Rainbow Electronics LM32 User Manual

LM32 Dual Thermal Diode Temperature Sensor with

LM32 Dual Thermal Diode Temperature Sensor with SensorPath

May 2004

SensorPath

™

Bus

General Description

The LM32 is a digital temperature sensor that measures 3 temperature zones and has a single-wire interface compatible with National Semiconductor’s SensorPath bus. SensorPath data is pulse width encoded, thereby allowing the LM32 to be easily connected to many general purpose microcontrollers. Several National Semiconductor Super I/O products include a fully integrated SensorPath master, that when connected to an LM32 can realize a hardware monitor function that includes limit checking for measured values, autonomous fan speed control and many other functions.

The LM32 measures the temperature of its own die as well as two external devices such as a processor thermal diode or a diode connected transistor. The LM32 can resolve temperatures up to 255˚C and down to -256˚C. The operating temperature range of the LM32 is 0˚C to +125˚C. The address programming pin allows two LM32s to be placed on one SensorPath bus.

Features

n SensorPath Interface

— 2 hardware programmable addresses

Typical Application

n 2 remote diode temperature sensor zones n Internal local temperature zone n 0.5 ˚C resolution n Measures temperatures up to 140 ˚C n 14-lead TSSOP package

Key Specifications

n Temperature Sensor Accuracy n Temperature Range:

— LM32 junction 0 ˚C to +85 ˚C — Remote Temp Accuracy 0 ˚C to +100 ˚C

n Power Supply Voltage +3.0 V to +3.6 V n Average Power Supply Current 0.5 mA (typ) n Conversion Time (all Channels) 22.5ms to 1456ms

3 ˚C (max)

Applications

n Microprocessor based equipment

(Motherboards, Video Cards, Base-stations, Routers,

ATMs, Point of Sale, …)

n Power Supplies

20071101

SensorPath™is a trademark of National Semiconductor Corporation

™

Bus

Connection Diagram

LM32

TSSOP-14

Order Number

LM32CIMT LM32

LM32CIMTX LM32

Package

Marking

CIMT

Package

Number

MTC14C 94 units per

MTC14C 2500 units in

Transport Media

rail

tape and reel

Top View

National Package Number MTC14C

20071102

Pin Description

Pin Number Pin Name Description Typical Connection

1, 6, 7,12, 13,

2 GND Ground System ground

3 V+/+3.3V_SBY Positive power supply pin Connected system 3.3 V standby power and

4 SWD SensorPath Bus line; Open-drain

5 ADD Digital input - device number select

8, 10 D1-, D2- Thermal diode analog voltage

9, 11 D1+, D2+ Thermal diode analog current

NC No Connect May be tied to V+, GND or left floating

to a 0.1 µF bypass capacitor in parallel with 100 pF. A bulk capacitance of approximately 10 µF needs to be in the near vicinity of the LM32.

Super I/O, Pull-up resistor, 1.6k

output

Pull-up to 3.3 V or pull-down to GND resistor, input for the serial bus device number

output and negative monitoring input

output and positive monitoring input

10k; must never be left floating

Remote Thermal Diode cathode

(THERM_DC) - Diode 1 should always be

connected to the processor thermal diode.

Diode 2 may be connected to an MMBT3904

or GPU thermal diode. A 100 pF capacitor

should be connected between respective D-

and D+ for noise filtering.

Remote Thermal Diode anode (THERM_DA) -

Diode 1 should always be connected to the

processor thermal diode. Diode 2 may be

connected to an MMBT3904 or GPU thermal

diode. A 100 pF capacitor should be

connected between respective D- and D+ for

noise filtering.

www.national.com 2

Block Diagram

LM32

20071103

www.national.com3

Absolute Maximum Ratings

LM32

(Notes 2, 1)

Supply Voltage (V

) −0.5 V to 6.0 V

Storage Temperature −65˚C to +150˚C

Soldering process must comply with National’s reflow temperature profile specifications. Refer to www.national.com/packaging/. (Note 6)

Voltage at Any Digital Input or Output Pin −0.5 V to 6.0 V

Voltage on D1+ and D2+ −0.5 V to (V+ + 0.05 V)

Current on D1- and D2-

Input Current per Pin(Note 3)

Package Input Current (Note 3)

1mA

5mA

30 mA

Package Power Dissipation (Note 4)

Output Sink Current 10 mA

ESD Susceptibility (Note 5)

Human Body Model 2500 V

Operating Ratings

(Notes 1, 2)

Temperature Range for Electrical Characteristics

LM32CIMT (T

MIN≤TA≤TMAX

Operating Temperature Range 0˚C ≤ T

Remote Diode Temperature (T Range -5˚C ≤T

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

) 0˚C ≤ TA≤ +85˚C

)

Machine Model 250 V

DC Electrical Characteristics

The following specifications apply for V+ = +3.0 VDCto +3.6 VDC, and all analog source impedance RS=50Ω unless other- wise specified in the conditions. Boldface limits apply for LM32CIMT T

= +25˚C. TAis the ambient temperature of the LM32; TJis the junction temperature of the LM32; TDis the junction tem-

A=TJ=TMIN

=0˚C to T

perature of the remote thermal diode.

POWER SUPPLY CHARACTERISTICS

Symbol Parameter Conditions

Typical

(Note 7)

V+ Power Supply Voltage 3.3

I+

Shutdown

Shutdown Power Supply Current

SensorPath Bus Inactive (Note 9)

SensorPath Bus Inactive; all

I+

Average

I+

Peak

Average Power Supply Current

Peak Power Supply Current

sensors enabled;

=182 ms; (Note 9)

CONV

SensorPath Bus Inactive (Note 9)

Power-On Reset Threshold Voltage

TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS

Parameter Conditions

Temperature Accuracy Using the Remote Thermal Diode, see (Note 11) for Thermal Diode Processor Type.

Temperature Accuracy Using the Local Diode T

= 0˚C to

TD= +25˚C

+85˚C

= 0˚C to

+85˚C

= 0˚C to

+85˚C

= 0˚C to +85˚C (Note 10)

TD= 0˚C to +100˚C

TD= +100˚C to +125˚C

Typical

(Note 7)

Remote Diode and Local Temperature Resolution 10 Bits

D− Source Voltage 0.7 V

Diode Source Current

D+−VD−

Low Current 11.75 µA

) = +0.65 V; High Current 188 280 µA (max)

Diode Source Current High Current to Low Current Ratio

=85˚C; all other limits

MAX

Limits

(Note 8)

3.0

3.6

260 420 µA (max)

900 µA (max)

3.3 mA (max)

1.6 V (min)

2.8 V (max)

Limits

(Note 8)

2.5 ˚C (max)

3 ˚C (max)

4 ˚C (max)

3 ˚C (max)

0.5 ˚C

≤ +125˚C

≤+140 ˚C

Units

(Limit)

V (min)

V (max)

Units

(Limits)

www.national.com 4

SWD and ADD DIGITAL INPUT CHARACTERISTICS

Symbol Parameter Conditions

SWD Logical High Input Voltage 2.1 V (min)

SWD Logical Low Input Voltage 0.8 V (max)

ADD Logical High Input Voltage 90%xV+ V (min)

ADD Logical Low Input Voltage 10%xV+ V (max)

Input Hysteresis 300 mV

SWD and ADD Input Current GND ≤ VIN≤ V+

SWD Input Current with V+ Open or Grounded

GND ≤ V

≤ 3.6V,

and V+ Open or

HYST

GND

Digital Input Capacitance 10 pF

SWD DIGITAL OUTPUT CHARACTERISTICS

Symbol Parameter Conditions

Open-drain Output Logic “Low” Voltage

OUT

Open-drain Output Off Current

Digital Output Capacitance 10 pF

IOL= 4mA 0.4 V (max)

= 50µA 0.2 V (max)

Typical

(Note 7)

Limits

(Note 8)

V+ + 0.5 V (max)

-0.5 V (min)

0.005

0.005 µA

Typical

(Note 7)

0.005

10 µA (max)

Limits

(Note 8)

10 µA (max)

LM32

Units

(Limit)

Units

(Limit)

AC Electrical Characteristics

The following specification apply for V+ = +3.0 VDCto +3.6 VDC, unless otherwise specified. Boldface limits apply for T

A=TJ=TMIN

=0˚C to T

specification revision 0.98. Please refer to that speciation for further details.

Symbol Parameter Conditions

HARDWARE MONITOR CHARACTERISTICS

CONV

Total Monitoring Cycle Time (Note 12) All Temperature readings

SensorPath Bus CHARACTERISTICS

INACT

SWD fall time (Note 15) R

SWD rise time (Note 15) R

Minimum inactive time (bus at high level) guaranteed by the slave before an attention request

Mtr0

Master drive for Data Bit 0 write and for Data Bit 0-1read

Mtr1

SFEdet

SLout1

MtrS

SLoutA

RST

Master drive for Data Bit 1 write 35.4 µs (min)

Time allowed for LM32 activity detection 9.6 µs (max)

LM32 drive for Data Bit 1 read by master 28.3 µs (min)

Master drive for Start Bit 80 µs (min)

LM32 drive for Attention Request 165 µs (min)

Master or LM32 drive for Reset 354 µs (min)

=85˚C; all other limits TA=TJ= 25˚C. The SensorPath Characteristics conform to the SensorPath

MAX

Typical

(Note 7)

Limits

(Note 8)

182 163.8 ms (min)

(Default)

=1.25 kΩ±30%,

pull-up

=400 pF

=1.25 kΩ±30%,

pull-up

=400 pF

200.2 ms (max)

300 ns (max)

1000 ns (max)

11 µs (min)

11.8 µs (min)

17.0 µs (max)

48.9 µs (max)

38.3 µs (max)

109 µs (max)

228 µs (max)

Units

(Limits)

www.national.com5

AC Electrical Characteristics (Continued)

LM32

The following specification apply for V+ = +3.0 VDCto +3.6 VDC, unless otherwise specified. Boldface limits apply for T

A=TJ=TMIN

=0˚C to T

=85˚C; all other limits TA=TJ= 25˚C. The SensorPath Characteristics conform to the SensorPath

MAX

specification revision 0.98. Please refer to that speciation for further details.

Symbol Parameter Conditions

RST_MAX

Maximum drive of SWD by an LM32, after the

Typical

(Note 7)

Limits

(Note 8)

500 ms (max)

power supply is raised above 3V

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 below for the LM32’s pins. The nominal breakdown voltage of the zener is 6.5 V. SNP stands for snap-back device.

) at any pin exceeds the power supplies (V

GND or V

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

Units

(Limits)

PIN#Pin

Name

Circuit

All Input Structure Circuits

1NC A

2 GND B

V+/

3.3V SB

4 SWD A

5 ADD A

6 NC none

7 NC none

Circuit A

Circuit B

8 D1- C

9 D1+ D

10 D2- C

11 D2+ D

12 NC none

13 NC none

14 NC A

Note 4: Thermal resistance junction-to-ambient in still air when attached to a printed circuit board with 1 oz. foil is 148 ˚C/W.

Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin.

Note 6: Reflow temperature profiles are different for lead-free and non lead-free 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 a SensorPath 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 LM32 and the thermal resistance. See (Note 4) for the thermal resistance to be used in the self-heating calculation.

Note 11: The accuracy of the LM32CIMT is guaranteed when using the thermal diode of an Intel 90 nm Pentium 4 processor or any thermal diode with a non-ideality factor of 1.011 and series resistance of 3.33Ω. When using a MMBT3904 type transistor as a thermal diode the error band will be typically shifted by -4.5 ˚C.

Note 12: This specification is provided only to indicate how often temperature data are updated.

Note 13: The output fall time is measured from (V

Note 14: The output rise time is measured from (V

Note 15: The rise and fall times are not tested but guaranteed by design.

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

IH min

IL max

Circuit C

)to(V

IL max

)to(V

IH min

Circuit D

www.national.com 6

Timing Diagrams

LM32

20071104

FIGURE 1. Timing for Data Bits 0, 1 and Start Bit. See Section 1.2 "SensorPath BIT SIGNALING" for further details.

www.national.com7

Timing Diagrams (Continued)

LM32

FIGURE 2. Timing for Attention Request and Reset. See Section 1.2 "SensorPath BIT SIGNALING" for further details.

www.national.com 8

20071105

+ 16 hidden pages