MAX6966AEE+ ,10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity ControlFeaturesThe MAX6966/MAX6967 serial-interfaced peripherals♦ High-Speed 26MHz SPI-™/QSPI-™/MICROWIRE™ ..
MAX6966AEE+ ,10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity ControlFeaturesThe MAX6966/MAX6967 serial-interfaced peripherals♦ High-Speed 26MHz SPI-™/QSPI-™/MICROWIRE™ ..
MAX6966ATE+ ,10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity ControlEVALUATION KIT AVAILABLEMAX6966/MAX696710-Port Constant-Current LED Drivers and I/OExpanders with P ..
MAX6967AEE+ ,10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity ControlELECTRICAL CHARACTERISTICS(Typical Operating Circuit, V+ = 2.25V to 3.6V, T = T to T , unless other ..
MAX6968AAE ,8-Port, 5.5V Constant-Current LED DriverFeaturesThe MAX6968 serial-interfaced LED driver provides♦ 25Mb Industry-Standard 4-Wire Serial Int ..
MAX6968AUE+ ,8-Port, 5.5V Constant-Current LED DriverFeaturesOUT2 7 10 OUT5Architectural LightingOUT3 8 9 OUT4TSSOP/PDIP/SSOP____ Maxim Integrated Produ ..
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 ..
MAX6966AEE+-MAX6966ATE+-MAX6967AEE+
10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control
AVAILABLE
EVALUATION KIT AVAILABLE
General DescriptionThe MAX6966/MAX6967 serial-interfaced peripherals
provide microprocessors with 10 I/O ports rated to 7V.
Each port can be individually configured as either:A 20mA constant-current LED driver (static or pulse-
width modulated (PWM)).A 10mA constant-current LED driver (static or PWM).An open-drain logic output.An overvoltage-protected Schmitt logic input.
Analog and switching LED intensity control is built in:Individual 8-bit PWM control per output.Individual 1-bit analog control (half/full) per output.Global 3-bit analog control applies to all LED outputs.
PWM timing of the 10 port outputs may be optionally
staggered, consecutively phased in 45°increments.
This spreads the PWM load currents over time in eight
steps, helping to even out the power-supply current
and reduce the RMS current.
The MAX6966/MAX6967 can be configured to awake
from shutdown on receipt of a minimum 3ms pulse on
the CSinput. This hardware-wakeup feature allows a
power-management controller or similar ASIC to enable
the MAX6966/MAX6967 with preconfigured LED intensi-
ty settings.
Shutdown can be programmed to wait up to 4s, fade
down the sink currents to zero for a period of 1/16s to
4s, and then shut down. A similar ramp-up from shut-
down can be programmed for 1/16s to 4s.
The MAX6966/MAX6967 support hot insertion. All port
pins remain high impedance in power-down (V+ = 0V)
with up to 8V asserted on them.
The DOUT/OSC pin can be configured as either the
serial interface data output or optional PWM clock
input. The MAX6966 powers up defaulting as DOUT
output. The MAX6967 defaults as OSC input.
For a similar part without the constant-current controls,
refer to the MAX7317 data sheet.
ApplicationsLCD BacklightsRGB LED Drivers
Keypad BacklightsPortable Equipment
LED Status IndicationCellular Phones
FeaturesHigh-Speed 26MHz SPI-™/QSPI-™/MICROWIRE™-
Compatible Serial Interface2.25V to 3.6V OperationI/O Ports Default to High-Z (LEDs Off) on Power-UpI/O Port Inputs Are Overvoltage Protected to 7VI/O Port Outputs Are 7V-Rated Open DrainI/O Port Outputs Are 10mA or 20mA Constant-
Current Static/PWM LED Drivers, or Open-Drain
Logic OutputsI/O Ports Support Hot InsertionIndividual 8-Bit PWM Intensity Control for Each LEDAny Output May Use or Not Use PWM ControlExit Shutdown (Warm Start) with Simple CSPulse Auto Ramp-Down into Shutdown Auto Ramp-Up Out from Shutdown0.8µA (typ), 2µA (max) Shutdown CurrentTiny 3mm x 3mm, 0.8mm High Thin QFN Package-40°C to +125°C Temperature Range
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
PARTTEMP
RANGE
PIN-
PACKAGE
TOP
MARK
PKG
CODE
MAX6966ATE-40°C to
+125°C
16 Thin QFN
3mm x 3mm x
0.8mm
ACFT1633-4
MAX6966AEE-40°C to
+125°C16 QSOP——
MAX6967ATE-40°C to
+125°C
16 Thin QFN
3mm x 3mm x
0.8mm
ACGT1633-4
MAX6967AEE-40°C to
+125°C16 QSOP——
SPI and QSPI are trademarks of Motorola, Inc.
MAX6966/MAX6967
Ordering Information
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
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 +4V
SCLK, DIN, CS, DOUT/OSC.........................-0.3V to (V+ + 0.3V)
P_ .............................................................................-0.3V to +8V
DC Current into P_ .............................................................24mA
DC Current into DOUT/OSC................................................10mA
Total GND Current............................................................280mA
Continuous Power Dissipation
16-Pin QSOP (derate 8.3mW/°C over TA= +70°C)....667mW
16-Pin QFN (derate 14.7mW/°C over TA= +70°C)...1176mW
Operating Temperature Range (TMINto TMAX).-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+ = 2.25V to 3.6V, TA= TMINto TMAX, unless otherwise noted. Typical values are at V+ = 3.3V, TA
+25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSOperating Supply VoltageV+2.253.60V
Output Load External Supply
Voltage P0–P9VEXT7V
TA = +25°C0.71.5
TA= TMIN to +85°C1.7
Standby Current
(Interface Idle, CS Run Disabled,
PWM Disabled, All Ports High
Impedance)
ISTBYCS at V+; other digital
inputs at V+ or GND
TA= TMIN to TMAX1.9
TA = +25°C390620
TA = TMIN to +85°C680
Supply-Current Interface Only
(CS Run Enabled, PWM
Disabled, All Ports High
Impedance)
fSCLK = 26MHz, other
digital inputs at V+ or
GND; DOUT unloadedTA = TMIN to TMAX730
TA = +25°C1.581.8
TA = TMIN to +85°C1.9
Delta Supply Current per 10mA
Port (Interface Idle, Global
Current Register Set to 0x07, One
Port's Output Register Set to
0x02 and Its Output Current
Register Bit Cleared; All Other
Ports’ Output Registers Set to
0x00, 0x01, or 0xFF)
ΔI+10Digital inputs at V+ or
GND
TA = TMIN to TMAX2
TA = +25°C3.23.6
TA = TMIN to +85°C3.8
Delta Supply Current per 20mA
PortInter face Id l e, Gl ob al C ur r ent
Reg i ster S et to 0x07, One P or t' s
Outp ut Reg i ster S et to 0x02 and Its
Outp ut C ur r ent Reg i ster Bi t S et; Al l
Other P or ts’ Outp ut Reg i ster s S et to
0x00, 0x01, or 0xFF)
ΔI+20Digital inputs at V+ or
GND
TA = TMIN to TMAX4.0
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
ELECTRICAL CHARACTERISTICS (continued)(Typical Operating Circuit, V+ = 2.25V to 3.6V, TA= TMINto TMAX, unless otherwise noted. Typical values are at V+ = 3.3V, TA=
+25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput High Voltage
(P0–P9, DIN, SCLK, CS, OSC)VIHP0–P9: output register set to 0x010.7 xV
Input Low Voltage
(P0–P9, DIN, SCLK, CS, OSC)VILP0–P9: output register set to 0x010.3 xV
Input Leakage Current
(P0–P9, DIN, SCLK, CS, OSC)IIH, IIL-0.2+0.2µA
Input Capacitance
(P0–P9, DIN, SCLK, CS, OSC)(Note 2)10pF
19.32021.1TA = +25°C9.51010.7
Port Nominal Sink Constant
Current
(P0–P9) (Global Current Register
Set to 0x07)
IOUT
Output register set to
0x02,
V+ = 3.3V, VEXT - VLED =
1V to 2.5V (Note 3)
TA = TMIN to
+85°C9.111.0
Port Logic Output Low Voltage
(P0–P9)VOLP_Output register set to 0x00,
ISINK = 0.5mA0.4V
Port Logic Output Low Short-
Circuit Current (P0–P9)
Output register set to 0x00,
VOLP_ = 5V10.820mA
Port Slew TimeFrom 20% current to 80% current2µs
TA = +25°C, V+ = 3.3V, VEXT - VLED = 1.4V,
IOUT = 20mA±1.5±4
Port Sink Constant-Current
MatchingΔIOUT
TA = +25°C, V+ = 3.3V, VEXT - VLED = 1.4V,
IOUT = 10mA±2±5
Output High Voltage
(DOUT)VOHDOUTISOURCE = 6mAV+ -
0.3VV
Output Low Voltage
(DOUT)VOLDOUTISINK = 6mA0.3V
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
TIMING CHARACTERISTICS(Typical Operating Circuit, V+ = 2.25V to 3.6V, TA= TMINto TMAX, unless otherwise noted. Typical values are at V+ = 3.3V, TA=
+25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInternal PWM Clock FrequencyfINT2700045000Hz
External PWM Clock FrequencyfOSC100kHz
SCLK Clock PeriodtCP38.4ns
SCLK Pulse Width HightCH19ns
SCLK Pulse Width LowtCL19ns
CS Fall to SCLK Rise Setup TimetCSS9.5ns
SCLK Rise to CS Rise Hold TimetCSH0ns
DIN Setup TimetDS9.5ns
DIN Hold TimetDH0ns
Output Data Propagation DelaytDO21ns
DOUT Output Rise and Fall
TimestFTCLOAD = 20pF10ns
Minimum CS Pulse HightCSW38.4ns
CS Pulse Low to Not Activate CS
RuntCSRUNCS run enabled640µs
CS Pulse Width to Activate CS
RuntCSRUNCS run enabled3ms
Note 1:All parameters tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2:Guaranteed by design.
Note 3:Port current is factory trimmed to meet a median sink current of 20mA and 10mA over all 10 ports. The ∆IOUTspecification
guarantees current matching between ports.
MAX6966/MAX6967
Typical Operating Characteristics(TA = +25°C, unless otherwise noted.)
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
STANDBY CURRENT (ISTBY1)
vs. TEMPERATUREMAX6966/67 toc01
TEMPERATURE (°C)
STANDBY CURRENT (
V+ = 3.6V
V+ = 3.3V
V+ = 2.7V
V+ = 2.25V
SUPPLY CURRENT (I+)
vs. TEMPERATUREMAX6966/67 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
V+ = 3.6V
V+ = 3.3V
V+ = 2.7V
V+ = 2.25V
OUTPUT SINKING CURRENT
vs. VEXT - VLED AT 10mAMAX6966/67 toc03
VEXT - VLED (V)
OUTPUT SINKING CURRENT (mA)321
OUTPUT SINKING CURRENT
vs. VEXT - VLED AT 20mAMAX6966/67 toc04
VEXT - VLED (V)
OUTPUT SINKING CURRENT (mA)321
INTERNAL OSCILLATOR FREQUENCY
vs. TEMPERATUREMAX6966/67 toc05
TEMPERATURE (°C)
FREQUENCY (kHz)
V+ = 3.6VV+ = 3.3V
V+ = 2.7VV+ = 2.25V
SAMPLE PWM WAVEFORMS2ms
OUTPUT
REGISTER
= 0x03
OUTPUT
REGISTER
= 0x80
OUTPUT
REGISTER
= 0xFE
MAX6966/67 toc06
STAGGER PWM PORT WAVEFORMS
(OUTPUT REGISTERS SET TO 0x80)2ms
PORT P4
PORT P0
PORT P1
MAX6966/67 toc07
MAX6966/MAX6967
Quick-Start GuideThis section describes how to configure a MAX6966 or
MAX6967 on power-up.
Software engineers can use this section as a plain-text
guide to the device’s initialization routine. Hardware
engineers can use this section to get a quick overview
of the device’s capabilities and feature tradeoffs:
Before power-up, all 10 I/O ports P0 to P9 are highimpedance. They may be connected to inputs up to
+7V or loads connected to independent rails up to
+7V. The SPI bus inputs (SCLK, CS, DIN) are not
overvoltage protected, and must not be driven from
a voltage higher than V+.
After power-up, all 10 I/O ports P0 to P9 remainhigh impedance. They may be connected to inputs
up to +7V or loads connected to V+ or independent
rails up to +7V. The ports are not configured as logic
inputs even though the ports are high impedance.
The device is in shutdown mode, and draws mini-
mum supply current regardless of I/O ports connec-
tions.
Decide whether the DOUT/OSC pin will be used
as SPI data output or PWM clock input, andchoose the MAX6966 or MAX6967 accordingly. If
any ports are used as logic input, or if the applica-
tion needs read-after-write validation, then
DOUT/OSC needs to be configured as DOUT. Note
that both the MAX6966 and MAX6967 can configure
DOUT/OSC as either DOUT output or OSC clock
input; the only difference is the power-up default.
Allocate port functionality for the 10 I/O ports. Allports have the same features, so allocate ports for
either software convenience or board-routing rea-
sons. Any port can be constant-current LED drivers
(static or PWM), an open-drain logic output, or a
logic input. If fewer than 10 ports are used as con-
stant-current drivers, see the Applications
Informationsection for details on how to optimize the
PWM phasing to minimize load supply-current mod-
ulation.
Decide how to implement LED intensity control.The MAX6966/MAX6967 provide:Individual 8-bit PWM control per constant-current
outputIndividual 1-bit analog control (half/full) per
constant-current outputGlobal 3-bit analog control, which applies to all
constant-current outputs
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
Pin Description
PIN
QSOPTQFNNAMEFUNCTION15SCLKSerial-Clock Input. On SCLK’s rising edge, data shifts into the internal shift register. On SCLK’s
falling edge, data is clocked out of DOUT. SCLK is active only while CS is low.
216CSChip-Select Input. Serial data is loaded into the shift register while CS is low. The most recent 16
bits of data latch on CS’s rising edge.
3–7,
1–5,
7-11P0-P9
I/O Ports. P0 to P9 can be configured as open-drain current-sink outputs rated at 20mA
maximum, or as CMOS-logic inputs, or as open-drain logic outputs. Loads should be connected
to a supply voltage no higher than 7V.6GNDGround12DOUT/OSC
Serial-Data Output. The data into DIN is valid at DOUT 15.5 clock cycles later. Use this pin to
daisy-chain several devices or allow data readback. Output is push-pull.
OSC Input. Apply a square-wave CMOS clock up to 100kHz as alternate PWM clock source.
The MAX6966 powers up with DOUT/OSC defaulting as DOUT output.
The MAX6967 powers up with DOUT/OSC defaulting as OSC input.13DINSerial-Data Input. Data from DIN loads into the internal 16-bit shift register on SCLK’s rising
edge.14V+Positive Supply Voltage. Bypass V+ to GND with a 0.1µF ceramic capacitor.PADExposed
padExposed Pad on Package Underside. Connect to GND.
MAX6966/MAX6967
The tradeoff for LED intensity control is between
depth of current-control resolution, noise constraints,
and software complexity:For high LED resolution where each LED needs
individual intensity settings, use the 8-bit PWM
control plus the 1-bit analog control to get 9 bits
of individual LED intensity control.For absolute maximum LED resolution where the
LED uses the same intensity settings, use the 8-
bit PWM control plus the 1-bit analog control,
plus the global 3-bit analog control to get 12 bits
of LED intensity control.For lowest noise applications where PWM cannot
be used, 1 bit of individual analog control is
available. If all LEDs use the same intensity set-
tings, the 1-bit analog control plus the global 3-
bit analog control provide 4 bits of static LED
intensity control.If the standard half/full constant-current settings
of 10mA/20mA are not acceptable, then the
global 3-bit analog control can be used to
reduce the currents for all the constant-current
outputs.
Take care with PC board layout. The MAX6966/MAX6967 are switching moderate currents in PWM
applications, so the MAX6966/MAX6967 and the
load supplies need careful decoupling to minimize
conducted noise. Also, the serial interface is fast, so
simple overshoot-damping terminations may be
required if the tracks are long.
Detailed DescriptionThe MAX6966/MAX6967 are general-purpose input/out-
put (GPIO) peripherals that provide 10 I/O ports, P0 to
P9, controlled through a high-speed SPI-compatible
serial interface. The 10 I/O ports can be used as logic
inputs, open-drain logic outputs, or constant-current
sinks in any combination. Ports withstand 7V indepen-
dent of the MAX6966’s or MAX6967’s supply voltage
whether used as logic inputs, logic outputs, or con-
stant-current sinks.
Ports configured as constant-current outputs can be set
to sink either a constant current of either 10mA or 20mA.
The static port current may be PWM with a duty cycle
ranging from 3/256 to 254/256 to reduce the average
current, or remain static.
Ports configured as open-drain logic outputs have a
relatively weak sink capability, which should still be
adequate for normal logic-level outputs. Open-drain
logic outputs typically require external pullup resistors
to the appropriate positive supply to provide the logic-
high reference. The weak drive means that the short-
circuit current is low enough that inadvertently driving
an LED from a port configured as a logic output is
unlikely to damage the LED.
The MAX6966/MAX6967 are rated for all 10 outputs to
carry their maximum 20mA loads at the same time. The
port configuration options are shown in Table1.
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
PORT TYPE
OUTPUT
REGISTER
CODE
BEHAVIOR OUT OF
SHUTDOWN (CONFIGURATION
REGISTER BIT D0 = 1)
BEHAVIOR IN SHUTDOWN
(CONFIGURATION REGISTER
BIT D0 = 0)
APPLICATION NOTESLow-logic
output0x00Logic-low output, not constant current
High-logic
output
Logic-high output with external pullup resistor; otherwise, high
impedance
Logic input
0x01
CMOS logic input
Lowest supply current
unaffected by shutdown
Constant-
current static
sink output
0x02Static constant-current sink
output
Full constant-current drive
with no PWM noise
Constant-
current PWM
output
0x03–0xFEPWM constant-current sink output
High impedance
Adjustable constant current
LED off0xFFLogic-high output with external pullup resistor; otherwise, high
impedanceLED off
Table 1. Port Configuration OptionsMAX6966/MAX6967
Figure1 shows the I/O port structure of the MAX6966/
MAX6967. I/O ports P0 to P9 default to high impedance
on power-up, so LED or other port loads connected
draw no current, and ports used as inputs do not load
their source signals.
Standby Mode and Operating CurrentWhen all the ports are configured as logic inputs or out-
puts (all output registers set to value 0x00 or 0x01) or
LED off (output register set to value 0xFF), the
MAX6966/MAX6967 operate at their lowest supply cur-
rent, called standby mode.
When PWM intensity control is used (one or more out-
put registers set to a value between 0x03 and 0xFE),
the operating current increases because the internal
PWM circuitry is running.
The operating current also increases whenever a port
that is set is active low as a constant-current output
(output register set to a value between 0x02 and 0xFE),
even if a load is not applied to the port. This current
increase is due to an internal current mirror being
enabled for that port output to provide the accurate
constant-current sink. There is a gated mirror for each
output, and each mirror is only enabled when required.
When PWM is used, a current mirror is only turned on
for the output’s on-time. This means that operating cur-
rent varies as constant-current outputs are turned on
and off through the serial interface, as well as by the
PWM intensity control.
Shutdown ModeIn shutdown mode, all ports configured as constant-cur-
rent outputs (output register set to a value between 0x02
and 0xFE) are switched off, and these outputs go high
impedance as if their registers were set to value 0xFF.
Ports configured as logic inputs or outputs (output regis-
ters set to value 0x00 or 0x01) are unaffected (Table1).
This means that any ports used for GPIOs are still fully
operational in shutdown mode, and port inputs can be
read and output ports can be toggled at any time using
the serial interface. The MAX6966/MAX6967 can there-
fore be used for a mix of logic inputs, logic outputs, and
PWM LED drivers, and only the LED drivers are turned
off automatically in shutdown.
The MAX6966/MAX6967 are put into shutdown mode
by clearing the run bit (bit D0) in the configuration reg-
ister (Table4). Shutdown is exited by setting the run bit
through the serial interface, or by using the CS run
option discussed below. The MAX6966/MAX6967 can
be configured and controlled in the normal way through
the serial interface in shutdown mode. All registers are
accessible in shutdown mode, and no register is
changed by shutdown mode. When shutdown mode is
exited, ports configured as constant-current outputs at
that time start instantly with their current PWM values.
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control8-BIT LATCH
OUTPUT PORT
REGISTER
PWM
GENERATOR
1-BIT LATCH
OUTPUT CURRENT
REGISTER
4-BIT DAC
3-BIT LATCH
GLOBAL CURRENT
REGISTER
READ I/O
PORT COMMAND
TO/FROM
SERIAL
INTERFACE
MSB
ENABLE
I/O PORT
ENABLE = 0x00
SET
CURRENT
POSITION A: 0x00 - 0x01
POSITION B: 0x02 - 0xFF
CLOSE SWITCH: 0x02-0xFE
Figure 1. Simplified Schematic of I/O Ports
MAX6966/MAX6967
If a port is changed from static logic low (0x00) or static
logic high (0x01) to a constant-current value
(0x02–0xFE) in shutdown mode, then that output is
automatically turned off (logic high, or high impedance)
like any other constant-current outputs that are dis-
abled in shutdown. When shutdown mode is exited, the
new constant-current output starts just like any other
constant-current outputs.
If a port is changed from a constant-current value
(0x02–0xFE) to static logic low (0x00) or static logic
high (0x01) in shutdown mode, then that output is
instantly set to that value as a GPIO output. When shut-
down mode is exited, the new GPIO output is unaffect-
ed just like any other GPIO outputs.
CS Run OptionThe MAX6966/MAX6967 can be configured so that a
relatively long pulse on the CSinput brings the driver
out of shutdown, as an alternative method to the normal
method of writing the configuration register through the
serial interface. When the CS run option is enabled, a
minimum pulse on CSsets the run bit in the configura-
tion register, bringing the driver out of shutdown and
activating any preconfigured ramp-up. Also, the SPI
interface must be operated at a minimum data rate to
ensure that a normal active-low CSpulse during a 16-
bit regular data transmission is not mistaken for a CS
run command.
The CS run timing uses the PWM clock, which is either
the internal nominal 32kHz oscillator or a user-provided
clock fed into the dual-use DOUT/OSC pin (see the PWM
Clocksection for details on configuring the PWM clock).
The minimum pulse on CSto trigger CS run and bring
the driver out of shutdown is 256 to 257 periods of the
PWM clock. For the internal oscillator, this time is 257 /
27000 = 9.52ms. For the external PWM clock, this time
is 257 / OSC and has a shortest possible time of
2.57ms when OSC is set to the maximum allowed
100kHz frequency.
The maximum pulse on CSto ensure that CS run is not
triggered (when enabled) is 255 periods of the PWM
clock. For the internal oscillator, this time is 255 / 45000
= 5.66ms. Since a transmission on the serial interface
comprises 16 clocks with CSlow, a minimum 2.83kHz
SCLK frequency ensures that CS run is not triggered.
For the external PWM clock, this time is 255 / OSC and
has a shortest time of 2.55ms when OSC is set to the
maximum allowed frequency of 100kHz.
The SPI serial interface circuitry is independent of the
CS run circuitry. Activity on SCLK and DIN is ignored
by the CS run circuitry. A slow SPI transmission to the
MAX6966/MAX6967 can therefore be used as both a
valid data transmission (read or write), and as a means
for exiting shutdown. The CS run action (i.e., setting the
run bit in the configuration register) occurs before any
coincident data transmission is processed. This means
that a slow transmission containing a write command to
the configuration register clearing the run bit would
work, since the write command is implemented internal-
ly after the CS run action that sets the run bit.
The "slow transmission" cut-off data rate is expected to
be lower than the SPI interface speed in the majority of
applications. If this is not the case, the CS run option
can still be used. Consider the situation when the
MAX6966/MAX6967 have been put into shutdown with
the CS run option enabled. The application uses the
MAX6966/MAX6967 with some ports configured as
logic inputs or outputs, which need to be accessed in
shutdown. The SPI interface speed is slow, so any
transmission brings the MAX6966/MAX6967 out of shut-
down. So, how are the I/O ports accessed in shut-
down The solution is to write the configuration register
disabling CS run (bit D1 = 0) and invoking shutdown
(bit D0 = 0) as the first command. Now any other regis-
ters can be accessed while the MAX6966/MAX6967
remain in shutdown. Finally, write the configuration reg-
ister reenabling CS run (bit D1 = 1) and invoking shut-
down (bit D0 = 0) to restore the original status.
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity ControlMAX6966/MAX6967
Register StructureThe MAX6966/MAX6967 contain 16 internal registers,
addressed as 0x00–0x09, and 0x10–0x15, which con-
figure and control the peripheral (Table2). Two
addresses, 0x0E and 0x0F, do not store data but return
the port input status when read. Four virtual addresses,
0x0A–0x0D allow more than one register to be written
with the same data to simplify software. The no-op
address, 0x20, causes no action when written or read,
and is used as a dummy register when accessing one
MAX6966/MAX6967 out of multiple cascaded devices.
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
COMMAND ADDRESSREGISTERD15D14D13D12D11D10D9D8
HEX
CODEPort P0 output level or PWMR/W00000000x00
Port P1 output level or PWMR/W00000010x01
Port P2 output level or PWMR/W00000100x02
Port P3 output level or PWMR/W00000110x03
Port P4 output level or PWMR/W00001000x04
Port P5 output level or PWMR/W00001010x05
Port P6 output level or PWMR/W00001100x06
Port P7 output level or PWMR/W00001110x07
Port P8 output level or PWMR/W00010000x08
Port P9 output level or PWMR/W00010010x09
Write ports P0 through P9 with same output level or
PWM0
Read port P0 output level or PWM1
00010100x0A
Write ports P0 through P3 with same output level or
PWM0
Read port P0 output level or PWM1
00010110x0B
Write ports P4 through P7 with same output level or
PWM0
Read port P4 output level or PWM1
00011000x0C
Write ports P8 or P9 with same output level or PWM0
Read port P8 output level or PWM100011010x0D
Read ports P7 through P0 inputs100011100x0E
Read ports P9 and P8 inputs100011110x0F
ConfigurationR/W00100000x10
Ramp-downR/W00100010x11
Ramp-upR/W00100100x12
Output current ISET70R/W00100110x13
Output current ISET98R/W00101000x14
Global currentR/W00101010x15
No-opR/W01000000x20
Factory reserved; do not write to this registerR/W11111010x7D
Table 2. Register Address MapMAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
REGISTER DATAREGISTERPOWER-UP CONDITIONADDRESS
CODE (HEX)D7D6D5D4D3D2D1D0Port P0 output level or PWMPort 0 high impedance0x0011111111
Port P1 output level or PWMPort 1 high impedance0x0111111111
Port P2 output level or PWMPort 2 high impedance0x0211111111
Port P3 output level or PWMPort 3 high impedance0x0311111111
Port P4 output level or PWMPort 4 high impedance0x0411111111
Port P5 output level or PWMPort 5 high impedance0x0511111111
Port P6 output level or PWMPort 6 high impedance0x0611111111
Port P7 output level or PWMPort 7 high impedance0x0711111111
Port P8 output level or PWMPort 8 high impedance0x0811111111
Port P9 output level or PWMPort 9 high impedance0x0911111111
Configuration (MAX6966
only)
Shutdown mode,
CS run disabled,
DOUT/OSC is DOUT output
Configuration (MAX6967
only)
Shutdown mode,
CS run disabled,
DOUT/OSC is OSC input
0x10000000
Ramp-downFade disabled0x1100000000
Ramp-up—0x1200000000
Output current ISET70IPEAK = 10mA for ports P7–P00x1300000000
Output current ISET98IPEAK = 10mA for ports P9, P80x1400000000
Global currentFull current0x1500000111
Table 3. Initial Power-Up Register Status
Initial Power-UpOn power-up, all control registers are reset (Table3).
Power-up status sets I/O ports P0 to P9 high imped-
ance, and puts the device into shutdown mode. This
means that any LED (or other) loads are effectively
turned off, and the MAX6966/MAX6967 start in its low-
est power condition.
PWM ClockAn internal 32kHz oscillator generates PWM timing. If
all output ports are set to static levels, the internal oscil-
lator and PWM logic are disabled automatically, and
the MAX6966/MAX6967 operating current is lowest.
The internal 32kHz oscillator can be replaced by a user
clock up to 100kHz if a precise or synchronized PWM
frequency source is desired. The clock is fed into the
dual-use DOUT/OSC pin, which is switched between a
port output and a clock input using the OSC bit in the
configuration register (Table4).
MAX6966/MAX6967
PWM Timing and PhasingA PWM period comprises 256 cycles of the nominal
32kHz PWM clock (Figure2). Ports can be set individu-
ally to a PWM duty between 3/256 and 254/256.
PWM timing can be configured one of two ways by the
setting of the stagger bit in the configuration register
(Table4). When the stagger bit is clear, all outputs using
PWM switch at the same time use the timing shown in
Figure2. All outputs therefore draw load current at exact-
ly the same time for the same PWM setting. This means
that if, for example, all outputs are set to 128/256 duty
cycle, the current draw would be zero (all loads off) for
half the time and full (all loads on) for the other half.
When the stagger bit is set, the PWM timing of the 10 port
outputs is staggered by 32 counts of the 256-count PWM
period (i.e., 1/8), distributing the port output switching
points across the PWM period (Figure3). The staggering
reduces the di/dt output-switching transient on the supply,
and also reduces the peak/mean current requirement.
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity ControlHIGH-Z
LOW
HIGH-Z
LOW
HIGH-Z
LOW
OUTPUT LOW 254/256 DUTY CONSTANT CURRENT WITH INPUT BUFFER DISABLED (PWM LED DRIVE)
HIGH-Z
LOW
0xFF
HIGH-Z
LOW
HIGH-Z
LOW
OUTPUT LOW 253/256 DUTY CONSTANT CURRENT WITH INPUT BUFFER DISABLED (PWM LED DRIVE)
OUTPUT STATIC-HIGH LOGIC DRIVE WITH INPUT BUFFER ENABLED (GPI)
OUTPUT STATIC-LOW LOGIC DRIVE WITH INPUT BUFFER ENABLED (GPI)
OUTPUT STATIC-LOW CONSTANT CURRENT WITH INPUT BUFFER DISABLED (STATIC LED DRIVE ON)
0xFD
0xFE
0x02
0x00
0x01
OUTPUT STATIC HIGH IMPEDANCE WITH INPUT BUFFER DISABLED (STATIC LED DRIVE OFF)
HIGH-Z
LOWOUTPUT LOW 3/256 DUTY CONSTANT CURRENT WITH INPUT BUFFER DISABLED (PWM LED DRIVE)0x03
HIGH-Z
LOW
OUTPUT LOW 252/256 DUTY CONSTANT CURRENT WITH INPUT BUFFER DISABLED (PWM LED DRIVE)0xFC
REGISTER
VALUE
OUTPUT
7.8125ms NOMINAL PWM PERIOD
HIGH-Z
LOWOUTPUT LOW 4/256 DUTY CONSTANT CURRENT WITH INPUT BUFFER DISABLED (PWM LED DRIVE)0x04
Figure 2. Static and PWM Constant-Current Waveforms
7.8125ms NOMINAL PWM PERIODNEXT PWM PERIODNEXT PWM PERIOD326496128160192224256
OUTPUTS P0, O8 IN-PHASE PWM PERIOD
OUTPUT P1, O9 STAGGERED PWM PERIOD
OUTPUT P3 STAGGERED PWM PERIOD
OUTPUT P4 STAGGERED PWM PERIOD
OUTPUT P5 STAGGERED PWM PERIOD
OUTPUT P6 STAGGERED PWM PERIOD
OUTPUT P7 STAGGERED PWM PERIOD
OUTPUTS P0, O8 IN-PHASE PWM PERIOD
OUTPUT P1, O9 STAGGERED PWM PERIOD
OUTPUT P3 STAGGERED PWM PERIOD
OUTPUT P4 STAGGERED PWM PERIOD
OUTPUT P5 STAGGERED PWM PERIOD
OUTPUT P6 STAGGERED PWM PERIOD
OUTPUT P7 STAGGERED PWM PERIOD
OUTPUTS P0, O8 IN-PHASE PWM PERIOD
OUTPUT P1, O9 STAGGERED PWM PERIOD
OUTPUT P2 STAGGERED PWM PERIODOUTPUT P2 STAGGERED PWM PERIOD
Figure 3. Staggered PWM Waveform
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
REGISTER DATAREGISTERR/W
ADDRESS
CODE
(HEX)D7D6D5D4D3D2D1D0
CONFIGURATIONDOUT
/OSCX
PWM
stagger
Hold-
off
status
Fade-
off
status
Ramp-
enable/
status
CS runSh u t d o w n /u n Write device configuration0
Ramp-
enableRead-back device configuration1
OSCX
StaggerHold-
off
Fade-
offRamp-
status
CS runRun
Shutdown mode (CS run disabled)Put or keep device in shutdown,
disable CS runXXXXXX00
Shutdown mode (CS run enabled)Put or keep device in shutdown,
enable CS run
0x10XXXXX10
Run mode(device is currently in run mode)0XXX0*0*XX1
u n ( e x it sh u t d o w n ) wit h o u t ra m p - u p (device is currently in shutdown);
bring device out of shutdown
instantly, ignoring fade register settingXXX0*0*0X1
Run (exit shutdown) with ramp-up(device is currently in shutdown);
bring device out of shutdown using
fade register ramp-up settingXXX0*0*1X1*1**0*
Run (abort shutdown sequence)(device is currently in hold-off/fade-off
sequence to shutdown);
bring device out of shutdown
instantly, ignoring fade register settingXXX*1*1
Status: shutdown mode1XX
Stagger000
CS run0
Status: in fade-off sequence to
shutdown mode1XX
Stagger010
CS run0
Status: in hold-off sequence to
shutdown mode1XX
Stagger100
CS run0
Status: run mode1XX
Stagger000
CS run1
Status: in ramp-up sequence to run
mode1XX
Stagger001
CS run1
PWM outputs are in phaseXXX0XXXXX
PWM outputs stagger phaseXXX1XXXXX
DOUT/OSC is DOUT output,
PWM clock source is internal oscillatorX0XXXXXXX
DOUT/OSC is OSC input,
PWM clock source is OSCX1XXXXXXX
Table 4. Configuration Register*Current read status of this bit.
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
REGISTER DATA
REGISTERR/W
ADDRESS
CODE
(HEX)D7D6D5D4D3D2D1D0Read input ports P7–P010x0EPort P7Port P6Port P5Port P4Port P3Port P2Port P1Port P0
Read input ports P9–P810x0F000000Port P9Port P8
Table 5. Input Ports RegisterThe stagger bit is ideally set or cleared when the
MAX6966/MAX6967 are in shutdown. If not, there may be
a perceived transient flicker in any PWM-controlled LEDs
because the fundamental PWM timing is being changed.
Configuration RegisterThe configuration register is used to select PWM phas-
ing between outputs, test fade status, enable hardware
startup from shutdown, and select shutdown or run
mode (Table4).
GPIO Port Direction ConfigurationThe 10 I/O ports P0 through P9 can be configured to
any combination of logic inputs, logic outputs, and con-
stant-current outputs. Configure any port as a logic
input by setting its output register to 0x01, which sets
the port output high impedance (Table6).
Input Ports RegistersReading an input port register returns the logic levels at
the I/O port pins for ports that have been configured as a
logic input (Table5). A port is configured as a logic input
by writing 0x01 to the port’s output register (Table5). An
input ports register returns logic 0 in the appropriate bit
position for a port not configured as a logic input.
The input ports registers are read only. A write to an
input ports register is ignored.
Output Registers and
PWM Intensity ControlThe MAX6966/MAX6967 use one 8-bit register to control
each output port (Table6). Each port may be configured
as a logic input, open-drain logic output, or constant-cur-
rent sink with programmable current and PWM duty
cycle. Ports withstand 7V independent of the MAX6966’s
or MAX6967’s supply voltage, whether used as logic
inputs, logic outputs, or constant-current sinks.
Ports configured as constant-current outputs sink a con-
stant current set by the output current registers (Table
and the global current registers (Table8). This current
may be PWM with a duty cycle ranging from 3/256 to
254/256 to reduce the average current, or remain static.
The 10 registers 0x00 through 0x09 control an I/O port
each (Table6). Five pseudo-register addresses, 0x0B
through 0x0F, allow groups of outputs to be set to the
same value with a single command by writing the same
data to multiple output registers.
PWM timing for LED intensity control is generated using
either the internal 32kHz oscillator, or an external clock
on DOUT/OSC. The PWM clock source is selected by
configuration register bit D7 (Table4). The MAX6966
powers up configured to use the internal 32kHz oscilla-
tor by default. The MAX6967 powers up configured to
use the external clock source by default.
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
REGISTER DATA
BINARYHEXREGISTERR/W
ADDRESS
CODE
(HEX)D7D6D5D4D3D2D1D0
PORT P0 LEVEL OR PWMX
MSBOUTPUT P0 LEVEL AND PWMLSBPort P0 is static-low logic-level logic
port with logic input buffer enabled;
reading this port returns 0. Still active
in shutdown.000000000x00
Port P0 is static-high logic-level logic
port (high impedance without external
pullup) or logic input with logic input
buffer enabled; reading this port
returns 0 or 1, depending on external
conditions. Still active in shutdown.000000010x01
Port P0 is static-low constant-current
sink (PWM disabled). Logic input
buffer is disabled; reading this port
always returns 0. High impedance in
shutdown.000000100x02
Port P0 duty cycle is 3/256 current
sink. GPI logic input buffer is
disabled; reading this port always
returns 0. High impedance in
shutdown.000000110x03
Port P0 duty cycle is 4/256 current
sink. GPI logic input buffer is
disabled; reading this port always
returns 0. High impedance in
shutdown.000001000x04X—————————
Port P0 duty cycle is 253/256 current
sink. GPI logic input buffer is
disabled; reading this port always
returns 0. High impedance in
shutdown.111111010xFD
Port P0 duty cycle is 254/256 current
sink. GPI logic input buffer is
disabled; reading this port always
returns 0. High impedance in
shutdown.111111100xFE
Port P0 is static high impedance
(PWM disabled). GPI logic input
buffer is disabled; reading this port
always returns 0. High impedance in
shutdown.
0x001111110xFF
Table 6. Output Registers FormatMAX6966/MAX6967
