Datasheet

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________________General Description

The MAX1619 is a precise digital thermometer that reports

the temperature of both a remote sensor and its own

package. The remote sensor is a diode-connected transis-

tor—typically a low-cost, easily mounted 2N3904 NPN

type—that replaces conventional thermistors or thermo-

couples. Remote accuracy is ±3°C for multiple transistor

manufacturers, with no calibration needed. The remote

channel 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 conversion rate

programmed by the user or programmed to operate in a

single-shot mode. The adjustable rate allows the user to

control the supply-current drain.

The MAX1619 is nearly identical to the popular MAX1617A,

with the additional feature of an overtemperature alarm out-

put (OVERT) that responds to the remote temperature; this

is optimal for fan control.

________________________Applications

Desktop and Notebook Central Office

Computers Telecom Equipment

Smart Battery Packs Test and Measurement

LAN Servers Multichip Modules

Industrial Controls

____________________________Features

♦ Two Channels Measure Both Remote and Local

Temperatures

♦ No Calibration Required

♦ SMBus 2-Wire Serial Interface

♦ Programmable Under/Overtemperature Alarms

♦ OVERT Output for Fan Control

♦ Supports SMBus Alert Response

♦ Supports Manufacturer and Device ID Codes

♦ Accuracy

±2°C (+60°C to +100°C, local)

±3°C (-40°C to +125°C, local)

±3°C (+60°C to +100°C, remote)

♦ 3µA (typ) Standby Supply Current

♦ 70µA (max) Supply Current in Auto-Convert Mode

♦ +3V to +5.5V Supply Range

♦ Write-Once Protection

♦ Small 16-Pin QSOP Package

MAX1619

Remote/Local Temperature Sensor with Dual-

Alarm Outputs and SMBus Serial Interface

________________________________________________________________

Maxim Integrated Products

MAX1619

SMBCLK

ADD0 ADD1

STBY

GND

ALERT

SMBDATA

DXP

DXN

INTERRUPT

TO µC

FAN

CONTROL

+3V TO +5.5V

200Ω

0.1µF

CLOCK

10k EACH

DATA

2N3904

2200pF

OVERT

___________________Pin Configuration

N.C.

STBY

SMBCLK

N.C.

SMBDATA

ALERT

ADD0

OVERT

TOP VIEW

MAX1619

QSOP

GND

DXP

ADD1

DXN

N.C.

GND

Typical Operating Circuit

19-1483; Rev 0; 4/99

PART

MAX1619MEE -55°C to +125°C

TEMP. RANGE PIN-PACKAGE

16 QSOP

Ordering Information

SMBus is a registered trademark of Intel Corp.

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.

Summary of content (20 pages)

PAGE 1
9-1483; Rev 0; 4/99 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface ____________________________Features The MAX1619 is a precise digital thermometer that reports the temperature of both a remote sensor and its own package. 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.
PAGE 2
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V DXP, ADD_ to GND ....................................-0.3V to (VCC + 0.3V) DXN to GND ..........................................................-0.3V to +0.8V SMBCLK, SMBDATA, ALERT, OVERT, STBY to GND............................................................-0.3V to +6V SMBDATA, ALERT, OVERT Current.......
PAGE 3
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface (VCC = +3.3V, TA = 0°C to +85°C, configuration byte = XCh, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS SMBus INTERFACE Logic Input High Voltage STBY, SMBCLK, SMBDATA; VCC = 3V to 5.5V Logic Input Low Voltage STBY, SMBCLK, SMBDATA; VCC = 3V to 5.5V Logic Output Low Sink Current ALERT, OVERT, SMBDATA forced to 0.4V ALERT, OVERT Output High Leakage Current ALERT, OVERT, forced to 5.
PAGE 4
ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.3V, TA = -55°C to +125°C, configuration byte = XCh, unless otherwise noted.) (Note 4) PARAMETER CONDITIONS MIN TYP MAX UNITS SMBus INTERFACE VCC = 3V 2.2 VCC = 5.5V 2.4 Logic Input High Voltage STBY, SMBCLK, SMBDATA Logic Input Low Voltage STBY, SMBCLK, SMBDATA; VCC = 3V to 5.5V Logic Output Low Sink Current ALERT, OVERT, SMBDATA forced to 0.4V ALERT, OVERT Output High Leakage Current ALERT, OVERT forced to 5.
PAGE 5
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface VIN = 100mVp-p 4 VIN = 50mVp-p VIN = 25mVp-p 40 10 2 30 VCC = 5V 20 VCC = 3.3V 10 0 0 0 0.1 1 10 0 100 20 40 80 60 1 100 10 100 1000 FREQUENCY (MHz) DXP–DXN CAPACITANCE (nF) SMBCLK FREQUENCY (kHz) STANDBY SUPPLY CURRENT vs. SUPPLY VOLTAGE OPERATING SUPPLY CURRENT vs.
PAGE 6
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface MAX1619 Pin Description PIN NAME FUNCTION 1 VCC Supply Voltage Input, 3V to 5.5V. Bypass to GND with a 0.1µF capacitor. A 200Ω series resistor is recommended but not required for additional noise filtering. 2 GND Not internally connected. Connect to GND to act against leakage paths from VCC to DXP. 3 DXP Combined Current Source and A/D Positive Input for Remote-Diode Channel.
PAGE 7
OVERT ALERT GND DXN DXP REMOTE TEMPERATURE DATA REGISTER DIODE FAULT LOCAL REMOTE - + Q Q POL R R S S DIGITAL COMPARATOR (REMOTE) 8 LOW-TEMPERATURE THRESHOLD (REMOTE TLOW) 8 HIGH-TEMPERATURE THRESHOLD (REMOTE THIGH) 8 - + - + MUX ADC SELECTED VIA SLAVE ADD = 0001 100 DIGITAL COMPARATOR (REMOTE OVERTEMP) ALERT RESPONSE ADDRESS REGISTER CONVERSION RATE REGISTER CONFIGURATION BYTE REGISTER HYSTERESIS THRESHOLD (REMOTE THYST) 8 STATUS BYTE REGISTER 8 WRITE HIGH-TEMPERATURE TH
PAGE 8
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface A/D Conversion Sequence If a Start command is written (or generated automatically in the free-running auto-convert mode), both channels are converted, and the results of both measurements are available after the end of conversion.
PAGE 9
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface 2) Do not route the DXP–DXN lines next to the deflection coils of a CRT. Also, do not route the traces across a fast memory bus, which can easily introduce +30°C error, even with good filtering. Otherwise, most noise sources are fairly benign. 3) Route the DXP and DXN traces in parallel and in close proximity to each other, away from any highvoltage traces such as +12VDC.
PAGE 10
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface Operating Characteristics). Between conversions, the instantaneous supply current is about 25µA due to the current consumed by the conversion rate timer. In standby mode, supply current drops to about 3µA. At very low supply voltages (under the power-on-reset threshold), the supply current is higher due to the address pin bias currents. It can be as high as 100µA, depending on ADD0 and ADD1 settings.
PAGE 11
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface Alarm Threshold Registers Two registers store ALERT threshold limits, with hightemperature (THIGH) and low-temperature (TLOW) registers for the remote A/D channel. There are no comparison registers for the local A/D channel. If either measured temperature equals or exceeds the corresponding alarm threshold value, an ALERT interrupt is asserted.
PAGE 12
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface If the remote channel is shorted (DXP to DXN or DXP to GND), the ADC reads 0000 0000 so as not to trip either the T HIGH or T LOW alarms at their POR settings. In applications that are never subjected to 0°C in normal operation, a 0000 0000 result can be checked to indicate a fault condition in which DXP is accidentally short circuited.
PAGE 13
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface MAX1619 Table 4.
PAGE 14
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface Table 6. Status-Byte Bit Assignments BIT NAME FUNCTION 7 (MSB) BUSY A high indicates that the ADC is busy converting. 6 RFU Reserved for future use. 5 RFU 4 RHIGH* DATA CONVERSION FREQUENCY (Hz) AVERAGE SUPPLY CURRENT (µA typ, at VCC = 3.3V) Reserved for future use. 00h 0.0625 30 A high indicates that the remote hightemperature alarm has activated. 01h 0.125 33 02h 0.25 35 03h 0.
PAGE 15
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface OPERATING MODE CONVERSION INITIATED BY: NEW CONVERSION FREQUENCY (CHANGED VIA WRITE TO WCRW) TIME UNTIL RLTS AND RRTE ARE UPDATED Autoconvert Power-on reset n/a (0.
PAGE 16
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface A B tLOW C D E F G H J I tHIGH K SMBCLK SMBDATA tSU:STA tHD:STA tSU:STO tSU:DAT 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 F = ACKNOWLEDGE BIT CLOCKED INTO MASTER G = MSB OF DATA CLOCKED INTO MASTER H = LSB OF DATA CLOCKED INTO MASTER tBUF I = ACKNOWLEDGE CLOCK PULSE J = STOP CONDIT
PAGE 17
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface MAX1619 Listing 1.
PAGE 18
MAX1619 Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface Listing 1.
PAGE 19
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface MAX1619 Listing 1. Pseudocode Example (continued) Programming Example: Clock-Throttling Control for CPUs Listing 1 gives an untested example of pseudocode for proportional temperature control of Intel mobile CPUs through a power-management microcontroller. This program consists of two main parts: an initialization routine and an interrupt handler.
PAGE 20
Remote/Local Temperature Sensor with DualAlarm Outputs and SMBus Serial Interface QSOP.EPS MAX1619 Package Information 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.