
CRF
OEH
OEL
t
f
t
r
52 ns
24 ns
24 ns
4ns
8ns
12 48 ns
= 10pF, 20% to 80% 12 ns
20 ns
15 ns
(Note 3) 140 ns
(Note 3) 310 ns
(Note 3) 140 ns
(Note 3) 340 ns
(Note 3) 140 ns
(Note 3) 330 ns
80% to 20% (Note 3) 250 ns
20% to 80% (Note 3) 150 ns
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