DataSheet39.com

What is G768D?

This electronic component, produced by the manufacturer "GMT", performs the same function as "Two Remote Temperature Sensors and One Fan Controller".


G768D Datasheet PDF - GMT

Part Number G768D
Description Two Remote Temperature Sensors and One Fan Controller
Manufacturers GMT 
Logo GMT Logo 


There is a preview and G768D download ( pdf file ) link at the bottom of this page.





Total 16 Pages



Preview 1 page

No Preview Available ! G768D datasheet, circuit

www.DataSheet4U.com
Global Mixed-mode Technology Inc.
G768D
Two Remote Temperature Sensors and One Fan Con-
troller with SMBus Serial Interface and System Reset
Circuit
Features
„Measures Two Remote Temperatures
„No Calibration Required
„SMBus 2-Wire Serial Interface
„Programmable Under/Over-temperature Alarms
„Programmable Thermal Shutdown Signal
„Supports SMBus Alert Response
„Accuracy: ±5°C (-40°C to + 125°C, remote)
±3°C (+60°C to + 100°C, remote)
„+4.5V to +5.5V Supply Range
„Fan speed control range: 3,000 to 30,000 rpm
„Fan speed accuracy: ±2%
„Built-in MOSFET switch
„Internal current-limit and over-temperature
protection for fan control
„Watchdog for fan control
„Alarm for fan failure
„Precision Monitoring of 5V Power-Supply
Voltage
„340ms Typical Power-On Reset Pulse Width
RESET Output
„Guaranteed RESET Valid to VCC=1V
„Power Supply Transient Immunity
„No External Components needed for reset
function
„Small, 16-Pin SSOP Package
Applications
„Desktop and Notebook
„Central Office Computers
„Telecom Equipment
„Smart Battery Packs
„Test and Measurement
„LAN Servers
„Multi-Chip Modules
„Industrial Controls
Pin Configuration
General Description
The G768D contains a precise digital thermometer, a
fan controller, and a system-reset circuit.
Except for one less fan controller, G768D is backward
compatible with G768B. G768D has 2 more functions,
fan-failure detection and programmable thermal shut-
down signal.
The thermometer reports the temperature of 2 remote
sensors. The remote sensors are diode-connected
transistors typically a low-cost, easily mounted
2N3904 NPN type that replace conventional thermis-
tors or thermocouples. Remote accuracy is ±5°C for
multiple transistor manufacturers, with no calibration
needed. The remote channel can also measure the die
temperature of other ICs, such as microprocessors,
that contain an on-chip, diode-connected transistor.
The 2-wire serial interface accepts standard System
Management Bus (SMBusTM) Write Byte, Read Byte,
Send Byte, and Receive Byte commands to program
the alarm thresholds and to read temperature data.
The data format is 7 bits plus sign, with each bit cor-
responding to 1°C, in two’s-complement format.
Measurements can be done automatically and
autonomously, with the conversion rate programmed
by the user or programmed to operate in a single-shot
mode. The adjustable rate allows the user to control
the supply-current drain.
G768D also contains a fan speed controller. It connects
directly to the fans and performs closed-loop control of
the fan speed independently. The only external compo-
nent required is a 10µF capacitor per channel. It deter-
mines the current fan speed based on the fan rotation
pulses and an externally supplied 32.768KHz clock.
Ordering Information
FANVCC 1
Vcc 2
DXP1 3
DXN 4
DXP2 5
RESET 6
DGND 7
AGND 8
G768D
16 TH_SHUT
15 Vcc
14 SMBCLK
13 NC
12 SMBDATA
11 ALERT
10 FG
9 CLK
PART NUMBER TEMP. RANGE PIN-PACKAGE
G768D
-55°C to +125°C
16SSOP
16Pin SSOP
Ver: 1.2
Apr 03, 2002
TEL: 886-3-5788833
http://www.gmt.com.tw
1

line_dark_gray
G768D equivalent
Global Mixed-mode Technology Inc.
Pin Description
G768D
PIN NAME
FUNCTION
1 FANVCC Output connected to VCC of fan.
2,15 VCC Supply Voltage Input, 4.5V to 5.5V. Bypass to GND with a 0.1µF capacitor.
Combined Current Source and A/D Positive Input for remote-diode channel 1. Do not leave DXP1 floating;
3 DXP1 tie DXP1 to DXN if no remote diode on channel 1 is used. Place a 2200pF capacitor between DXP1 and
DXN for noise filtering.
Combined Current Sink and A/D Negative Input. DXN is common negative node of both remote diodes on
4
DXN
channel 1 and 2. The traces of DXP1-DXN and DXP2-DXN pairs should be routed independently. The
common DXN should be connected together as close as possible to the IC. DXN is internally connected to
the GND pin for signal ground use.
Combined Current Source and A/D Positive Input for remote-diode channel 2. Do not leave DXP2 floating;
5 DXP2 tie DXP2 to DXN if no remote diode on channel 2 is used. Place a 2200pF capacitor between DXP2 and
DXN for noise filtering.
6 RESET RESET Output remains low while VCC is below the reset threshold, and for 340ms after VCC rises above
the reset threshold.
7 DGND Digital Ground.
8 AGND Analog Ground.
9 CLK 32.768KHz clock input for fan controller.
10 FG Fan pulse input.
11 ALERT SMBus Alert (interrupt) Output, open drain.
12 SMBDATA SMBus Serial-Data Input / Output, open drain.
13 NC
14 SMBCLK SMBus Serial-Clock Input.
16 TH_SHUT Thermal Shutdown Output, push-pull output.
Detailed Description
The G768D (patents pending) is a 3-in-1 IC. It consists
of one temperature sensor, 1 fan speed controller and
provides system-reset function.
The temperature sensor is designed to work in con-
junction with an external micro-controller (µC) or other
intelligence in thermostatic, process-control, or moni-
toring applications. The µC is typically a powerman-
agement or keyboard controller, generating SMBus se-
rial commands by "bit-banging" general-purpose in-
put-output (GPIO) pins or via a dedicated SMBus inter-
face block.
Essentially a 12-bit serial analog-to-digital converter
(ADC) with a sophisticated front end, the G768D con-
tains a switched current source, a multiplexer, an ADC,
an SMBus interface, one fan controller, a reset circuit
and associated control logic (Figure 1).
Temperature data from the ADC is loaded into two
data registers, where it is automatically compared with
data previously stored in four over/under-temperature
alarm registers.
ADC and Multiplexer
The ADC is an averaging type that integrates over a
60ms period (each channel, typical).
The multiplexer automatically steers bias currents
through two remote diodes, measures their forward
voltages, and computes their temperatures. All chan-
nels are converted automatically once the conversion
process has started, either in free-running or sin-
gle-shot mode. If one of the two channels is not used,
the device still performs all measurements, and the
user can simply ignore the results of the unused
channel. If the remote diode channel is unused, tie
DXPx to DXN rather than leaving the pins open.
The DXN input is internally connected to the ground
node inside the chip to set up the analog to digital
(A/D) inputs for a differential measurement. The
worst-case DXP-DXN differential input voltage range
is 0.25V to 0.95V.
Excess resistance in series with the remote diode causes
about +1/2°C error per ohm. Likewise, 200µV of offset
voltage forced on DXP-DXN causes about 1°C error.
Ver: 1.2
Apr 03, 2002
TEL: 886-3-5788833
http://www.gmt.com.tw
5


line_dark_gray

Preview 5 Page


Part Details

On this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for G768D electronic component.


Information Total 16 Pages
Link URL [ Copy URL to Clipboard ]
Download [ G768D.PDF Datasheet ]

Share Link :

Electronic Components Distributor


An electronic components distributor is a company that sources, stocks, and sells electronic components to manufacturers, engineers, and hobbyists.


SparkFun Electronics Allied Electronics DigiKey Electronics Arrow Electronics
Mouser Electronics Adafruit Newark Chip One Stop


Featured Datasheets

Part NumberDescriptionMFRS
G768The function is Remote/Local Temperature Sensor/ 2 Fan Controllers with SMBus Serial Interface and System Reset Circuit. ETCETC
G768BThe function is Remote/Local Temperature Sensor/ 2 Fan Controllers with SMBus Serial Interface and System Reset Circuit. ETCETC
G768DThe function is Two Remote Temperature Sensors and One Fan Controller. GMTGMT

Semiconductors commonly used in industry:

1N4148   |   BAW56   |   1N5400   |   NE555   |  

LM324   |   BC327   |   IRF840  |   2N3904   |  



Quick jump to:

G768     1N4     2N2     2SA     2SC     74H     BC     HCF     IRF     KA    

LA     LM     MC     NE     ST     STK     TDA     TL     UA    



Privacy Policy   |    Contact Us     |    New    |    Search