Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsMAX6694TE9A+

General Description

The MAX6694 precision multichannel temperature sen-

sor monitors its own temperature and the temperatures

of up to four external diode-connected transistors. All

temperature channels have programmable alert thresh-

olds. Channels 1 and 4 also have programmable

overtemperature thresholds. When the measured tem-

perature of a channel exceeds the respective thresh-

old, a status bit is set in one of the status registers. Two

open-drain outputs, OVERT and ALERT, assert corre-

sponding to these bits in the status register.

The 2-wire serial interface supports the standard system

management bus (SMBus™) protocols: write byte, read

byte, send byte, and receive byte for reading the tem-

perature data and programming the alarm thresholds.

The MAX6694 is specified for a -40°C to +125°C oper-

ating temperature range and is available in 16-pin

TSSOP and 5mm x 5mm thin QFN packages.

Applications

Desktop Computers

Notebook Computers

Workstations

Servers

Features

o Four Thermal-Diode Inputs

o Beta Compensation (Channel 1)

o Local Temperature Sensor

o 1.5°C Remote Temperature Accuracy (+60°C to

+100°C)

o Temperature Monitoring Begins at POR for Fail-

Safe System Protection

o ALERT and OVERT Outputs for Interrupts,

Throttling, and Shutdown

o STBY Input for Hardware Standby Mode

o Small, 16-Pin TSSOP and TQFN Packages

o 2-Wire SMBus Interface

MAX6694

5-Channel Precision Temperature Monitor

with Beta Compensation

________________________________________________________________

Maxim Integrated Products

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

GND

SMBCLK

SMBDATA

DXN2

DXP2

DXN1

DXP1

N.C.

STBYDXN4

DXP4

DXN3

DXP3

MAX6694

ALERT

OVERT

100pF

0.1µF

TO SYSTEM

SHUTDOWN

INTERRUPT

TO µP

DATA

CLK

4.7kΩ

EACH

+3.3V

CPU

Typical Application Circuit

19-4097; Rev 0; 4/08

SMBus is a trademark of Intel Corp.

Pin Configurations appear at end of data sheet.

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX6694UE9A+ -40°C to +125°C 16 TSSOP

MAX6694TE9A+ -40°C to +125°C 16 TQFN-EP*

Denotes a lead-free package.

EP = Exposed pad.

Note: Slave address is 1001 101.

Summary of content (18 pages)

PAGE 1
9-4097; Rev 0; 4/08 5-Channel Precision Temperature Monitor with Beta Compensation The MAX6694 precision multichannel temperature sensor monitors its own temperature and the temperatures of up to four external diode-connected transistors. All temperature channels have programmable alert thresholds. Channels 1 and 4 also have programmable overtemperature thresholds. When the measured temperature of a channel exceeds the respective threshold, a status bit is set in one of the status registers.
PAGE 2
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation ABSOLUTE MAXIMUM RATINGS VCC, SMBCLK, SMBDATA, ALERT, OVERT, STBY to GND ....................................................-0.3V to +6.0V DXP_ to GND..............................................-0.3V to (VCC + 0.3V) DXN_ to GND ........................................................-0.3V to +0.8V SMBDATA, ALERT, OVERT Current....................-1mA to +50mA DXIV_ Current .............................................................
PAGE 3
5-Channel Precision Temperature Monitor with Beta Compensation (VCC = +3.0V to +3.6V, VSTBY = VCC, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN High level, channel 1 Remote-Diode Source Current Undervoltage-Lockout Threshold IRJ UVLO TYP MAX Low level, channel 1 20 High level, channels 2, 3, 4 80 100 120 Low level, channels 2, 3, 4 8 10 12 2.30 2.80 2.
PAGE 4
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.0V to +3.6V, VSTBY = VCC, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.
PAGE 5
-Channel Precision Temperature Monitor with Beta Compensation SOFTWARE STANDBY SUPPLY CURRENT vs. SUPPLY VOLTAGE 3.5 3.4 3.3 550 500 450 3.2 MAX6694 toc03 2 CHANNEL 2 1 0 -1 -2 CHANNEL 1 -4 -5 350 3.2 3.3 3.4 3.5 3.6 3.0 3.2 3.4 SUPPLY VOLTAGE (V) LOCAL TEMPERATURE ERROR vs. DIE TEMPERATURE REMOTE-DIODE TEMPERATURE ERROR vs. POWER-SUPPLY NOISE FREQUENCY 2 1 0 -1 3 2 CHANNEL 2 1 0 -1 -2 -3 0 25 50 75 100 125 CHANNEL 1 0.010 0.100 1.000 10.
PAGE 6
5-Channel Precision Temperature Monitor with Beta Compensation MAX6694 Pin Description PIN TSSOP 6 TQFN-EP NAME FUNCTION 1 15 DXP1 Combined Current Source and A/D Positive Input for Channel 1 Remote Transistor. Connect to the emitter of a low beta transistor. Leave unconnected or connect to VCC if no remote transistor is used. Place a 100pF capacitor between DXP1 and DXN1 for noise filtering. 2 16 DXN1 Base Input for Channel 1 Remote Diode.
PAGE 7
5-Channel Precision Temperature Monitor with Beta Compensation The MAX6694 is a precision multichannel temperature monitor that features one local and four remote temperature-sensing channels with a programmable alert threshold for each temperature channel and a programmable overtemperature threshold for channels 1 and 4 (see Figure 1). Communication with the MAX6694 is achieved through the SMBus serial interface and a dedicated alert output.
PAGE 8
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation SMBus Digital Interface 350µA. During either software or hardware standby, data is retained in memory. During hardware standby, the SMBus interface is inactive. During software standby, the SMBus interface is active and listening for SMBus commands. The timeout is enabled if a start condition is recognized on SMBus. Activity on the SMBus causes the supply current to increase.
PAGE 9
5-Channel Precision Temperature Monitor with Beta Compensation tLOW B C tHIGH E D F G I H J K MAX6694 A M L SMBCLK SMBDATA tSU:STA tHD:STA 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. tHD:DAT tSU:STO tBUF J = ACKNOWLEDGE CLOCKED INTO SLAVE. K = ACKNOWLEDGE CLOCK PULSE. L = STOP CONDITION. M = NEW START CONDITION. F = ACKNOWLEDGE BIT CLOCKED INTO MASTER.
PAGE 10
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation can be read from the local temperature and remote temperature registers. The remaining 3 bits for remote diode 1 can be read from the extended temperature register. If extended resolution is desired, the extended resolution register should be read first. This prevents the most significant bits from being overwritten by new conversion results until they have been read.
PAGE 11
5-Channel Precision Temperature Monitor with Beta Compensation MAX6694 Table 3.
PAGE 12
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation Configuration Byte Functions There are three read-write configuration registers (Tables 4, 5, and 6) that can be used to control the MAX6694’s operation. Configuration 1 Register The configuration 1 register (Table 4) has several functions. Bit 7 (MSB) is used to put the MAX6694 either in software standby mode (STOP) or continuous conversion mode. Bit 6 resets all registers to their POR conditions and then clears itself.
PAGE 13
5-Channel Precision Temperature Monitor with Beta Compensation BIT NAME POR STATE 7 (MSB) STOP 0 Standby Mode Control Bit. If STOP is set to logic 1, the MAX6694 stops converting and enters standby mode. 6 POR 0 Reset Bit. Set to logic 1 to put the device into its power-on state. This bit is selfclearing. 5 TIMEOUT 0 Timeout Enable Bit. Set to logic 0 to enable SMBus timeout. 4 Reserved 0 Reserved. Must set to 0. 3 Resistance cancellation 1 Resistance Cancellation Bit.
PAGE 14
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation Table 7. Status 1 Register BIT NAME POR STATE 7 (MSB) Reserved 0 — 6 Local ALERT 0 Local Channel High-Alert Bit. This bit is set to logic 1 when the local temperature exceeds the temperature threshold limit in the local ALERT highlimit register. 5 Reserved 0 — 4 Reserved 0 — 3 Remote 4 ALERT 0 Channel 4 Remote-Diode High-Alert Bit.
PAGE 15
5-Channel Precision Temperature Monitor with Beta Compensation MAX6694 Table 9. Status 3 Register BIT NAME POR STATE 7 (MSB) Reserved 0 — 6 Reserved 0 Not Used. 0 at POR, then 1. 5 Reserved 0 Not Used. 0 at POR, then 1. 4 Diode fault 4 0 Channel 4 Remote-Diode Fault Bit. This bit is set to 1 when DXP4 and DXN4 are open circuit or when DXP4 is connected to VCC. 3 Diode fault 3 0 Channel 3 Remote-Diode Fault Bit.
PAGE 16
MAX6694 5-Channel Precision Temperature Monitor with Beta Compensation can be violated. The forward voltage at the highest expected temperature must be greater than 0.25V at 10µA, and at the lowest expected temperature, the forward voltage must be less than 0.95V at 100µA. Large power transistors must not be used. Also, ensure that the base resistance is less than 100Ω.
PAGE 17
;; @@ 5-Channel Precision Temperature Monitor with Beta Compensation Twisted-Pair and Shielded Cables Use a twisted-pair cable to connect the remote sensor for remote-sensor distances longer than 8in or in very noisy environments. Twisted-pair cable lengths can be between 6ft and 12ft before noise introduces excessive errors. For longer distances, the best solution is a shielded twisted pair like that used for audio microphones.
PAGE 18
TOP VIEW SMBDATA ALERT TOP VIEW 16 GND DXN1 2 15 SMBCLK 14 SMBDATA DXN3 6 11 OVERT DXP4 7 10 N.C. DXN4 8 9 8 7 MAX6694 6 5 16 + STBY N.C. STBY DXN4 DXP4 4 12 VCC 14 15 3 DXP3 5 13 SMBCLK GND DXP1 DXN1 2 13 ALERT 1 MAX6694 DXN2 4 DXP2 DXN2 DXP3 DXN3 DXP2 3 12 11 10 9 + DXP1 1 VCC OVERT Pin Configurations TSSOP TQFN-EP* *EXPOSED PAD. CONNECT EP TO GND. Package Information Chip Information PROCESS: BiCMOS For the latest package outline information, go to www.maxim-ic.