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LM95234

www.ti.com

SNIS136D –AUGUST 2006–REVISED MARCH 2013

LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and

TruTherm™ Technology

Check for Samples: LM95234

FEATURES

– (e.g. Laptop, Desktop, Workstations,

Server)

• Accurately Senses Die Temperature of 4

• Electronic Test Equipment

Remote ICs or Diode Junctions and Local

Temperature

• Office Electronics

• TruTherm BJT Beta Compensation Technology

DESCRIPTION

Accurately Senses Sub-micron Process

LM95234 is an 11-bit digital temperature sensor with

Thermal Diodes

a 2-wire System Management Bus (SMBus) interface

• Programmable Digital Filters and Analog Front

that can very accurately monitor the temperature of

End Filter

four remote diodes as well as its own temperature

• 0.125°C LSb Temperature Resolution

that includes patent pending remote diode

TruTherm™ BJT beta compensation beta

• 0.03125°C LSb Remote Temperature

compensation technology. The four remote diodes

Resolution with Digital Filter Enabled

can be external devices such as microprocessors,

• +127.875°C/–128°C and 0°C/255°C Remote

graphics processors or diode-connected 2N3904s.

Ranges

The LM95234's TruTherm BJT beta compensation

• Remote Diode Fault Detection, Model

technology allows sensing of 90 nm or 65 nm process

Selection and Offset Correction

thermal diodes accurately.

• Mask and Status Register Support

The LM95234 reports temperature in two different

formats for +127.875°C/–128°C range and 0°C/255°C

• 3 Programmable TCRIT Outputs with

range. The LM95234 TCRIT1, TCRIT2 and TCRIT3

Programmable Shared Hysteresis and Fault-

outputs are triggered when any unmasked channel

Queue

exceeds its corresponding programmable limit and

• Programmable Conversion Rate and Shutdown

can be used to shutdown the system, to turn on the

Mode One-shot Conversion Control

system fans or as a microcontroller interrupt function.

• SMBus 2.0 Compatible Interface, Supports

The current status of the TCRIT1, TCRIT2 and

TIMEOUT TCRIT3 pins can be read back from the status

registers. Mask registers are available for further

• Three-level Address Pin

control of the TCRIT outputs.

• 14-pin WSON Package

Two LM95234 remote temperature channels have

programmable digital filters while the other two

KEY SPECIFICATIONS

remote channels utilize a fault-queue to minimize

• Local Temperature Accuracy ±2.0°C (max)

unwanted TCRIT events when temperature spikes

are encountered.

• Remote Diode Temperature Accuracy ±0.875°C

(max)

For optimum flexibility and accuracy, each LM95234

• Supply Voltage 3.0V to 3.6V

channel includes registers for sub-micron process or

2N3904 diode model selection as well as offset

• Average Supply Current (1Hz conversion rate)

correction. A three-level address pin allows

connection of up to 3 LM95234s to the same SMBus

APPLICATIONS

master. The LM95234 includes power saving

• Processor/Computer System Thermal

functions such as: programmable conversion rate,

Management

shutdown mode, and disabling of unused channels.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2TruTherm is a trademark of Texas Instruments.

3All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (44 pages)

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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm™ Technology Check for Samples: LM95234 FEATURES 1 • 23 • • • • • • • • • • • • Accurately Senses Die Temperature of 4 Remote ICs or Diode Junctions and Local Temperature TruTherm BJT Beta Compensation Technology Accurately Senses Sub-micron Process Thermal Diodes Programmable Digital Filters and Analog Front End Filter 0.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Connection Diagram NC 1 14 TCRIT3 VDD 2 13 SMBCLK D4+ 3 12 SMBDAT D3+ 4 11 TCRIT2 TCRIT1 LM95234 D- 5 10 D2+ 6 9 A0 D1+ 7 8 GND Figure 1. WSON-14 TOP VIEW Simplified Block Diagram 3.0V-3.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 PIN DESCRIPTIONS Label Pin # Function Typical Connection NC 1 No Connect Not connected. May be left floating, connected to GND or VDD. VDD 2 Positive Supply Voltage Input DC Voltage from 3.0V to 3.6V. VDD should be bypassed with a 0.1 µF capacitor in parallel with 100 pF. The 100 pF capacitor should be placed as close as possible to the power supply pin.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Typical Application +3.3V Standby C3 10 PF C2 0.1 PF C1* 100 pF C4** 100 pF SO DIMM Q1 MMBT3904 1 C5** 100 pF 2 3 HDD Q2 MMBT3904 NC VDD D4+ 4 D3+ 5 D6 D2+ 7 D1+ GPU C6** 100 pF R1 10k 14 TCRIT3 13 SMBCLK 12 SMBDAT 11 TCRIT2 10 TCRIT1 9 A0 8 GND R3 10k R4 1.3k R5 1.3k SMBCLK SMBDAT SMBus Master LM95234 C7** 100 pF PROCESSOR R2 10k * Note, place close to LM95234 pins. ** Note, optional - place close to LM95234 pins.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Temperature-to-Digital Converter Electrical Characteristics Unless otherwise noted, these specifications apply for VDD = +3.0Vdc to 3.6Vdc. Boldface limits apply for TA = TJ = TMIN ≤ TA ≤ TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. Parameter TA = -40°C to +125°C (3) (4) Temperature Error Using Local Diode Temperature Error Using Remote Diode Typical (1) Conditions (5) ±1 ±2 °C (max) 65 nm Intel Processor ±0.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Logic Electrical Characteristics DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for VDD = +3.0Vdc to 3.6Vdc. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA= TJ=+25°C, unless otherwise noted. Symbol Parameter Conditions Typical (1) Limits (2) Units (Limit) SMBDAT, SMBCLK INPUTS VIN(1) Logical “1” Input Voltage 2.1 V (min) VIN(0) Logical “0”Input Voltage 0.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 SMBus DIGITAL SWITCHING CHARACTERISTICS (continued) Unless otherwise noted, these specifications apply for VDD=+3.0 Vdc to +3.6 Vdc, CL (load capacitance) on output lines = 80 pF. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. The switching characteristics of the LM95234 fully meet or exceed the published specifications of the SMBus version 2.0.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics 3.0 Thermal Diode Capacitor or PCB Leakage Current Effect on Remote Diode Temperature Reading Conversion Rate Effect on Average Power Supply Current VDD = +3.3V AVERAGE I DD (mA) 2.5 TA = 25°C 2.0 1.5 1.0 0.5 0.0 100 1000 10000 CONVERSION TIME (ms) Figure 3. Figure 4.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 FUNCTIONAL DESCRIPTION LM95234 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) interface that can monitor the temperature of four remote diodes as well as its own temperature. The LM95234 can be used to very accurately monitor the temperature of up to four external devices such as microprocessors, graphics processors or diode-connected 2N3904 transistor.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 5. 6. 7. 8. 9. www.ti.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 POWER-ON-DEFAULT STATES LM95234 always powers up to these known default states. The LM95234 remains in these states until after the first conversion. 1. All Temperature readings set to 0°C until the end of the first conversion 2. Diode Model Select: Remote 1 set to 65 nm Intel processor, Remote 2-4 set to MMBT3904 3. Remote offset for all channels 0°C 4. Configuration: Active converting, Fault Queue enabled for Remote 3 and 4 5.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com R1F[1:0] or R2F[1:0] Filter Setting 0 0 No Filter 0 1 Filter (equivalent to Level 2 filter of the LM86/LM89) 1 0 Reserved 1 1 Enhanced Filter (Filter with transient noise clipping) Figure 9 through Figure 11 describe the filter output in response to a step input and an impulse input. Figure 9. Seventeen and fifty degree step response Figure 10.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Remote 4 Temperature Readings Remote 4 Tcrit Limit Register Value n+11 n+9 n+10 n+8 n+7 n+6 n+5 n+4 n+3 n+2 n n+1 Status 4 Register R4T3 Bit SAMPLE NUMBER Figure 13. Fault Queue Response Diagram (with 0°C hysteresis) TEMPERATURE DATA FORMAT Temperature data can only be read from the Local and Remote Temperature value registers.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com When the digital filter is enabled on Remote 1 and 2 channels temperature data is represented by a 13-bit unsigned binary or 12-bit plus sign (two's complement) word with an LSb equal to 0.03125°C. Table 4. 13-bit, 2's Complement (12-bit plus sign) Temperature Digital Output Binary Hex +125°C 0111 1101 0000 0000 7D00h +25°C 0001 1001 0000 0000 1900h +1°C 0000 0001 0000 0000 0100h +0.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 SMBDAT OPEN-DRAIN OUTPUT The SMBDAT output is an open-drain output and does not have internal pull-ups. A “high” level will not be observed on this pin until pull-up current is provided by 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 without effecting the SMBus desired data rate.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Logic diagrams for the TCRIT1, TCRIT2, and TCRIT3 outputs Status 1 (Diode Fault) Status 1 (Diode Fault) R4DO R4DO R4DS R4DS R3DO R3DO R3DS R3DS R2DO R2DO R2DS R2DS R1DO R1DO R1DS R1DS Status 2 (TCRIT1) Status 3 (TCRIT2) R4T1 R4T2 R3T1 R3T2 R2T1 TCRIT1 R2T2 R1T1 R1T2 LT1 LT2 TCRIT1 Mask TCRIT2 Mask R4TM R4TM R3TM R3TM R2T1M R2T2M R1T1M R1T2M LTM LTM TCRIT2 Figure 15.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com If enabled, local temperature is compared to the user programmable Local Tcrit Limit Register (Default Value = 85°C). The result of this comparison is stored in Status Register 2, Status Register 3 and Status Register 4 (see Logic diagrams for the TCRIT1, TCRIT2, and TCRIT3 outputs).
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 DIODE FAULT DETECTION The LM95234 is equipped with operational circuitry designed to detect fault conditions concerning the remote diodes. In the event that the D+ pin is detected as shorted to GND, D−, VDD or D+ is floating, the Remote Temperature reading is –128.000 °C if signed format is selected and 0 °C if unsigned format is selected. In addition, the appropriate status register bits RD1M or RD2M (D1 or D0) are set.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com 1 9 1 9 SMBCLK SMBDAT A6 A5 A4 A3 A2 D7 Ack by LM95234 A1 D6 A0 R/W Start by Master D5 Frame 1 Serial Bus Address Byte D4 D3 D2 D1 D0 Ack by Stop LM95234 by Master Frame 2 Command Byte Figure 20.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 ONE-SHOT CONVERSION The One-Shot register is used to initiate a round of conversions and comparisons when the device is in standby mode, after which the device returns to standby. This is not a data register and it is the write operation that causes the one-shot conversion. The data written to this address is irrelevant and is not stored. A zero will always be read from this register.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Table 8.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Bit(s) Bit Name Read/ Write Description 7 SIGN RO Sign bit 6 64 RO bit weight 64°C 5 32 RO bit weight 32°C 4 16 RO bit weight 16°C 3 8 RO bit weight 8°C 2 4 RO bit weight 4°C 1 2 RO bit weight 2°C 0 1 RO bit weight 1°C Bit(s) Bit Name Read/ Write Description 7 1/2 RO bit weight 1/2°C (0.5°C) 6 1/4 RO bit weight 1/4°C (0.25°C) 5 1/8 RO bit weight 1/8°C (0.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Bit(s) Bit Name Read/ Write Description 7 1/2 RO bit weight 1/2°C (0.5°C) 6 1/4 RO bit weight 1/4°C (0.25°C) 5 1/8 RO bit weight 1/8°C (0.125°C) 4 0 or 1/16 RO When the digital filter is disabled this bit will always read "0". When the digital filter is enabled this bit will report 1/16°C (0.0625°C) bit state. 3 0 or 1/32 RO When the digital filter is disabled this bit will always read "0".
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 DIODE CONFIGURATION REGISTERS Diode Model Select Register Name Command Read/ Byte Write (Hex) Diode Model Select 0x30 R/W D7 D6 D5 D4 D3 D2 D1 D0 POR Default (Hex) 0 0 0 R4TE R3TE R2TE R1TE 0 0x02 Bit(s) Bit Name Read/ Write Description 7-5 0 RO Reserved – will report "0" when read.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Bit(s) Bit Name Read/ Write Description 5–2 – RO Reserved – will report "0" when read.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Filter Setting Register Name Command Read/ Byte Write (Hex) Filter Setting 0x06 R/W D7 D6 D5 D4 D3 D2 D1 D0 POR Default (Hex) – – – – R2F1 R2F0 R1F1 R1F0 0x0F Bit(s) Bit Name Read/ Write Description 7–4 – RO Reserved – will report "0" when read.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Bit(s) Bit Name Read/ Write Description 7–5 - RO Reserved – will report "0" when read.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Bit(s) Bit Name Read/ Write Description 0 LT2 RO Local Tcrit Status: 1 – indicates that local reading is greater than or equal to the value set in Local Tcrit Limit register 0 – indicates that local reading is less than the value set in Local Tcrit Limit register minus the Common Hysteresis value Status 4 (TCRIT3) Status bits for TCRIT3. When one or more of these bits are set and if not masked the TCRIT3 output will activate.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Bit(s) Bit Name Read/ Write Description 2 R2TD RO Remote 2 TruTherm BJT beta compensation on and 3904 detect: 1 – indicates that for channel 2 TruTherm is ON and 3904 connected 0 – indicates proper operation 1 R1TD RO Remote 1 TruTherm BJT beta compensation on and 3904 detect: 1 – indicates that for channel 4 TruTherm is ON and 3904 connected 0 – indicates proper operation 0 – RO Reserved – will report "0" when read.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Bit(s) Bit Name Read/ Write Description 0 1 R/W bit weight 1°C Remote Limit Registers The range for these registers is 0°C to 255°C.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Bit(s) Bit Name Read/ Write Description 7 0 RO Read only bit will always report "0". 6 0 RO Read only bit will always report "0". 5 0 RO Read only bit will always report "0".
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 • • • • • • T = Absolute Temperature in Kelvin k = 1.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com Calculating Total System Accuracy The voltage seen by the LM95234 also includes the IFRS voltage drop of the series resistance. The non-ideality factor, η, is the only other parameter not accounted for and depends on the diode that is used for measurement. Since ΔVBE is proportional to both η and T, the variations in η cannot be distinguished from variations in temperature.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 Transistor Equation ηT, non-ideality Processor Family Intel Processor on 65 nm process Series R,Ω min typ max 0.997 1.001 1.005 Diode Equation ηD, non-ideality Processor Family 4.52 Series R,Ω min typ max 1 1.0065 1.0125 Pentium III CPUID 68h/PGA370Socket/ Celeron 1.0057 1.008 1.0125 Pentium 4, 423 pin 0.9933 1.0045 1.0368 Pentium 4, 478 pin 0.9933 1.0045 1.0368 Pentium 4 on 0.13 micron process, 2 - 3.06 GHz 1.
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LM95234 SNIS136D – AUGUST 2006 – REVISED MARCH 2013 www.ti.com PCB LAYOUT FOR MINIMIZING NOISE Figure 24. Ideal Diode Trace Layout In a noisy environment, such as a processor mother board, layout considerations are very critical. Noise induced on traces running between the remote temperature diode sensor and the LM95234 can cause temperature conversion errors. Keep in mind that the signal level the LM95234 is trying to measure is in microvolts. The following guidelines should be followed: 1.
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LM95234 www.ti.com SNIS136D – AUGUST 2006 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision C (March 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM95234CISD/NOPB WSON NHL 14 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM95234CISDX/NOPB WSON NHL 14 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM95234CISD/NOPB WSON NHL 14 1000 210.0 185.0 35.0 LM95234CISDX/NOPB WSON NHL 14 4500 367.0 367.0 35.
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MECHANICAL DATA NHL0014B SDA14B (Rev A) www.ti.
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