G781 Datasheet, PDF (1/1 Pages) List of Unclassifed Manufacturers – ±1°C Remote and Local Temperature Sensor with SMBus Serial Interface

Global Mixed-mode Technology
G781
±1°C Remote and Local Temperature Sensor with
SMBus Serial Interface
Features
„ Two Channels: Measures Both Remote and
Local Temperatures
„ No Calibration Required
„ Built-in Noise-Buster for Remote Sensor
„ SMBus 2-Wire Serial Interface
„ Programmable Under/Overtemperature Alarms
„ Supports SMBus Alert Response
„ Accuracy:
±1°C (+60°C to +100°C, remote)
±3°C (+60°C to + 100°C, local)
„ 320µA (typ) Average Supply Current During
Conversion
„ +3V to +5.5V Supply Range
„ Small 8-Lead SOP , MSOP and TDFN Package
„ Remote Temperature Measurment up to 160°C
by using offset shifting method (see “Measure
Remote Temperature Higher Than 127°C” sec-
tion)
Applications
Desktop and Notebook
Computers
Smart Battery Packs
LAN Servers
Industrial Controllers
Central Office
Telecom Equipment
Test and Measurement
Multi-Chip Modules
Ordering Information
ORDER NUMBER
(Pb free/Green)
G781f
G781P8f
G781RDf
G781-1f
G781-1P8f
G781-1RDf
MARKING
G781
G781
781
G781-1
G781-1
781-1
General Description
The G781 is a precise digital thermometer that reports
the temperature of both a remote sensor and its own
package. The remote sensor is a diode-connected tran-
sistor typically a low-cost, easily mounted 2N3904 NPN
type that replace conventional thermistors or thermo-
couples. Remote accuracy is ±1°C with no calibration
needed. It also has a build-in noise filtering function in
remote sensor measuring the diode temperature. The
remote channel can also measure the die temperature
of other ICs, such as microprocessors, that contain an
on-chip, diode-connected transistor.
The 2-wire serial interface accepts standard System
Management Bus (SMBus) Write Byte, Read Byte,
Send Byte, and Receive Byte commands to program
the alarm thresholds and to read temperature data.
The data format is 11bits plus sign, with each bit cor-
responding to 0.125°C, in two’s-complement format.
Measurements can be done automatically and
autonomously, with the conversion rate programmed
by the user or programmed to operate in a single-shot
mode. The adjustable rate allows the user to control
the supply current drain.
The G781 and G781-1 have the same functions but
different SMBus slave addresses. This allows for one
of each to be on the bus at the same time.
The G781 is available in a small, 8-pin SOP, MSOP
and TDFN surface-mount package.
TEMP.
RANGE
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
PACKAGE
SOP-8
MSOP-8
TDFN3X3-8
SOP-8
MSOP-8
TDFN3X3-8
Pin Configuration
VCC 1
DXP 2
DXN 3
THERM 4
G781/G781-1
8
7
6
5
SMBCLK
VCC
SMBDATA _DXP
ALERT ^DXN
THERM
GND
G781/G781-1
1
8 SMBCLK
2
7 SMBDATA
Thermal
3
Pad
6 ALERT
4
5 GND
SOP-8/MSOP-8
TDFN3X3-8
Typical Application Circuit
0.1µF
3V TO 5.5V
2N3904
VCC
DXP
SMBCLK
SMBDATA
DXN
2200pF
ALERT
THERM
GND
10kΩ EACH
CLOCK
DATA
INTERRUPT TO µC
Note: Recommend connecting the Thermal Pad to the GND or let it keep floating.
Ver: 2.4
Dec 28, 2012
1
TEL: [phone]
http://www.gmt.com.tw