MAX6968AUE+ ,8-Port, 5.5V Constant-Current LED DriverFeaturesOUT2 7 10 OUT5Architectural LightingOUT3 8 9 OUT4TSSOP/PDIP/SSOP____ Maxim Integrated Produ ..
MAX6969AUG+ ,16-Port, 5.5V Constant-Current LED DriverFeaturesOUT4 9 16 OUT11Architectural LightingOUT5 10 15 OUT10OUT6 11 14 OUT9*Future product—contact ..
MAX6969AUG+ ,16-Port, 5.5V Constant-Current LED DriverFeaturesThe MAX6969 serial-interfaced LED driver provides 16♦ 25Mb, Industry-Standard, 4-Wire Seria ..
MAX6969AWG ,16-Port, 5.5V Constant-Current LED DriverApplicationsCLK 3 22 DOUTVariable Message SignsLE 4 21 OEMarquee DisplaysMAX6969AUGOUT0 5 20 OUT15M ..
MAX6969AWG+ ,16-Port, 5.5V Constant-Current LED Driverapplications requiring a watchdogtimer, refer to the MAX6979, which includes a fail-safeTypical App ..
MAX696CPE ,Microprocessor Supervisory CircuitsFeatures
. Adjustable Low Line monitor and Power Down
Reset
. Power OK/Reset Time Delay
. ..
MB401 , 40 Amp Single Phase Bridge Rectifier 50 to 1000 Volts
MB401 , 40 Amp Single Phase Bridge Rectifier 50 to 1000 Volts
MB401 , 40 Amp Single Phase Bridge Rectifier 50 to 1000 Volts
MB40166 ,AD/DA CONVERTERFUJITSU SEMICONDUCTORDS04-28500-5EDATA SHEETASSPAD/DA CONVERTERMB40166/MB401761-CHANNEL 6-BIT AD/DA ..
MB40176 ,AD/DA CONVERTERFUJITSU SEMICONDUCTORDS04-28500-5EDATA SHEETASSPAD/DA CONVERTERMB40166/MB401761-CHANNEL 6-BIT AD/DA ..
MB40176 ,AD/DA CONVERTERFUJITSU SEMICONDUCTORDS04-28500-5EDATA SHEETASSPAD/DA CONVERTERMB40166/MB401761-CHANNEL 6-BIT AD/DA ..
MAX6968AAE-MAX6968AUE+
8-Port, 5.5V Constant-Current LED Driver
General DescriptionThe MAX6968 serial-interfaced LED driver provides
eight open-drain, constant-current sinking LED driver
outputs rated at 5.5V. The MAX6968 operates from a 3V
to 5.5V supply. The MAX6968 supply and the LEDs’
supply or supplies may power up in any order. The
constant-current outputs are programmed together to
up to 55mA using a single external resistor. The
MAX6968 operates with a 25Mb, industry-standard, 4-
wire serial interface.
The MAX6968 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 the output
DOUT eight clock cycles later to allow cascading of
multiple MAX6968s. 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 OEgates 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 MAX6977 data sheet that automatically detects
open-circuit LEDs.
For safety-related applications requiring a watchdog
timer, refer to the MAX6978 data sheet that includes a
fail-safe feature that blanks the display if the serial inter-
face becomes inactive for more than 1s.
The MAX6968 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 -40°C to +125°C temperature range.
Features25Mb Industry-Standard 4-Wire Serial Interface at 5V3V to 5.5V Logic Supply8 Constant-Current LED Outputs Rated at 5.5V Up to 55mA Continuous Current per OutputOutput Current Programmed by Single Resistor3% Current Matching Between Outputs6% Current Matching Between ICs-40°C to +125°C Temperature Range
MAX6968
8-Port, 5.5V Constant-Current LED DriverGNDV+
SET
DOUT
OUT7
OUT6
OUT5
OUT4
TOP VIEW
MAX6968AUE
MAX6968APE
MAX6968AAE
TSSOP/PDIP/SSOPDIN
CLK
OUT1
OUT0
OUT2
OUT3
Pin Configuration
Ordering Information19-3555; Rev 2; 7/05
Typical Application Circuit and Selector Guide appear at
end of data sheet.
ApplicationsVariable Message Signs
Marquee Displays
Point-of-Order Signs
Traffic Signs
Gaming Features
Architectural Lighting
PARTTEMP RANGEPIN-PACKAGEMAX6968AUE-40°C to +125°C16 TSSOP-EP*
MAX6968APE-40°C to +125°C16 PDIP
MAX6968AAE-40°C to +125°C16 SSOP
*EP = Exposed pad.
MAX6968
8-Port, 5.5V Constant-Current LED Driver
ABSOLUTE MAXIMUM RATINGSStresses 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 +6V
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 SSOP (derate 7.1mW/°C above +70°C)............571mW
16-Pin PDIP (derate 10.5mW/°C above +70°C)............842mW
16-Pin TSSOP (derate 21.3mW/°C over = +70°C) ..............................................................1702mW
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= TMINto TMAX, unless otherwise noted. Typical values are at V+ = 5V, TA= +25°C.)
(Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSOperating Supply VoltageV+3.05.5V
Output VoltageVOUT5.5V
Standby Current
(Interface Idle, All Output Ports
High Impedance, RSET = 360Ω)All logic inputs at V+ or GND, DOUT
unloaded4.55.6mA
Standby Current
(Interface Running, All Output
Ports High Impedance,
RSET = 360Ω)fCLK = 5MHz, OE = V+, DIN and LE = V+
or GND, DOUT unloaded4.76mA
Supply Current
(Interface Idle, All Output Ports
Active Low, RSET = 360Ω)All logic inputs at V+ or GND,
DOUT unloaded1025mA
Input High Voltage
DIN, CLK, LE, OEVIH0.7 V+V
Input Low Voltage
DIN, CLK, LE, OEVIL0.3 V+V
Hysteresis Voltage
DIN, CLK, LE, OEΔVI0.8V
Input Leakage Current
DIN, CLK, LE, OEIIH, IIL-1+1µA
Output High-Voltage DOUTVOHISOURCE = 4mAV + 0.5V V
Output Low VoltageVOLISINK = 4mA0.5V
Output Current OUT_IOUTV+ = 3V to 5.5V, VOUT = 0.5V to 2.5V,
RSET = 360Ω425056mA
Output Leakage Current OUT_ILEAKOE = V+, VOUT = V+1µA
Watchdog TimeouttWD1s
MAX6968
8-Port, 5.5V Constant-Current LED Driver
5V TIMING CHARACTERISTICS(Typical Operating Circuit, V+ = 4.5V to 5.5V, TA= TMINto TMAX, unless otherwise noted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSCLK Clock PeriodtCP40ns
CLK Pulse-Width HightCH19ns
CLK Pulse-Width LowtCL19ns
DIN Setup TimetDS4ns
DIN Hold TimetDH8ns
DOUT Propagation DelaytDO1232ns
DOUT Rise and Fall TimetDR, tDFCDOUT = 10pF, 20% to 80%10ns
LE Pulse-Width HightLW20ns
LE Setup TimetLS10ns
LE Rising to OUT_ Rising DelaytLRR(Note 2)100ns
LE Rising to OUT_ Falling DelaytLRF(Note 2)280ns
CLK Rising to OUT_ Rising DelaytCRR(Note 2)100ns
CLK Rising to OUT_ Falling DelaytCRF(Note 2)310ns
OE Rising to OUT_ Rising DelaytOEH100ns
OE Falling to OUT_ Falling DelaytOEL300ns
LED Output OUT_ Turn-On Fall
Timetf80% to 20%200ns
LED Output OUT_ Turn-Off Rise
Timetr20% to 80%120ns
MAX6968
8-Port, 5.5V Constant-Current LED Driver
Typical Operating Characteristics(TA = +25°C, unless otherwise noted.)
3.3V TIMING CHARACTERISTICS(Typical Operating Circuit, V+ = 3V to 5.5V, TA= TMINto TMAX, unless otherwise noted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSCLK Clock PeriodtCP52ns
CLK Pulse-Width HightCH24ns
CLK Pulse-Width LowtCL24ns
DIN Setup TimetDS4ns
DIN Hold TimetDH8ns
DOUT Propagation DelaytDO1248ns
DOUT Rise and Fall TimetDR, tDFCDOUT = 10pF, 20% to 80%10ns
LE Pulse-Width HightLW20ns
LE Setup TimetLS15ns
LE Rising to OUT_ Rising DelaytLRR100ns
LE Rising to OUT_ Falling DelaytLRF310ns
CLK Rising to OUT_ Rising DelaytCRR100ns
CLK Rising to OUT_ Falling DelaytCRF330ns
OE Rising to OUT_ Rising DelaytOEH100ns
OE Falling to OUT_ Falling DelaytOEL330ns
LED Output OUT_ Turn-On Fall
Timetf80% to 20%200ns
LED Output OUT_ Turn-Off Rise
Timetr20% to 80%120ns
Note 1:All parameters tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2:See Figure 3.
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS OFF,
RSET = 720Ω)MAX6968 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +125°CTA = +85°C
TA = -40°C
TA = +25°C
MAX6968 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +125°C
TA = +85°C
TA = -40°C
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS
OFF, RSET = 360Ω)TA = +25°C
MAX6968 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS
ON, RSET = 720Ω)TA = +125°C
TA = +85°C
TA = +25°CTA = -40°C
MAX6968
8-Port, 5.5V Constant-Current LED Driver
Typical Operating Characteristics (continued)(TA = +25°C, unless otherwise noted.)
MAX6968 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS ON, RSET = 360Ω)TA = +125°CTA = +85°C
TA = +25°CTA = -40°C1.01.50.52.02.53.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (RSET = 720Ω, V+ = 3.3V)MAX6968 toc05
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C1.01.50.52.02.53.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (RSET = 360Ω, V+ = 3.3V)MAX6968 toc06
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C1.01.50.52.02.53.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (RSET = 720Ω, V+ = 5.0V)MAX6968 toc07
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C1.01.50.52.02.53.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (RSET = 360Ω, V+ = 5.0V)MAX6968 toc08
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (RSET = 720Ω, VOUT = 2V)
MAX6968 toc09
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (RSET = 360Ω, VOUT = 2V)
MAX6968 toc10
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
TA = +125°C
TA = +85°C
TA = +25°CTA = -40°C1000500150020002500
PORT OUTPUT CURRENT
vs. RSET RESISTANCE (V+ = 5.0V)MAX6968 toc11
RSET RESISTANCE (Ω)
PORT OUTPUT CURRENT (mA)
MAX6968
8-Port, 5.5V Constant-Current LED Driver
Pin Description
PINNAMEFUNCTIONGNDGroundDINSerial-Data Input. Data is loaded into the internal 8-bit shift register on CLK’s rising edge.CLKSerial-Clock Input. Data is loaded into the internal 8-bit shift register on CLK’s rising edge.
4LELoad-Enable Input. Data is loaded transparently from the internal shift register to the output latch while
LE is high. Data is latched into the output latch on LE's falling edge, and retained while LE is low.
5–12OUT0–OUT7LED Driver Outputs. OUT0–OUT7 are open-drain, constant-current sinking outputs rated to 5.5V.OEO utp ut- E nab l e Inp ut. H i g h for ces outp uts OUT0–OUT7 to hi g h i m p ed ance, w i thout al ter i ng the contents of
the outp ut l atches. Low enab l es outp uts OUT0–OUT7 to fol l ow the state of the outp ut l atches.DOUTSerial-Data Output. Data is clocked out of the 8-bit internal shift register to DOUT on CLK’s rising edge.SETLED Current Setting. Connect SET to GND through a resistor (RSET) to set the maximum LED current.V+Positive Supply Voltage. Bypass V+ to GND with a 0.1µF ceramic capacitor.
PADE xp osed p ad *Exposed pad on package underside. Connect to GND.
SERIAL-TO-PARALLEL SHIFT REGISTER
LATCHES
OUT0
OUT1
OUT2
DOUTDIN
CLK
OUT7
CONSTANT-CURRENT SINKS
OUT5
OUT6
POWER-ON
RESETV+
CURRENT
REFERENCE
GNDGNDD7D7D7
RSET
MAX6968
Figure 1. MAX6968 Block Diagram
*TSSOP package only.
Detailed DescriptionThe MAX6968 LED driver comprises a 4-wire serial
interface driving eight constant-current sinking open-
drain output ports. The outputs drive LEDs in either
static or multiplex applications (Figure 1). The constant-
current outputs are guaranteed for current accuracy
not only with chip-supply voltage variations (5V ±10%
and 3V to 5.5V), but also over a realistic range of driver
output voltage drop (0.5V to 2.5V). The drivers use cur-
rent-sensing feedback circuitry (not simple current mir-
rors) to ensure very small current variations over the full
allowed range of output voltage (see the Typical
Operating Characteristics).
The 4-wire serial interface comprises an 8-bit shift reg-
ister and an 8-bit transparent latch. The shift register is
written through a clock input CLK and a data input DIN
and the data propagates to a data output DOUT. The
data output allows multiple drivers to be cascaded and
operated together. The contents of the 8-bit shift regis-
ter are loaded into the transparent latch through a latch
enable input LE. The latch is transparent to the shift
register outputs when high, and latches the current
state on the falling edge of LE.
Each driver output is an open-drain constant-current
sink that should be connected to the cathode of either
a single LED or a series string of multiple LEDs. The
LED anode can be connected to a supply voltage of up
to 5.5V, independent of the MAX6968 supply, V+. The
constant-current capability is up to 55mA per output,
set for all eight outputs by an external resistor, RSET.
Initial Power-Up and OperationAn internal reset circuit clears the internal registers of
the MAX6968 on power-up. All outputs OUT0–OUT7,
therefore, initialize high impedance, and the interface
output DOUT initializes low, regardless of the initial
logic levels of the CLK, DIN, OE, and LE inputs.
4-Wire Serial InterfaceThe serial interface on the MAX6968 is a 4-wire serial
interface using four inputs (DIN, CLK, LE, OE) and a
data output (DOUT). This interface is used to write dis-
play data to the MAX6968. The serial-interface data
word length is 8 bits, D0–D7. See Figure 2.
The functions of the five interface pins are as follows.
DIN is the serial data input, and must be stable when it
is sampled on the rising edge of CLK. Data is shifted in,
MSB first. This means that data bit D7 is clocked in first,
followed by 7 more data bits finishing with the LSB D0.
MAX6968
8-Port, 5.5V Constant-Current LED DriverD6
tDS
tDH
tCL
tCP
tDO
tOEW
tOELtr
tOEH
tLS
tLW
tCHD0
CLK
DIN
DOUT
OUT_
80%
20%
tLF
Figure 2. 4-Wire Serial-Interface Timing Diagram
