MAX6655_06 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – Dual Remote/Local Temperature Sensors and Four-Channel Voltage Monitors

19-2117; Rev 1; 5/06
Dual Remote/Local Temperature Sensors and
Four-Channel Voltage Monitors
General Description
The MAX6655/MAX6656 are precise voltage and tem-
perature monitors. The digital thermometer reports the
temperature of two remote sensors and its own die tem-
perature. The remote sensors are diode-connected
transistors—typically a low-cost, easily mounted
2N3906 PNP type—that replace conventional thermis-
tors or thermocouples. Remote accuracy is ±1°C for
multiple transistor manufacturers with no calibration
necessary. The remote channels can also measure the
die temperature of other ICs, such as microprocessors,
that contain a substrate-connected PNP with its collec-
tor grounded and its base and emitter available for tem-
perature-sensing purposes. The temperature is
digitized with 11-bit resolution.
The MAX6655/MAX6656 also measure their own supply
voltage and three external voltages with 8-bit resolution.
Each voltage input’s sensitivity is set to give approxi-
mately 3/4-scale output code when the input voltage is
at its nominal value. The MAX6655 operates at +5V
supply and its second voltage monitor is 3.3V. The
MAX6656 operates on a +3.3V supply and its second
voltage monitor is 5V.
The 2-wire serial interface accepts standard SMBus™
Write Byte, Read Byte, Send Byte, and Receive Byte
commands to program the alarm thresholds and to read
data. The MAX6655/MAX6656 also provide SMBus alert
response and timeout functions. The MAX6655/MAX6656
measure automatically and autonomously, with the con-
version rate programmable. The adjustable rate allows
the user to control the supply current.
In addition to the SMBus ALERT output, the MAX6655/
MAX6656 feature an OVERT output, which is used as a
temperature reset that remains active only while the
temperature is above the maximum temperature limit.
The OVERT output is optimal for fan control or for sys-
tem shutdown.
Applications
Notebooks
Thin Clients
Servers
Workstations
Communication
Equipment
Desktop PC
S.
*P,
Is
ae
c-
SMBus is a trademark of Intel Corp.
Features
♦ Three Temperature Channels
Two Remote PN Junctions
One Local Sensor
♦ Four Voltage Channels
+12V, +5V, +3.3V, +2.5V
Three External Monitors
One Internal Supply Monitor
♦ 11-Bit, 0.125°C Resolution
♦ High Accuracy: ±1°C Over +60°C to +100°C
Temperature Range
♦ Programmable Under/Over-Threshold Alarms
♦ Programmable Power-Saving Mode
♦ No Calibration Required
♦ SMBus/I²C-Compatible Interface
♦ OVERT Output for Fan Control and System
Shutdown
Ordering Information
PART
MAX6655MEE
MAX6656MEE
TEMP RANGE
-55°C to +125°C
-55°C to +125°C
PIN-
PACKAGE
16 QSOP
16 QSOP
PKG
CODE
E16-5
E16-5
Typical Application Circuit appears at end of data sheet.
Pin Configuration
TOP VIEW
V_CC 1
DXP1 2
DXN1 3
ADD0 4
ADD1 5
DXP2 6
DXN2 7
GND 8
MAX6655
MAX6656
QSOP
16 STBY
15 SMBCLK
14 OVERT
13 SMBDATA
12 ALERT
11 V_IN2
10 V_IN1
9 V_IN3
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