G7951 Global Mixed-mode Technology Inc. Three Remote Temperature Sensors and One PWM Mode Fan Controllers with SMBus Serial Interface Features General Description Measures Three Remote Temperatures Adjustable Offset for Each Sensor via SMBus 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 2 and Programmable Software Thermal Shutdown for Sensor 1,3. 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 The G7951 contains 3 precise digital thermometers, one fan controllers, hardware and software thermal shutdown. PWM Mode Speed Control The 2-wire serial interface accepts standard System Management Bus (SMBusTM) Write Byte, Read Byte, Send Byte, and Receive Byte commands. G7951 SMBus address is 7ah for write and 7bh for read. And supports writting protection function by command 20h to prevent error behavior of µP. 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 G7951 also support offset adjust function via SMBus to fix the error due to different CPU diode or parasitic resistors. Closed Loop Speed Control and programmable 8 Bits Open Loop PWM Duty cycle Control for FAN Wide Speed Control Range for FAN, Accuracy within 2%, when SET_CNT1 > 50 Internal Current- limit and Over-temperature Protection for the Fan SSOP-16 & TQFN4X4-24 Package G7951 contains one PWM mode fan controllers. FAN controller performs closed-loop and open-loop control. G7951 determines the current fan speed based on the FG inputs and an externally supplied 32.768kHz clock. G7951 also provide ALERT for fan fail and out of control event. Applications Desktop and Notebook Central Office Computers Telecom Equipment Smart Battery Packs Industrial Controls LAN Servers The G7951 provides hardware and software thermal shutdown. The hardware thermal shutdown is for the sensor 2. The trigger point is set external resistors. The trigger points of software thermal shutdown are set via SMBus. If thermal shutdown event occurs, THERM pin outputs low. 5 12 ALERT DXP1 6 11 CLK SGND1 7 10 THERM DP2DN3 8 9 DN2DP3 DVCC NC NC 20 19 FOUT 16 SDA VCC 4 DXP1 SGND1 Thermal Pad 15 ALERT 5 14 CLK 6 13 THERM 12 VCC 3 NC SDA SCL GND 11 13 4 SCL NC 17 NC 14 18 2 9 GND 3 1 FG 10 FG THERM_SET NC DVCC NC 15 22 NC 2 24 THERM_SET 8 FOUT 7 16 DP2DN3 1 DN2DP3 NC 23 NC G7951 21 Pin Configuration G7951 TQFN4X4-24 SSOP-16 Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation. SMBusTM is a trademark of Intel Corp. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Oct 18, 2010 1 Global Mixed-mode Technology Inc. G7951 Ordering Information ORDER NUMBER MARKING TEMP. RANGE PACKAGE (Green) G7951S11U G7951 -55°C to +125°C SSOP-16 G7951R51U 7951 -55°C to +125°C TQFN4X4-24 Note:S1:SSOP-16 R5: TQFN4X4-24 1: Bonding Code U: Tape & Reel TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Oct 18, 2010 2