19-3837; Rev 0; 10/05 Precision Temperature Monitor for DDR Memory Modules The MAX6604 high-precision temperature sensor is designed for thermal monitoring functions in DDR memory modules. The device is readable and programmable through the 2-wire SMBus™/I2C-compatible interface. Three address inputs set the bus address for the temperature sensor to provide up to eight devices on one bus. The internal thermal sensor continuously monitors the temperature and updates the temperature data eight times per second. The master can read the temperature data at any time. Since the thermal sensor is located on the memory module, temperature data recorded accurately represents the temperature of the components on the module. Consequently, the MAX6604 provides a much more accurate measurement of module temperature than techniques involving temperature sensors on the motherboard. In addition, the device responds more quickly to temperature changes on the module than a motherboard sensor. The MAX6604 also features an interrupt-output indicator for temperature-threshold monitoring. The threshold levels are programmable through the digital interface. The MAX6604 operates from -20°C to +125°C, and is available in JEDEC-standard 8-pin TSSOP and TDFN (MO-229-WCED-2) packages. Features ♦ JEDEC Compliant ♦ ±1°C Temperature-Monitoring Accuracy ♦ Overtemperature Interrupt with Programmable Threshold ♦ +2.7V to +3.6V Operating Voltage Range ♦ SMBus/I 2C-Compatible Interface ♦ 300µA Typical Operating Current ♦ 3µA Typical Shutdown Current ♦ -20°C to +125°C Operating Temperature Range ♦ 8-Pin TSSOP and TDFN (MO-229-WCED-2) Packages Ordering Information PART TEMP RANGE MAX6604ATA -20°C to +125°C PIN-PACKAGE PKG CODE 8 TDFN-EP** T823-1 (MO229-WCED-2) MAX6604AHA -20°C to +125°C 8 TSSOP H8-1 **EP = Exposed paddle. Applications Pin Configurations Memory Modules Desktop Computers TOP VIEW VCC EVENT SCL 8 Notebook Computers 7 6 SDA 5 Workstations Networking Equipment MAX6604 Typical Application Circuit appears at end of data sheet. SMBus is a trademark of Intel Corporation. 1 2 3 4 A0 A1 A2 GND TDFN-EP** A0 1 8 VCC A1 2 7 EVENT A2 3 6 SCL GND 4 5 SDA MAX6604 TSSOP ________________________________________________________________ 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 MAX6604 General Description MAX6604 Precision Temperature Monitor for DDR Memory Modules ABSOLUTE MAXIMUM RATINGS All Input and Output Voltages ..................................-0.3V to +6V Continuous Power Dissipation (TA = +70°C) 8-Pin TDFN (derate 16.7mW/°C above +70°C) ......1333.3mW 8-Pin TSSOP (derate 8.1mW/°C above +70°C) ........646.7mW ESD Protection (all pins, Human Body Model) ....................±2kV Junction Temperature ......................................................+150°C Operating Temperature Range .........................-20°C to +125°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. ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +3.6V, TA = -20°C to +125°C, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25°C.) (Note 1) PARAMETER Operating Supply Voltage Range SYMBOL CONDITIONS VCC MIN Temperature Resolution +3V ≤ VCC ≤ +3.6V, +75°C ≤ TA ≤ +95°C Temperature Accuracy Power-On Reset (POR) Threshold TYP +2.7 MAX UNITS +3.6 V 0.125 °C 11 bits -1 +1 +3V ≤ VCC ≤ +3.6V, +40°C ≤ TA ≤ +125°C -2 +2 +3V ≤ VCC ≤ +3.6V, -20°C ≤ TA ≤ +125°C -3 +3 VCC falling edge °C 2.0 V POR Threshold Hysteresis 90 mV Undervoltage-Lockout Threshold 2.4 Operating Current During conversion 0.3 Standby Current 3 Conversion Time tCONV Conversion Rate fCONV 8 Logic-Input High Voltage (SCL, SDA) VIH 2.1 Logic-Input Low Voltage (SCL, SDA) VIL V 0.5 mA 6 µA 125 ms Hz DIGITAL INTERFACE (Note 2) Logic-Input Hysteresis (SCL, SDA) Leakage Current (EVENT, SCL, SDA, A2, A1, A0) 500 ILEAK VIN = GND or VCC Logic-Output Low Voltage (SDA, EVENT) VOL IPULL_UP = 350µA Logic-Output Low Sink Current (SDA, EVENT) IOL VOL = 0.6V Input Capacitance (SCL, SDA) CIN Serial-Clock Frequency fSCL 2 V 0.8 -1 V mV +1 µA 50 mV 6 mA 5 10 _______________________________________________________________________________________ pF 100 kHz Precision Temperature Monitor for DDR Memory Modules (VCC = +2.7V to +3.6V, TA = -20°C to +125°C, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25°C.) (Note 1) PARAMETER Bus Free Time Between STOP and START Condition SYMBOL CONDITIONS tBUF MIN TYP MAX 4.7 Repeat START Condition Setup Time tSU:STA 90% to 90% START Condition Hold Time tHD:STA 10% of SMBDATA to 90% of SMBCLK STOP Condition Setup Time tSU:STO 90% of SMBCLK to 10% of SMBDATA UNITS µs 4.7 µs 4 µs 4 µs Clock Low Period tLOW 10% to 10% 4.7 µs Clock High Period tHIGH 90% to 90% 4 µs Data Hold Time tHD:DAT Data Setup Time tSU:DAT Receive SCL/SDA Rise Time Receive SCL/SDA Fall Time Pulse Width of Spike Suppressed 90% of SMBDATA to 10% of SMBCLK 300 ns 250 ns tR 1000 tF tSP 0 ns 300 ns 50 ns Note 1: All parameters are tested at TA = +25°C. Specifications over temperature are guaranteed by design. Note 2: Guaranteed by design. _______________________________________________________________________________________ 3 MAX6604 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (Typical values are at VCC = +3.3V, TA = +25°C.) 3 VCC = 3.0V 2 VCC = 2.7V VCC = 3.6V 340 320 300 280 1 VCC = 2.7V 0 0 50 100 VCC = 3.3V 1 0 -1 VCC = 3.6V -3 -50 150 VCC = 3.0V -2 VCC = 3.0V 260 -50 2 TEMPERATURE ERROR (°C) VCC = 3.6V 4 VCC = 3.3V SUPPLY CURRENT (µA) VCC = 3.3V 3 MAX6604 toc02 5 TEMPERATURE ERROR vs. TEMPERATURE 360 MAX6604 toc01 6 SUPPLY CURRENT vs. TEMPERATURE MAX6604 toc03 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE SHUTDOWN SUPPLY CURRENT (µA) TEMPERATURE (°C) 0 50 100 150 TEMPERATURE (°C) -50 0 50 100 150 TEMPERATURE (°C) 2.5 2.0 MAX6604 toc04 TEMPERATURE ERROR vs. POWER SUPPLY NOISE FREQUENCY TEMPERATURE ERROR (°C) MAX6604 Precision Temperature Monitor for DDR Memory Modules SQUARE WAVE APPLIED TO VCC WITH NO BYPASS CAPACITOR 200mVPP 1.5 1.0 20mVPP 0.5 0 0.1 10 1,000 100,000 POWER SUPPLY NOISE FREQUENCY (kHz) Pin Description 4 PIN NAME 1 A0 Address Input. Must connect to GND or VCC to set value. 2 A1 Address Input. Must connect to GND or VCC to set value. 3 A2 Address Input. Must connect to GND or VCC to set value. 4 GND Ground 5 SDA Serial-Data Input/Output. Open drain. Connect to a pullup resistor. 6 SCL 7 EVENT 8 VCC FUNCTION Serial-Clock Input. Connect to a pullup resistor. Event Output. Open drain. Connect to a pullup resistor. Supply Voltage. Connect a 0.1µF capacitor to GND as close as possible to the device. _______________________________________________________________________________________ Precision Temperature Monitor for DDR Memory Modules The MAX6604 high-precision temperature sensor continuously monitors temperature and updates the temperature data eight times per second. The device functions as a slave on the SMBus/I2C-compatible interface. The master can read the temperature data at any time through the digital interface. The MAX6604 also features an open-drain, event-output indicator for temperature-threshold monitoring. Serial Interface SMBus/I2C The MAX6604 is readable and programmable through the SMBus/I2C-compatible interface. The device functions as a slave on the interface. Figure 1 shows the general timing diagram of the clock (SCL) and the data (SDA) signals for the SMBus/I2C-compatible interface. The SDA and SCL bus lines are at logic-high when the bus is not in use. Pullup resistors from the bus lines to the supply are required when push-pull circuitry is not driving the lines. The data on the SDA line can change only when the SCL line is low. Start and stop conditions occur when SDA changes state while the SCL line is high (Figure 1). Data on SDA must be stable for the duration of the setup time (tSU:DAT) before SCL goes high. Data on SDA is sampled when SCL toggles high with data on SDA is stable for the duration of the hold time (tHD:DAT). Note that a segment of data is transmitted in an 8-bit byte. A total of nine clock cycles are required to transfer a byte to the MAX6604. Since the MAX6604 employs 16-bit registers, data is transmitted or received in two 8-bit bytes (16 bits). The device acknowledges the successful receipt for each byte by pulling the SDA line low (issuing an ACK) during the ninth clock cycle of each byte transfer. From a software perspective, the MAX6604 appears as a set of 16-bit registers that contain temperature data, alarm threshold values, and control bits. A standard SMBus/I2C-compatible, 2-wire serial interface reads temperature data and writes control bits and alarm threshold data. Each device responds to its own SMBus/I2C slave address, which is selected using A0, A1, and A2. See the Device Addressing section for details. The MAX6604 employs standard I2C/SMBus protocols using 16-bit registers: write word and read word. Write a word of data (16 bits) by first sending MAX6604’s I2C address (0011-A2-A1-A0-0), then sending the 8-bit command byte, followed by the first 8-bit data byte. Note that the slave issues an acknowledge after each byte is written. After the first 8-bit data byte is written, the MAX6604 also returns an acknowledge. However, the master does not generate a stop condition after the first byte has been written. The master continues to write the second byte of data with the slave acknowledging. After the second byte has been written, the master then generates a stop condition. See Figure 2. To read a word of data, the master generates a new start condition and sends MAX6604’s I2C address with the R/W bit high (1010-A2-A1-A0-1), then sends the 8bit command byte. Again, the MAX6604 issues an ACK for each byte received. The master again sends the device address, following an acknowledge. Next, the master reads the contents of the selected register, beginning with the most significant bit, and acknowledges if the most significant data byte is successfully received. Finally, the master reads the least significant data byte and issues a NACK, followed by a stop condition to terminate the read cycle. SDA tBUF tSU:STA tSU:DAT tHD:STA tSU:STO tHD:DAT SCL tLOW tHD:STA tR tF START CONDITION REPEATED START CONDITION STOP CONDITION Figure 1. SDA and SCL Timing Diagram _______________________________________________________________________________________ 5 MAX6604 Detailed Description MAX6604 Precision Temperature Monitor for DDR Memory Modules Write Word Format S ADDRESS R/W ACK COMMAND 7 bits ACK DATA 8 bits Slave Address: equivalent to chip-select line of a 3-wire interface ACK Command Byte: selects to which register you are writing ACK DATA P 8 bits (LSB) 8 bits (MSB) Data Byte: data goes into the register set by the co mma nd byte Read Word Format S ADDRESS R/W ACK 7 bits ACK S ADDRESS R ACK Command Byte: selects to which register you are writing R/W = Read/Write Shaded = Slave transmission DATA ACK DATA 8 bits (MSB) 8 bits Slave Address: equivalent to chip-select line of a 3-wire interface S = Start condition P = Stop condition COMMAND Slave Address: repeated due to change in dataflow direction NA P 8 bits (LSB) Data Bytes: reads from the register set by the command byte ACK = Acknowledge NA = Not acknowledged Figure 2. SMBus/I2C Protocols Device Addressing The temperature sensor is accessed through the SMBus/I2C bus using an 8-bit address. The temperature sensor address begins with 0011 and is followed by the logic states of the A2, A1, and A0 inputs. These inputs must be hardwired to either GND or VCC. The three address inputs set the bus address for the temperature sensor to allow up to eight devices on one bus. The 8th bit (R/W) dictates a read or write operation. Set the R/W bit low for a write operation and set the R/W bit high for a read operation. See Table 1 for a summary of the device address. Temperature Sensor The thermal sensor continuously monitors the temperature and records the temperature data at least eight times per second. Temperature data is latched internally by the MAX6604 and can be read by software from the bus host at any time. Access to the temperature sensor is through the slave ID of 0011-A2-A1-A0. The I2C address-selection inputs (A2, A1, A0) allow up to eight such devices to coexist on the same bus. Consequently, eight memory modules can be supported, given each module has one such slave device address slot. Upon application of power, the MAX6604’s configuration registers are set to their default values. Table 2 lists the various temperature registers and their default states. Note that all registers are 16 bits in length. 6 Table 1. MAX6604 Sensor Address FUNCTION Temperature sensor ADDRESS 0 0 1 1 A2 A1 A0 R/W Table 2. MAX6604 Registers ADDRESS POR STATE 00h 0017h Capability register 01h 0000h Configuration register 02h 0000h Alarm-temperature upper-boundary trip register 03h 0000h Alarm-temperature lower-boundary trip register 04h 0000h Critical-temperature trip register 05h 0000h Temperature register 06h 004Dh Manufacturer’s ID register 07h 3E00h Device ID/revision register 08h–0Eh 0000h Vendor-defined registers (not used) DESCRIPTION _______________________________________________________________________________________ Precision Temperature Monitor for DDR Memory Modules The EVENT output indicates conditions such as the temperature crossing a predefined boundary. It operates in one of the three modes: interrupt mode, comparator mode, and critical-temperature-only mode. Figure 3 shows an example of the measured temperature vs. time, with the corresponding behavior of the EVENT output in each of these modes. See the EVENT Operation Modes section for descriptions of the two modes. The EVENT modes are selected using the configuration register. Event-output polarity can be set to active high or active low through the configuration register (bit 1). The EVENT output can also be disabled so that EVENT is always high impedance (bit 3). Upon device power-up, the default condition for the EVENT output is high impedance. Writing a 1 to bit 3 of the configuration register enables the EVENT output. EVENT Thresholds Alarm Window Trip The MAX6604 provides a comparison window with an upper-temperature trip point and a lower-temperature trip point, programmed through the alarm-upperboundary register and the alarm-lower-boundary register, respectively. When enabled, the EVENT output triggers whenever entering or exiting (crossing above or below) the alarm window (Figure 3). Critical Trip The critical temperature setting is programmed in the critical temperature register. When the temperature reaches the critical temperature value in this register (and EVENT is enabled), the EVENT output asserts and cannot be deasserted until the temperature drops below the critical temperature threshold. EVENT Operation Modes Comparator Mode In comparator mode, the EVENT output behaves like a window-comparator output that asserts when the temperature is outside the window. Reads/writes on the MAX6604’s registers do not affect the EVENT output in comparator mode. The EVENT signal remains asserted until the temperature goes inside the alarm window or the window thresholds are reprogrammed so that the current temperature is within the alarm window. Interrupt Mode In interrupt mode, EVENT asserts whenever the temperature crosses an alarm window threshold. After such an event occurs, writing a 1 to the clear event bit in the configuration register deasserts the EVENT output until the next trigger condition occurs. The trip threshold value in TEMP CRITICAL ALARM WINDOW TIME S/W CLEARS EVENT EVENT# IN INTERRUPT EVENT# IN COMPARATOR MODE EVENT# IN CRITICAL-TEMPERATURE-ONLY MODE Figure 3. EVENT Behavior in Interrupt, Comparator, and Critical-Temperature-Only Modes _______________________________________________________________________________________ 7 MAX6604 EVENT-Output Functionality the critical temperature register is likely to be higher than that of the alarm-upper-boundary register. As a result, when the temperature is above the critical temperature, it is likely that it is above the alarm-upper-boundary as well. In interrupt mode, EVENT asserts when the temperature crosses the alarm upper boundary. If the EVENT output is cleared and the temperature continues to increase until it crosses the critical temperature threshold, EVENT asserts again. Because the temperature is greater than the critical temperature threshold, a clear event command does not clear the EVENT output. Once the temperature drops below the critical temperature, EVENT deasserts immediately. If the EVENT output is not cleared before the temperature goes above the critical temperature threshold, EVENT remains asserted. Attempting a clear event command has no effect until the temperature drops below the critical temperature, at which point EVENT deasserts immediately because of the earlier clear event command. If no clear event command is attempted, EVENT remains asserted after the temperature drops below the critical temperature. At this point, a clear event command deasserts EVENT. Detailed Register Descriptions Capability Register (Read Only) [Address = 00h, POR = 0017h] This register indicates the capabilities of the thermal sensor, including accuracy, temperature range, and resolution. See Table 3 for register details. Configuration Register (Read/Write) [Address = 01h, POR = 0000h] This register controls the various features of EVENT functionality, and controls the bit for thermal-sensor shutdown mode. See Table 4 for register details. Hysteresis When enabled, hysteresis is applied to temperature variations around trigger points. For example, consider the behavior of the alarm window bit (bit 14 of the temperature register) when the hysteresis is set to 3°C. As the temperature rises, bit 14 is set to 1 (temperature is above the alarm window) when the temperature register contains a value that is greater than the value in the alarm temperature upper boundary register. If the temperature decreases, bit 14 remains set until the measured temperature is less than or equal to the value in the alarm temperature upper boundary register minus 3°C. Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 RFU RFU TRES1 TRES0 Wider range Higher precision Has alarm and critical trips RFU 8 Bit 10 RFU RFU BIT Bit 11 RFU Bit 12 RFU Bit 13 RFU Bit 14 RFU Bit 15 RFU Table 3. Capability Register (Read Only) RFU MAX6604 Precision Temperature Monitor for DDR Memory Modules DEFINITION (DESCRIPTIONS IN BOLD TYPE APPLY TO THE MAX6604) 0 Basic capability 1: Has alarm and critical trips capability 1 Accuracy 0 = Default accuracy ±2°C over the active and ±3°C monitor ranges 1 = High accuracy ±1°C over the active and ±2°C monitor ranges 2 Wider range 0 = Values lower than 0°C are clamped and represented as binary value 0 1 = Can read temperature below 0°C and set sign bit accordingly 4:3 Temperature resolution 00 = 0.5°C LSB 01 = 0.25°C LSB 10 = 0.125°C LSB 11 = 0.0625°C LSB 15:5 0: Reserved for future use (RFU). Must be zero. _______________________________________________________________________________________ Precision Temperature Monitor for DDR Memory Modules Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EVENT mode RFU Bit 6 EVENT polarity RFU Bit 7 Critical EVENT only RFU Bit 8 EVENT output control RFU Bit 9 EVENT output status RFU BIT Bit 10 Clear EVENT Bit 11 Alarm window lock bit Bit 12 Critical trip lock bit Bit 13 Shutdown mode Bit 14 Hysteresis Bit 15 DEFINITION (DESCRIPTIONS IN BOLD TYPE ARE THE DEFAULT VALUES) 0 EVENT mode 0 = Comparator output mode (default) 1 = Interrupt mode When either of the lock bits is set, this bit cannot be altered until unlocked. 1 EVENT polarity 0 = Active low (default) 1 = Active high When either of the lock bits is set, this bit cannot be altered until unlocked. 2 Critical EVENT only 0 = EVENT output on alarm or critical temperature mode (default) 1 = EVENT only if temperature is above the value in the critical temp register When the alarm window lock bit is set, this bit cannot be altered until unlocked. 3 EVENT output control 0 = EVENT output disabled (default) [Disabled means EVENT remains in an inactive voltage level] 1 = EVENT output enabled When either of the lock bits is set, this bit cannot be altered until unlocked. 4 EVENT output status (read only) 0 = EVENT output condition is not being asserted by this device 1 = EVENT output is being asserted by this device due to alarm window or critical trip condition The actual conditions causing an EVENT output can be determined from the temperature register. Interrupt mode can be cleared by writing to the clear EVENT bit. Writing to this bit has no effect; this bit is not affected by the polarity setting. 5 Clear EVENT (write only) 0 = No effect 1 = Clears active event in interrupt mode. Writing to this register has no effect in comparator mode When read, this bit always returns to zero. 6 Alarm window lock bit 0 = Alarm trips are not locked and can be altered (default) 1 = Alarm trip register settings cannot be altered This bit is initially cleared. When set, this bit returns a 1 and remains locked until cleared by the internal power-on reset. Lock bits and other configuration register bits are updated during the same write; double writes are not necessary. 7 Critical trip lock bit 0 = Critical trip is not locked and can be altered (default) 1 = Critical trip register settings cannot be altered This bit is initially cleared. When set, this bit returns a 1 and remains locked until cleared by the internal power-on reset. Lock bits and other configuration register bits are updated during the same write; double writes are not necessary. _______________________________________________________________________________________ 9 MAX6604 Table 4. Configuration Register (Read/Write) Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EVENT mode Bit 5 EVENT polarity Bit 6 Critical EVENT only Bit 7 EVENT output control Bit 8 EVENT output status RFU Bit 9 Clear EVENT RFU Bit 10 Alarm window lock bit Bit 11 Critical trip lock bit Bit 12 Shutdown mode Bit 13 Hysteresis Bit 14 RFU RFU Bit 15 RFU Table 4. Configuration Register (Read/Write) (continued) BIT DEFINITION (DESCRIPTIONS IN BOLD TYPE ARE THE DEFAULT VALUES) 8 Shutdown mode 0 = Enable temperature monitoring (default) 1 = Shutdown temperature monitoring When shutdown occurs, the thermal-sensing device and analog-to-digital converter are disabled to save power; no EVENT output signals are generated. When either of the lock bits is set, this bit cannot be set until unlocked. However, it can be cleared at any time. 10:9 Hysteresis enable 00 = Disable hysteresis 01 = Enable hysteresis at 1.5°C 10 = Enable hysteresis at 3°C 11 = Enable hysteresis at 6°C 15:11 0: Reserved for future use (RFU). Must be zero. Similarly, the below alarm window bit (bit 13 of the temperature register) is set to 0 (temperature is equal to or above the alarm window lower boundary trip temperature) when the value in the temperature register is equal to or greater than the value in the alarm-temperature lower-boundary register. As the temperature decreases, bit 13 is set to 1 when the value in the temperature register is equal to or less than the value in the alarmtemperature lower-boundary register minus 3°C. Note that hysteresis is also applied to EVENT output functionality. When either of the lock bits is set, the hys- teresis bits cannot be altered. Hysteresis is applied to both alarm window comparisons and critical temperature comparisons. Alarm-Temperature Upper-Boundary Trip Register (Read/Write) [Address = 02h, POR = 0000h] The data format for the upper-boundary trip threshold is in two’s complement with one LSB = 0.25°C. The alarmtemperature upper-boundary trip register has a -256.00°C to +255.75°C range. All unused bits are set to zero. Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 Sign MSB 128°C 64°C 32°C 16°C 8°C 4°C 2°C 1°C 0.5°C 0.25°C 0 0 Table 5. Alarm-Temperature Upper-Boundary Trip Register (Read/Write) 0 MAX6604 Precision Temperature Monitor for DDR Memory Modules 10 ______________________________________________________________________________________ Precision Temperature Monitor for DDR Memory Modules MAX6604 BELOW ALARM WINDOW BIT FUNCTION ABOVE ALARM WINDOW BIT Temperature slope Threshold temperature Temperature slope Threshold temperature Sets Falling TL - Hyst Rising TH Clears Rising TL Falling TH - Hyst TH TH - HYST TL TL - HYST BELOW WINDOW BIT ABOVE WINDOW BIT Figure 4. Hysteresis Applied to Temperature Comparisons Alarm-Temperature Lower-Boundary Trip Register (Read/Write) [Address = 03h, POR = 0000h] The data format for the lower-boundary trip threshold is in two’s complement with one LSB = 0.25°C. The alarmtemperature lower-boundary trip register has a -256.00°C to +255.75°C range. All unused bits are set to zero. Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 0 Sign MSB 128°C 64°C 32°C 16°C 8°C 4°C 2°C 1°C 0.5°C 0.25°C 0 0 Table 6. Alarm-Temperature Lower-Boundary Trip Register (Read/Write) ______________________________________________________________________________________ 11 Critical Temperature Register (Read/Write) [Address = 04h, POR = 0000h] perature register has a -256.00°C to +255.75°C range. All unused bits are set to zero. The data format for the critical temperature value is in two’s complement with one LSB = 0.25°C. Critical tem- 0 0 Sign MSB 128°C 64°C 32°C 16°C Bit 7 Bit 6 Temperature Register (Read Only) [Address = 05h, POR = 0000h] Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 Bit 8 0 Bit 9 0.25°C Bit 10 0.5°C Bit 11 1°C Bit 12 2°C Bit 13 4°C Bit 14 8°C Bit 15 0 Table 7. Critical Temperature Register (Read/Write) are not affected by the status of the EVENT or configuration bits (e.g., event output control, clear event, etc.). If neither the above alarm window (bit 14) nor the below alarm window (bit 13) are set (i.e., both are 0), the current temperature is within the alarm window. The data format is two’s complement with one LSB = 0.125°C. All unused bits are set to zero. The most significant bit has a resolution of 128°C. The trip status bits represent the internal temperature trip detection, and BIT 12 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Below alarm window Sign MSB 128°C 64°C 32°C 16°C 8°C 4°C 2°C 1°C 0.5°C 0.25°C 0.125°C 0 Bit 15 Above alarm window Table 8. Temperature Register (Read Only) Above critical trip MAX6604 Precision Temperature Monitor for DDR Memory Modules DEFINITION 13 Below alarm window 0 = Temperature is equal to or above the alarm window lower boundary temperature 1 = Temperature is below the alarm window (temperature < alarm temperature lower boundary minus the hysteresis) 14 Above alarm window 0 = Temperature is equal to or below the alarm window upper boundary temperature minus the hysteresis 1 = Temperature is above the alarm window (temperature > alarm temperature upper boundary) 15 Above critical trip 0 = Temperature is below the critical temperature setting minus the hysteresis 1 = Temperature is equal to or above the critical temperature setting (temperature ≥ critical temperature) ______________________________________________________________________________________ Precision Temperature Monitor for DDR Memory Modules Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 1 Table 10. Device ID and Revision Register (Read Only) [Address = 07h, POR = 3E00h] Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Device ID (0011-1110) Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Device revision (0000-0000) Typical Application Circuit VCC 0.1µF 1 A0 VCC 8 2 A1 EVENT 7 3 A2 4 GND MAX6604 10kΩ 10kΩ 10kΩ TO SMBus/I2C MASTER SCL 6 SDA 5 Chip Information PROCESS: BiCMOS ______________________________________________________________________________________ 13 MAX6604 Table 9. Manufacturer’s ID Register (Read Only) [Address = 06h, POR = 004Dh] 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.) 8L, TDFN.EPS MAX6604 Precision Temperature Monitor for DDR Memory Modules PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.80mm 21-0174 14 ______________________________________________________________________________________ A 1 2 Precision Temperature Monitor for DDR Memory Modules DIMENSIONS SYMBOL MIN. NOM. MAX. A E 0.70 2.95 0.75 3.00 0.80 3.05 D A1 L 1.95 0.00 0.30 2.00 0.02 0.40 2.05 0.05 0.50 k A2 0.20 MIN. 0.20 REF. N 8 ND e b 0.18 4 0.50 BSC 0.25 EXPOSED PAD PACKAGE E2 D2 PKG. CODE MIN. NOM. MAX. MIN. NOM. MAX. T823-1 1.60 1.75 1.90 1.50 1.63 1.75 0.30 PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.80mm 21-0174 A 2 2 ______________________________________________________________________________________ 15 MAX6604 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.) 8L TSSOP.EPS MAX6604 Precision Temperature Monitor for DDR Memory Modules 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Springer is a registered trademark of Maxim Integrated Products, Inc.