MAX6642ATT90+T Maxim Integrated Products, MAX6642ATT90+T Datasheet - Page 7

• Manufacturer Part Number: MAX6642ATT90+T
• Description: IC TEMP SENSOR SMBUS 6-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX6642ATT90+T

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, 0°C ~ 150°C
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: No
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 6-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MAX6642ATT90+T; MAX6642ATT90+TTR

register was previously selected by a Write Byte
instruction. Use caution when using the shorter proto-
cols in multimaster systems, as a second master could
overwrite the command byte without informing the first
master.
Read temperature data from the read internal tempera-
ture (00h) and read external temperature (01h) regis-
ters. The temperature data format for these registers is
8 bits for each channel, with the LSB representing +1°C
(Table 1).
Read the additional bits from the read extended tem-
perature byte register (10h, 11h), which extends the
data to 10 bits and the resolution to +0.25°C per LSB
(Table 2).
When a conversion is complete, the main temperature
register and the extended temperature register are
updated.
Two registers store ALERT threshold values—one each
for the local and remote channels. If either measured
temperature equals or exceeds the corresponding
ALERT threshold value, the ALERT interrupt asserts
unless the ALERT bit is masked.
The power-on-reset (POR) state of the local ALERT
T
the remote ALERT T
A continuity fault detector at DXP detects an open cir-
cuit on DXP, or a DXP short to V
or short circuit exists, the external temperature register
is loaded with 1111 1111 and status bit 2 (OPEN) of the
status byte is set to 1. Immediately after POR, the status
register indicates that no fault is present. If a fault is
Figure 3. SMBus Read Timing Diagram
HIGH
Temperature Sensor with Overtemperature Alarm
SMBCLK
SMBDATA
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
register is +70°C (0100 0110). The POR state of
t
SU:STA
A
t
HD:STA
_______________________________________________________________________________________
HIGH
Alarm Threshold Registers
t
LOW
register is +120°C (0111 1000).
B
±1°C, SMBus-Compatible Remote/Local
t
HIGH
Diode Fault Detection
CC
t
SU:DAT
or GND. If an open
C
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO MASTER
H = LSB OF DATA CLOCKED INTO MASTER
D
E
F
present upon power-up, the fault is not indicated until
the end of the first conversion. Diode faults do not set
the ALERT output.
The ALERT interrupt occurs when the internal or external
temperature reading exceeds a high temperature limit
(user programmed). The ALERT interrupt output signal is
latched and can be cleared only by reading the status
register after the fault condition no longer exists or by
successfully responding to the alert response address. If
Table 1. Main Temperature Register
(High Byte) Data Format
Table 2. Extended Resolution
Temperature Register (Low Byte) Data
Format
t
Diode fault (short or open)
HD:DAT
FRACTIONAL TEMP (°C)
G
TEMP (°C)
130.00
127.00
126.00
<0.00
0.000
0.250
0.500
0.750
0.00
25
H
I = ACKNOWLEDGE CLOCK PULSE
J = STOP CONDITION
K = NEW START CONDITION
I
ALERT Interrupts
DIGITAL OUTPUT
DIGITAL OUTPUT
1 000 0010
0 111 1111
0 111 1110
0 001 1001
0 000 0000
0 000 0000
1 111 1111
00XX XXXX
01XX XXXX
10XX XXXX
11XX XXXX
t
SU:STO
J
t
BUF
K
7