GMT G7923 Three remote temperature sensors and one fan controllers with smbus serial interface and system reset circuit Datasheet

Global Mixed-mode Technology Inc.
G7923
Three Remote Temperature Sensors and One Fan
Controllers with SMBus Serial Interface and System
Reset Circuit
Features
General Description
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The G7923 contains 3 precise digital thermometers, one
fan controllers, hardware and software thermal shutdown,
and a system-reset circuit.
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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
The thermometers report the temperature of 3 remote
sensors. The remote sensors are diode-connected transistors 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 (SMBusTM) 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 performs closed-loop and open-loop control. G7923 determines the current fan speed based on the FG inputs and
an externally supplied 32.768kHz clock. The driving ability 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) supervisory circuit used to monitor the power supplies in
µP and digital systems. Reset threshold is set to
4.38V typical.
Applications
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Desktop and Notebook
Central Office Computers
Telecom Equipment
Smart Battery Packs
Industrial Controls
LAN Servers
Ordering Information
ORDER
NUMBER
MARKING
TEMP.
RANGE
PACKAGE
(Green)
G7923R51U
7923
-55°C to +125°C
TQFN4X4-24
Note: R5: TQFN4X4-24
1: Bonding Code
U: Tape & Reel
Ver: 1.0
Nov 03, 2009
1
TEL: 886-3-5788833
http://www.gmt.com.tw
G7923
Global Mixed-mode Technology Inc.
FG1
DVCC
FAN1
DVCC
SCL
N.C.
24
23
22
21
20
19
Pin Configuration
VCCS
1
18
SDA
DXN1
2
17
DGND
16
ALERT
15
CLK
DXP1
3
DXN2
4
DXP2
5
14
RESET
DXN3
6
13
X2
11
12
THERMTRIP
POWER_OK
9
10
8
N.C.
THERM_SET
THERM
7
DXP3
Thermal
Pad
G7923 TQFN4X4-24
Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.
SMBusTM is a trademark of Intel Corp.
Ver: 1.0
Nov 03, 2009
2
TEL: 886-3-5788833
http://www.gmt.com.tw
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