MAX7502MUA+T

EVALUATION KIT AVAILABLE MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection General Description The MAX7500–MAX7504 temperature sensors accurately measure temperature and provide an overtemperature alarm/interrupt/shutdown output. These devices convert the temperature measurements to digital form using a high-resolution, sigma-delta, analog-to-digital converter (ADC). Communication is through an I2C-compatible 2-wire serial interface. The MAX7500/MAX7501/MAX7502 integrate a timeout feature that offers protection against I2C bus lockups. The MAX7503/MAX7504 do not include the timeout feature. The 2-wire serial interface accepts standard write byte, read byte, send byte, and receive byte commands to read the temperature data and configure the behavior of the open-drain overtemperature shutdown output. The MAX7500 features three address select lines, while the MAX7501–MAX7504 feature two address select lines and a RESET input. The MAX7500/MAX7501/MAX7502s’ 3.0V to 5.5V supply voltage range, low 250μA supply current, and a lockup-protected I2C-compatible interface make them ideal for a wide range of applications, including personal computers (PCs), electronic test equipment, and office electronics. The MAX7500–MAX7504 are available in 8-pin μMAX® and SO packages and operate over the -55°C to +125°C temperature range. Applications ●● ●● ●● ●● ●● PCs Servers Office Electronics Electronic Test Equipment Industrial Process Control Features ●● Timeout Prevents Bus Lockup (MAX7500, MAX7501, MAX7502) ●● Hardware Reset for Added Protection ●● I2C Bus Interface ●● 3.0V to 5.5V Supply Voltage Range ●● 250μA (typ) Operating Supply Current ●● 3μA (typ) Shutdown Supply Current ●● ±1.5°C (max) Temperature Accuracy (-25°C to +100°C, 3-σ) ●● μMAX, SO Packages Save Space ●● Separate Open-Drain OS Output Operates as Interrupt or Comparator/Thermostat Input ●● Register Readback Capability ●● Improved LM75 Second Source Ordering Information/ Selector Guide PART TEMP RANGE MAX7500MSA -55°C to +125°C PINRESET TIMEOUT PACKAGE 8 SO Pin Configurations appear at end of data sheet. +3.0V TO +5.5V +3.0V TO +5.5V 4.7kΩ 4.7kΩ SDA +VS SCL A0 OS GND MAX7500 A1 A2 19-3382; Rev 5; 11/16 +VS SDA TO I2C MASTER SCL OS GND μMAX is a registered trademark of Maxim Integrated Products, Inc. X Ordering Information/Selector Guide continued at end of data sheet. Typical Application Circuits TO I2C MASTER — MAX7501 MAX7502 MAX7503 MAX7504 A0 A1 RESET MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Absolute Maximum Ratings (Note 1) +VS to GND..............................................................-0.3V to +6V OS, SDA, SCL to GND..........................................-0.3V to +6.0V All Other Pins to GND................................-0.3V to (+VS + 0.3V) Input Current at Any Pin (Note 2)........................................+5mA Package Input Current (Note 2)........................................+20mA ESD Protection (all pins, Human Body Model, Note 3)...±2000V Continuous Power Dissipation (TA = +70°C) 8-Pin μMAX (derate 4.5mW/°C above +70°C).............362mW 8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW Operating Temperature Range.......................... -55°C to +125°C Junction Temperature.......................................................+150°C Storage Temperature Range............................. -65°C to +150°C Lead Temperature (soldering, 10s).................................. +300°C Soldering Temperature (reflow) Lead(Pb)-free...............................................................+260°C Containing lead(Pb)......................................................+240°C Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its rated operating conditions. Note 2: When the input voltage (VI) at any pin exceeds the power supplies (VI < VGND or VI > + VS), the current at that pin should be limited to 5mA. The 20mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to 4. Note 3: Human Body Model, 100pF discharged through a 1.5kΩ resistor. 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. Electrical Characteristics (+VS = +3.0V to +5.5V, TA = -55°C to +125°C, unless otherwise noted. Typical values are at +VS = +3.3V, TA = +25°C.) (Notes 4, 5) PARAMETER SYMBOL Accuracy, 6-σ Accuracy, 3-σ (Note 5) Resolution Conversion Time Quiescent Supply Current CONDITIONS MIN MAX -2.0 ±2.0 -55°C ≤ TA ≤ +125°C -3.0 ±3.0 -25°C ≤ TA ≤ +100°C -1.5 +1.5 -55°C ≤ TA ≤ +125°C -2.0 +2.0 9 (Note 6) 100 I2C inactive 0.25 Shutdown mode, +VS = 3V Shutdown mode, +VS = 5V +VS Supply Voltage Range TYP -25°C ≤ TA ≤ +100°C °C °C bits ms 0.5 3 mA µA 5 3.0 UNITS 5.5 V 0.8 V 6 Conversions OS Output Saturation Voltage IOUT = 4.0mA (Note 7) OS Delay (Note 8) TOS Default Temperature (Note 9) 80 °C (Note 9) 75 °C THYST Default Temperature 1 LOGIC (SDA, SCL, A0, A1, A2) Input High Voltage VIH Input Low Voltage VIL Input High Current IIH Input Low Current Input Capacitance Output High Current Output Low Voltage www.maximintegrated.com IIL +VS x 0.7 VIN = 5V VIN = 0V All digital inputs VIN = 5V IOL = 3mA V +VS x 0.3 V 0.005 1.0 µA 0.005 1.0 µA 1 µA 0.4 V 5 pF Maxim Integrated │  2 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Electrical Characteristics (continued) (+VS = +3.0V to +5.5V, TA = -55°C to +125°C, unless otherwise noted. Typical values are at +VS = +3.3V, TA = +25°C.) (Notes 4, 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 400 kHz I2C-COMPATIBLE TIMING (Note 10) Serial Clock Frequency Minimum RESET Pulse Width Bus Free Time Between STOP and START Conditions START Condition Hold Time STOP Condition Setup Time Clock Low Period Clock High Period START Condition Setup Time Data Setup Time Data Hold Time fSCL Bus timeout inactive tBUF tHD:STA tSU:STO 90% of SCL to 10% of SDA tLOW tHIGH DC 1 µs 1.3 µs 0.6 µs 100 ns 1.3 µs 0.6 µs tSU:STA 90% of SCL to 90% of SDA 100 ns 10% of SDA to 10% of SCL 100 ns tHD:DAT 10% of SCL to 10% of SDA (Note 11) tSU:DAT 0 0.9 µs Maximum Receive SCL/SDA Rise Time tR Minimum Receive SCL/SDA Rise Time tR Maximum Receive SCL/SDA Fall Time tF Minimum Receive SCL/SDA Fall Time tF (Note 12) Transmit SDA Fall Time tF (Note 12) 20 + 0.1 x CB 250 ns Pulse Width of Suppressed Spike tSP (Note 13) 0 50 ns SDA Time Low for Reset of Serial Interface tTIMEOUT 150 300 ms (Note 12) MAX7500/MAX7501/MAX7502 (Note 14) 300 ns 20 + 0.1 x CB ns 300 ns 20 + 0.1 x CB ns Note 4: All parameters are measured at +25°C. Values over the temperature range are guaranteed by design. Note 5: There are no industry-wide standards for temperature accuracy specifications. These values allow comparison to vendors who use 3-σ limits. Note 6: This specification indicates how often temperature data is updated. The devices can be read at any time without regard to conversion state, while yielding the last conversion result. Note 7: For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy due to internal heating. Note 8: OS delay is user programmable up to six “over-limit” conversions before OS is set to minimize false tripping in noisy environments. Note 9: Default values set at power-up. Note 10: All timing specifications are guaranteed by design. Note 11: A master device must provide a hold time of at least 300ns for the SDA signal to bridge the undefined region of SCL’s falling edge. Note 12: CB = total capacitance of one bus line in pF. Tested with CB = 400pF. Note 13: Input filters on SDA, SCL, and A_ suppress noise spikes less than 50ns. Note 14: Holding the SDA line low for a time greater than tTIMEOUT causes the devices to reset SDA to the IDLE state of the serial bus communication (SDA set high). www.maximintegrated.com Maxim Integrated │  3 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) 280 +VS = +5V 270 260 +VS = +3V 250 240 230 -55 -25 5 35 65 95 125 5 4 TYPICAL PARTS 1.0 +VS = +5V 4 1.5 ACCURACY vs. TEMPERATURE MAX7500 toc03 2.0 MAX7500 toc02 290 6 SHUTDOWN SUPPLY CURRENT (µA) MAX7500 toc01 QUIESCENT SUPPLY CURRENT (µA) 300 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE ACCURACY (°C) QUIESCENT SUPPLY CURRENT vs. TEMPERATURE 3 +VS = +3V 2 0.5 0 -0.5 -1.0 1 0 -1.5 -55 TEMPERATURE (°C) -25 5 35 65 95 125 -2.0 -55 -25 5 35 65 95 125 TEMPERATURE (°C) TEMPERATURE (°C) Pin Description PIN MAX7500 MAX7501– MAX7504 NAME 1 1 SDA Serial Data Input/Output Line. Open drain. Connect SDA to a pullup resistor. 2 2 SCL Serial Data Clock Input. Open drain. Connect SCL to a pullup resistor. 3 3 OS Overtemperature Shutdown Output. Open drain. Connect OS to a pullup resistor. 4 4 GND 5 — A2 — 5 RESET 6 6 A1 2-Wire Interface Address Input. Connect A1 to GND or +VS to set the desired I2C bus address. Do not leave unconnected (see Table 1). 7 7 A0 2-Wire Interface Address Input. Connect A0 to GND or +VS to set the desired I2C bus address. Do not leave unconnected (see Table 1). 8 8 +VS Detailed Description FUNCTION Ground 2-Wire Interface Address Input. Connect A2 to GND or +VS to set the desired I2C bus address. Do not leave unconnected (see Table 1). Active-Low Reset Input. Pull RESET low for longer than the minimum reset pulse width to reset the I2C bus and all internal registers to their POR values. Positive Supply Voltage Input. Bypass to GND with a 0.1µF bypass capacitor. The MAX7500–MAX7504 temperature sensors measure temperature, convert the data into digital form using a sigma-delta ADC, and communicate the conversion results through an I2C-compatible 2-wire serial interface. These devices accept standard I2C commands to read www.maximintegrated.com the data, set the overtemperature alarm (OS) trip thresholds, and configure other characteristics. The MAX7500 features three address select lines (A0, A1, A2) while the MAX7501–MAX7504 feature two address select lines (A0, A1) and a RESET input. The MAX7500–MAX7504 operate from +3.0V to +5.5V supply voltages and consume 250μA of supply current. Maxim Integrated │  4 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Table 1. I2C Slave Addresses BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 MAX7500 DEVICE 1 0 0 1 A2 A1 A0 RD/W MAX7501 1 0 0 1 1 A1 A0 RD/W MAX7502 1 0 0 1 0 A1 A0 RD/W MAX7503 1 0 0 1 1 A1 A0 RD/W MAX7504 1 0 0 1 0 A1 A0 RD/W SDA tSU:DAT tHD:DAT tLOW tSU:STA tHD:STA tBUF tSU:STO SCL tHIGH tHD:STA tR tF START CONDITION (S) REPEATED START CONDITION (SR) ACKNOWLEDGE (A) STOP CONDITION (P) START CONDITION (S) PARAMETERS ARE MEASURED FROM 10% TO 90%. Figure 1. Serial Bus Timing I2C-Compatible Bus Interface From a software perspective, the MAX7500–MAX7504 appear as a set of byte-wide registers that contain temperature data, alarm threshold values, and control bits. A standard I2C-compatible 2-wire serial interface reads temperature data and writes control bits and alarm threshold data. Each device responds to its own I2C slave address, which is selected using A0, A1, and A2. See Table 1. The MAX7500–MAX7504 employ four standard I2C protocols: write byte, read byte, send byte, and receive byte www.maximintegrated.com (Figures 1, 2, and 3). The shorter receive byte protocol allows quicker transfers, provided that the correct data register was previously selected by a read-byte instruction. Use caution when using the shorter protocols in multimaster systems, as a second master could overwrite the command byte without informing the first master. The MAX7500 has eight different slave addresses available; therefore, a maximum of eight MAX7500 devices can share the same bus. The MAX7501–MAX7504 each have four different slave addresses available. Maxim Integrated │  5 www.maximintegrated.com START BY MASTER START BY MASTER START BY MASTER ADDRESS BYTE ADDRESS BYTE ADDRESS BYTE POINTER BYTE ACK BY MAX7500– MAX7504 REPEAT START BY MASTER ADDRESS BYTE ACK BY MAX7500– MAX7504 ACK BY MAX7500– MAX7504 ACK BY MAX7500– MAX7504 POINTER BYTE POINTER BYTE CONFIGURATION BYTE MOST-SIGNIFICANT DATA BYTE (c) THIGH AND TLOW WRITE ACK BY MAX7500– MAX7504 (b) CONFIGURATION REGISTER WRITE ACK BY MAX7500– MAX7504 ACK BY MAX7500– MAX7504 DATA BYTE LEAST-SIGNIFICANT DATA BYTE STOP COND BY ACK BY MASTER MAX7500– MAX7504 (a) TYPICAL POINTER SET FOLLOWED BY IMMEDIATE READ FROM CONFIGURATION REGISTER ACK BY MAX7500– MAX7504 ACK BY MAX7500– MAX7504 STOP COND BY MASTER NO ACK BY MASTER STOP COND BY MASTER MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Figure 2. I2C-Compatible Timing Diagram (Write) Maxim Integrated │  6 www.maximintegrated.com START BY MASTER START BY MASTER START BY MASTER ADDRESS BYTE REPEAT START BY MASTER ADDRESS BYTE ADDRESS BYTE MOST-SIGNIFICANT DATA BYTE ACK BY MASTER LEAST-SIGNIFICANT DATA BYTE ACK BY MAX7500– MAX7504 POINTER BYTE MOST-SIGNIFICANT DATA BYTE ACK BY MAX7500– MAX7504 ACK BY MASTER DATA BYTE NO ACK BY MASTER (c) TYPICAL 1-BYTE READ FROM CONFIGURATION REGISTER WITH PRESET POINTER. ACK BY MAX7500– MAX7504 STOP COND BY MASTER NO ACK BY MASTER LEAST-SIGNIFICANT DATA BYTE (b) TYPICAL POINTER SET FOLLOWED BY IMMEDIATE READ FOR 2-BYTE REGISTER SUCH AS TEMP, THIGH, TLOW. ADDRESS BYTE ACK BY MASTER (a) TYPICAL 2-BYTE READ FROM PRESET POINTER LOCATION SUCH AS TEMP, THIGH, TLOW. ACK BY MAX7500– MAX7504 NO ACK BY MASTER STOP COND BY MASTER STOP COND BY MASTER MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Figure 3. I2C-Compatible Timing Diagram (Read) Maxim Integrated │  7 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Table 2. Register Functions REGISTER NAME ADDRESS (HEX) POR STATE (HEX) POR STATE (BINARY) POR STATE (°C) READ/ WRITE Temperature 00 — — — Read only Configuration 01 00 0000 0000 — R/W THYST 02 4B0 0100 1011 0 75 R/W 03 500 0101 0000 0 80 R/W TOS Table 3. Temperature Register Definition UPPER BYTE LOWER BYTE D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Sign bit 1= Negative 0 = Positive MSB 64°C 32°C 16°C 8°C 4°C 2°C 1°C LSB 0.5°C X X X X X X X X = Don’t care. Register Descriptions The MAX7500–MAX7504 have an internal pnp-junctionbased temperature sensor whose analog output is converted to digital form using a 9-bit sigma-delta ADC. The measured temperature and temperature configurations are controlled by the temperature, configuration, THYST, and TOS registers. See Table 2. Temperature Register Read the measured temperature through the temperature register. The temperature data format is 9 bits, two’s complement, and the register is read out in 2 bytes: an upper byte and a lower byte. Bit D15 is the sign bit. When bit D15 is 1, the temperature reading is negative. When bit D15 is zero, the temperature reading is positive. Bits D14–D7 contain the temperature data, with the LSB representing 0.5°C and the MSB representing 64°C (see Table 3). The MSB is transmitted first. The last 7 bits of the lower byte, bits D6–D0, are don’t cares. When reading the temperature register, bits D6–D0 must be ignored. When Table 4. Temperature Data Output TEMPERATURE (°C) DIGITAL OUTPUT BINARY hex +125 0111 1101 0xxx xxxx 7D0x +25 0001 1001 0xxx xxxx 190x +0.5 0000 0000 1xxx xxxx 008x 0 0000 0000 0xxx xxxx 000x -0.5 1111 1111 1xxx xxxx FF8x -25 1110 0111 0xxx xxxx E70x -55 1100 1001 0xxx xxxx C90x www.maximintegrated.com the measured temperature is greater than +127.5°C, the value stored in the temperature register is clipped to 7F8h. When the measured temperature is below -64°C, the value in the temperature register is clipped to BF8h. During the time of reading the temperature register, any changes in temperature are ignored until the read is completed. The temperature register is updated upon completion of the next conversion. Table 3 lists the temperature register definition. Configuration Register The 8-bit configuration register sets the fault queue, OS polarity, shutdown control, and whether the OS output functions in comparator or interrupt mode. When writing to the configuration register, set bits D7, D6, and D5 to zero. See Table 5. Bits D4 and D3, the fault queue bits, determine the number of faults necessary to trigger an OS condition. See Table 6. The number of faults set in the queue must occur to trip the OS output. The fault queue prevents OS false tripping in noisy environments. Set bit D2, the OS polarity bit, to zero to force the OS output active low. Set bit D2 to 1 to set the OS output polarity to active high. OS is an open-drain output under all conditions and requires a pullup resistor to output a high voltage. See Figure 4. Set bit D1, the comparator/interrupt bit to zero to run the overtemperature shutdown block in comparator mode. In comparator mode, OS is asserted when the temperature rises above the TOS value. OS is deasserted when the temperature drops below the THYST value. Maxim Integrated │  8 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Table 5. Configuration Register Definition D7 D6 0 D5 0 D4 0 D3 Fault queue Fault queue Table 6. Configuration Register Fault Queue Bits D4 D3 NO. OF FAULTS 0 0 1 (POR state) 0 1 2 1 0 4 1 1 6 D2 D1 D0 OS polarity Comparator/ interrupt Shutdown TOS TEMPERATURE THYST OS OUTPUT (COMPARATOR MODE) OS SET ACTIVE LOW See Figure 4. Set bit D1 to 1 to run the overtemperature shutdown block in interrupt mode. OS is asserted in interrupt mode when the temperature rises above the TOS value or falls below the THYST value. OS is deasserted only after performing a read operation. OS OUTPUT (INTERRUPT MODE) OS SET ACTIVE LOW READ OPERATION READ OPERATION READ OPERATION Figure 4. OS Timing Diagram Set bit D0, the shutdown bit, to zero for normal operation. Set bit D0 to 1 to shut down the MAX7500–MAX7504 internal blocks, dropping the supply current to 3μA. The I2C interface remains active as long as the shutdown bit is set. The TOS, THYST, and configuration registers can still be written to and read from while in shutdown. In interrupt mode, exceeding TOS also asserts OS. OS remains asserted until a read operation is performed on any of the registers. Once OS has asserted due to crossing above TOS and is then reset, it is asserted again only when the temperature drops below THYST. The output remains asserted until it is reset by a read. Putting the MAX7500–MAX7504 into shutdown mode also resets OS. TOS and THYST Registers In comparator mode, the OS output behaves like a thermostat. The output asserts when the temperature rises above the limit set in the TOS register. The output deasserts when the temperature falls below the limit set in the THYST register. In comparator mode, the OS output can be used to turn on a cooling fan, initiate an emergency shutdown signal, or reduce system clock speed. The TOS and THYST registers are accessed with 2 bytes, with bits D15–D7 containing the data. Bits D6–D0 are don’t cares when writing to these two registers and readback zeros when reading from these registers. The LSB represents 0.5°C while the MSB represents 64°C. See Table 7. Table 7. TOS and THYST Register Definitions UPPER BYTE COMMAND LOWER BYTE D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Write Sign bit 1 = negative 0 = positive MSB 64°C 32°C 16°C 8°C 4°C 2°C 1°C LSB 0.5°C X X X X X X X Read Sign bit 1 = negative 0 = positive MSB 64°C 32°C 16°C 8°C 4°C 2°C 1°C LSB 0.5°C 0 0 0 0 0 0 0 X = Don’t care. www.maximintegrated.com Maxim Integrated │  9 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Shutdown Set bit D0 in the configuration register to 1 to place the MAX7500–MAX7504 in shutdown mode and reduce supply current to 3μA. Power-Up and Power-Down The MAX7500–MAX7504 power up to a known state, as indicated in Table 2. Some of these settings are summarized below: ●● Comparator mode ●● TOS = +80°C +VS A0 A1 MAX7504 A2/RESET SDA SMBus INTERFACE BLOCK SCL DATA ●● THYST = +75°C ●● Pointer = 00 REGISTER SELECT Internal Registers The MAX7500–MAX7504s’ pointer register selects between four data registers. See Figure 5. At powerup, the pointer is set to read the temperature register at address 00. The pointer register latches the last location to which it was set. All registers are read and write, except the temperature register, which is read only. Read from the MAX7500–MAX7504 in one of two ways. If the location latched in the pointer register is set from the previous read, the new read consists of an address byte, followed by retrieving the corresponding number of data bytes. If the pointer register needs to be set to a new address, perform a read operation by writing an address byte, pointer byte, repeat start, and another address byte. An inadvertent 8-bit read from a 16-bit register, with the D7 bit low, can cause the MAX7500–MAX7504 to stop in a state where the SDA line is held low. Ordinarily, this would prevent any further bus communication until the master sends nine additional clock cycles or SDA goes high. At that time, a stop condition resets the device. With the MAX7500/MAX7501/MAX7502, if the additional clock www.maximintegrated.com ADDRESS POINTER REGISTER (SELECTS REGISTER FOR COMMUNICATION) ●● OS active low Write to the configuration register by writing an address byte, a data pointer byte, and a data byte. If 2 data bytes are written, the second data byte overrides the first. If more than 2 data bytes are written, only the first 2 bytes are recognized while the remaining bytes are ignored. The TOS and THYST registers require 1 address byte and 1 pointer byte and 2 data bytes. If only 1 data byte is written, it is saved in bits D15–D8 of the respective register. If more than 2 data bytes are written, only the first 2 bytes are recognized while the remaining bytes are ignored. OS TEMPERATURE (READ ONLY) POINTER = 0000 0000 CONFIGURATION (READ/WRITE) POINTER = 0000 0001 TOS SET POINT (READ/WRITE) POINTER = 0000 0011 THYST SET POINT (READ/WRITE) POINTER = 0000 0010 GND Figure 5. Block Diagram cycles are not generated by the master, the bus resets and unlocks after the bus timeout period has elapsed. The MAX7501–MAX7504 can be reset by pulsing RESET low. Bus Timeout Communication errors sometimes occur due to noise pickup on the bus. In the worst case, such errors can cause the slave device to hold the data line low, thereby preventing other devices from communicating over the bus. The MAX7500/MAX7501/MAX7502s’ internal bus timeout circuit resets the bus and releases the data line if the line is low for more than 250ms. When the bus timeout is active, the minimum serial clock frequency is limited to 6Hz. RESET The RESET input on the MAX7501/MAX7504 provides a way to reset the I2C bus and all the internal registers to their initial POR values. To reset, apply a low pulse with a duration of at least 1μs to the RESET input. Maxim Integrated │  10 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Applications Information Ordering Information/ Selector Guide continued Digital Noise The MAX7500–MAX7504 feature an integrated lowpass filter on both the SCL and the SDA digital lines to mitigate the effects of bus noise. Although this filtering makes communication robust in noisy environments, good layout practices are always recommended. Minimize noise coupling by keeping digital traces away from switching power supplies. Ensure that digital lines containing high-speed data communications cross at right angles to the SDA and SCL lines. Excessive noise coupling into the SDA and SCL lines on the MAX7500–MAX7504—specifically noise with amplitude greater than 400mVP-P (the MAX7500– MAX7504s’ typical hysteresis), overshoot greater than 300mV above +VS, and undershoot more than 300mV below GND—may prevent successful serial communication. Serial bus no-acknowledge is the most common symptom, causing unnecessary traffic on the bus. Care must be taken to ensure proper termination within a system with long PCB traces or multiple parts on the bus. Resistance can be added in series with the SDA and SCL lines to further help filter noise and ringing. If it proves to be necessary, a 5kΩ resistor should be placed in series with the SCL line, placed as close as possible to SCL. This 5kΩ resistor, with the 5pF to 10pF stray capacitance of the MAX7500–MAX7504 provide a 6MHz to 12MHz lowpass filter, which is sufficient filtering in most cases. Chip Information PART TEMP RANGE MAX7500MSA+ -55°C to +125°C 8 SO — X MAX7500MUA -55°C to +125°C 8 µMAX — X MAX7500MUA+ -55°C to +125°C 8 µMAX — X MAX7501MSA -55°C to +125°C 8 SO X X MAX7501MSA+ -55°C to +125°C 8 SO X X MAX7501MUA -55°C to +125°C 8 µMAX X X MAX7501MUA+ -55°C to +125°C 8 µMAX X X MAX7502MSA -55°C to +125°C 8 SO X X MAX7502MSA+ -55°C to +125°C 8 SO X X MAX7502MUA -55°C to +125°C 8 µMAX X X MAX7502MUA+ -55°C to +125°C 8 µMAX X X MAX7503MSA -55°C to +125°C 8 SO X — MAX7503MSA+ -55°C to +125°C 8 SO X — MAX7503MUA -55°C to +125°C 8 µMAX X — MAX7503MUA+ -55°C to +125°C 8 µMAX X — MAX7504MSA -55°C to +125°C 8 SO X — MAX7504MSA+ -55°C to +125°C 8 SO X — MAX7504MUA -55°C to +125°C 8 µMAX X — MAX7504MUA+ -55°C to +125°C 8 µMAX X — PROCESS: CMOS Pin Configurations TOP VIEW SDA 1 8 +VS SCL 2 7 A0 OS 3 6 A1 GND 4 5 A2 MAX7500 µMAX, SO 1 SCL 2 OS 3 GND 4 MAX7501– MAX7504 µMAX, SO www.maximintegrated.com 8 +VS 7 A0 6 A1 5 RESET PINRESET TIMEOUT PACKAGE +Denotes a lead(Pb)-free/RoHS-compliant package. Maxim Integrated │  11 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN NO. 8 SO S8-2 21-0041 90-0096 8 μMAX U8-1 21-0036 90-0092 www.maximintegrated.com Maxim Integrated │  12 MAX7500–MAX7504 Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection Revision History REVISION NUMBER REVISION DATE PAGES CHANGED DESCRIPTION 0 8/04 Initial release of MAX7500 — 1 10/04 Initial release of MAX7501/MAX7502 All 2 6/05 Initial release of MAX7503/MAX7504 All 3 8/08 Various corrections and edits to clarify specifications; added Typical Application Circuits 4 10/10 Removed the UL certified bullet from the Features section as the parts have never been certified 5 11/16 Corrected markings of RESET and TIMEOUT functions in Ordering Information table 1–4, 11, 12, 13 1 1, 10, 11 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. ©  2016 Maxim Integrated Products, Inc. │  13