G7923 Datasheet, PDF (1/2 Pages) Global Mixed-mode Technology Inc – Three Remote Temperature Sensors and One Fan Controllers with SMBus Serial Interface and System Reset Circuit

Global Mixed-mode Technology Inc.
G7923
Three Remote Temperature Sensors and One Fan
Controllers with SMBus Serial Interface and System
Reset Circuit
Features
„ Measures Three Remote Temperatures
„ Adjustable Offset for Each Sensor via SMBus
„ Support Single-Core, Dual-Core and Quad-Core
CPU Application
„ Accuracy: ±1°C (+60°C to +100°C)
±3°C (-10°C to +120°C)
„ +4.5V to +5.5V Supply Range
„ Programmable Hardware Thermal Shutdown
for Sensor 3 and Programmable Software
Thermal Shutdown for Sensor 1, 2.
„ SMBus 2-Wire Serial Interface With Writting
Protection Function.
„ Alert Signal for Diode Fault, Fan Fail, and Fan
Out of Control
„ Supports SMBus Alert Response
„ Fan Drivers Using Linear Control Algorithm
with Built-in MOSFET
„ Closed Loop Speed Control and programmable
8 Bits Open Loop Voltage Control for Fan1
„ Wide speed control range for Fan1, Accuracy
within 2%, when SET_CNT1 > 50
„ Internal Current- limit and Over-temperature
Protection for the Fan
„ Reset Function Precision Monitoring of 5V
Power-Supply Voltage
„ Measure Thermal Diode with Transistor Model
„ Support 45nm, 65nm and 90nm CPU thermal
diode
„ Internal Clock 32768Hz, Accuracy ±3% from
25°C to 80°C at 5V VCC
„ Programmable to Use External Clock
„ TQFN4X4-24 Package
Applications
„ Desktop and Notebook
„ Central Office Computers
„ Telecom Equipment
„ Smart Battery Packs
„ Industrial Controls
„ LAN Servers
General Description
The G7923 contains 3 precise digital thermometers, one
fan controllers, hardware and software thermal shutdown,
and a system-reset circuit.
The thermometers report the temperature of 3 remote
sensors. The remote sensors are diode-connected tran-
sistors typically a low-cost, easily mounted 2N3904 NPN
type or the diode built-in in CPU. Remote accuracy is
±1°C for multiple transistor manufacturer. The G7923
also support offset adjust function via SMBus to fix the
error due to different CPU diode or parasitic resistors.
The 2-wire serial interface accepts standard System
Management Bus (SMBus^TM) Write Byte, Read Byte,
Send Byte, and Receive Byte commands. The SMBus
address is 7ah for write and 7bh for read, and supports
writting protection function by command 20h to prevent
error behavior of µP.
G7923 contains one fan controllers. FAN1 controller per-
forms closed-loop and open-loop control. G7923 deter-
mines the current fan speed based on the FG inputs and
an externally supplied 32.768kHz clock. The driving abil-
ity of FAN1 is 500mA. G7923 also provide ALERT for fan
fail and out of control event.
The G7923 provides hardware and software thermal
shutdown. The hardware thermal shutdown is for the
sensor 3. The trigger point is set by external resistors.
The trigger points of software thermal shutdown are set
via SMBus. If thermal shutdown event occurs, THERM
pin outputs low.
The G7923 contains a microprocessor (µP) super-
visory circuit used to monitor the power supplies in
µP and digital systems. Reset threshold is set to
4.38V typical.
Ordering Information
ORDER
NUMBER
G7923R51U
Note: R5: TQFN4X4-24
1: Bonding Code
U: Tape & Reel
MARKING
7923
TEMP.
RANGE
-55°C to +125°C
PACKAGE
(Green)
TQFN4X4-24
Ver: 1.0
Nov 03, 2009
1
TEL: [phone]
http://www.gmt.com.tw