Datasheet

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General Description

The MAX6636 precision multichannel temperature sen-

sor monitors its own temperature and the temperatures

of up to six external diode-connected transistors. All

temperature channels have programmable alert thresh-

olds. Channels 1, 4, 5, and 6 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 MAX6636 is specified for a -40°C to +125°C oper-

ating temperature range and is available in a 20-pin

TSSOP package.

Applications

Desktop Computers

Notebook Computers

Workstations

Servers

Features

♦ Six Thermal-Diode Inputs

♦ Local Temperature Sensor

♦ 1°C Remote Temperature Accuracy (+60°C to +100°C)

♦ Temperature Monitoring Begins at POR for Fail-

Safe System Protection

♦ ALERT and OVERT Outputs for Interrupts,

Throttling, and Shutdown

♦ STBY Input for Hardware Standby Mode

♦ Small, 20-Pin TSSOP Package

♦ 2-Wire SMBus Interface

♦ Penryn CPU-Compatible

♦ Pin- and Register-Compatible with MAX6689

MAX6636

7-Channel Precision Temperature Monitor

________________________________________________________________

Maxim Integrated Products

Ordering Information

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.

DXN4

DXP4

DXN3

DXP3

DXP6

DXN6DXN5

DXP5

MAX6636

ALERT

OVERT

STBY

2200pF

CPU

2200pF

GPU

0.1μF

TO SYSTEM

SHUTDOWN

INTERRUPT

TO μP

DATA

CLK

+3.3V

4.7kΩ

EACH

Typical Application Circuit

19-3004; Rev 0; 12/07

PART

PIN-

PACKAGE

SLAVE

ADDRESS

PKG CODE

MAX6636UP9A+ 20 TSSOP 1001 101 U20-2

SMBus is a trademark of Intel Corp.

Note: Device specified over the -40°C to +125°C temperature

range.

Denotes lead-free package.

Pin Configuration appears at end of data sheet.

Summary of content (18 pages)

PAGE 1
9-3004; Rev 0; 12/07 7-Channel Precision Temperature Monitor The MAX6636 precision multichannel temperature sensor monitors its own temperature and the temperatures of up to six external diode-connected transistors. All temperature channels have programmable alert thresholds. Channels 1, 4, 5, and 6 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
MAX6636 7-Channel Precision Temperature Monitor ABSOLUTE MAXIMUM RATINGS VCC, SCK, SDA, ALERT, OVERT, STBY to GND ......-0.3V to +6V DXP_ to GND..............................................-0.3V to (VCC + 0.3V) DXN2, DXN3, DXN4, DXN5, DXN6 to GND...........-0.3V to +0.8V SDA, ALERT, OVERT Current .............................-1mA to +50mA DXN Current .......................................................................±1mA Continuous Power Dissipation (TA = +70°C) 20-Pin TSSOP (derate 11.
PAGE 3
7-Channel Precision Temperature Monitor (VCC = +3.0V to +5.5V, VSTBY = VCC, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0.8 V SMBus INTERFACE (SCL, SDA), STBY Logic-Input Low Voltage VIL Logic-Input High Voltage VIH VCC = 3.0V 2.2 VCC = 5.0V 2.4 Input Leakage Current V -1 Output Low Voltage VOL Input Capacitance CIN +1 ISINK = 6mA 0.
PAGE 4
Typical Operating Characteristics (VCC = 3.3V, VSTBY = VCC, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 7 6 5 4 3 2 1 350 345 340 335 330 320 4.3 4.8 3.8 4.3 4.8 5.3 5 MAX6636 toc04 75 2 1 0 -1 -2 100mVP-P 4 3 TEMPERATURE ERROR (°C) 3 2 1 0 -1 -2 -3 -3 -4 -4 -5 0 25 50 75 100 125 0.1 1 DIE TEMPERATURE (°C) FREQUENCY (MHz) LOCAL TEMPERATURE ERROR vs. POWER-SUPPLY NOISE FREQUENCY REMOTE TEMPERATURE ERROR vs.
PAGE 5
7-Channel Precision Temperature Monitor REMOTE TEMPERATURE ERROR vs. COMMON-MODE NOISE FREQUENCY 0 3 2 1 0 -1 -2 -3 MAX6636 toc09 100mVP-P -0.5 TEMPERATURE ERROR (°C) TEMPERATURE ERROR (°C) 4 MAX6636 toc08 5 TEMPERATURE ERROR vs. DXP-DXN CAPACITANCE -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4 -4.5 -5 0.001 -5.0 0.01 0.
PAGE 6
7-Channel Precision Temperature Monitor MAX6636 Pin Description (continued) PIN NAME FUNCTION 9 DXP5 Combined Current Source and A/D Positive Input for Channel 5 Remote Diode. Connect to the anode of a remote-diode-connected temperature-sensing transistor. Leave unconnected or connect to VCC if no remote diode is used. Place a 2200pF capacitor between DXP5 and DXN5 for noise filtering. 10 DXN5 Cathode Input for Channel 5 Remote Diode.
PAGE 7
-Channel Precision Temperature Monitor MAX6636 VCC DXP1 MAX6636 ADC DXN1 DXP2 10/100μA ALARM ALU DXN2 OVERT AVERT DXP3 DXN3 COUNT INPUT BUFFER DXP4 REGISTER BANK COMMAND BYTE COUNTER REMOTE TEMPERATURES DXN4 LOCAL TEMPERATURES REF DXP5 ALERT THRESHOLD OVERT THRESHOLD DXN5 ALERT RESPONSE ADDRESS DXP6 SMBus INTERFACE DXN6 STBY SCL SDA Figure 1. Internal Block Diagram ed, and the temperature registers are not updated. The previous data is not changed and remains available.
PAGE 8
MAX6636 7-Channel Precision Temperature Monitor WRITE BYTE FORMAT S ADDRESS WR ACK COMMAND 7 BITS ACK DATA 8 BITS ACK P 8 BITS SLAVE ADDRESS: EQUIVALENT TO CHIP-SELECT LINE OF A 3-WIRE INTERFACE 1 DATA BYTE: DATA GOES INTO THE REGISTER SET BY THE COMMAND BYTE (TO SET THRESHOLDS, CONFIGURATION MASKS, AND SAMPLING RATE) READ BYTE FORMAT S ADDRESS WR ACK 7 BITS COMMAND ACK S SLAVE ADDRESS: EQUIVALENT TO CHIP-SELECT LINE ADDRESS RD COMMAND BYTE: SELECTS WHICH REGISTER YOU ARE REDING F
PAGE 9
7-Channel Precision Temperature Monitor B tLOW C D E F G H tHIGH I J K L MAX6636 A M 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 SLAVE. H = LSB OF DATA CLOCKED INTO SLAVE. tBUF I = MASTER PULLS DATA LINE LOW. J = ACKNOWLEDGE CLOCKED INTO SLAVE.
PAGE 10
MAX6636 7-Channel Precision Temperature Monitor ALERT Response Address The SMBus alert response interrupt pointer provides quick fault identification for simple slave devices that lack the complex logic needed to be a bus master. Upon receiving an interrupt signal, the host master can broadcast a receive byte transmission to the alert response slave address (see the Slave Address section). Then, any slave device that generated an interrupt attempts to identify itself by putting its own address on the bus.
PAGE 11
7-Channel Precision Temperature Monitor MAX6636 Table 3.
PAGE 12
MAX6636 7-Channel Precision Temperature Monitor Table 4. Configuration 1 Register BIT NAME POR STATE 7 (MSB) STOP 0 Standby-Mode Control Bit. If STOP is set to logic 1, the MAX6636 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 Fast remote 1 0 Channel 1 Fast-Conversion Bit.
PAGE 13
7-Channel Precision Temperature Monitor BIT NAME POR STATE FUNCTION 7 (MSB) Reserved 0 — 6 Reserved 0 — 5 Mask OVERT 6 0 Channel 6 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 6 OVERT. 4 Mask OVERT 5 0 Channel 5 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 5 OVERT. 3 Mask OVERT 4 0 Channel 4 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 4 OVERT. 2 Reserved 0 — 1 Reserved 0 — 0 Channel 1 Remote-Diode OVERT Mask Bit.
PAGE 14
MAX6636 7-Channel Precision Temperature Monitor 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 Remote 6 ALERT 0 Channel 6 Remote-Diode High-Alert Bit.
PAGE 15
7-Channel Precision Temperature Monitor BIT NAME POR STATE FUNCTION 7 (MSB) Reserved 0 — 6 Reserved 0 — 5 Remote 6 OVERT 0 Channel 6 Remote-Diode Overtemperature Status Bit. This bit is set to logic 1 when the channel 6 remote-diode temperature exceeds the temperature threshold limit in the remote 6 OVERT high-limit register. 4 Remote 5 OVERT 0 Channel 5 Remote-Diode Overtemperature Status Bit.
PAGE 16
MAX6636 7-Channel Precision Temperature Monitor ADC Noise Filtering The integrating ADC has good noise rejection for lowfrequency signals, such as power-supply hum. In environments with significant high-frequency EMI, connect an external 2200pF capacitor between DXP_ and DXN_. Larger capacitor values can be used for added filtering, but do not exceed 3300pF because it can introduce errors due to the rise time of the switched current source.
PAGE 17
7-Channel Precision Temperature Monitor Chip Information TOP VIEW + DXP1 1 20 GND DXN1 2 19 SMBCLK DXP2 3 18 SMBDATA DXN2 4 17 ALERT DXP3 5 MAX6636 16 VCC DXN3 6 15 OVERT DXP4 7 14 N.C.
PAGE 18
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.) TSSOP4.40mm.EPS MAX6636 7-Channel Precision Temperature Monitor PACKAGE OUTLINE, TSSOP 4.40mm BODY 21-0066 I 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.