MAX6966AEE ,2.25 V to 3.6 V, 10-port constant-current LED driver and I/O expander 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™ ..
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 ..
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
2.25 V to 3.6 V, 10-port constant-current LED driver and I/O expander with PWM intensity control
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
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
Ordering Information19-3487; Rev 0; 11/04
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
MAX6966/MAX6967
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)
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)
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)
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.
Typical Operating Characteristics(TA = +25°C, unless otherwise noted.)
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
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
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.
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
Table 1. Port Configuration Options
MAX6966/MAX6967Figure1 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 ControlFigure 1. Simplified Schematic of I/O Ports
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.
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
MAX6966/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
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
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).
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.
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity ControlFigure 2. Static and PWM Constant-Current Waveforms
Figure 3. Staggered PWM Waveform
MAX6966/MAX6967
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
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 ControlThe 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 (Table7)
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
