ADT7421ARMZ-REEL ON Semiconductor, ADT7421ARMZ-REEL Datasheet - Page 2

• Manufacturer Part Number: ADT7421ARMZ-REEL
• Description: IC TEMP MONITOR 8-MSOP
• Manufacturer: ON Semiconductor
• Type: Temperature Sensorr

Specifications of ADT7421ARMZ-REEL

• Input Type: Logic
• Output Type: Logic
• Interface: 2-Wire SMBus
• Current - Supply: 4mA
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Full Temp Accuracy: +/- 2.75 C, +/- 3.25 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Cancellation, where up to 50 W (typical) of resistance in
series with the temperature monitoring transistor can be
automatically cancelled from the temperature result,
allowing noise filtering.
resistance cancellation provides critical high accuracy
temperature sensing on 45 nm CPU’s and GPU’s.
thermal transistor accurate to ±1°C and the ambient
temperature accurate to ±1°C. The temperature measurement
range defaults to 0°C to +125°C, compatible with the
ADM1032, but it can be switched to a wider measurement
range of −40°C to +125°C.
PIN ASSIGNMENT
Pin No.
Another feature of the ADT7421 is Series Resistance
The combination of Beta cancellation and series
The ADT7421 can measure the temperature of a remote
D+
D–
1
2
3
4
5
6
7
8
2
3
TEMPERATURE
ANALOG
ON−CHIP
SENSOR
ADT7421
ALERT / THERM2
MUX
EXTERNAL DIODE OPEN−CIRCUIT
V
Mnemonic
1
DD
THERM
SDATA
SCLK
GND
V
D+
D−
DD
BUSY
CONVERTER
GND
A−TO−D
5
RUN/STANDBY
REMOTE TEMPERATURE
LOCAL TEMPERATURE
Positive Supply, 3.0 V to 3.6 V.
Positive Connection to Remote Temperature Sensor. (Anode)
Negative Connection to Remote Temperature Sensor. (Cathode)
Open-Drain Output. Can be used to turn a fan on/off or throttle a CPU clock in the event of an
overtemperature condition. Requires pullup resistor.
Supply Ground Connection.
Open-Drain Logic Output Used as Interrupt or SMBus ALERT. This can also be configured as a
second THERM output. Requires pullup resistor.
Logic Input/Output, SMBus Serial Data. Open-Drain Output. Requires pullup resistor.
Logic Input, SMBus Serial Clock. Requires pullup resistor.
CONVERSION RATE
VALUE REGISTER
REMOTE OFFSET
VALUE REGISTER
REGISTER
REGISTER
Figure 1. Block Diagram
http://onsemi.com
SDATA
STATUS REGISTER
7
2
SMBus INTERFACE
extended, switchable temperature measurement range.
interface, compatible with system management bus
(SMBus) standards. The default SMBus address of the
ADT7421 is 0x4C. An ADT7421−2 is available with a
SMBus address of 0x4D. This is useful if more than one
ADT7421 is used on the same SMBus.
temperature is out of range. The THERM output is a
comparator output that allows on/off control of a cooling
fan. The ALERT output can be reconfigured as a second
THERM output, if required.
The ADT7421 has a configurable ALERT output and an
The ADT7421 communicates over a 2−wire serial
An ALERT output signals when the on−chip or remote
SCLK
8
Description
REMOTE TEMPERATURE
REMOTE TEMPERATURE
EXTERNAL THERM LIMIT
LOCAL TEMPERATURE
LOCAL TEMPERATURE
HIGH−LIMIT REGISTER
HIGH−LIMIT REGISTER
LOW−LIMIT REGISTER
LOW−LIMIT REGISTER
LOCAL THERM LIMIT
ADDRESS POINTER
CONFIGURATION
REGISTERS
REGISTERS
REGISTERS
REGISTER
INTERRUPT
MASKING
6
4
ALERT/THERM2
THERM