MAX6638 Datasheet, PDF (1/19 Pages) Maxim Integrated Products – Temperature Monitor with Dual Serial Interface

19-3895; Rev 1; 1/06
Temperature Monitor with
Dual Serial Interface
General Description
The MAX6638 thermal-management sensor includes
internal (local) and external (remote) digital temperature
sensors and two independent SMBus™ serial ports. The
remote temperature accuracy is ±1.0°C, and the local
temperature accuracy is ±2°C. The MAX6638 also fea-
tures extended temperature resolution data available in
0.125°C increments.
The MAX6638 provides three system alarms: channel 1
alert (ALERT1), overtemperature (OVERT1), and chan-
nel 2 alert (ALERT2) that contain programmable thresh-
olds set independently by each of the SMBus serial
ports (SMBus1 and SMBus2). Each alert output asserts
when any of four temperature conditions is violated:
local overtemperature, remote overtemperature, local
undertemperature, or remote undertemperature. The
overtemperature signal asserts when the temperature
rises above the value in the overtemperature limit regis-
ter. Use the OVERT1 output to activate a cooling fan or
trigger a system shutdown.
Each of the 2-wire serial-interface ports accepts stan-
dard System Management Bus (SMBus) write byte, read
byte, send byte, and receive byte commands indepen-
dently of one another with total collision avoidance han-
dled by the MAX6638. Each SMBus can operate its own
unique serial-data rate to access any register in the
MAX6638 for data reads or data writes. The MAX6638
manages all dual-port data register access functions
providing a seamless, conflict-free integration into a
multimaster architecture for thermal management.
The MAX6638 performs measurements autonomously,
at the programmed conversion rate, or in a single-con-
version mode. Each SMBus port can set the conversion
rate with the higher conversion and update rate domi-
nating the average power-supply current. Single-con-
version requests have a maximum delay of two
conversion cycles with channel-conversion manage-
ment and cycling regulated by the dual-port controller.
The MAX6638 operating temperature range is -40°C to
+125°C and measures temperatures between 0°C and
+145°C. The MAX6638 is available in a 16-pin, 4mm x
4mm TQFN with exposed paddle package.
Graphics Cards
Applications
Notebook Computers
Computer Motherboard Systems
Desktop Computers
Workstations
Features
♦ Two Independent SMBus/I²C*-Compatible
Interfaces with Collision Avoidance
♦ High Accuracy
±1.0°C from +85°C to +100°C (Remote)
♦ Remote and Local Temperature Measurements
♦ Three Programmable Output Alarms: ALERT1,
OVERT1, and ALERT2
♦ Programmable Conversion Rates
♦ 11-Bit Low-Noise Integrating ADC
♦ No Calibration Required
♦ Autoscan Conversions
Ordering Information
PART
TEMP
RANGE
PIN-
PACKAGE
16 TQFN-EP*
MAX6638ATE+ -40°C to +125°C _{(4mm x 4mm)}
PKG
CODE
T1644-4
*EP = Exposed paddle.
+Denotes lead-free package.
Pin Configuration
TOP VIEW
12 11 10 9
N.C. 13
ALERT2 14
SDA2 15
MAX6638
SCK2 16 ₊
1
2
3
4
8 GND
7 N.C.
6 I.C.
5 N.C.
TQFN-EP
Typical Operating Circuit appears at end of data sheet.
SMBus is a trademark of Intel Corporation.
*Purchase of I²C components from Maxim Integrated Products,
Inc., or one of its sublicensed Associated Companies, conveys
a license under the Philips I²C Patent Rights to use these com-
ponents in an I²C system, provided that the system conforms to
the I²C Standard Specification as defined by Philips.
________________________________________________________________ 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.