View MAX6634_289376.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-2120; Rev 0; 8/01
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface
General Description
The MAX6633/MAX6634/MAX6635 combine a temperature sensor, a programmable overtemperature alarm, and an SMBusTM/I2CTM-compatible serial interface into a single package. They convert their die temperatures into digital values using internal analog-to-digital converters (ADCs). The result of the conversion is then held in a temperature register as a 12-bit + sign value, allowing 0.0625C resolution, readable at any time through the serial interface. The devices are capable of reading temperatures up to +150C. The MAX6633/MAX6634/MAX6635 feature a shutdown mode that saves power by turning off everything except the power-on reset (POR) and the serial interface. The devices can be configured to separate addresses, allowing multiple devices to be used on the same bus. The MAX6633 has four address pins, allowing up to 16 devices to be connected to a single bus. The MAX6634 has three address pins, allowing up to eight devices to be connected to a single bus. The MAX6635 has two address pins, allowing up to four devices to be connected to a single bus. The MAX6633/MAX6634/MAX6635 make temperature data available for transfer over the serial interface. The MAX6634 incorporates a dual-mode ALERT output (open drain) and can serve as an upgraded alternative to the LM75. The MAX6635 includes an ALERT output and an OVERT output (both open drain) and can function as an upgraded replacement for the LM76 in most applications. The MAX6634/MAX6635 feature user-programmable temperature thresholds. All three devices come in an 8-pin SO package. o +3V to +5.5V Supply Range o Accuracy 1C max (0C to +50C) 1.5C max (-20C to +85C) 2.5C max (-40C to +125C) 2.5C typ (+150C) o User-Programmable Temperature Thresholds (MAX6634/MAX6635) o User-Configurable Alarm Output(s) (MAX6634/MAX6635) o Ability to Respond to SMBus/I2C-Compatible Alert Response Address (MAX6634/MAX6635) o OVERT Output for System Shutdown (MAX6635) o Multiple Devices per Bus 16 devices (MAX6633) 8 devices (MAX6634) 4 devices (MAX6635)
Features
MAX6633/MAX6634/MAX6635
Ordering Information
PART MAX6633MSA MAX6634MSA MAX6635MSA TEMP. RANGE -55C to +150C -55C to +150C -55C to +150C PIN-PACKAGE 8 SO 8 SO 8 SO
Typical Operating Circuit
VCC 0.1F +3.0V TO +5.5V 8 VCC 10k 1k 1k 10k
Applications
Battery Temperature Alarms PC Temperature Control Automotive Equipment
Pin Configurations appear at end of data sheet.
ALERT
5
TO INTERRUPT CONTROLLER TO SMBus/I2C MASTER
MAX6635 SDA 1 SCL 2
OVERT
3
TO SYSTEM SHUTDOWN
SMBus is a trademark of Intel Corp. I2C is a trademark of Philips Corp.
A0 A1 GND 7 6 4
________________________________________________________________ Maxim Integrated Products
1
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.
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
ABSOLUTE MAXIMUM RATINGS
VCC, SDA, SCL ......................................................-0.3V to +6.0V All Other Pins ................................................-0.3V to VCC +0.3V SDA, ALERT, OVERT Current .............................-1mA to +50mA ESD Protection (Human Body Model)................................2000V Continuous Power Dissipation (TA = +70C) 8-Pin SO (derate 5.88mW/C above +70C)................471mW Junction Temperature ......................................................+150C Operating Temperature Range .........................-55C to +150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) ................................+300C
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 = +3.0V to +5.5V, TA = -55C to +125C, unless otherwise noted. Typical values are VCC = +3.3V, TA = +25C, unless otherwise noted.)
PARAMETER Supply Range SYMBOL VCC 0C TA = +50C, VCC = +3.3V -20C TA = +85C, VCC = +3.3V Accuracy (Note 1) -40C TA = 125C, VCC = +3.3V TA = -55C, VCC = +3.3V TA = +150C, VCC = +3.3V Power-Supply Rejection Ratio POR Threshold Hysteresis Supply Current in Shutdown Average Operating Current Peak Operating Current (Note 2) Conversion Rate DIGITAL INTERFACE Logic Input Low Voltage Logic Input High Voltage Input Leakage Current Output Low Sink Current Output Leakage Current Input Capacitance VIL VIH II_LEAK IOL IO_LEAK CIN VCC = +3.0V to +5.5V VCC = +3V VCC = +5.5V VIN = GND or VCC VOL = 0.6V (SMBDATA, ALERT, OVERT) ALERT, OVERT at VCC 5 6 1 2.2 2.4 1 0.65 V V A mA A pF VCC = +3.0V, SMBus inactive VCC = +5.5V, SMBus inactive VCC = +3.0V, SMBus inactive VCC = +5.5V, SMBus inactive VCC = +3.0V, SMBus inactive VCC = +5.5V, SMBus inactive 1.4 PSRR CONDITIONS MIN 3.0 -1.0 -1.5 -2.5 -2.8 0.4 0.6 1.0 1.5 2.5 0.2 90 12 20 150 200 270 350 2 350 700 2.4 20 30 0.5 C/V mV A A A Hz TYP MAX 5.5 +1.0 +1.5 +2.5 +2.8 C UNITS V
TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS
2
_______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +5.5V, TA = -55C to +125C, unless otherwise noted. Typical values are VCC = +3.3V, TA = +25C, unless otherwise noted.)
PARAMETER Serial Clock Frequency Bus Free Time Between STOP and START Condition START Condition Setup Time Repeat START Condition Setup Time START Condition Hold Time STOP Condition Setup Time Data Setup Time Data Hold Time (Note 4) Receive SCL/SDA Rise Time SCL/SDA Fall Time (Note 4) Clock Low Period Clock High Period SMBus Timeout tSU:STA tHD:STA tSU:STO tSU:DAT tHD:DAT tR tF tLOW tHIGH 10% to 10% 90% to 90% 4.7 4 25 48 90% to 90% 10% of SMBDATA to 90% of SMBCLK 90% of SMBCLK to 10% of SMBDATA 90% of SMBDATA to 10% of SMBCLK SYMBOL fSCL tBUF CONDITIONS MIN 10 4.7 4.7 4.7 4 4 250 300 1 300 TYP MAX 100 UNITS kHz s s s s s ns ns s ns s s ms
MAX6633/MAX6634/MAX6635
SMBus TIMING (Note 3, Figures 1, 2, and 3)
Note 1: Note 2: Note 3: Note 4:
Guaranteed by design and characterization. Peak operating current measured during conversion. See Figure 4. Guaranteed by design, not production tested. A master device must provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of SCL's falling edge.
_______________________________________________________________________________________
3
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
Typical Operating Characteristics
(VCC = +3.3V, TA = +25C, unless otherwise noted.)
SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE
MAX6633/4/5 toc01
AVERAGE SUPPLY CURRENT vs. TEMPERATURE
MAX6633/4/5 toc02
TEMPERATURE ERROR vs. SUPPLY NOISE FREQUENCY
VIN = SQUARE WAVE APPLIED TO VCC WITH NO BYPASS CAPACITOR
MAX6633/4/5 toc03
50 SHUTDOWN SUPPLY CURRENT (A)
400 AVERAGE SUPPLY CURRENT (A)
5 4 TEMPERATURE ERROR (C) 3
40
300 VCC = +5.5V 200
30
VCC = +5.5V
VIN = 200mVp-p 2 1 VIN = 200mVp-p 0 -1
20
10 VCC = +3.3V 0 -55 0 55 TEMPERATURE (C) 110 165
100
VCC = +3.3V
0 -55 0 55 TEMPERATURE (C) 110 165
10
10k SUPPLY NOISE FREQUENCY (Hz)
10M
RESPONSE TO THERMAL SHOCK
90 80 TEMPERATURE (C) 70 60 50 40 30 20 10 0 0 5 10 TIME (s) 15 20 -3 -40 VCC = +5.5V DEVICE IMMERSED IN +85C FLUORINERT BATH
MAX6633/4/5 toc04
100
TEMPERATURE ERROR vs. TEMPERATURE
MAX6633/4/5 toc05
3
TEMPERATURE ERROR (C)
2 VCC = +3.3V 0 VCC = +5.5V -2
0
40
80
120
160
TEMPERATURE (C)
4
_______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface
Pin Description
PIN MAX6633 1 2 3 4 5 6 7 8 -- -- MAX6634 1 2 -- 4 5 6 7 8 3 -- MAX6635 1 2 -- 4 -- 6 7 8 5 3 NAME SDA SCL A3 GND A2 A1 A0 VCC ALERT OVERT FUNCTION Serial Data Input/Output. Open drain. Serial Clock Input Address Pin Ground Address Pin Address Pin Address Pin Supply Voltage Input. +3.0V to +5.5V. Bypass VCC to GND with a 0.1F capacitor. ALERT Output. Open drain. OVERT Output. Open drain.
MAX6633/MAX6634/MAX6635
Detailed Description
The MAX6633/MAX6634/MAX6635 continuously convert their die temperatures into digital values using their integrated ADCs. The resulting data is readable at any time through the SMBus/I2C-compatible serial interface. The device functions as a slave on the SMBus interface, supporting Write Byte, Write Word, Read Byte, and Read Word commands. Separate addresses can be configured using the individual address pins. Figures 5, 6, and 7 show the functional diagrams of the MAX6633/MAX6634/MAX6635, respectively.
devices to be connected to a single bus line. Table 1 shows the full SMBus/I2C address for each device type.
Control Registers (MAX6633)
Three registers control the operation of the MAX6633 (Figure 5 and Tables 2 through 6). The Pointer register is the first addressed and determines which of the other two registers is acted upon. The other two are the Temperature and Configuration registers. The temperature value is stored as 12 bits plus a sign bit, read only, and contains the latest temperature data. The true register length is 16 bits, with the lower 3 unused in this part. The digital temperature data contained in the temperature register is in C, using a two's-complement format with 1LSB corresponding to 0.0625C. The Configuration register is 8 bits, read/write, and contains the SMBus timeout disable bit, fault queue enable bit, and the shutdown bit.
SMBus/I2C-Compatible Operation
The MAX6633/MAX6634/MAX6635 are readable and programmable through their SMBus/I 2C-compatible serial interface. Figures 1, 2, and 3 show the timing details of the clock (SCL) and data (SDA) signals. The devices function as slaves on the SMBus and support Write Byte, Write Word, Read Byte, and Read Word commands. Figure 8 is the MAX6633/MAX6634/ MAX6635 programmer's model.
Control Registers (MAX6634)
Six registers control the operation of the MAX6634 (Figure 6 and Tables 2 through 7). The pointer register is the first addressed and determines which of the other five registers is acted upon. The other five are the Temperature, Configuration, High-Temperature (T HIGH ), Low-Temperature (T LOW ), and Hysteresis (THYST) registers. The temperature value is stored as 12 bits plus a sign bit, read only, and contains the latest temperature data. The true register length is 16 bits, with the lowest 2 used as status bits, and the third bit (D2) is unused. The digital temperature data contained in the temperature register is in C, using a two's-complement format with 1LSB corresponding to 0.0625C.
5
Addressing
Separate addresses can be configured using the individual address pins. The address of each device is selected by connecting the address (A_) pins to one of two potentials: GND or VCC. The MAX6635 makes two address pins available (A0, A1), allowing up to four devices to be connected to a single bus line. The MAX6634 makes three address pins available (A0, A1, A2), allowing up to eight devices to be connected to a single bus line. The MAX6633 makes four address pins available (A0, A1, A2, A3), allowing as many as 16
_______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
Write Byte Format S ADDRESS WR 7 bits Slave Address: equivalent to chip-select line of a 3wire interface Write Word Format S ADDRESS 7 bits Slave Address: equivalent to chip-select line of a 3-wire interface ACK COMMAND ACK 8 bits Command Byte: selects register you are writing to DATA ACK P 8 bits Data Byte: data goes into the register set by the command byte
WR
ACK
COMMAND 8 bits
ACK
Command Byte: selects register you are writing to
DATA ACK DATA 8 bits 8 bits (MSB) (LSB) Data Bytes: data goes into the register set by the command byte
ACK
P
Read Byte Format S ADDRESS WR ACK 7 bits Slave Address: equivalent to chip-select line COMMAND ACK 8 bits Command Byte: selects register you are reading from S ADDRESS RD ACK 7 bits Slave Address: repeated due to change in data-flow direction DATA /// P 8 bits Data Byte: reads from the register set by the command byte
Read Word Format S ADDRESS WR 7 bits Slave Address: equivalent to chipselect line S = Start condition P = Stop condition
ACK
COMMAND 8 bits
ACK
S
ADDRESS 7 bits
RD
ACK
Command Byte: selects register you are reading from Shaded = Slave transmission /// = Not acknowledged
Slave Address: repeated due to change in data-flow direction
DATA ACK DATA /// 8 bits 8 bits (MSB) (LSB) Data Bytes: reads from the register set by the command byte
P
Figure 1. SMBus Protocols
A B C D E F G H I J K L M
tLOW
tHIGH
SMBCLK
SMBDATA tSU:STA tHD:STA tSU:DAT tHD:DAT F = ACKNOWLEDGE BIT CLOCKED INTO MASTER G = MSB OF DATA CLOCKED INTO SLAVE H = LSB OF DATA CLOCKED INTO SLAVE I = SLAVE PULLS SMBDATA LINE LOW
tSU:STO tBUF J = ACKNOWLEDGE CLOCKED INTO MASTER K = ACKNOWLEDGE CLOCK PULSE L = STOP CONDITION, DATA EXECUTED BY SLAVE M = NEW START CONDITION
A = START CONDITION B = MSB OF ADDRESS CLOCKED INTO SLAVE C = LSB OF ADDRESS CLOCKED INTO SLAVE D = R/W BIT CLOCKED INTO SLAVE E = SLAVE PULLS SMBDATA LINE LOW
Figure 2. SMBus Write Timing Diagram 6 _______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
A tLOW SMBCLK B tHIGH C D E F G H I J K L M
SMBDATA
tSU:STA tHD:STA A = START CONDITION B = MSB OF ADDRESS CLOCKED INTO SLAVE C = LSB OF ADDRESS CLOCKED INTO SLAVE D = R/W BIT CLOCKED INTO SLAVE
tSU:DAT E = SLAVE PULLS SMBDATA LINE LOW F = ACKNOWLEDGE BIT CLOCKED INTO MASTER G = MSB OF DATA CLOCKED INTO MASTER H = LSB OF DATA CLOCKED INTO MASTER I = MASTER PULLS DATA LINE LOW J = ACKNOWLEDGE CLOCKED INTO SLAVE K = ACKNOWLEDGE CLEAR PULSE
tSU:STO
tBUF
L = STOP CONDITION, DATA EXECUTED BY SLAVE M = NEW START CONDITION
Figure 3. SMBus Read Timing Diagram
CONVERSION PERIOD 0.5s MAX6633/MAX6634/MAX6635 0.25s ADC CONVERSION TIME MAX6633/MAX6634/MAX6635
Figure 4. ADC Conversion Timing Diagram
The Configuration register is 8 bits, read/write, and contains the SMBus timeout disable bit, fault queue enable bit, the temperature alarm output polarity select bits, the interrupt mode select bit, and the shutdown bit. Registers THIGH and TLOW are 16 bits, read/write, and contain the values that trigger ALERT. Register THYST is 16 bits, read/write, and contains the values by which the temperature must rise or fall beyond THIGH or TLOW, before ALERT deasserts.
VCC
Control Registers (MAX6635)
Seven registers control the operation of the MAX6635 (Figure 7 and Tables 2 through 7). The Pointer register is the first addressed and determines which of the other six registers is acted upon. The other six are the Temperature, Configuration, High-Temperature (T HIGH ), Low-Temperature (T LOW ), Maximum Temperature (TMAX), and Hysteresis (THYST) registers. The temperature value is stored as 12 bits plus a sign bit, read only, and contains the latest temperature data. The true register length is 16 bits, with the lower three used as status bits. The digital temperature data contained in the temperature register is in C, using a two's-complement format with 1LSB corresponding to 0.0625C. The Configuration register is 8 bits, read/write, and contains the SMBus timeout disable bit, fault queue enable bit, the temperature alarm output polarity select bits, the interrupt mode select bit, and the shutdown
12 BIT + SIGN ADC
CONFIGURATION
TEMPERATURE SDA SCL A0 A1 A2 A3
SMBus INTERFACE
Figure 5. MAX6633 Functional Diagram
_______________________________________________________________________________________
7
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
VCC
CMP 12 BIT + SIGN ADC ALERT CMP
CONFIGURATION
TEMPERATURE
TLOW
THIGH SDA SCL A0 A1 A2
SMBus INTERFACE
Figure 6. MAX6634 Functional Diagram
VCC
CMP
OVERT
CMP 12 BIT + SIGN ADC ALERT CMP
CONFIGURATION
TEMPERATURE
TMAX
TLOW
THIGH SDA SCL A0 A1
SMBus INTERFACE
Figure 7. MAX6635 Functional Diagram 8 _______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
SDA SCL DATA INTERFACE
ADDRESS
POINTER REGISTER (SELECTS REGISTER FOR COMMUNICATION)
TEMPERATURE (READ ONLY) POINTER = 00h
CONFIGURATION (READ/WRITE, SETS OPERATING MODES) POINTER = 01h TMAX SET POINT (READ/WRITE) POINTER = 03h (MAX6635 ONLY)
THYST SET POINT (READ/WRITE) POINTER = 02h (MAX6634/MAX6635 ONLY)
TLOW SET POINT (READ/WRITE) POINTER = 04h (MAX6634/MAX6635 ONLY)
THIGH SET POINT (READ/WRITE) POINTER = 05h (MAX6634/MAX6635 ONLY)
Figure 8. MAX6633/MAX6634/MAX6635 Programmer's Model
_______________________________________________________________________________________
9
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
TMAX TMAX - THYST
THIGH THIGH - THYST
TLOW + THYST TLOW
ALERT COMPARATOR MODE ALERT INTERRUPT MODE OVERT COMPARATOR MODE ONLY * * * * *
*IN INTERRUPT MODE, READING THE DEVICE CLEARS ALERT. OTHERWISE, IT WOULD REMAIN LOW INDEFINITELY UNTIL CLEARED.
Figure 9. Alarm Output and Reset Diagram
bit. Registers THIGH and TLOW are 16 bits, read/write, and contain values that trigger ALERT and OVERT. Register THYST is 16 bits, read/write, and contains the values by which the temperature must rise or fall beyond T HIGH , T LOW , or T MAX , before ALERT or OVERT deassert.
Fault Queue (MAX6634/MAX6635)
A programmable fault queue on the MAX6634/ MAX6635 eliminates spurious alarm activity in noisy environments. The queue sets the number of consecutive out-of-tolerance temperature readings that must occur before the ALERT or OVERT alarm outputs are toggled. An out-of-tolerance reading is above THIGH or TMAX or below TLOW. The fault queue depth defaults to 1 at power-up and may be programmed--through the Configuration register--to four consecutive conversions. Any time the conversion result is in tolerance, and the particular alarm output is not asserted, the queue is cleared, even if it contains some out-of-tolerance counts. Additionally, the fault queue automatically clears at power-up and in shutdown. Whenever the fault queue is cleared, the alarm outputs are deasserted. Figure 9 is the alarm output and reset diagram.
Temperature Conversion
An on-chip bandgap reference produces a signal proportional to absolute temperature (PTAT), as well as the temperature-stable reference voltage necessary for the analog-to-digital conversion. The PTAT signal is digitized by the on-board ADC to a resolution of 0.0625C. The resulting digital value is placed in the Temperature register. The temperature conversion runs continuously and asynchronously from the serial interface at a rate of 500ms per conversion. When the Temperature register is read, the conversion in progress is aborted. The bus transaction is completed by a stop condition.
10
______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
VCC +3V TO +5.5V HEATER
VCC +3V TO +5.5V
+12V 12V 300mA MOTOR LOGIC-LEVEL MOSFET
8
8 4k RELAY 5VDC, 20mA 125VAC, 1A
FAN 10k 3
OVERT
MAX6634
ALERT 3 2N3904 HEATER SUPPLY 4
MAX6635
4
Figure 10. Simple Thermostat
Figure 11. Fan Controller
Temperature Alert (MAX6634/MAX6635)
ALERT has programmable polarity and two modes: comparator and interrupt. Polarity and mode are selected through the Configuration register (Table 4). The ALERT output is open drain. Interrupt Mode With ALERT in interrupt mode, the MAX6634/MAX6635 look for a THIGH or a TLOW fault. The ALERT pin asserts an alarm for an undertemperature fault, as well as for an overtemperature fault. Once either fault has occurred, it remains active until deasserted by a read of any register. The device then begins to look for a temperature change crossing the hysteresis level. The activation of ALERT is subject to the depth of the fault queue. For example: If THIGH is set to 100C, THYST is set to 20C, and the fault queue depth is set to 4, ALERT does not assert until four consecutive conversions exceed 100C. If the temperature is then read through the I2C-compatible interface, ALERT deasserts. ALERT asserts again when four consecutive conversions are less than 80C. Comparator Mode In comparator mode, ALERT is asserted when the number of consecutive conversions exceeding the value in the THIGH register, or lower than the value in the TLOW register, is equal to the depth of the fault queue. ALERT deasserts when the number of consecutive conversions
less than THIGH - THYST or greater than TLOW + THYST is equal to the depth of the fault queue. For example: If THIGH is set to 100C, TLOW is set to 80C, and the fault queue depth is set to four, ALERT does not assert until four consecutive conversions exceed 100C, or are below 80C. ALERT only deasserts if four consecutive conversions are less than THIGH - THYST or greater than TLOW + THYST. Comparator mode allows autonomous clearing of an ALERT fault without the intervention of a master and is ideal to use for driving a thermostat (Figure 10).
Overtemperature Alarm (MAX6635)
The MAX6635 also includes an overtemperature output that is always in comparator mode. Whenever the temperature exceeds a value in the programmable TMAX register, OVERT is asserted. OVERT only deasserts after the temperature drops below TMAX - THYST. When the fault queue is activated, OVERT is subject to that queue, which sets the number of faults that must occur before OVERT asserts or deasserts. This helps prevent spurious alarms in noisy environments. Comparator mode also allows autonomous clearing of an OVERT fault without the intervention of a master and thus is ideal to use for driving a cooling fan (Figure 11). In this application, the polarity of OVERT is active high.
Shutdown
The MAX6633/MAX6634/MAX6635 feature a shutdown mode, accessible through the serial interface that saves power by turning off everything except the POR
11
______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
and the serial interface. Enter shutdown by programming the shutdown bit of the Configuration register high. While in shutdown, the Temperature register retains the last conversion result and can be read at any time. The ADC is turned off, reducing the device current draw to 30A (max). The outputs of ALERT and OVERT are latched upon entering shutdown, and the fault queue is held in reset. After coming out of shutdown, the Temperature register continues to read the last converted temperature, until the next conversion result is available.
Table 1. Address Selection
MAX6633 A3 GND GND GND GND GND GND GND GND VCC VCC VCC VCC VCC VCC VCC VCC A2 GND GND GND GND VCC VCC VCC VCC GND GND GND GND VCC VCC VCC VCC A2 GND GND GND GND VCC VCC VCC VCC A1 GND GND VCC VCC GND GND VCC VCC GND GND VCC VCC GND GND VCC VCC MAX6634 A1 GND GND VCC VCC GND GND VCC VCC MAX6635 A1 GND GND VCC VCC A0 GND VCC GND VCC ADDRESS 1001 000 1001 001 1001 010 1001 011 A0 GND VCC GND VCC GND VCC GND VCC ADDRESS 1001 000 1001 001 1001 010 1001 011 1001 100 1001 101 1001 110 1001 111 A0 GND VCC GND VCC GND VCC GND VCC GND VCC GND VCC GND VCC GND VCC ADDRESS 1000 000 1000 001 1000 010 1000 011 1000 100 1000 101 1000 110 1000 111 1001 000 1001 001 1001 010 1001 011 1001 100 1001 101 1001 110 1001 111
Thermal Considerations
The MAX6633/MAX6634/MAX6635 supply current is typically 200A when the serial interface is inactive. When used to drive high-impedance loads, the devices dissipate negligible power; therefore, the die temperature is essentially the same as the package temperature. The key to accurate temperature monitoring is good thermal contact between the MAX6633/MAX6634/ MAX6635 package and the monitored device or circuit. Heat flows in and out of plastic packages primarily through the leads. Short, wide copper traces leading to the temperature monitor ensure that heat transfers quickly and reliably. The rise in die temperature due to self-heating is given by the following formula: TJ = PDISSIPATION x JA where P DISSIPATION is the power dissipated by the MAX6633/MAX6634/MAX6635, and JA is the package's thermal resistance. The typical thermal resistance is 170C/W for the 8-pin SO package. To limit the effects of self-heating, minimize the output currents. For example, if the MAX6634/MAX6635 sink 4mA with the maximum ALERT VL specification of 0.8V, an additional 3.2mW of power is dissipated within the IC. This corresponds to a 0.54C rise in the die temperature.
Applications Information
Figure 10 shows the MAX6634 used as a simple thermostat to control a heating element. Figure 11 shows the MAX6635 used as a temperature-triggered fan controller.
Chip Information
TRANSISTOR COUNT: 12,085 PROCESS: BiCMOS
12
______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
Table 2. Pointer Register Bit Assignments
ADDRESS 00h 01h 02h 03h 04h 05h DESCRIPTION Temperature register (READ only) Configuration-Byte register THYST register TMAX register TLOW register THIGH register POR STATE 0000h 00h 0100h 2800h 0500h 2000h
Table 3. Temperature Register
D15 MSB (Sign) D14 Bit 12 D13 Bit 11 D12 Bit 10 D11 Bit 9 D10 Bit 8 D9 Bit 7 D8 Bit 6 D7 Bit 5 D6 Bit 4 D5 Bit 3 D4 Bit 2 D3 Bit 1 D2 TMAX D1 THIGH D0 TLOW
D15: MSB is the first sign bit. D2, D1, D0: Flag bits for TMAX, THIGH, TLOW. 1LSB = 0.0625C. Temperature is stored in two's complement format.
Table 4. Configuration Register
D7 0 D6 0 D5 SMB Timeout Disable D4 Fault Queue Enable D3 ALERT Polarity D2 OVERT Polarity D1 Comparator or Interrupt D0 Shutdown
Power-on default = 0h. D0: 0 = normal operation; 1 = shutdown. D1: 0 = comparator mode; 1 = interrupt mode. D2 to D3: 0 = active low; 1 = active high. D5: 0 = normal SMBus operation; 1 = full I2C compatibility. D7 to D6: Reserved locations, always write zeros.
______________________________________________________________________________________
13
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
Table 5. Fault Queue Depth
D4 0 1 NO. OF FAULTS 1 (DEFAULT) 4
Table 6. Output Code vs. Temperature
TEMP. (C) DIGITAL OUTPUT CODE BINARY MSB +150.0000 +125.0000 +25.0000 +0.0625 0.0000 -0.0625 -25.0000 -55.0000 LSB 4B00 3E80 0C80 0008 0000 FFF8 F370 E470 HEX
0100 1011 0000 0XXX 0011 1110 1000 0XXX 0000 1100 1000 0XXX 0000 0000 0000 1XXX 0000 0000 0000 0XXX 1111 1111 1111 1XXX 1111 0011 0111 0XXX 1110 0100 0111 0XXX
Table 7. THIGH, TLOW, TMAX, and THYST Registers
D15 MSB (Sign) D14 Bit 7 D13 Bit 6 D12 Bit 5 D11 Bit 4 D10 Bit 3 D9 Bit 2 D8 Bit 1 D7 LSB D6 0 D5 0 D4 0 D3 0 D2 0 D1 0 D0 0
D6 to D0: Reads all zeros, cannot be written. 1LSB = 1C. Power-On Default: THIGH = +64C (2000h), TLOW = +10C (0500h), TMAX = +80C (2008h), THYST = 2C (0100h).
14
______________________________________________________________________________________
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface
Pin Configurations
TOP VIEW
MAX6633/MAX6634/MAX6635
SDA 1 SCL 2
8 7
VCC A0 A1 A2
SDA 1 SCL 2
8 7
VCC A0 A1 A2
SDA 1 SCL 2
8 7
VCC A0 A1 ALERT
MAX6633
A3 3 6 5 ALERT 3 GND 4 GND 4
MAX6634
6 5 OVERT 3 GND 4
MAX6635
6 5
SO
SO
SO
______________________________________________________________________________________
15
12-Bit Plus Sign Temperature Sensors with SMBus/I2C-Compatible Serial Interface MAX6633/MAX6634/MAX6635
Package Information
SOICN.EPS
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 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

▲Up To Search▲

Price & Availability of MAX6634

	To Download MAX6634 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .