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Global Mixed-mode Technology Inc.
G751
Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface
General Description Features
SMBus interface Programmable Trip Point (TOS) and Hysteresis (THYST) Separate open-drain output pin operates as interrupt or comparator at output Register readback capability Power up defaults permit stand-alone operation as thermostat Shutdown mode to minimize power consumption Up to 8 G751s can be connected to a single bus The G751 is a temperature sensor, Delta-Sigma analog-to-digital converter, and digital over- temperature detector with SMBus interface. The host can query the G751 at any time to read temperature. The open-drain Over temperature Shutdown (O.S.) output becomes active when the temperature exceeds a programmable limit. This pin can operate in either "Comparator" or "Interrupt" mode. The host can program both the temperature alarm threshold (TOS) and the temperature at which the alarm condition goes away (THYST). In addition, the host can read back the contents of the G751's TOS and THYST registers. The sensor powers up in Comparator mode with default thresholds of 50C TOS 45C THYST. for G751-1 and 80C TOS , 75C THYST for G751-2.
Key Specifications
Supply Voltage Supply Current operating 3.0V to 5.5V 280A (typ) 1mA (max) 2A(typ) 2C (max) 3C (max)
shutdown Temperature Accuracy -25C to 100C -55C to 125C
Ordering Information
PART TOS THYST Transport Media PACKAGE
8 SOP 8 SOP G751-1 50C/45C 2500 Units on Tape and Reel G751-2 80C /75C 2500 Units on Tape and Reel
Applications
System Thermal Management Personal Computers Office Electronics Electronic Test Equipment
Pin Configuration
Typical Application
+VS 3V to 5.5V Typical Bypass 0.1 F (Unless mounted close to Processor)
G751
7 SMBDATA SMBCLK O.S. GND 1 2 3 4 8 7 6 5 +Vs A0 A1 A2 Address(Set as desired) A0 A1 A2 1 SMBDATA Interface 2 SMBCLK 6 5
8
G751
To Processor O.S. Out Interrupt Line
3
8Pin SOP
4
O.S. Set for active low for wire OR'd multiple interrupt line
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Global Mixed-mode Technology Inc.
Absolute Maximum Ratings.
Supply Voltage..................................-0.3V to 6.5V Voltage at any Pin......................-0.3V to +Vs +0.3V Input Current at any Pin..................................5mA Package Input Current..................................20mA O.S. Output Sink Current...............................10mA O.S. Output Voltage.......................................6.5V Storage Temperature.....................-65C to +150C Soldering Information, Lead Temperature SOP Package Vapor Phase (60 seconds)............................215C Infrared (15 seconds)...................................220C ESD Susceptibility Human Body Model.....................................2000V Machine Model.............................................200V
G751
Operating Ratings
Specified Temperature Range................TMIN to TMAX -55C to +125C Supply Voltage Range (+Vs)..............+3.0V to +5.5V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for +Vs=+3.3v Vdc. Boldface limits apply for TA=TJ=TMIN to TMAX; all other limits TA=TJ= +25C, unless otherwise noted. PARAMETER
Accuracy Resolution Temperature Conversion Time Quiescent Current
CONDITIONS
TA=-25C to +100C TA=-55C to +125C
TYPICAL
LIMITS 2.0 3.0
UNITS
C (max) Bits Ms Ma mA (max) A V (max) Conversions (min) Conversions (max) C C
9 100 SMBus Inactive SMBus Active Shutdown Mode IOUT = 4.0mA
0.25
1.0 1 0.8 1 6 50/80 45/75
O.S. Output Saturation Voltage O.S. Delay TOS Default Temperature G751-1/G751-2 THYST Default Temperature G751-1/G751-2
Block Diagram
8 +VS 3.0V - 5.5V
Temperature
3
Threshold 9-Bit Delta-Sigma Analog-to-Digital Converter TOS Set Point Register Set Point Comparator Reset
O.S.
Silicon Bandgap Temperature Sensor
Configuration Register
Pointer Register
T HYST Set Point Register
A0 A1 A2
7 6 5
1
Two-Wire Interface
2
SMBDATA SMBCLK
4
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Global Mixed-mode Technology Inc.
Logic Electrical Characteristics
G751
Digital DC Characteristics Unless otherwise noted, these specifications apply for +Vs=+3.3 Vdc. Boldface limits apply for TA=TJ=TMIN to TMAX; all other limits TA=TJ=+25C, unless otherwise noted. SYMBOL PARAMETER CONDITIONS TYPICAL LIMITS UNITS
VIN (1) VIN (0) IIN (1) IIN (0) CIN IOH VOL tOF Logical "1" Input Voltage Logical "0" Input Voltage Logical "1"Intput Current Logical "0"Intput Current All Digital Inputs High Level Output Current Low Level Output Voltage Output Fall Time VIN=5V VIN=0V VOH=5V IOL=3ma CL=400pF,IO=3ma 0.005 -0.005 20 +Vsx 0.7 x +Vs + 0.5 -0.3 +Vsx0.3 x 1.0 -1.0 100 0.4 250 V (min) V (max) V (min) V (max) A A PF A (max) V (max) ns (max)
SMBus Digital Switching Characteristics Unless otherwise noted, these specifications apply for +Vs = +3.3 Vdc and CL (load capacitance) on output lines = 80pF unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25C, unless otherwise noted. The switching characteristics of the G751 fully meet or exceed the published specifications of the SMBus. The following parameters are the timing relationships between SMBCLK and SMBDATA signals related to the G751. They are not the SMBus specifications. SYMBOL
t1 t2 t3 t4 t5
PARAMETER
SMBCLK (Clock) Period Data in Set-Up Time to SMBCLK High Data Out Stable after SMBCLK Low SMBDATA Low Set-Up Time to SMBCLK Low (Start Condition) SMBDATA High Hold Time after SMBCLK High (Stop Condition)
CONDITIONS TYPICAL
LIMITS
2.5 100 0 100 100
UNITS
s (min) ns (min) ns (min) ns (min) ns (min)
Pin Description
PIN LABEL FUNCTION TYPICAL CONNECTION
From Controller From Controller Pull Up Resistor, Controller Interrupt Line Ground Ground (Low, "0") or +Vs (High, "1") DC Voltage from 3V to 5.5V 1 SMBDATA SMBus Serial Bi-Directional Data Line 2 SMBCLK SMBus Clock Input 3 O.S. Overtemperature Shutdown Open Drain Output 4 GND Power Supply Ground 5,6,7 A0-A2 User-Set SMBus Address Inputs 8 +Vs Positive Supply Voltage Input
t1 SMBCLK
SMBDATA Data in
t4
t5
t2 SMBDATA Data out
t3
Logic Electrical Characteristics
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Global Mixed-mode Technology Inc.
G751
0,1111,1010 Output Code
+25C
+0.5C 0,0011,0010 0,0000,0001 Temperature 0,0000,0000 0C -55C 1,1111,1111 1,1100,1110 -0.5C +125C
-25C
1,1001,0010
Temperature-to-Digital Transfer Function (Non-linear scale for clarity)
Functional Description
The G751 temperature sensor incorporates a band-gap type temperature sensor and 9-bit ADC (Delta-Sigma Analog- to-Digital Converter). The temperature data output of the G751 is available at all times via the SMBus. If a conversion is in progress, it will be stopped and restarted after the read. A digital comparator is also incorporated that compares a series of readings, the number of which is user-selectable, to user-programmable setpoint and hysteresis values. The comparator trips the O.S. output line, which is programmable for mode and polarity. O.S. Output, TOS and THYST Limits In Comparator mode the O.S. Output behaves like a thermostat. The output becomes active when temperature exceeds the TOS limit, and leaves the active state when the temperature drops below the THYST limit. In this mode the O.S. output can be used to turn a cooling fan on, initiate an emergency system shutdown, or reduce system clock speed. Shutdown mode does not reset O.S. state in a comparator mode. In interrupt mode exceeding TOS also makes O.S. active but O.S. will remain active indefinitely until reset by reading any register via the SMBus interface. Once O.S. has been activated by crossing TOS, then reset, it can activated again only by Temperature going below THYST. Again, it will remain active indefinitely until being reset by a read. Placing the G751 in shutdown mode also resets the O.S. output.
Default Modes G751 always powers up in a known state. G751 power up default conditions are: 1. Comparator mode 2. TOS set to 50C for G751-1, to 80C for G751-2 3. THYST set to 45C for G751-1, to 75C for G751-2 4. O.S. active low 5. Pointer set to "00"; Temperature Register With these operating conditions G751 can act as a stand-alone thermostat with the above temperature settings. Connection to an SMBus is not required. SMBus Interface The G751 operates as a slave on the SMBus, so the SMBCLK line is an input (no clock is generated by the G751) and the SMBDATA line is a bi-directional serial data path. According to SMBus specifications, the G751 has a 7-bit slave address. The four most significant bits of the slave address are hard wired inside the G751 and are "1001". The three least significant bits of the address are assigned to pins A2-A0, and are set by connecting these pins to ground for a low, (0); or to +Vs for a high, (1). Therefore, the complete slave address is: 1
MSB
0
0
1
A2
A1
A0
LSB
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*
G751
*
*read any register or placed in shut down
Shutdown Mode Shutdown mode is enabled by setting the shutdown bit in the Configuration register via the SMBus. Shutdown mode reduces power supply current to 1 A typical. In interrupt mode O.S. is reset if previously set and is undefined in Compatator mode during shutdown. The SMBus interface remains active. Activity on the clock and data lines of the SMBus may slightly increase shutdown mode quiescent current. TOS, THYST, and Configuration registers can be read from and written to in shutdown mode. Fault Queue A fault queue of up to 6 faults is provided to prevent false tripping of O.S. when the G751 is used in noisy environments. The number of faults set in the queue must occur consecutively to set the O.S. output. Comparator/Interrupt Mode As indicated in the O.S. Output Temperature Response Diagram, Figure 1, the events that trigger O.S. are identical for either Comparator or Interrupt mode. The most important difference is that in Interrupt mode the O.S. will remain set indefinitely once it has been set. To reset O.S. while in Interrupt mode, perform a read from any register in the G751. O.S. Output The O.S. output is an open-drain output and does not have an internal pull-up. A "high" level will not be observed on this pin until pull-up current is provided from some external source, typically a pull-up resistor. Choice of resistor value depends on many system factors but, in general, the pull-up resistor should be as large as possible. This will minimize any errors due to internal heating of the G751. The maximum resistance of the pull up, based on G751 specification for High Level Output Current, to provide a 2V high level, is 30k. O.S. Polarity The O.S. output can be programmed via the configuration register to be either active low (default mode), or active high. In active low mode the O.S. output goes low when triggered exactly as shown on the O.S. Output Temperature Response Diagram, Figure 1. Active high simply inverts the polarity of the O.S. output.
*
O.S.
(Comparator Mode)
O.S.
Figure1 O.S. Output Temperature Response Diagram Temperature Data Format Temperature data can be read from the Temperature, TOS Set Point, and THYST Set Point registers; and written to the TOS Set Point, and THYST Set Point registers. Temperature data is represented by a 9-bit, two's complement word with an LSB (Least Significant Bit) equal to 0.5C: TEMPERATURE +125C +25C +0.5C 0C -0.5C -25C -55C DIGITAL OUTPUT BINARY HEX 0 1111 1010 0FAh 0 0011 0010 032h 0 0000 0001 001h 0 0000 0000 000h 1 1111 1111 1FFh 1 1100 1110 1CEh 1 1001 0010 192h
(Interrupt Mode)
THYST
Temperature response Shown for O.S. set for active low.
TOS
Time
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Internal Register Structure
SMBDATA SMBCLK Data Interface
G751
Address
Pointer Register (Selects register for communication Register Select Temperature (Read-only) Pointer = 00000000 Configuration (Read-write, sets operating Mode) Pointer = 00000001
TOS Set Point (Read-write) Pointer = 00000011
THYST Set Point (Read-write) Pointer = 00000010
There are four data registers in the G751, selected by the Pointer register. At power-up the Pointer is set to "00"; the location for the Temperature Register. The Pointer register latches whatever the last location it was set to. In Interrupt Mode, a read from the G751, or placing the device in shutdown mode, resets the O.S. output. All registers are read and write, except the Temperature register which is read only. A write to the G751 will always include the address byte and the Pointer byte. A write to the Configuration register requires one data byte, and the TOS and THYST registers require two data bytes. Reading the G751 can take place either of two ways: If the location latched in the Pointer is correct (most of the time it is expected that the Pointer will point to Temperature register because it will be the data most frequently read from the G751), then the read can simply consist of an address byte, followed by retrieving the corresponding number of data bytes. If the Pointer needs to be set, than an address byte, pointer byte, repeat start, and another address byte will accomplish a read.
SMBCLK
The first data byte is the most significant byte with most signification bit first, permitting only as much data as necessary to be read to determine temperature condition. For instance, if the first four bits of the temperature data indicates an overtemperature condition, the host processor could immediately take action to remedy the excessive temperatures. At the end of a read, the G751 can accept either Acknowledge or No Acknowledge from the Master (No Acknowledge is typically used as a signal for the salve that the Master has read its last byte). An inadvertent 8-bit read from a 16-bit register, with the D7 bit low, can cause the G751 to stop in a state where the SDA line is held low as shown in Figure 2. This can prevent any further bus communication until at least 9 additional clock cycles have occurred. Alternatively, the master can issue clock cycles until SDA goes high, at which time issuing a "Stop" condition will reset the G751.
SMBDATA
A2 A1 A0 R/W Bit D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Start by Master
Ack by G751
Address Byte
Most Significant Data Byter
Ack by Master
Ack Stop by Cond Master by Master
Intended Stop by Master but G751 locks SMBDATA low
Master detects the error of its ways
Figure 2. Inadvertent 8-Bit Read from 16-Bit Register where D7 is Zero
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Global Mixed-mode Technology Inc.
Pointer Register (Selects which registers will be read from or written to): P7
0
G751
P2
0
P6
0
P5
0
P4
0
P3
0
P1
P0
Register Select
P0-P1 :Register Select: P1
0 0 1 1
P0
0 1 0 1
REGISTER
Temperature (Read only) (Power-up default) Configuration (Read/Write) THYST (Read/Write) TOS (Read/Write)
P2-P7 :Must be kept zero. Temperature Register (Read Only): D15
MSB
D14
Bit 7
D13
Bit 6
D12
Bit 5
D11
Bit 4
D10
Bit 3
D9
Bit 2
D8
Bit 1
D7
LSB
D6
X
D5
X
D4
X
D3
X
D2
X
D1
X
D0
X
D0-D6 :Undefined D7-D15 :Temperature Data. One LSB = 0.5C. Two's complement format. Configuration Register (Read/Write): D7
0
D6
0
D5
0
D4
D3
Fault Queue
D2
O.S. Polarity
D1
Cmp/Int
D0
Shutdown
Power up default is with all bits "0" (zero). D0 :Shutdown : When set to 1 the G751 goes to low power shutdown mode. D1 :Comparator / Interrupt mode : 0 is Comparator mode, 1 is Interrupt mode. D2 :O.S. Polarity : 0 is active low, 1 is active high. O.S. is an open-drain output under all conditions. D3-D4 :Fault Queue : Number of faults necessary to detect before setting O.S. output to avoid false tripping due to noise : D4
0 0 1 1
D3
0 1 0 1
NUMBER OF FAULTS
1 (Power-up default) 2 4 6
D5-D7 :These bits are used for production testing and must be kept zero for normal operation. THYST and TOS Register (Read/Write): D15
MSB
D14
Bit 7
D13
Bit 6
D12
Bit 5
D11
Bit 4
D10
Bit 3
D9
Bit 2
D8
Bit 1
D7
LSB
D6
X
D5
X
D4
X
D3
X
D2
X
D1
X
D0
X
D0-D6 :Undefined D7-D15 :THYST Or TOS Trip Temperature Data. Power up default is TOS = 50C /80C for G751-1/G751-2, THYST = 45C /75C for G751-1/G751-2.
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Global Mixed-mode Technology Inc.
SMBus Timing Diagrams
1 9 1 9 1 9
G751
1
0
0
1
A2
A1
A0
R/W
D7
D6
D5
D4
D3
D2
D1
D0
D7
D6
D5
D4
D3
D2
D1
D0
Start by Master Address Byte
Ack by G751
Ack by Master
No Ack by Master
Most Significant Data Byte
Least Significant Data Byte
Stop Cond by Master
1
9
1
9
1
0
0
1
A2
A1
A0
R/W
0
0
0
0
0
0
D1
D0
Start by Master Address Byte
Ack by G751
Ack by G751
Pointer Byte
1
9
1
9
1
9
1
0
0
1
A2
A1
A0
R/W
D7
D6
D5
D4
D3
D2
D1
D0
D7
D6
D5
D4
D3
D2
D1
D0
Repeat Start by Master
Ack by G751
Ack by Master
No Ack by Master
Address Byte
Most Significant Data Byte
Least Significant Data Byte
Stop Cond by Master
1
9
1
9
1
0
0
1
A2
A1
A0
R/W
D7
D6
D5
D4
D3
D2
D1
D0
Start by Master Address Byte
Ack by G751
Ack by G751
Pointer Byte
Stop Cond by Master
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Ver: 2.2 Nov 07 2001
9 1 9 1 9 9 A1 A0 R/W 1 0 0 0 0 0 D3 R/W 0 0 D7 D1 D0 0 D4 D1 D6 D0 1 A2 A1 A0 D5 D2 Ack by G751
1
1
0
0
1 A2
Start by Master Pointer Byte
Ack Repeat by Start Master by Master
Address Byte
Address Byte
Ack by G751
Data Byte
No Ack Stop Cond by Master by Master
(a) Typical Pointer Set followed by Immediate Read from Configuration Register
Timing Diagrams (Continued)
1 9 1 9 9
1
1 R/W D0 Ack by Master Ack by G751 Ack by G751
0 A2 A0 0 0 D1 D0 0 A1 0 D2 0 0 D4
0
1
0 0 0 D3 D1
Start by Master Pointer Byte Configuration Byte
Address Byte
Stop Cond by Master
Global Mixed-mode Technology Inc.
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(b) Configuration Register Write
9 1 9 1 9 1 9 A2 A1 R/W Ack by G751 0 A0 0 0 D1 D0 Ack by Master 0 0 0 D7 D6 D5 D4 D3 D2 D1 D0 Ack by G751 D7 D6 D5 D4 D3 D2 D1 D0 Ack by G751 Stop Cond by Master
1
1
0
0
1
Start by Master Pointer Byte
Address Byte
Most Significant Data Byte
Least Significant Data Byte
(c) TOS and THYST Write
G751
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Package Information
C
G751
E
H
L D 7
(4X)
A2 A1 e B
A
y
Note: 1. Package body sizes exclude mold flash and gate burrs 2. Dimension L is measured in gage plane 3. Tolerance 0.10mm unless otherwise specified 4. Controlling dimension is millimeter converted inch dimensions are not necessarily exact. SYMBOL
A A1 A2 B C D E e H L y
MIN.
1.35 0.10 ----0.33 0.19 4.80 3.80 ----5.80 0.40 ----0
DIMENSION IN MM NOM.
1.60 ----1.45 ----------------1.27 -----------------
MAX.
1.75 0.25 ----0.51 0.25 5.00 4.00 ----6.20 1.27 0.10 8
MIN.
0.053 0.004 ----0.013 0.007 0.189 0.150 ----0.228 0.016 ----0
DIMENSION IN INCH NOM.
0.063 ----0.057 ----------------0.050 -----------------
MAX.
0.069 0.010 ----0.020 0.010 0.197 0.157 ----0.244 0.050 0.004 8
Taping Specification
Feed Direction Typical SOP Package Orientation
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