Maxim MAX1618MUB Datasheet

________________General Description
The MAX1618 precise digital thermometer reports the temperature of a remote sensor. The remote sensor is a diode-connected transistor—typically a low-cost, easily mounted 2N3904 NPN type—that replaces conventional thermistors or thermocouples. Remote accuracy is ±3°C for multiple transistor manufacturers, with no calibration needed. The MAX1618 can also measure the die temper­ature of other ICs, such as microprocessors, that contain an on-chip, diode-connected transistor.
The 2-wire serial interface accepts standard System Management Bus (SMBus™) Write Byte, Read Byte, Send Byte, and Receive Byte commands to program the alarm thresholds and to read temperature data. The data format is 7 bits plus sign, with each bit corresponding to 1°C, in two’s complement format. Measurements can be done automatically and autonomously, with the 16Hz conversion rate or programmed to operate in a single-shot mode.
The thermostat mode configures the ALERT output as an interrupt or as a temperature reset that remains active only while the temperature is above the maximum temperature limit or below the minimum temperature limit. The ALERT output polarity in thermostat mode can be configured for active high or active low. Fan control is implemented using this ALERT output.
The MAX1618 is available in a small (1.1mm high) 10-pin µMAX package.
________________________Applications
Desktop and Notebook Central Office Computers Telecom Equipment
Smart Battery Packs Test and Measurement
LAN Servers Multichip Modules
Industrial Controls
____________________________Features
Single Channel: Measures Remote CPU
Temperature
No Calibration Required
SMBus 2-Wire Serial Interface
Programmable Under/Overtemperature Alarms
Overtemperature Output for Fan Control
(Thermostat Mode)
Supports SMBus Alert Response Accuracy
±3°C (+60°C to +100°C) ±5°C (-55°C to +120°C)
3µA (typ) Standby Supply Current
900µA (max) Supply Current in Autoconvert Mode
+3V to +5.5V Supply Range
Small 10-Pin µMAX Package
MAX1618
Remote Temperature Sensor
with SMBus Serial Interface
________________________________________________________________ Maxim Integrated Products 1
___________________Pin Configuration
1
2
3
4
5
10
9
8
7
6
ALERT
SMBDATA
SMBCLK
STBYDXN
GND
ADD1
ADD0
MAX1618
µMAX
TOP VIEW
V
CC
DXP
Typical Operating Circuit
19-1495; Rev 1; 10/99
PART
MAX1618MUB -55°C to +125°C
TEMP. RANGE PIN-PACKAGE
10 µMAX
Ordering Information
SMBus is a trademark of Intel Corp. Patents Pending
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
2N3904
STBY
SMBCLK
ALERT
GND
200
3V TO 5.5V
10k EACH
CLOCK
DATA
INTERRUPT TO µC
0.1µF
2200pF
V
CC
MAX1618
DXP
DXN
ADD0 ADD1
SMBDATA
Autoconvert mode, average
MAX1618
Remote Temperature Sensor with SMBus Serial Interface
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +3.3V, configuration byte register = X8h, TA= 0°C to +85°C, unless otherwise noted.)
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.
VCCto GND..............................................................-0.3V to +6V
DXP, ADD_ to GND ....................................-0.3V to (V
CC
+ 0.3V)
DXN to GND ..........................................................-0.3V to +0.8V
SMBCLK, SMBDATA, ALERT, STBY to GND ...........-0.3V to +6V
SMBDATA Current.................................................-1mA to 50mA
DXN Current. ......................................................................±1mA
ESD Protection (all pins, Human Body Model).. .............± 2000V
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 5.6mW/°C above +70°C) ....................444mW
Operating Temperature Range (extended)......-55°C to +125°C
Junction Temperature.....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10sec) ............................+300°C
CONDITIONSSYMBOL UNITSMIN TYP MAXPARAMETER
Monotonicity guaranteed Bits
8
Temperature Resolution (Note 1)
V
CC
V
3 5.5
Supply-Voltage Range
TR= +60°C to +100°C
°C
-3 3
Temperature Error, Remote Diode (Note 2)
mV
50
Undervoltage Lockout Hysteresis
VCCinput, disables A/D conversion, rising edge
mV
50
POR Threshold Hysteresis
VCC, falling edge V
1 1.7 2.5
Power-On Reset Threshold
UVLO V
2.6 2.8 2.95
Undervoltage Lockout Threshold
Hardware or software standby, SMBCLK at 10kHz
µA
5
Standby Supply Current
From stop bit to conversion complete
SMBus static
t
CONV
ms
47 62 78
Conversion Time
µA
450 900
Average Operating Supply Current
µA
80 100 120
Remote-Diode Source Current
Autoconvert mode
V
0.7
DXN Source Voltage
81012
%
-25 25
Conversion Rate Timing Error
µA
310
Standby Supply Current
VCC= 3.0V to 5.5V
Momentary upon power-on reset
V
IL
V
0.8
STBY,
SMBCLK, SMBDATA
Input Low Voltage
VCC= 3.0V V
IH
V
2.2
STBY SMBCLK, SMBDATA Input High Voltage
SMBCLK, SMBDATA forced to 0.4V mA
6
SMBCLK, SMBDATA Output Low Sink Current
Logic inputs forced to VCCor GND µA
-1 1
STBY,
SMBCLK, SMBDATA
Input Current
µA
160
ADDO, ADD1 Bias Current
TR= +55°C to +125°C
-5 5
Autoconvert mode, average measured over 4sec, 16 conv/sec
DXP forced to DXN + 0.65V, ID = 1 (high)
High level
Low level
SMBus INTERFACE
ADC AND POWER SUPPLY
MAX1618
Remote Temperature Sensor
with SMBus Serial Interface
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.3V, configuration byte register = X8h, TA= 0°C to +85°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS
(VCC= +3.3V, configuration byte register = X8h, TA= -55°C to +125°C, unless otherwise noted.) (Note 5)
CONDITIONS
Monotonicity guaranteed
TR= +60°C to +100°C
Bits8Temperature Resolution (Note 1)
-3 3
TR= -55°C to +125°C
°C
-5 5
Initial Temperature Error, Remote Diode (Note 2)
V3 5.5Supply-Voltage Range
From stop bit to conversion complete
Autoconvert mode
ms47 62 78Conversion Time
%-25 25Conversion-Rate Timing Error
UNITSMIN TYP MAXPARAMETER
CONDITIONSSYMBOL
ALERT forced to 5.5V
µA
1
ALERT Output High Leakage Current
ALERT forced to 0.4V
mA
6
ALERT Output Low Sink Current
UNITSMIN TYP MAXPARAMETER
(Note 3) kHz
DC 100
SMBus Clock Frequency
90% to 90% points t
HIGH
µs
4
SMBCLK Clock High Time
10% to 10% points t
LOW
µs4.7SMBCLK Clock Low Time
90% to 10% pointst
F
ns
300
SMBCLK, SMBDATA Fall Time
90% to 90% points
10% to 90% points
t
SU:STA
ns
500
SMBus Repeated Start Condition Setup Time
µs
4.7
SMBus Start Condition Setup Time
t
R
µs
1
SMBCLK, SMBDATA Rise Time
pF
5
SMBCLK, SMBDATA Input Capacitance
90% of SMBCLK to 10% of SMBDATAt
SU:STO
µs
4
SMBus Stop Condition Setup Time
(Note 4)
10% of SMBDATA to 90% of SMBCLK
t
HD:DAT
µs
0
SMBus Data-Hold Time
90% of SMBDATA to 10% of SMBCLKt
SU:DAT
ns
250
SMBus Data Valid to SMBCLK Rising-Edge Time
t
HD:STA
µs
4
SMBus Start Condition Hold Time
Master clocking in data µs
1
SMBCLK Falling Edge to SMBus Data-Valid Time
Between start/stop condition t
BUF
µs
4.7
SMBus Bus Free Time
V
CC
t
CONV
SYMBOL
40
-40 1 100
TEMPERATURE ERROR
vs. LEAKAGE RESISTANCE
-20
-30
-10
0
10
20
30
MAX1618 toc01
LEAKAGE RESISTANCE (M)
TEMPERATURE ERROR (°C)
10
PATH = DXP TO GND AND CONFIG = H00
PATH = DXP TO GND AND CONFIG = H08
PATH = DXP TO VCC (5.0V) AND CONFIG = H08
PATH = DXP TO VCC (5.0V) AND CONFIG = H00
-8
-5
-6
-7
-4
-3
-2
-1
0
1
2
0.005 0.05 0.5 5 50
TEMPERATURE ERROR vs.
POWER-SUPPLY NOISE FREQUENCY
MAX1618 toc03
POWER-SUPPLY NOISE FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
VIN = SQUARE WAVE APPLIED TO V
CC
WITH NO 0.1µF VCC CAPACITOR
VIN = 100mVp-p
VIN = 250mVp-p
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
-1.00
0.00
-0.50
1.00
0.50
2.00
1.50
2.50
-55 -15 5-35 25 45 65 85 105 125
TEMPERATURE ERROR
vs. REMOTE-DIODE TEMPERATURE
MAX1618 toc02
TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
CENTRAL CMPT3904 RANDOM SAMPLE
MAX1618
Remote Temperature Sensor with SMBus Serial Interface
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.3V, configuration byte register = X8h, TA= -55°C to +125°C, unless otherwise noted.) (Note 5)
Note 1: Guaranteed, but not 100% tested. Note 2: A remote diode is any diode-connected transistor from Table 7. T
R
is the junction temperature of the remote diode. See Remote Diode Selection for remote-diode forward voltage requirements. Temperature specification guaranteed for a diode with ideality factor (M
TR
= 1.013). Additional error = (1.013/m - 1) · 273 + Temp where M = Ideality of remote diode used.
Note 3: The SMBus logic block is a static design that works with clock frequencies down to DC. While slow operation is possible, it
violates the 10kHz minimum clock frequency and SMBus specifications and may monopolize the bus.
Note 4: Note that a transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SMBCLK’s
falling edge.
Note 5: Specifications from -55°C to +125°C are guaranteed by design, not production tested.
CONDITIONS UNITSMIN TYP MAXPARAMETER
VCC= 3.0V 2.2
STBY, SMBCLK, SMBDATA Input High Voltage
V
2.4
ALERT forced to 0.4V
mA1
ALERT Output Low Sink Current
VCC= 5.5V
VCC= 3.0V to 5.5V 0.8
STBY, SMBCLK, SMBDATA Input Low Voltage
V
Logic inputs forced to VCCor GND -2 2
STBY, SMBCLK, SMBDATA Input Current
µA
SMBCLK, SMBDATA forced to 0.6V 6
SMBCLK, SMBDATA Output Low Sink Current
mA
ALERT forced to 5.5V
µA1
ALERT Output High Leakage Current
SMBus INTERFACE
MAX1618
Remote Temperature Sensor
with SMBus Serial Interface
_______________________________________________________________________________________ 5
____________________________Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
120
100
80
60
40
TEMPERATURE ERROR (°C)
20
TEMPERATURE ERROR vs.
COMMON-MODE NOISE FREQUENCY
AC-COUPLED TO DXN 2200pF DXN-DXP CAPACITOR
VIN = 100mVp-p
VIN = 50mVp-p
0
10 100 1000
COMMON-MODE NOISE FREQUENCY (MHz)
MAX1618 toc04
STANDBY SUPPLY CURRENT
vs. CLOCK FREQUENCY
50
40
30
VCC = 5V
TEMPERATURE ERROR
vs. DXP-DXN CAPACITANCE
0
-10
TEMPERATURE ERROR (°C)
-20 0806020 40 100
DXP-DXN CAPACITANCE (nF)
MAX1618 toc06
VCC = 5V
MAX1618 toc05
20
10
STANDBY SUPPLY CURRENT (µA)
0
1 10 100 1000
CLOCK FREQUENCY (kHz)
VCC = 3.3V
STANDBY SUPPLY CURRENT
100
90
80
70
60
50
40
30
20
STANDBY SUPPLY CURRENT (µA)
10
0
vs. SUPPLY VOLTAGE
ADD0, ADD1 = GND
ADD0, ADD1 = HIGH-Z
021 345
SUPPLY VOLTAGE (V)
MAX1618 toc07
TEMPERATURE (°C)
RESPONSE TO THERMAL SHOCK
120
110
100
90
80
70
60
50
40
30
20
-2 2 40 6 8 101214161820
10-PIN µMAX IMMERSED IN +115°C FLUORINERT BATH
TIME (sec)
MAX1618 toc08
MAX1618
Remote Temperature Sensor with SMBus Serial Interface
6 _______________________________________________________________________________________
Pin Description
Detailed Description
The MAX1618 is a temperature sensor designed to work in conjunction with an external microcontroller (µC) or other intelligence in thermostatic, process-con­trol, or monitoring applications. The µC is typically a power-management or keyboard controller, generating SMBus serial commands by “bit-banging” general-pur­pose input-output (GPIO) pins or through a dedicated SMBus interface block.
Essentially an 8-bit serial analog-to-digital converter (ADC) with a sophisticated front end, the MAX1618 contains a switched-current source, a multiplexer, an ADC, an SMBus interface, and the associated control logic (Figure 1). Temperature data from the ADC is loaded into a data register, where it is automatically compared with data previously stored in over/under­temperature alarm threshold registers. The alarm threshold registers can be set for hysteretic fan control.
ADC and Multiplexer
The averaging ADC integrates over a 30ms period (typ) with excellent noise rejection. The ADC converts at a rate of 16Hz. The multiplexer automatically steers bias
currents through the remote diode, measures the for­ward voltage, and computes the temperature.
The DXN input is biased at 0.65V above ground by an internal diode to set up the analog-to-digital (A/D) inputs for a differential measurement. The worst-case DXP-DXN differential input voltage range is 0.25V to
0.95V.
Excess resistance in series with the remote diode causes about +1/2°C error/. A 200µV offset voltage at DXP-DXN causes about +1°C error.
A/D Conversion Sequence
If a Start command is written (or generated automatical­ly in the free-running autoconvert mode), the result of the measurement is available after the end of conver­sion. A BUSY status bit in the status byte shows that the device is performing a new conversion. The result of the previous conversion is always available even when the ADC is busy.
SMBus Serial-Data Input/Output. Open drain.SMBDATA9
SMBus Alert (Interrupt) Output. Open drain.
ALERT
10
Combined Current Source and A/D Positive Input. Do not leave DXP floating. Place a 2200pF capacitor between DXP and DXN for noise filtering.
DXP5
Supply Voltage Input. Bypass to GND with a 0.1µF capacitor.V
CC
6
Hardware-Standby Input. Temperature and comparison threshold data are retained in standby mode. Low = standby mode. High = operating mode.
STBY
7
SMBus Serial-Clock InputSMBCLK8
Combined Current Sink and A/D Negative Input. DXN is normally biased to a diode voltage above ground.
DXN4
GroundGND3
PIN
SMBus Slave Address Select Input. (See Table 6.) ADD0 and ADD1 are sampled upon power-up. Excess capacitance (>50pF) at the address pins when floating may cause address-recognition problems.
ADD12
SMBus Slave Address Select Input. (See Table 6.) ADD0 and ADD1 are sampled upon power-up. Excess capacitance (>50pF) at the address pins when floating may cause address-recognition problems.
ADD01
FUNCTIONNAME
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