G794 Datasheet, PDF (1/1 Pages) Global Mixed-mode Technology Inc – Two Remote and One Local Temperature Sensors and 3/4 Fan Controllers with SMBus Interface

Global Mixed-mode Technology Inc.
G793/G794
Two Remote and One Local Temperature Sensors
and 3/4 Fan Controllers with SMBus Interface
Features
„ Measures Two Remote and One Local Tem-
peratures
„ Adjustable Offset for Each Sensor via SMBus
„ Accuracy: Remote ±1°C (+20°C to +80°C)
±3°C (-10°C to +120°C)
„ +4.5V to +5.5V Supply Range
„ Alert Signal for Diode Fault, Fan Fail, and Fan
Out of Control
„ Supports SMBus Alert Response
„ Fan Drivers Using Linear Control Algorithm
„ Closed Loop Speed Control and programmable
8 Bits Open Loop Voltage Control for Fan
„ Wide speed control range for Fan, Accuracy
within 2%, when FANx_SET_CNT > 50
„ Internal Current-limit and Over-temperature
Protection for the Fan Controllers
„ Build-In Inverters for Driving Crystal
„ 20-Pin TSSOP Package
Applications
„ Projector, LCD TV, PDP TV
„ Desktop and Notebook
„ Central Office Computers
„ Telecom Equipments
„ Industrial Controls
„ LAN Servers
General Description
The G793/G794 contains 3 precise digital thermome-
ters, 3/4 fan controllers, fan failure detection.
The thermometers report the temperature of 2 remote
sensors and 1 local sensor. The remote sensors are di-
ode-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 manu-
facturer. Local accuracy is ±3°C. The G793/G794 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 72h for write and 73h for read.
G793/G794 contains 3/4 controllers. FAN controller per-
forms closed-loop and open-loop control. G793/G794
determines the current fan speed based on the FG inputs
and an externally supplied 32.768kHz clock. The driving
ability is 5mA. G793/G794 also provides ALERT for fan
fail and out of control event.
SMBus^TM is a trademark of Intel Corp
Ordering Information
ORDER
NUMBER
MARKING
TEMP.
RANGE
PACKAGE
(Green)
G793D5U
G793
-55°C to +125°C
TSSOP-20
G794D5U
G794
-55°C to +125°C
TSSOP-20
Note: D5: TSSOP-20
U: Tape & Reel
GMT Inc. does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and GMT Inc. reserves the right at
any time without notice to change said circuitry and specifications.
Pin Configuration
FAN2 1
FG2 2
FAN1 3
FG1 4
ALERT 5
AVCC 6
DXP1 ₇
SGND1 8
DXP2 9
SGND2 10
G793
TSSOP-20
20 FAN3
19 FG3
18 NC
17 NC
16 GND
15 DVCC
14 SCL
13 SDA
12 X2
11 X1/CLK
FAN2 1
FG2 ²
FAN1 3
FG1 ⁴
ALERT 5
AVCC ⁶
DXP1 7
SGND1 8
DXP2 9
SGND2 10
G794
TSSOP-20
20 FAN3
19 FG3
18 FAN4
17 FG4
16 GND
15 DVCC
14 SCL
13 SDA
12 X2
11 X1/CLK
Ver: 2.0
Oct 18, 2010
TEL: [phone]
http://www.gmt.com.tw
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