NSC LM64CILQX-F, LM64CILQ-F Datasheet

December 2003

LM64

1˚C Remote Diode Temperature Sensor with PWM Fan

Control and 5 GPIO’s

LM64

1˚C Remote Diode Temperature Sensor with PWM Fan Control and 5 GPIO’s

General Description

The LM64 is a remote diode temperature sensor with PWM fan control. The LM64 accurately measures its own temperature and that of a remote diode. The LM64 remote temperature accuracy is factory trimmed for a MMBT3904 diodeconnected transistor with a 16˚C offset for high temperatures. T

The LM64 features a PWM, open-drain, fan control output, 5 GPIO (General Purpose Input/Output) and 5 GPD (General Purpose Default) pins. The 8-step Lookup Table allows for a non-linear fan speed vs. temperature transfer function often used to quiet acoustic fan noise.

ACTUAL DIODE JUNCTION

LM64

+ 16˚C

Features

n Accurately senses remote and local diode temperatures n Integrated PWM fan speed control output n Programmable 8-step Lookup Table for quieting fans n ALERT and T_Crit open-drain outputs n Tachometer input for measuring fan RPM n 10 bit plus sign remote diode temperature data format,

with 0.125˚C resolution

n SMBus 2.0 compatible interface, supports TIMEOUT n 5 General Purpose Input/Output pins n 5 General Purpose Default input pins n 24-pin LLP package

Key Specifications

n Remote Diode Temperature Accuracy (includes

quantization error)

Ambient Temp Diode Temp Max Error

30˚C to 50˚C 120˚C to 140˚C

0˚C to 85˚C 25˚C to 140˚C

n Local Temp Accuracy (includes quantization error)

Ambient Temp Max Error

25˚C to 125˚C

n Power Supply Requirements

Supply DC Voltage 3.0 V to 3.6 V

Supply DC Current 1.1 mA (typ)

1.0˚C (max)

3.0˚C (max)

Applications

n Computer Processor Thermal Management n Graphics Processor Thermal Management n Voltage Regulator Modules n Electronic Instrumentation n Power Supplies n Projectors

Connection Diagram

20065501

Pin Descriptions

LM64

Pin Name Input/Output Function and Connection

1 GPIO1

2 GPIO2

3 GPIO3

4 PWM

Digital Input/

Open-Drain Output

Digital Input/

Open-Drain Output

Digital Input/

Open-Drain Output

Open-Drain

Digital Output

Power Supply Input

General Purpose Open-Drain Digital Output or Digital Input. Typical pull-up resistor is 10 kΩ to V

General Purpose Open-Drain Digital Output or Digital Input. Typical pull-up resistor is 10 kΩ to VDD.

General Purpose Open-Drain Digital Output or Digital Input. Typical pull-up resistor is 10 kΩ to V

Open-Drain Digital Output. Connect to fan drive circuitry. The power-on default for this pin is low (pin 4 pulled to ground).

Connect to a low-noise +3.3

0.3 VDC power supply, and bypass to GND with a 0.1 µF ceramic capacitor in parallel with a 100 pF ceramic capacitor. A bulk capacitance of 10 µF needs to be in the vicinity of the LM64’s V pin.

6 D+ Analog Input

7 D- Analog Input

8 T_Crit

Open-Drain

Digital Output

Connect to the anode (positive side) of the remote diode. A 2.2 nF ceramic capacitor must be connected between pins 6 and 7.

Connect to the cathode (negative side) of the remote diode. A 2.2 nF ceramic capacitor must be connected between pins 6 and 7.

Open-Drain Digital Output. Typical pull-up resistor is 3 kΩ to V

9 N/C N/A No Connection.

10 N/C N/A No Connection.

11 N/C N/A No Connection.

12 A0 Digital Input

SMBus Address Select pin. If High, the SMBus address is 0x4E or, if Low, the SMBus address is 0x18. Typical pull-up resistor is 10 kΩ to V

13 GND Ground This is the analog and digital ground return.

14 ALERT

Open-Drain

Digital Output

15 TACH Digital Input

16 SMBDAT

Digital Input/

Open-Drain Output

This pin is an open-drain ALERT Output. Typical pull-up resistor is 3 kΩ to

This pin is a digital tachometer input. Typical pull-up resistor is 3 kΩ to

This is the bi-directional SMBus data line. Typical pull-up resistor is 1.5 kΩ

to V

17 SMBCLK Digital Input This is the SMBus clock input. Typical pull-up resistor is 1.5 kΩ to V

18 GPIO5

19 GPIO4

Digital Input/

Open-Drain Output

Digital Input/

Open-Drain Output

20 GPD1 Digital Input

21 GPD2 Digital Input

22 GPD3 Digital Input

23 GPD4 Digital Input

24 GPD5 Digital Input

General Purpose Open-Drain Digital Output or Digital Input. Typical pull-up resistor is 10 kΩ to V

General Purpose Default Input Pin. Typical pull-up resistor is 10 kΩ to V Always connect to a logical High or Low level.

General Purpose Default Input Pin. Typical pull-up resistor is 10 kΩ to VDD. Always connect to a logical High or Low level.

General Purpose Default Input Pin. Typical pull-up resistor is 10 kΩ to V Always connect to a logical High or Low level.

General Purpose Default Input Pin. Typical pull-up resistor is 10 kΩ to VDD. Always connect to a logical High or Low level.

General Purpose Default Input Pin. Typical pull-up resistor is 10 kΩ to V Always connect to a logical High or Low level.

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Simplified Block Diagram

LM64

Ordering Information

Part Description Order Number Top Mark Transport Media

LM64 24-pin LLP LM64CILQ-F 64CILQF 1000 Units in Tape and Reel

LM64 24-pin LLP LM64CILQX-F 64CILQF 4500 Units in Tape and Reel

LM64 Evaluation Board

With Software and Manual

20065502

LM64EVAL N/A Packaged

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Typical Application

LM64

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20065503

LM64

Absolute Maximum Ratings (Notes 1,

Supply Voltage, V

Voltage on SMBDAT, SMBCLK,

ALERT, T_Crit, PWM Pins −0.5 V to 6.0 V

Voltage on Other Pins −0.3 V to (V

Input Current, D− Pin

−0.3 V to 6.0 V

+0.3V)

1mA

ESD Susceptibility (Note 4)

Human Body Model 2000 V

Machine Model 200 V

SMT Soldering Information

See National Semiconductor Application Note AN-1187, "Leadless Leadframe Package" for information on SMT Assembly using LLP Packages. This is available at http://www.national.com/an/AN/AN-1187.pdf.

Input Current at All Other Pins (Note 3) 5 mA

Package Input Current (Note 3) 30 mA

Package Power Dissipation (Note 5)

SMBDAT, ALERT, T_Crit, PWM pins

Output Sink Current 10 mA

Storage Temperature −65˚C to +150˚C

Operating Ratings (Notes 1, 2)

LM64 Operating Temperature Range 0˚C ≤ T

Remote Diode Temperature Range 25˚C ≤ T

Electrical Characteristics T

MIN

≤ +85˚C

≤ +140˚C

≤ TA≤ T

MAX

Supply Voltage Range (VDD) +3.0 V to +3.6 V

DC Electrical Characteristics

TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS The following specifications apply for VDD= 3.0 VDC to

3.6 VDC, and all analog source impedance R

A=TMIN

to T

; all other limits TA= +25˚C.

MAX

Parameter Conditions

Temperature Error using a diode-connected MMBT3904 transistor. T

is the Remote

Diode Junction Temperature. T

D=TLM64

+ 16˚C

Temperature Error Using the Local Diode T

Remote Diode Resolution 11 Bits

Local Diode Resolution 8 Bits

Conversion Time of All Temperatures Fastest Setting 31.25 34.4 ms (max)

D− Source Voltage 0.7 V

Diode Source Current

=50Ω unless otherwise specified in the conditions. Boldface limits apply for

= +30˚C to

+50˚C

= +0˚C to

+85˚C

= +25˚C to +125˚C (Note 10)

TD= +120˚C to +140˚C

TD= +25˚C to +140˚C

Typical

(Note 7)

Limits

(Note 8)

1 ˚C (max)

3 ˚C (max)

Units

(Limits)

0.125 ˚C

1˚C

D+−VD−

Current

) = +0.65 V; High

160

Low Current 13

315 µA (max)

110 µA (min)

20 µA (max)

7 µA (min)

Operating Electrical Characteristics

Parameter

ALERT, T_Crit and PWM Output Saturation Voltage

Conditions

ALERT, T_Crit

OUT

4mA 6mA 0.4

6mA 0.55

PWM

Typ

(Note 7)

Power-On-Reset Threshold Voltage 2.4 V (max)

Supply Current (Note 9) SMBus Inactive, 16 Hz

Conversion Rate

1.1 2.0 mA (max)

STANDBY Mode 320 µA

Limits

(Note 8)

V (max)

1.8 V (min)

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Units

AC Electrical Characteristics

LM64

The following specifications apply for VDD= 3.0 VDC to 3.6 VDC, and all analog source impedance RS=50Ω unless other- wise specified in the conditions. Boldface limits apply for T

A=TMIN

Symbol Parameter Conditions

to T

; all other limits TA= +25˚C.

MAX

Typical

(Note 7)

Limits

(Note 8)

TACHOMETER ACCURACY

Fan Control Accuracy

10 % (max)

Fan Full-Scale Count 65535 (max)

Fan Counter Clock Frequency 90 kHz

Fan Count Update Frequency 1.0 Hz

FAN PWM OUTPUT

Frequency Accuracy

10 % (max)

Digital Electrical Characteristics

Symbol Parameter Conditions

Logical High Input Voltage 2.1 V (min)

Logical Low Input Voltage 0.8 V (max)

Logical High Input Current VIN=V

Logical Low Input Current VIN= GND −0.005 −10 µA (max)

Digital Input Capacitance 20 pF

Typical

(Note 7)

0.005 +10 µA (max)

Limits

(Note 8)

Units

(Limit)

Units

(Limit)

SMBus Logical Electrical Characteristics

The following specifications apply for VDD= 3.0 VDC to 3.6 VDC, and all analog source impedance RS=50Ω unless other- wise specified in the conditions. Boldface limits apply for T

A=TMIN

to T

Symbol Parameter Conditions

SMBDAT OPEN-DRAIN OUTPUT

Logic Low Level Output Voltage IOL=4mA 0.4 V (max)

High Level Output Current V

OUT=VDD

SMBDAT, SMBCLK INPUTS

HYST

Logical High Input Voltage 2.1 V (min)

Logical Low Input Voltage 0.8 V (max)

Logic Input Hysteresis Voltage 400 mV

; all other limits TA= +25˚C.

MAX

Typical

(Note 7)

0.03 10 µA (max)

Limits

(Note 8)

Units

(Limit)

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SMBus Digital Switching Characteristics

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 T

A=TJ;TMIN

≤ TA≤ T

switching characteristics of the LM64 fully meet or exceed the published specifications of the SMBus version 2.0. The following parameters are the timing relationships between SMBCLK and SMBDAT signals related to the LM64. They adhere to but are not necessarily the same as the SMBus bus specifications.

Symbol Parameter Conditions

SMB

LOW

HIGH

TIMEOUT

SMBus Clock Frequency 10

SMBus Clock Low Time From V

SMBus Clock High Time From V

SMBus Rise Time (Note 11) 1 µs (max)

SMBus Fall Time (Note 12) 0.3 µs (max)

Output Fall Time CL= 400 pF, IO=3mA 250 ns (max)

SMBData and SMBCLK Time Low for Reset of Serial Interface See (Note 13)

SU:DAT

HD:DAT

HD:STA

Data In Setup Time to SMBCLK High 250 ns (min)

Data Out Hold Time after SMBCLK Low 300

Hold Time after (Repeated) Start Condition. After this period the first clock is generated.

SU:STO

Stop Condition SMBCLK High to SMBDAT Low (Stop Condition Setup)

SU:STA

SMBus Repeated Start-Condition Setup Time, SMBCLK High to SMBDAT Low

BUF

SMBus Free Time between Stop and Start Conditions

; all other limits TA=TJ= +25˚C, unless otherwise noted. The

MAX

Limits

(Note 8)

100

IN(0) max

IN(1) min

to V

IN(0) max

IN(1) min

4.7 µs (min)

4.0 50

25 35

930

4.0 µs (min)

100 ns (min)

4.7 µs (min)

Units

(Limit)

kHz (min)

kHz (max)

µs (min)

µs (max)

ms (min)

ms (max)

ns (min)

ns (max)

LM64

FIGURE 1. SMBus Timing Diagram for SMBCLK and SMBDAT Signals

20065504

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Notes

LM64

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

functional, but do not guarantee performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions.

Note 2: All voltages are measured with respect to GND, unless otherwise noted.

Note 3: When the input voltage (V

components and/or ESD protection circuitry are shown in the table below, for the LM64’s pins, by an "X" when it exists. Care should be taken not to forward bias the parasitic diode, D1, present on pins D+ and D−. Doing so by more than 50 mV may corrupt temperature measurements.

) at any pin exceeds the power supplies (V

GND or V

V+), the current at that pin should be limited to 5 mA. Parasitic

Pin Name PIN

D1 D2 D3 D4 D5 D6 R1 SNP ESD CLAMP

GPIO1 1 X X X

GPIO2 2 X X X

GPIO3 3 X X X

PWM 4 X X X

5 X

D+ 6 XX XXX X

D− 7 XX XXX X

T_Crit

8X XXX

A0 12 X

ALERT

14 X X X X

TACH 15 X X X

SMBDAT 16 X X X

SMBCLK 17 X

GPIO5 18 X X X

GPIO4 19 X X X

GPD1 20 X

GPD2 21 X

GPD3 22 X

GPD4 23 X

GPD5 24 X

20065505

FIGURE 2. ESD Protection Input Structure

Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin. See Figure 2 above for the ESD

Protection Input Structure.

Note 5: See the National Semiconductor Application Note AN-1187 for Thermal Resistance Junction-to-Ambient Temperature.

Note 6: See the National Semiconductor Application Note AN-1187 for recommendations on SMT assembly using the LLP packages.

Note 7: “Typicals” are at T

Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 9: The supply current will not increase substantially with an SMBus transaction.

Note 10: Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the internal power

dissipation of the LM64 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation.

Note 11: The output rise time is measured from (V

Note 12: The output fall time is measured from (V

Note 13: Holding the SMBData and/or SMBCLK lines Low for a time interval greater than t

SMBDAT and SMBCLK pins to a high impedance state.

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= 25˚C and represent most likely parametric norm. They are to be used as general reference values not for critical design calculations.

IL max

IH min

- 0.15 V) to (V

+ 0.15 V) to (V

IH min

IL min

+ 0.15 V).

- 0.15 V).

will reset the LM64’s SMBus state machine, therefore setting

TIMEOUT

1.0 Functional Description

The LM64 Remote Diode Temperature Sensor with Integrated Fan Control incorporates a ∆V sensor using a Local or Remote diode and a 10-bit plus sign ∆Σ ADC (Delta-Sigma Analog-to-Digital Converter). The pulse-width modulated (PWM) open-drain output, with a pull-up resistor, can drive a switching transistor to modulate the fan. The LM64 can measure the fan speed on the pulses from the fan’s open-collector tachometer output, pulled up by a 1.5 kΩ resistor to V

. The ALERT open-drain output will

be pulled low under certain conditions descibed in the sections below. The T_Crit open-drain output will be pulled low when the T_Crit setpoint temperature limit is exceeded. This behaves as a typical comparator function without any latching.

The LM64’s two-wire interface is compatible with the SMBus Specification 2.0 . For more information the reader is directed to www.smbus.org.

In the LM64, digital comparators are used to compare the measured Local Temperature (LT) to the Local High Setpoint user-programmable temperature limit register. The measured Remote Temperature (RT) is digitally compared to the Remote High Setpoint (RHS), the Remote Low Setpoint (RLS), and the Remote T_CRIT Setpoint (RCS) userprogrammable temperature limits. An ALERT output will occur when the measured temperature is: (1) higher than either the High Setpoint or the T_CRIT Setpoint, or (2) lower than the Low Setpoint. The ALERT Mask register allows the user to prevent the generation of these ALERT outputs.

The temperature hysteresis is set by the value placed in the Hysteresis Register (TH).

The LM64 may be placed in a low power Standby mode by setting the Standby bit found in the Configuration Register. In the Standby mode continuous conversions are stopped. In Standby mode the user may choose to allow the PWM output signal to continue, or not, by programming the PWM Disable in Standby bit in the Configuration Register.

The Local Temperature reading and setpoint data registers are 8-bits wide. The format of the 11-bit remote temperature data is a 16-bit left justified word. Two 8-bit registers, high and low bytes, are provided for each setpoint as well as the temperature reading. Two Remote Temperature Offset (RTO) Registers: High Byte and Low Byte (RTOHB and RTOLB) may be used to correct the temperature readings by adding or subtracting a fixed value based on a different non-ideality factor of the thermal diode if different from the graphics processor thermal diode. See Section 4.1 Thermal Diode Non-Ideality.

1.1 CONVERSION SEQUENCE

The LM64 takes approximately 31.25 ms to convert the Local Temperature (LT), Remote Temperature (RT), and to update all of its registers. The Conversion Rate may be modified using the Conversion Rate Register. When the conversion rate is modified a delay is inserted between conversions, the actual conversion time remains at

31.25 ms. Different Conversion Rates will cause the LM64 to draw different amounts of supply current as shown in Figure

-based temperature

LM64

20065506

FIGURE 3. Supply Current vs Conversion Rate

1.2 THE ALERT OUTPUT

When the ALERT Mask bit in the Configuration register is written as zero the ALERT interrupts are enabled.

The LM64’s ALERT pin is versatile and can produce three different methods of use to best serve the system designer: (1) as a temperature comparator (2) as a temperature-based interrupt flag, and (3) as part of an SMBus ALERT System. The three methods of use are further described below. The ALERT and interrupt methods are different only in how the user interacts with the LM64.

The remote temperature (RT) reading is associated with a T_CRIT Setpoint Register, and both local and remote temperature (LT and RT) readings are associated with a HIGH setpoint register (LHS and RHS). The RT is also associated with a LOW setpoint register (RLS). At the end of every temperature reading a digital comparison determines whether that reading is above its HIGH or T_CRIT setpoint or below its LOW setpoint. If so, the corresponding bit in the ALERT Status Register is set. If the ALERT mask bit is low, any bit set in the ALERT Status Register, with the exception of Busy or Open, will cause the ALERT output to be pulled low. Any temperature conversion that is out of the limits defined in the temperature setpoint registers will trigger an ALERT. Additionally, the ALERT Mask Bit must be cleared to trigger an ALERT in all modes.

The three different ALERT modes will be discussed in the following sections.

1.2.1 ALERT Output as a Temperature Comparator

When the LM64 is used in a system in which does not require temperature-based interrupts, the ALERT output could be used as a temperature comparator. In this mode, once the condition that triggered the ALERT to go low is no longer present, the ALERT is negated (Figure 4). For example, if the ALERT output was activated by the comparison of LT>LHS, when this condition is no longer true, the ALERT will return HIGH. This mode allows operation without software intervention, once all registers are configured during set-up. In order for the ALERT to be used as a temperature comparator, the Comparator Mode bit in the Remote Diode Temperature Filter and Comparator Mode Register must be asserted. This is not the power-on default state.

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