GMT G760A Datasheet
Global Mixed-mode Technology Inc.
Fan Speed PWM Controller
Features
Constant Fan Speed Control
PWM control for stable operation
Build-in MOSFET switch
SMBus interface
Internal short-circuit protection
On/Off control provided
Applications
Notebook PC
Industrial PC
LAN Switch
Servers
Telecom equipment
Industrial Control
G760A
General Description
G760 is a single chip solution for fan speed control,
packaged in a space saving SO-8 package. It connects directly to the fan and performs closed-loop
control of the fan speed. The only external component required is a 10µF capacitor. It determined the
current fan speed based on the fan rotation pulses
and an externally supplied clock. It uses pulse width
modulation (PWM) method and an on-chip
MOSFET to control the fan speed to ±2% of the
programmed speed. The desired fan speed is programmed via the SMBus. The actual fan speed and
fan status can be read via the SMBus. Short-circuit
protection is implemented to prevent damages to
the fan and this IC itself. An On/Off control pin is
also provided.
Ordering Information
Pin configuration
OUT
OUT
F.G.
F.G.
ON/OFF
ON/OFF
GND
GND
1
1
2
2
3
3
4
4
PART* TEMP. RANGE PIN-PACKAGE
G760A 0°C to +70°C 8-SOP
G760A
G760A
8Pin SOP
8Pin SOP
V
V
8
8
7
7
SMBDATA
SMBDATA
6
6
SMBCLKLK
SMBCLKLK
5
5
CLK
CLK
CC
CC
Ver 4.3
Oct 28, 2002
1
TEL: 886-3-5788833
http://www.gmt.com.tw
Global Mixed-mode Technology Inc.
G760A
Absolute Maximum Ratings
PARAMETER SYMBOL MAXIMUM UNITS
Supply Voltage VCC -0.3 to +7 V
Operating Temperature Range TA 0 to +70 °C
Junction Temperature Range TJ 0 to +125 °C
Storage Temperature Range T
-65 to +150 °C
STG
Lead Temperature (solding) 10 seconds TL 300 °C
Electrical Characteristics
(Unless specified: VCC = 5V, TA = 25°C)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Supply voltage VCC 4.5 5 5.5 V
Shutdown current On/Off = 0V 2 5 µA
MOSFET on resistance 0.2 0.25
Short-circuit current limit 0.5 A
Input logic low VIL 0.8 V
Input logic high VIH 2.4 V
Average Output current 350 mA
FG input Positive-going threshold voltage VCC=5V 1.8 V
FG input Negative-going threshold voltage VCC=5V 0.7 V
FG input Hysteresis voltage VCC=5V 1.1 V
Ω
Application Circuit
3.3V to 5V
5V
5V
10µF
10µF
3.3V to 5V
Diode 1N4148 is optional
Block Diagram
OUT
OUT
ON/OFF
ON/OFF
10k
V
V
IN
IN
FG
FG
FAN
FAN
*
*
1N4148
1N4148
FG
FG
ON/OFF
ON/OFF
10 µF
10 µF
FAN
FAN
CONTROL
CONTROL
LOGIC
LOGIC
1
1
2
2
3
3
4
4
8
8
7
7
6
6
5
5
PWM DUT Y
PWM DUT Y
LOGIC
LOGIC
SET_CNT
SET_CNT
ACT_CNT
ACT_CNT
32.768KHz
32.768KHz
10k
10k
10k
VCC
VCC
Ver 4.3
Oct 28, 2002
CLK
CLK
SMBus CONTROL
SMBus CONTROL
LOGIC
LOGIC
FAN_STA
FAN_STA
2
SMBDATA
SMBDATA
SMBCLK
SMBCLK
TEL: 886-3-5788833
http://www.gmt.com.tw
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