MAX6956ATL ,2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port LED Display Driver and I/O ExpanderFeatures2The MAX6956 compact, serial-interfaced LED display 400kbps I C-Compatible Serial Interfac ..
MAX6956ATL ,2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port LED Display Driver and I/O ExpanderApplicationsISET 1 28 V+Set-Top Boxes Bar Graph DisplaysGND 2 27 AD1Panel Meters Industrial Control ..
MAX6957AAI+ ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O ExpanderFeatures®The MAX6957 compact, serial-interfaced LED display ● High-Speed 26MHz SPI-/QSPI™-/MICROWI ..
MAX6957AAX ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O ExpanderApplicationsMAX6957AGL* -40°C to +125°C 40 QFNSet-Top Boxes*Future product—contact factory for avai ..
MAX6957AAX+ ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O ExpanderMAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander
MAX6957ANI+ ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O ExpanderElectrical Characteristics(Typical Operating Circuit, V+ = 2.5V to 5.5V, T = T to T , unless otherw ..
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 ..
MAX6956ATL
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port LED Display Driver and I/O Expander
General DescriptionThe MAX6956 compact, serial-interfaced LED display
driver/I/O expander provide microprocessors with up to
28 ports. Each port is individually user configurable to
either a logic input, logic output, or common-anode
(CA) LED constant-current segment driver. Each port
configured as an LED segment driver behaves as a
digitally controlled constant-current sink, with 16 equal
current steps from 1.5mA to 24mA. The LED drivers are
suitable for both discrete LEDs and CA numeric and
alphanumeric LED digits.
Each port configured as a general-purpose I/O (GPIO)
can be either a push-pull logic output capable of sink-
ing 10mA and sourcing 4.5mA, or a Schmitt logic input
with optional internal pullup. Seven ports feature config-
urable transition detection logic, which generates an
interrupt upon change of port logic level. The MAX6956
is controlled through an I2C™-compatible 2-wire serial
interface, and uses four-level logic to allow 16 I2C
addresses from only 2 select pins.
The MAX6956AAX and MAX6956ATL have 28 ports
and are available in 36-pin SSOP and 40-pin thin QFN
packages, respectively. The MAX6956AAI and
MAX6956ANIhave 20 ports and are available in 28-pin
SSOP and 28-pin DIP packages, respectively.
For an SPI-interfaced version, refer to the MAX6957
data sheet. For a lower cost pin-compatible port
expander without the constant-current LED drive capa-
bility, refer to the MAX7300 data sheet.
ApplicationsSet-Top BoxesBar Graph Displays
Panel MetersIndustrial Controllers
White GoodsSystem Monitoring
Automotive
Features400kbps I2C-Compatible Serial Interface2.5V to 5.5V Operation-40°C to +125°C Temperature Range20 or 28 I/O Ports, Each Configurable as
Constant-Current LED Driver
Push-Pull Logic Output
Schmitt Logic Input
Schmitt Logic Input with Internal Pullup11µA (max) Shutdown Current16-Step Individually Programmable Current
Control for Each LEDLogic Transition Detection for Seven I/O Ports
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
Pin Configurations19-2414; Rev 2; 11/03
Typical Operating Circuit appears at end of data sheet.
Ordering InformationPurchase of I2C components of Maxim Integrated Products, Inc.,
or one of its sublicensed Associated Companies, conveys a
license under the Philips I2C Patent Rights to use these compo-
nents in an I2C system, provided that the system conforms to the2C Standard Specification as defined by Philips.
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
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) .............................................................................-0.3V to +6V
SCL, SDA, AD0, AD1................................................-0.3V to +6V
All Other Pins................................................-0.3V to (V+ + 0.3V)
P4–P31 Current ................................................................±30mA
GND Current.....................................................................800mA
Continuous Power Dissipation
28-Pin PDIP (derate 20.8mW/°C above TA= +70°C)1667mW
28-Pin SSOP (derate 9.5mW/°C above TA= +70°C)..762mW
36-Pin SSOP (derate 11.8mW/°C above TA= +70°C)..941mW
40-Pin QFN (derate 26.3mW/°C above TA= +70°C)..2105mW
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
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
Note 1:All parameters tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2:Guaranteed by design.
Note 3:A master device must provide a hold time of at least 300ns for the SDA signal (referred to VILof the SCL signal) in order to
bridge the undefined region of SCL’s falling edge.
Note 4:Cb= total capacitance of one bus line in pF. tRand tFmeasured between 0.3V+ and 0.7V+.
Note 5:ISINK≤6mA. Cb= total capacitance of one bus line in pF. tRand tFmeasured between 0.3V+ and 0.7V+.
ELECTRICAL CHARACTERISTICS (continued)(Typical Operating Circuit, V+ = 2.5V to 5.5V, TA= TMINto TMAX, unless otherwise noted.) (Note 1)
TIMING CHARACTERISTICS (Figure 2)
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
OPERATING SUPPLY CURRENT
vs. TEMPERATUREMAX6956 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX6956 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (
OPERATING SUPPLY CURRENT vs. V+
(NO LOADS)
MAX6956 toc03
V+ (V)
SUPPLY CURRENT (mA)
LED DRIVER SINK CURRENT
vs. V+
MAX6956 toc04
V+ (V)
PORT SINK CURRENT (mA)
GPO SOURCE CURRENT vs. TEMPERATURE
(OUTPUT = 1)
MAX6956 toc07
TEMPERATURE (°C)
PORT SOURCE CURRENT (mA)
LED DRIVER SINK CURRENT
vs. TEMPERATURE
MAX6956 toc05
TEMPERATURE (°C)
PORT SINK CURRENT (mA)
GPO SINK CURRENT vs. TEMPERATURE
(OUTPUT = 0)
MAX6956 toc06
TEMPERATURE (°C)
PORT SINK CURRENT (mA)
GPI PULLUP CURRENT
vs. TEMPERATURE
MAX6956 toc08
TEMPERATURE (°C)
PULLUP CURRENT (
GPO SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
MAX6956 toc09
TEMPERATURE (°C)
PORT CURRENT (mA)
__________________________________________Typical Operating Characteristics
(RISET= 39kΩ, TA = +25°C, unless otherwise noted.)
Detailed DescriptionThe MAX6956 LED driver/GPIO peripheral provides up
to 28 I/O ports, P4 to P31, controlled through an I2C-com-
patible serial interface. The ports can be configured to
any combination of constant-current LED drivers, logic
inputs and logic outputs, and default to logic inputs on
power-up. When fully configured as an LED driver, the
MAX6956 controls up to 28 LED segments with individ-
ual 16-step adjustment of the constant current through
each LED segment. A single resistor sets the maximum
segment current for all segments, with a maximum of
24mA per segment. The MAX6956 drives any combina-
tion of discrete LEDs and CA digits, including seven-
segment and starburst alphanumeric types.
Figure 1 is the MAX6956 functional diagram. Any I/O
port can be configured as a push-pull output (sinking
10mA, sourcing 4.5mA), or a Schmitt-trigger logic
input. Each input has an individually selectable internal
pullup resistor. Additionally, transition detection allows
seven ports (P24 through P30) to be monitored in any
maskable combination for changes in their logic status.
A detected transition is flagged through a status regis-
ter bit, as well as an interrupt pin (port P31), if desired.
The Typical Operating Circuitshows two MAX6956s
working together controlling three monocolor 16-seg-
ment-plus-DP displays, with five ports left available for
GPIO (P26–P31 of U2).
The port configuration registers set the 28 ports, P4 to
P31, individually as either LED drivers or GPIO. A pair
of bits in registers 0x09 through 0x0F sets each port’s
configuration (Tables 1 and 2).
The 36-pin MAX6956AAX has 28 ports, P4 to P31. The
28-pin MAX6956ANI and MAX6956AAI make only 20
ports available, P12 to P31. The eight unused ports
should be configured as outputs on power-up by writ-
ing 0x55 to registers 0x09 and 0x0A. If this is not done,
the eight unused ports remain as floating inputs and
quiescent supply current rises, although there is no
damage to the part.
Register Control of I/O Ports and LEDs
Across Multiple DriversThe MAX6956 offers 20 or 28 I/O ports, depending on
package choice. These can be applied to a variety of
combinations of different display types, for example:
seven, 7-segment digits (Figure 7). This example
requires two MAX6956s, with one digit being driven by
both devices, half by one MAX6956, half by the other
(digit 4 in this example). The two drivers are static, and
therefore do not need to be synchronized. The
MAX6956 sees CA digits as multiple discrete LEDs. To
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956simplify access to displays that overlap two MAX6956s,
the MAX6956 provides four virtual ports, P0 through P3.
To update an overlapping digit, send the same code
twice as an eight-port write, once to P28 through P35 of
the first driver, and again to P0 through P7 of the sec-
ond driver. The first driver ignores the last 4 bits and
the second driver ignores the first 4 bits.
Two addressing methods are available. Any single port
(bit) can be written (set/cleared) at once; or, any
sequence of eight ports can be written (set/cleared) in
any combination at once. There are no boundaries; it is
equally acceptable to write P0 through P7, P1 through
P8, or P31 through P38 (P32 through P38 are nonexis-
tent, so the instructions to these bits are ignored).
Using 8-bit control, a seven-segment digit with a deci-
mal point can be updated in a single byte-write, a 14-
segment digit with DP can be updated in two byte-
writes, and 16-segment digits with DP can be updated
in two byte-writes plus a bit write. Also, discrete LEDs
and GPIO port bits can be lit and controlled individually
without affecting other ports.
ShutdownWhen the MAX6956 is in shutdown mode, all ports are
forced to inputs (which an be read), and the pullup cur-
rent sources are turned off. Data in the port and control
registers remain unaltered, so port configuration and
output levels are restored when the MAX6956 is taken
out of shutdown. The display driver can still be pro-
grammed while in shutdown mode. For minimum sup-
ply current in shutdown mode, logic inputs should be at
GND or V+ potential. Shutdown mode is exited by set-
ting the S bit in the configuration register (Table 8).
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
Shutdown mode is temporarily overridden by the dis-
play test function.
Serial Interface
Serial AddressingThe MAX6956 operates as a slave that sends and
receives data through an I2C-compatible 2-wire inter-
face. The interface uses a serial data line (SDA) and a
serial clock line (SCL) to achieve bidirectional commu-
nication between master(s) and slave(s). A master (typ-
ically a microcontroller) initiates all data transfers to and
from the MAX6956, and generates the SCL clock that
synchronizes the data transfer (Figure 2).
The MAX6956 SDA line operates as both an input and
an open-drain output. A pullup resistor, typically 4.7kΩ,
is required on SDA. The MAX6956 SCL line operates
only as an input. A pullup resistor, typically 4.7kΩ, is
required on SCL if there are multiple masters on the 2-
wire interface, or if the master in a single-master system
has an open-drain SCL output.
Each transmission consists of a START condition
(Figure 3) sent by a master, followed by the MAX6956
7-bit slave address plus R/Wbit (Figure 6), a register
address byte, one or more data bytes, and finally a
STOP condition (Figure 3).
Start and Stop ConditionsBoth SCL and SDA remain high when the interface is
not busy. A master signals the beginning of a transmis-
sion with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956has finished communicating with the slave, it issues a
STOP (P) condition by transitioning SDA from low to
high while SCL is high. The bus is then free for another
transmission (Figure 3).
Bit TransferOne data bit is transferred during each clock pulse.
The data on SDA must remain stable while SCL is high
(Figure 4).
AcknowledgeThe acknowledge bit is a clocked 9th bit, which the
recipient uses to handshake receipt of each byte of
data (Figure 5). Thus, each byte transferred effectively
requires 9 bits. The master generates the 9th clock
pulse, and the recipient pulls down SDA during the
acknowledge clock pulse, such that the SDA line is sta-
ble low during the high period of the clock pulse. When
the master is transmitting to the MAX6956, the
MAX6956 generates the acknowledge bit because the
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956 is the recipient. When the MAX6956 is trans-
mitting to the master, the master generates the
acknowledge bit because the master is the recipient.
Slave AddressThe MAX6956 has a 7-bit-long slave address (Figure 6).
The eighth bit following the 7-bit slave address is the
R/Wbit. It is low for a write command, high for a read
command.
The first 3 bits (MSBs) of the MAX6956 slave address
are always 100. Slave address bits A3, A2, A1, and A0
are selected by address inputs, AD1 and AD0. These
two input pins may be connected to GND, V+, SDA, or
SCL. The MAX6956 has 16 possible slave addresses
(Table 3) and therefore, a maximum of 16 MAX6956
devices may share the same interface.
Message Format for Writing
the MAX6956A write to the MAX6956 comprises the transmission of
the MAX6956’s slave address with the R/Wbit set to
zero, followed by at least 1 byte of information. The first
byte of information is the command byte. The com-
mand byte determines which register of the MAX6956
is to be written by the next byte, if received. If a STOP
condition is detected after the command byte is
received, then the MAX6956 takes no further action
(Figure 8) beyond storing the command byte.
Any bytes received after the command byte are data
bytes. The first data byte goes into the internal register of
the MAX6956 selected by the command byte (Figure 9). If
multiple data bytes are transmitted before a STOP condi-
tion is detected, these bytes are generally stored in subse-
quent MAX6956 internal registers because the command
byte address generally autoincrements (Table 4).
Message Format for Reading The MAX6956 is read using the MAX6956’s internally
stored command byte as address pointer, the same
way the stored command byte is used as address
pointer for a write. The pointer generally autoincre-
ments after each data byte is read using the same rules
as for a write (Table 4). Thus, a read is initiated by first
configuring the MAX6956’s command byte by perform-
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
ing a write (Figure 8). The master can now read n con-
secutive bytes from the MAX6956, with the first data
byte being read from the register addressed by the ini-
tialized command byte. When performing read-after-
write verification, remember to reset the command
byte’s address because the stored control byte
address generally has been autoincremented after the
write (Table 4). Table 5 is the register address map.
Operation with Multiple MastersIf the MAX6956 is operated on a 2-wire interface with
multiple masters, a master reading the MAX6956
should use a repeated start between the write, which
sets the MAX6956’s address pointer, and the read(s)
that takes the data from the location(s). This is because
it is possible for master 2 to take over the bus after
master 1 has set up the MAX6956’s address pointer but
before master 1 has read the data. If master 2 subse-
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
MAX6956quently changes, the MAX6956’s address pointer, then
master 1’s delayed read may be from an unexpected
location.
Command Address Autoincrementing Address autoincrementing allows the MAX6956 to be
configured with the shortest number of transmissions
by minimizing the number of times the command
address needs to be sent. The command address
stored in the MAX6956 generally increments after each
data byte is written or read (Table 4).
Initial Power-UpOn initial power-up, all control registers are reset, the
current registers are set to minimum value, and the
MAX6956 enters shutdown mode (Table 6).
LED Current ControlLED segment drive current can be set either globally or
individually. Global control simplifies the operation
when all LEDs are set to the same current level,
because writing just the global current register sets the
current for all ports configured as LED segment drivers.
It is also possible to individually control the current
drive of each LED segment driver. Individual/global
brightness control is selected by setting the configura-
tion register I bit (Table 9). The global current register
(0x02) data are then ignored, and segment currents are
set using register addresses 0x12 through 0x1F (Tables
12, 13, and 14). Each segment is controlled by a nibble
of one of the 16 current registers.
Transition (Port Data Change) DetectionPort transition detection allows any combination of the
seven ports P24–P30 to be continuously monitored for
changes in their logic status (Figure 11). A detected
change is flagged on the transition detection mask reg-
ister INT status bit, D7 (Table 15). If port P31 is config-
ured as an output (Tables 1 and 2), then P31 also
automatically becomes an active-high interrupt output
(INT), which follows the condition of the INT status bit.
Port P31 is set as output by writing bit D7 = 0 and bit
D6 = 1 to the port configuration register (Table 1). Note
that the MAX6956 does not identify which specific
port(s) caused the interrupt, but provides an alert that
one or more port levels have changed.
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
