19-3787; Rev 1; 9/06 KIT ATION EVALU E L B AVAILA I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Applications Cell Phones SAN/NAS Servers Ordering Information PART TEMP RANGE PINPACKAGE MAX7322AEE+ -40°C to +125°C 16 QSOP MAX7322ATE+ -40°C to +125°C 16 TQFN-EP* (3mm x 3mm) — — 8 — Up to 8 — MAX7322 4 Yes — 4 MAX7323 Up to 4 — Up to 4 4 MAX7328 Up to 8 — Up to 8 — MAX7329 Up to 8 — Up to 8 — O6 — Up to 8 O7 Yes INT 8 MAX7321 I4 6 GND 5 I3 MAX7322 AD0 15 2 3 4 O1 I2 AD2 1 O0 *EP + OPENPUSH-PULL DRAIN OUTPUTS OUTPUTS MAX7319 MAX7320 7 T1633-4 INTERRUPT MASK 9 V+ 14 ADD INPUTS 10 I5 E16-4 PART 11 8 — Selector Guide 12 SDA 13 PKG CODE *EP = Exposed paddle. SCL TOP VIEW TOP MARK +Denotes lead-free package. Notebooks Satellite Radio Automotive Pin Configurations RST 16 Features ♦ 400kHz I2C Serial Interface ♦ +1.71V to +5.5V Operation Voltage ♦ 4 Push-Pull Output Ports Rated at 20mA Sink Current ♦ 4 Input Ports with Maskable, Latching Transition Detection ♦ Input Ports are Overvoltage Protected to +6V ♦ Transient Changes are Latched, Allowing Detection Between Read Operations ♦ INT Output Alerts Change on Any Selection of Inputs ♦ AD0 and AD2 Inputs Select from 16 Slave Addresses ♦ Low 0.6µA (typ) Standby Current ♦ -40°C to +125°C Operating Temperature Range — — TQFN (3mm x 3mm) Pin Configurations continued at end of data sheet. Typical Application Circuit and Functional Diagram appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX7322 General Description The MAX7322 2-wire serial-interfaced peripheral features four push-pull outputs and four input ports with selectable internal pullups. Input ports are overvoltage protected to +6V and feature transition detection with interrupt output. The four input ports are continuously monitored for state changes (transition detection). The interrupt is latched, allowing detection of transient changes. Any combination of inputs can be selected using the interrupt mask to assert the open-drain INT output. When the MAX7322 is subsequently accessed through the serial interface, any pending interrupt is cleared. The four push-pull outputs are rated to sink 20mA, and are capable of driving LEDs. The RST input clears the serial interface, terminating any I2C communication to or from the MAX7322. The MAX7322 uses two address inputs with four-level logic to allow 16 I2C slave addresses. The slave address also sets the power-up default logic state for the four output ports, and enables or disables internal 40kΩ pullups for the input ports. The MAX7322 is one device in a family of pin-compatible port expanders with a choice of input ports, open-drain I/O ports, and push-pull output ports (see Table 1). The MAX7322 is available in 16-pin QSOP and TQFN packages, and is specified over the -40°C to +125°C automotive temperature range. MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) Supply Voltage V+....................................................-0.3V to +6V SCL, SDA, AD0, AD2, RST, INT, I2–I5......................-0.3V to +6V O0, O1, O6, O7 .................................................-0.3 to V+ + 0.3V O0, O1, O6, O7 Output Current........................................±25mA SDA Sink Current ............................................................... 10mA INT Sink Current..................................................................10mA Total V+ Current..................................................................50mA Total GND Current ...........................................................100mA Continuous Power Dissipation (TA = +70°C) 16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW 16-Pin TQFN (derate 15.6mW/°C above +70°C) .......1250mW 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 Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS (V+ = +1.71V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA = +25°C.) (Note 1) PARAMETER Operating Supply Voltage Power-On Reset Voltage Standby Current (Interface Idle) Supply Current (Interface Running) SYMBOL CONDITIONS V+ MIN 1.71 1.6 V ISTB 0.6 1.5 µA I+ fSCL = 400kHz; other digital inputs at V+ 23 55 µA VIL Input Leakage Current SDA, SCL, AD0, AD2, RST, I2–I5 IIH, IIL V+ < 1.8V 0.8 x V+ V+ ≥ 1.8V 0.7 x V+ V V+ < 1.8V 0.2 x V+ V+ ≥ 1.8V 0.3 x V+ SDA, SCL, AD0, AD2, RST, at V+ or GND, internal pullup disabled -0.2 Input Capacitance SDA, SCL, AD0, AD2, RST, I2–I5 +0.2 10 VOL 90 180 V+ = +2.5V, ISINK = 10mA 110 210 V+ = +3.3V, ISINK = 15mA 130 230 140 250 VOH V+ = +1.71V, ISOURCE = 2mA V+ - 250 V+ - 30 V+ = +2.5V, ISOURCE = 5mA V+ - 360 V+ - 70 V+ = +3.3V, ISOURCE = 5mA V+ - 260 V+ - 100 V+ = +5V, ISOURCE = 10mA V+ - 360 V+ - 120 Output Low Voltage SDA VOLSDA ISINK = 6mA Output Low Voltage INT VOLINT ISINK = 5mA RPU 25 V µA pF V+ = +1.71V, ISINK = 5mA V+ = +5V, ISINK = 20mA 2 V SCL and SDA and other digital inputs at V+ Input Low Voltage SDA, SCL, AD0, AD2, RST, I2–I5 Port Input Pullup Resistor UNITS 5.50 V+ falling VIH Output High Voltage O0, O1, O6, O7 MAX VPOR Input High Voltage SDA, SCL, AD0, AD2, RST, I2–I5 Output Low Voltage O0, O1, O6, O7 TYP mV mV 250 mV 130 250 mV 40 55 kΩ _______________________________________________________________________________________ I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs (V+ = +1.71V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 4 µs Port Output Data Valid tPPV CL ≤ 100pF Port Input Setup Time tPSU CL ≤ 100pF 0 µs Port Input Hold Time tPH CL ≤ 100pF 4 µs INT Input Data Valid Time tIV CL ≤ 100pF 4 µs INT Reset Delay Time from STOP tIP CL ≤ 100pF 4 µs INT Reset Delay Time from Acknowledge tIR CL ≤ 100pF 4 µs TIMING CHARACTERISTICS (V+ = +1.71V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 400 kHz Serial Clock Frequency fSCL Bus Free Time Between a STOP and a START Condition tBUF 1.3 µs Hold Time (Repeated) START Condition tHD, STA 0.6 µs Repeated START Condition Setup Time tSU, STA 0.6 µs STOP Condition Setup Time tSU, STO Data Hold Time tHD, DAT Data Setup Time tSU, DAT 100 ns tLOW tHIGH 1.3 0.7 µs µs SCL Clock Low Period SCL Clock High Period 0.6 µs (Note 2) 0.9 µs Rise Time of Both SDA and SCL Signals, Receiving tR (Notes 3, 4) 20 + 0.1Cb 300 ns Fall Time of Both SDA and SCL Signals, Receiving tF (Notes 3, 4) 20 + 0.1Cb 300 ns Fall Time of SDA, Transmitting tF,TX (Notes 3, 4) 20 + 0.1Cb 250 ns Pulse Width of Spike Suppressed tSP (Note 5) Capacitive Load for Each Bus Line Cb (Note 3) RST Pulse Width tW 500 ns tRST 1 µs RST Rising to START Condition Setup Time 50 ns 400 pF Note 1: All parameters are tested at TA = +25°C. Specifications over temperature are guaranteed by design. Note 2: A master device must provide a hold time of at least 300ns for the SDA signal (referred to VIL of the SCL signal) in order to bridge the undefined region of SCL’s falling edge. Note 3: Guaranteed by design. Note 4: Cb = total capacitance of one bus line in pF. tR and tF measured between 0.3 x V+ and 0.7 x V+ with ISINK ≤ 6mA. Note 5: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns. _______________________________________________________________________________________ 3 MAX7322 PORT AND INTERRUPT INT TIMING CHARACTERISTICS Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) 1.4 1.2 V+ = +5.0V 1.0 V+ = +3.3V V+ = +2.5V 0.8 0.6 0.4 fSCL = 400kHz V+ = +5.0V 50 SUPPLY CURRENT (μA) V+ = +1.71V 40 V+ = +3.3V 30 20 V+ = +2.5V 10 0.2 V+ = +1.71V 0 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) TEMPERATURE (°C) OUTPUT VOLTAGE LOW vs. TEMPERATURE OUTPUT VOLTAGE HIGH vs. TEMPERATURE 6 MAX7322 toc03 0.40 0.30 0.25 V+ = +3.3V ISINK = 15mA 0.20 V+ = +5.0V ISINK = 20mA 0.15 0.10 0.05 V+ = +1.71V ISINK = 5mA 0 V+ = +2.5V ISINK = 10mA V+ = +5.0V ISOURCE = 10mA 5 OUTPUT VOLTAGE HIGH (V) 0.35 MAX7322 toc04 STANDBY CURRENT (μA) 1.6 MAX7322 toc01 fSCL = 0kHz 1.8 60 MAX7322 toc02 SUPPLY CURRENT vs. TEMPERATURE STANDBY CURRENT vs. TEMPERATURE 2.0 OUTPUT VOLTAGE LOW (V) MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs V+ = +3.3V ISOURCE = 5mA 4 3 2 V+ = +1.71V ISOURCE = 2mA 1 V+ = +2.5V ISOURCE = 5mA 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) Pin Description PIN NAME FUNCTION QSOP TQFN 1, 3 15, 1 AD0, AD2 2 16 RST 4, 5, 11, 12, 2, 3, 9, 10 6, 7, 9, 10 4, 5, 7, 8 I2–I5 Input Ports. I2 to I5 are CMOS-logic inputs protected to +6V. 8 6 GND Ground 4 Address Inputs. Select device slave address with AD0 and AD2. Connect AD0 and AD2 to either GND, V+, SCL, or SDA to give four logic combinations (see Table 2). Reset Input. Active Low. Drive RST low to clear the 2-wire interface. O0, O1, O6, O7 Push-Pull Output Ports 13 11 INT Interrupt Output, Active Low. INT is an open-drain output. 14 12 SCL I2C-Compatible Serial Clock Input 15 13 SDA I2C-Compatible Serial Data I/O 16 14 V+ Positive Supply Voltage. Bypass V+ to GND with a ceramic capacitor of at least 0.047µF. — EP EP Exposed Paddle. Connect exposed pad to GND. _______________________________________________________________________________________ I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs MAX7319–MAX7329 Family Comparison The MAX7319–MAX7323 family consists of five pincompatible, eight-port expanders. Each version is optimized for different applications. The MAX7328 and MAX7329 are industry-standard parts. The MAX7324–MAX7327 family consists of four pincompatible, 16-port expanders that integrate the functions of the MAX7320 and one of either MAX7319, MAX7321, MAX7322, or MAX7323. Functional Overview The MAX7322 is a general-purpose port expander operating from +1.71V to +5.5V supply that provides four push-pull output ports with 20mA sink, 10mA source drive capability, and four input ports that are overvoltage protected to +6V independent of supply voltage. The MAX7322 is rated to sink a total of 100mA and source a total of 50mA from all four combined outputs. The MAX7322 is set to one of 16 I2C slave addresses (0x60 to 0x6F) using address inputs AD2 and AD0, and is accessed over an I2C serial interface up to 400kHz. The RST input clears the serial interface in case of a bus lockup, terminating any serial transaction to or from the MAX7322. Table 1. MAX7319–MAX7329 Family Comparison PART INPUT OPENI2C SLAVE DRAIN INPUTS INTERRUPT ADDRESS MASK OUTPUTS PUSHPULL OUTPUTS I2C DATA WRITE I2C DATA READ APPLICATION 8-PORT EXPANDERS Input-only versions: 8 input ports with programmable latching transition detection interrupt and selectable pullups. MAX7319 110xxxx 8 Yes — — <I7–I0 interrupt mask> MAX7320 101xxxx — — — 8 <O7–O0 port outputs> <I7–I0 port inputs> <I7–I0 transition flags> <O7-O0 port inputs> Offers maximum versatility for automatic input monitoring. An interrupt mask selects which inputs cause an interrupt on transitions, and transition flags identify which inputs have changed (even momentarily) since the ports were last read. Output-only versions: 8 push-pull outputs with selectable power-up default levels. Push-pull outputs offer faster rise time than opendrain outputs, and require no pullup resistors. _______________________________________________________________________________________ 5 MAX7322 Detailed Description MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Table 1. MAX7319–MAX7329 Family Comparison (continued) PART INPUT OPENI2C SLAVE DRAIN INPUTS INTERRUPT ADDRESS MASK OUTPUTS PUSHPULL OUTPUTS I2C DATA WRITE I2C DATA READ APPLICATION I/O versions: 8 open-drain I/O ports with latching transition detection interrupt and selectable pullups. MAX7321 MAX7322 110xxxx 110xxxx Up to 8 4 — Yes Up to 8 — — <P7–P0 port outputs> <P7–P0 port inputs> <P7–P0 transition flags> 4 <O7, O6 outputs, I5–I2 interrupt mask, O1, O0 outputs> <O7, O6, I5–I2, O1, O0 port inputs> <0, 0, I5–I2 transition flags, 0, 0> MAX7323 110xxxx Up to 4 — Up to 4 4 <port outputs> <O7, O6, P5–P2, O1, O0 port inputs> <0, 0, P5–P2 transition flags, 0, 0> MAX7328 MAX7329 0100xxx 0111xxx Up to 8 — Up to 8 — <P7–P0 port outputs> <P7–P0 port inputs> Open-drain outputs can level shift the logic-high state to a higher or lower voltage than V+ using external pullup resistors. Any port can be used as an input by setting the opendrain output to logic-high. Transition flags identify which inputs have changed (even momentarily) since the ports were last read. 4 input-only, 4 output-only versions: 4 input ports with programmable latching transition detection interrupt and selectable pullups; 4 push-pull outputs with selectable power-up default levels. 4 I/O, 4 output-only versions: 4 open-drain I/O ports with latching transition detection interrupt and selectable pullups. 4 push-pull outputs with selectable power-up default levels. 8 open-drain I/O ports with nonlatching transition detection interrupt and pullups on all ports. All ports power up as inputs (or logic-high outputs). Any port can be used as an input by setting the opendrain output to logic-high. 6 _______________________________________________________________________________________ I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs MAX7322 Table 1. MAX7319–MAX7329 Family Comparison (continued) PART INPUT OPENI2C SLAVE DRAIN INPUTS INTERRUPT ADDRESS MASK OUTPUTS PUSHPULL OUTPUTS I2C DATA WRITE I2C DATA READ APPLICATION 16-PORT EXPANDERS MAX7324 MAX7325 MAX7326 MAX7327 101xxxx and 110xxxx 8 Yes — 8 — — Software equivalent to a MAX7320 plus a MAX7319. Up to 8 — Up to 8 8 — — Software equivalent to a MAX7320 plus a MAX7321. 4 Yes — 12 — — Software equivalent to a MAX7320 plus a MAX7322. Up to 4 — Up to 4 12 — — Software equivalent to a MAX7320 plus a MAX7323. When the MAX7322 is read through the serial interface the actual logic levels at the ports are read back. The four input ports offer latching transition detection functionality. All input ports are continuously monitored for changes. An input change sets 1 of 4 flag bits that identify the changed input(s). All flags are cleared upon a subsequent read or write transaction to the MAX7322. A latching interrupt output, INT, is programmed to flag input data changes on the four input ports through an interrupt mask register. By default, data changes on any input port force INT to a logic low. The interrupt output INT and all transition flags are deasserted when the MAX7322 is next accessed through the serial interface. Internal pullup resistors to V+ are selected by the address select inputs, AD0 and AD2. Pullups are enabled on the input ports in groups of two (see Table 2). Output port power-up logic states are selected by the address select inputs AD0 and AD2. Ports default to logic-high or logic-low on power-up in groups of two (see Table 2). Initial Power-Up On power-up, the transition detection logic is reset, and INT is deasserted. The interrupt mask register is set to 0x3C, enabling the interrupt output for transitions on all four input ports. The transition flags are cleared to indicate no data changes. The power-up default state of the four push-pull outputs are set according to the I2C slave address selection inputs, AD0 and AD2 (Table 2). Power-On Reset (POR) The MAX7322 contains an integral POR circuit that ensures all registers are reset to a known state on power-up. When V+ rises above VPOR (1.6V max), the POR circuit releases the registers and 2-wire interface for normal operation. When V+ drops to less than VPOR, the MAX7322 resets all register contents to the POR defaults (Table 2). RST Input The active-low RST input operates as a reset that voids any current I 2C transaction involving the MAX7322, forcing the MAX7322 into the I2C STOP condition. The reset action does not clear the interrupt output (INT). Standby Mode When the serial interface is idle, the MAX7322 automatically enters standby mode, drawing minimal supply current. Slave Address and Input Pullup Selection/Default Logic State Address inputs AD0 and AD2 determine the MAX7322 slave address, select which inputs have pullup resistors and set the default logic state for outputs. Pullups are enabled on the input ports in groups of two (see Table 2). The MAX7319, MAX7321, MAX7322, and MAX7323 use a different range of slave addresses (110xxxx) than the MAX7320 (101xxxx). The MAX7322 slave address is determined on each I2C transmission, regardless of whether the transmission is actually addressing the MAX7322. The MAX7322 distinguishes whether address inputs AD2 and AD0 are connected to SDA or SCL instead of fixed logic levels V+ or GND during this transmission. This means that the MAX7322 slave address can be configured dynamically in the application without cycling the device supply. _______________________________________________________________________________________ 7 On initial power-up, the MAX7322 cannot decode the address inputs AD2 and AD0 fully until the first I2C transmission. AD0 and AD2 initially appear to be connected to V+ or GND. This is important because the address selection determines the power-up logic state, and whether pullups are enabled. However, at powerup, the I2C SDA and SCL bus interface lines are high impedance at the pins of every device (master or slave) connected to the bus, including the MAX7322. This is guaranteed as part of the I2C specification. Therefore, address inputs AD2 and AD0 that are connected to SDA or SCL normally appear at power-up to be connected to V+. The port selection logic uses AD0 to select whether pullups are enabled for ports I2 and I3, and to set the initial logic state for ports O0 and O1. AD2 selects whether pullups are enabled for ports I4 and I5 and sets the internal logic state for ports O6 and O7. The rule is that a logic-high, SDA, or SCL connection selects the pullups and sets the default logic state high. A logiclow deselects the pullups and sets the default logic state low (Table 2). This means that the port configuration is correct on power-up for a standard I2C configuration, where SDA or SCL are pulled up to V+ by the external I2C pullup resistors. There are circumstances where the assumption that SDA = SCL = V+ on power-up is not true—for example, in applications in which there is legitimate bus activity during power-up. Also, if SDA and SCL are terminated with pullup resistors to a different supply voltage than the MAX7322’s supply voltage, and if that pullup supply rises later than the MAX7322’s supply, then SDA or SCL may appear at power-up to be connected to GND. In such applications, use the four address combinations that are selected by connecting address inputs AD2 and AD0 to V+ or GND (shown in bold in Table 2). These selections are guaranteed to be correct at power-up, independent of SDA and SCL behavior. If one of the other 12 address combinations is used, an unexpected combination of pullups might be asserted until the first I2C transmission (to any device, not necessarily the MAX7322) is put on the bus, and an unexpected combination of ports may initialize as logic-low outputs instead of inputs or logic-high outputs. Port Inputs Port inputs switch at CMOS logic levels as determined by the expander’s supply voltage, and are overvoltage tolerant to +6V, independent of the expander’s supply voltage. Port Input Transition Detection All four input ports are monitored for changes since the expander was last accessed through the serial interface. The state of the I/O ports is stored in an internal Table 2. MAX7322 Address Map PIN CONNECTION 8 DEVICE ADDRESS 40kΩ INPUT PULLUPS ENABLED OUTPUTS POWER—UP DEFAULT AD0 A6 A5 A4 A3 A2 A1 A0 O7 O6 O1 O0 I5 I4 I3 I2 O1 O0 SCL GND 1 1 0 0 0 0 0 1 1 I5 I4 I3 0 0 Y Y — — SCL V+ 1 1 0 0 0 0 1 1 1 1 1 Y Y Y Y SCL SCL 1 1 0 0 0 1 0 1 1 1 1 Y Y Y Y SCL SDA 1 1 0 0 0 1 1 1 1 1 1 Y Y Y Y SDA GND 1 1 0 0 1 0 0 1 1 0 0 Y Y — — SDA V+ 1 1 0 0 1 0 1 1 1 1 1 SDA SCL 1 1 0 0 1 1 0 1 1 1 1 SDA SDA 1 1 0 0 1 1 1 1 1 1 1 GND GND 1 1 0 1 0 0 0 0 0 0 0 GND V+ 1 1 0 1 0 0 1 0 0 1 1 GND SCL 1 1 0 1 0 1 0 0 0 1 1 GND SDA 1 1 0 1 0 1 1 0 0 1 1 V+ GND 1 1 0 1 1 0 0 1 1 0 0 Inputs I2 O7 O6 Y Y Y Y Y Y Y Y Y Y Y Y — — — — — — Y Y — — Y Y — — Y Y Y Y — — V+ V+ 1 1 0 1 1 0 1 1 1 1 1 Y Y Y Y V+ SCL 1 1 0 1 1 1 0 1 1 1 1 Y Y Y Y V+ SDA 1 1 0 1 1 1 1 1 1 1 1 Y Y Y Y _______________________________________________________________________________________ Pullups are not enabled for push-pull outputs AD2 Pullups are not enabled for push-pull outputs MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs The MAX7322 includes a 4-bit interrupt mask register that selects which inputs generate an interrupt upon change. Each input’s transition flag is set when its input changes, independent of the interrupt mask register settings. The interrupt mask register allows the processor to be interrupted for critical events, while the inputs and the transition flags can be polled periodically to detect less-critical events. The INT output is not reasserted during a read sequence to avoid recursive reentry into an interrupt service routine. Instead, if a data change occurs that would normally cause the INT output to be set, the INT assertion is delayed until the STOP condition. INT is not reasserted upon a STOP condition if the changed input data is read before the STOP occurs. The INT logic ensures that unnecessary interrupts are not asserted, yet data changes are detected and reported no matter when the change occurs. Transition Detection Masks The transition detection logic incorporates a change flag and an interrupt mask bit for each of the four input ports. The four change flags can be read through the serial interface, and the 4-bit interrupt mask is set through the serial interface. Each port’s change flag is set when that port’s input changes, and the change flag remains set even if the input returns to its original state. The port’s interrupt mask determines whether a change on that input port generates an interrupt. Enable interrupts for high-priority inputs using the interrupt mask. The interrupt allows the system to respond quickly to changes on these inputs. Poll the MAX7322 periodically to monitor lessimportant inputs. The change flags indicate whether a permanent or transient change has occurred on any input since the MAX7322 was last accessed. Port Outputs Write one byte to the MAX7322 to set the output port levels for the four push-pull outputs, and the interrupt mask for the four inputs simultaneously. Serial Interface Serial Addressing The MAX7322 operates as a slave that sends and receives data through an I2C interface. The interface uses a serial-data line (SDA) and a serial-clock line (SCL) to achieve bidirectional communication between master(s) and slave(s). The master initiates all data transfers to and from the MAX7322 and generates the SCL clock that synchronizes the data transfer (Figure 1). SDA tSU,STA tSU,DAT tLOW tBUF tHD,STA tSU,STO tHD,DAT tHIGH SCL tHD,STA tR tF START CONDITION REPEATED START CONDITION STOP CONDITION START CONDITION Figure 1. 2-Wire Serial Interface Timing Details _______________________________________________________________________________________ 9 MAX7322 “snapshot” register for transition monitoring. The snapshot is continuously compared with the actual input conditions, and if a change is detected for any port input, then an internal transition flag is set for that port, and INT is asserted to signal a state change. The four port inputs are sampled (internally latched into the snapshot register) and the old transition flags cleared during the I2C acknowledge of every MAX7322 read and write access. The previous port transition flags are read through the serial interface as the second byte of a 2-byte read sequence. A long read sequence (more than 2 bytes) can be used to poll the expander continuously without the overhead of resending the slave address. If more than 2 bytes are read from the expander, the expander repeatedly returns the input port data alternating with the transition flags. The inputs are repeatedly resampled and the transition flags repeatedly reset for each pair of bytes read. All changes that occur during a long read sequence are detected and reported. MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs SDA operates as both an input and an open-drain output. A pullup resistor, typically 4.7kΩ, is required on SDA. SCL 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 sent by a master, followed by the MAX7322’s 7-bit slave address plus R/W bit, one or more data bytes, and finally a STOP condition (Figure 2). START and STOP Conditions Both SCL and SDA remain high when the interface is not busy. A master signals the beginning of a transmission with a START (S) condition by transitioning SDA from high to low while SCL is high. When the master has finished communicating with the slave, the master 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 2). Acknowledge The acknowledge bit is a clocked 9th bit the recipient uses to acknowledge receipt of each byte of data (Figure 4). 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 stable low during the high period of the clock pulse. When the master is transmitting to the MAX7322, the MAX7322 generates the acknowledge bit because the device is the recipient. When the MAX7322 is transmitting to the master, the master generates the acknowledge bit because the master is the recipient. SDA SCL Bit Transfer One data bit is transferred during each clock pulse. The data on SDA must remain stable while SCL is high (Figure 3). DATA LINE STABLE; CHANGE OF DATA DATA VALID ALLOWED Figure 3. Bit Transfer CLOCK PULSE FOR ACKNOWLEDGMENT START CONDITION SDA SCL SCL S P START CONDITION STOP CONDITION Figure 2. START and STOP Conditions 10 1 2 SDA BY TRANSMITTER SDA BY RECEIVER S Figure 4. Acknowledge ______________________________________________________________________________________ 8 9 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Accessing the MAX7322 The MAX7322 is accessed through an I2C interface. The transition flags are cleared, and INT is deasserted each time the device acknowledges the I 2 C slave address. A single-byte read from the MAX7322 returns the status of the four input ports and the four output ports (read back as inputs). A 2-byte read returns the status of the four input ports and the four output ports (as for a single-byte read), followed by the transition flags for the four input ports. A multibyte write to the MAX7322 repeatedly sets the logic state of the four output ports and the 4-bit interrupt mask register. . SDA 1 1 0 A3 A2 A1 A0 R/W ACK LSB MSB SCL Figure 5. Slave Address ______________________________________________________________________________________ 11 MAX7322 A multibyte read (more than 2 bytes before the I2C STOP bit) repeatedly returns the port data, alternating with the transition flags. As the data is resampled for each transmission, and the transition flags are reset each time, a multibyte read continuously returns the current data and identifies any changing ports. If a port data change occurs during the read sequence, INT is reasserted after the I2C STOP bit. The MAX7322 does not generate another interrupt during a singlebyte or multibyte read. Port data is sampled during the preceding I 2 C acknowledge bit (the acknowledge bit for the I2C slave address in the case of a single-byte or 2-byte read). A single-byte write to the MAX7322 sets the logic state of the four output ports and the 4-bit interrupt mask resistor, and clears both the internal transition flags and the INT output when the device acknowledges the slave address byte. Slave Address The MAX7322 has a 7-bit-long slave address (Figure 5). The eighth bit following the 7-bit slave address is the R/W bit. It is low for a write command, and high for a read command. The first (A6), second (A5), and third (A4) bits of the MAX7322 slave address are always 1, 1, and 0. Connect AD2 and AD0 to GND, V+, SDA, or SCL to select slave address bits A3, A2, A1, and A0. The MAX7322 has 16 possible slave addresses (Table 2), allowing up to 16 MAX7322 devices on an I2C bus. MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Reading from the MAX7322 the MAX7322 transmits the current port data, clears the change flags, and restarts the transition detection. INT deasserts during the slave address acknowledge. The new snapshot data is the current input port data transmitted to the master, so any input port changes that occur during the transmission are detected. INT remains high until the STOP condition. A read from the MAX7322 starts with the master transmitting the MAX7322’s slave address with the R/W bit set high. The MAX7322 acknowledges the slave address, and samples the ports during the acknowledge bit. INT deasserts during the slave address acknowledge. Typically, the master reads one or two bytes from the MAX7322, each byte being acknowledged by the master upon reception with the exception of the last byte. When the master reads one byte from the MAX7322 and subsequently issues a STOP condition (Figure 6), The master can read two bytes from the MAX7322 and then issue a STOP condition (Figure 7). In this case, the MAX7322 transmits the current port data, followed by the change flags. The change flags are then cleared, and transition detection restarts. INT deasserts during the slave address acknowledge. The new snapshot PORTS S = START CONDITION P = STOP CONDITION SHADED = SLAVE TRANSMISSION N = NOT ACKNOWLEDGE S 1 1 O6 O7 0 MAX7322 SLAVE ADDRESS 1 A D7 R/W I5 D6 I4 D5 I3 D4 O1 I2 D3 D2 ACKNOWLEDGE FROM MAX7322 O0 D1 D0 N P PORT SNAPSHOT PORT SNAPSHOT SCL tPH PORTS tIV tPSU tIR INT OUTPUT tIP INT REMAINS HIGH UNTIL STOP CONDITION Figure 6. Reading from the MAX7322 (1 Data Byte) PORT INPUTS S = START CONDITION P = STOP CONDITION SHADED = SLAVE TRANSMISSION N = NOT ACKNOWLEDGE S 1 1 O7 0 MAX7322 SLAVE ADDRESS 1 A D7 R/W O6 D6 I5 D5 PORT SNAPSHOT I4 I3 D4 D3 INTERRUPT FLAGS I1 I2 D2 D1 O0 D0 PORT SNAPSHOT 0 A D7 0 D6 F5 D5 F4 D4 F3 D3 F2 D2 0 0 D1 D0 ACKNOWLEDGE FROM MAX7322 N P PORT SNAPSHOT SCL tPH PORTS tPSU tIV INT OUTPUT tIR INT REMAINS HIGH UNTIL STOP CONDITION Figure 7. Reading from the MAX7322 (2 Data Bytes) 12 ______________________________________________________________________________________ tIP I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Writing to the MAX7322 A write to the MAX7322 starts with the master transmitting the MAX7322’s slave address with the R/W bit set low. The MAX7322 acknowledges the slave address, and samples the ports (takes a snapshot) during acknowledge. INT deasserts during the slave acknowledge. The master proceeds to transmit 1 or more bytes of data. The MAX7322 acknowledges these subsequent bytes of data and updates the four output ports and the 4-bit interrupt mask register with each new byte until the master issues a STOP condition (Figure 8). 1 SCL 2 3 4 5 6 7 S The MAX7322 can operate from a higher supply voltage, such as +3V, while the I2C interface and/or some of the four input ports I2–I5 are driven from a lower logic level, such as +2.5V. Apply a minimum voltage of 0.7 x V+ to assert a logic-high on any input. For example, a MAX7322 operating from a +5V supply may not recognize a +3.3V nominal logic-high. One solution for input-level translation is to drive the MAX7322 inputs from open-drain outputs. Use a pullup resistor to V+ or a higher supply to ensure a high logic voltage of greater than 0.7 x V+. DATA TO INTERRUPT MASK 0 START CONDITION The MAX7322’s SDA, SCL, AD0, AD2, input RST, INT, and input ports I2–I5 are overvoltage protected to +6V independent of V+. This allows the MAX7322 to operate from a lower supply voltage, such as +3.3V, while the I2C interface and/or some of the four input ports are driven from a higher logic level, such as +5V. 8 SLAVE ADDRESS SDA Port Input and I2C Interface Level Translation from Higher or Lower Logic Voltages A DATA TO INTERRUPT MASK A DATA 1 A DATA 2 ACKNOWLEDGE FROM SLAVE R/W ACKNOWLEDGE FROM SLAVE ACKNOWLEDGE FROM SLAVE INTERNAL WRITE TO PORT DATA OUT FROM PORT DATA 1 VALID tPV DATA 2 VALID tPV S = START CONDITION P = STOP CONDITION SHADED = SLAVE TRANSMISSION N = NOT ACKNOWLEDGE Figure 8. Writing to the MAX7322 ______________________________________________________________________________________ 13 MAX7322 Applications Information data is the current port data transmitted to the master, so any input port changes occurring during the transmission are detected. INT remains high until the STOP condition. MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Port Structures Each of the four output ports O0, O1, O6, and O7 has protection diodes to V+ and to GND (Figure 9). When a port output is driven to a voltage lower than GND, the appropriate protection diode clamps the output to a diode drop above V+ or below GND. When the MAX7322 is powered down (V+ = 0), each output port appears as a diode clamp to GND (Figure 9). Each of the four input ports I2–I5 has a protection diode to GND (Figure 10). When a port input is driven to a voltage lower than GND, the protection diode will clamp the input to a diode drop below GND. Each of the four inputs ports I2–I5 also has a 40kΩ (typ) pullup resistor that can be enabled or disabled. When a port is driven to a voltage higher than V+, the body diode of the pullup enable switch conducts and the 40kΩ pullup resistor is enabled. When the MAX7322 is powered down (V+ = 0), each input port appears as a 40kΩ pullup resistor in series with a diode connected to zero. Input ports are protected to +6V under any of these circumstances (Figure 10). therefore, requires all four paralleled outputs. Any combination of outputs can be used as part of a load-sharing design, because any combination of ports can be set or cleared at the same time by writing to the MAX7322. Do not exceed a total sink current of 100mA for the device. The MAX7322 must be protected from the negative voltage transient generated when switching off inductive loads (such as relays), by connecting a reversebiased diode across the inductive load. Choose the peak current for the diode to be greater than the inductive load’s operating current. Power-Supply Considerations The MAX7322 operates with a supply voltage of +1.71V to +5.5V over the -40°C to +125°C temperature range. Bypass the supply to GND with a ceramic capacitor of at least 0.047µF as close to the device as possible. For the TQFN version, additionally connect the exposed pad to GND. Driving LED Loads When driving LEDs from one of the four output ports O0, O1, O6, or O7, a resistor must be connected in series with the LED to limit the LED current to no more than 20mA. Connect the LED cathode to the MAX7322 port, and the LED anode to V+ through the series current-limiting resistor, RLED. Set the port output low to light the LED. Choose the resistor value according to the following formula: RLED = (VSUPPLY - VLED - VOL) / ILED where: RLED is the resistance of the resistor in series with the LED (Ω). V SUPPLY is the supply voltage used to drive the LED (V). VLED is the forward voltage of the LED (V). VOL is the output low voltage of the MAX7322 when sinking ILED (V). ILED is the desired operating current of the LED (A). For example, to operate a 2.2V red LED at 10mA from a +5V supply: RLED = (5 - 2.2 - 0.07) / 0.010 = 270Ω V+ V+ MAX7322 PORTS O0, O1, O6, O7 OUTPUT Figure 9. MAX7322 Push-Pull Output Port Structure V+ V+ PULLUP MAX7322 ENABLE 40kΩ INPUT Driving Load Currents Higher than 20mA The MAX7322 can be used to drive loads, such as relays, that draw more than 20mA by paralleling outputs. Use at least one output per 20mA of load current; for example, a 5V 330mW relay draws 66mA, and 14 Figure 10. MAX7322 Input Port Structure ______________________________________________________________________________________ PORTS I2–I5 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs Typical Application Circuit 3.3V AD0 AD2 SCL INPUT SDA I/O PORTS I2C CONTROL FILTER INT POWERON RESET RST O0 O1 I2 I3 I4 I5 O6 O7 0.047μF V+ μC SCL SCL SDA SDA RST RST INT INT O7 MAX7322 O6 I5 I4 I3 I2 AD0 AD2 GND O1 O0 OUTPUT OUTPUT INPUT INPUT INPUT INPUT OUTPUT OUTPUT MAX7322 Chip Information Pin Configurations (continued) PROCESS: BiCMOS TOP VIEW AD0 1 + 16 V+ RST 2 15 SDA AD2 3 14 SCL O0 4 MAX7322 13 INT O1 5 12 O7 I2 6 11 O6 I3 7 10 I5 GND 8 9 I4 QSOP ______________________________________________________________________________________ 15 MAX7322 Functional Diagram Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) (NE - 1) X e E MARKING 12x16L QFN THIN.EPS MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs E/2 D2/2 (ND - 1) X e D/2 AAAA e CL D D2 k CL b 0.10 M C A B E2/2 L E2 0.10 C C L 0.08 C C L A A2 A1 L L e e PACKAGE OUTLINE 8, 12, 16L THIN QFN, 3x3x0.8mm 21-0136 16 ______________________________________________________________________________________ I 1 2 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs PKG 8L 3x3 12L 3x3 REF. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. A 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 b 0.25 0.30 0.35 0.20 0.25 0.30 0.20 0.25 0.30 D 2.90 3.00 3.10 2.90 3.00 3.10 2.90 3.00 3.10 E 2.90 3.00 3.10 2.90 3.00 3.10 2.90 3.00 3.10 e L 0.55 0.75 0.45 0.55 0.65 0.30 0.40 N 8 12 16 ND 2 3 4 NE 2 3 4 0 A1 A2 k 0.05 0.02 0 0.20 REF 0.25 - 0.02 0.05 0 0.20 REF - 0.25 - EXPOSED PAD VARIATIONS 0.50 BSC. 0.50 BSC. 0.65 BSC. 0.35 16L 3x3 0.02 0.50 0.05 0.20 REF - 0.25 - PKG. CODES E2 D2 MIN. NOM. MAX. MIN. NOM. MAX. PIN ID JEDEC TQ833-1 0.25 0.70 1.25 0.25 0.70 1.25 0.35 x 45° T1233-1 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEEC WEED-1 T1233-3 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEED-1 T1233-4 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEED-1 T1633-2 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEED-2 T1633F-3 0.65 0.80 0.95 0.65 0.80 0.95 0.225 x 45° WEED-2 T1633FH-3 0.65 0.80 0.95 0.65 0.80 0.95 0.225 x 45° WEED-2 T1633-4 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEED-2 T1633-5 0.95 1.10 1.25 0.95 1.10 1.25 0.35 x 45° WEED-2 - NOTES: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES. N IS THE TOTAL NUMBER OF TERMINALS. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm FROM TERMINAL TIP. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS. DRAWING CONFORMS TO JEDEC MO220 REVISION C. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY. WARPAGE NOT TO EXCEED 0.10mm. PACKAGE OUTLINE 8, 12, 16L THIN QFN, 3x3x0.8mm 21-0136 I 2 ______________________________________________________________________________________ 2 17 MAX7322 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) QSOP.EPS MAX7322 I2C Port Expander with 4 Push-Pull Outputs and 4 Inputs PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH 21-0055 F 1 1 Revision History Pages changed at Rev 1: 1–18 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
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