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LM61

2.7V, SOT-23 or TO-92 Temperature Sensor

General Description

The LM61 is a precision integrated-circuit temperature sen-

sor that can sense a −30˚C to +100˚C temperature range

while operating from a single +2.7V supply. The LM61’s

output voltage is linearly proportional to Celsius (Centigrade)

temperature (+10 mV/˚C) and has a DC offset of +600 mV.

The offset allows reading negative temperatures without the

need for a negative supply. The nominal output voltage of the

LM61 ranges from +300 mV to +1600 mV for a −30˚C to

+100˚C temperature range. The LM61 is calibrated to pro-

vide accuracies of

2.0˚C at room temperature and

3˚C

over the full −25˚C to +85˚C temperature range.

The LM61’s linear output, +600 mV offset, and factory cali-

bration simplify external circuitry required in a single supply

environment where reading negative temperatures is re-

quired. Because the LM61’s quiescent current is less than

125 µA, self-heating is limited to a very low 0.2˚C in still air.

Shutdown capability for the LM61 is intrinsic because its

inherent low power consumption allows it to be powered

directly from the output of many logic gates.

Features

n Calibrated linear scale factor of +10 mV/˚C

n Rated for full −30˚ to +100˚C range

n Suitable for remote applications

n UL Recognized Component

Applications

n Cellular Phones

n Computers

n Power Supply Modules

n Battery Management

n FAX Machines

n Printers

n HVAC

n Disk Drives

n Appliances

Key Specifications

Accuracy at 25˚C

2.0 or

3.0˚C

(max)

Accuracy for −30˚C to +100˚C

4.0˚C (max)

Accuracy for −25˚C to +85˚C

3.0˚C (max)

Temperature Slope +10 mV/˚C

Power Supply Voltage Range +2.7V to +10V

Current Drain

25˚C 125 µA (max)

Nonlinearity

0.8˚C (max)

Output Impedance 800 Ω (max)

Typical Application

01289702

= (+10 mV/˚C x T ˚C) + 600 mV

Temperature (T) Typical V

+100˚C +1600 mV

+85˚C +1450 mV

+25˚C +850 mV

0˚C +600 mV

−25˚C +350 mV

−30˚C +300 mV

FIGURE 1. Full-Range Centigrade Temperature Sensor (−30˚C to +100˚C)

Operating from a Single Li-Ion Battery Cell

February 2004

LM61 2.7V, SOT-23 or TO-92 Temperature Sensor

Summary of content (10 pages)

PAGE 1
LM61 2.7V, SOT-23 or TO-92 Temperature Sensor General Description Applications The LM61 is a precision integrated-circuit temperature sensor that can sense a −30˚C to +100˚C temperature range while operating from a single +2.7V supply. The LM61’s output voltage is linearly proportional to Celsius (Centigrade) temperature (+10 mV/˚C) and has a DC offset of +600 mV. The offset allows reading negative temperatures without the need for a negative supply.
PAGE 2
LM61 Connection Diagrams TO-92 SOT-23 01289701 01289725 Top View See NS Package Number MA03B See NS Package Number Z03A Ordering Information Order Number Device Marking Supplied In LM61BIM3 T1B 1000 Units on Tape and Reel LM61BIM3X T1B 3000 Units on Tape and Reel LM61CIM3 T1C 1000 Units on Tape and Reel LM61CIM3X T1C 3000 Units on Tape and Reel LM61BIZ LM61BIZ Bulk LM61CIZ LM61CIZ Bulk www.national.
PAGE 3
Supply Voltage +12V to −0.2V Output Voltage (+VS + 0.6V) to −0.
PAGE 4
LM61 Electrical Characteristics (Continued) Note 10: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output due to heating effects can be computed by multiplying the internal dissipation by the thermal resistance. Note 11: For best long-term stability, any precision circuit will give best results if the unit is aged at a warm temperature, and/or temperature cycled for at least 46 hours before long-term life test begins.
PAGE 5
Start-Up Response 01289722 01289714 FIGURE 2. Printed Circuit Board Used for Heat Sink to Generate All Curves. 1⁄2" Square Printed Circuit Board with 2 oz. Copper Foil or Similar. accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may operate at cold temperatures where condensation can occur.
PAGE 6
LM61 1.0 Mounting Still air (Continued) SOT-23* SOT-23** TO-92* TO-92*** no heat sink small heat fin no heat sink small heat fin θJA TJ − T A θJA TJ − T A θJA TJ − T A θJA (˚C/W) (˚C) (˚C/W) (˚C) (˚C/W) (˚C) (˚C/W) (˚C) 450 0.26 260 0.13 180 0.09 140 0.07 180 0.09 90 0.05 70 0.03 Moving air T J − TA *Part soldered to 30 gauge wire. **Heat sink used is 1⁄2" square printed circuit board with 2 oz. foil with part attached as shown in Figure 2.
PAGE 7
LM61 2.0 Capacitive Loads (Continued) 01289717 FIGURE 6. Simplified Schematic 3.0 Applications Circuits 01289718 FIGURE 7. Centigrade Thermostat 01289719 FIGURE 8. Conserving Power Dissipation with Shutdown 7 www.national.
PAGE 8
LM61 4.0 Recommended Solder Pads for SOT-23 Package 01289720 www.national.
PAGE 9
LM61 Physical Dimensions inches (millimeters) unless otherwise noted SOT-23 Molded Small Outline Transistor Package (M3) Order Number LM61BIM3, LM61BIM3X, LM61CIM3 or LM61CIM3X NS Package Number MA03B 9 www.national.
PAGE 10
LM61 2.7V, SOT-23 or TO-92 Temperature Sensor Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-92 Plastic Package (Z) Order Number LM61BIZ or LM61CIZ NS Package Number Z03A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1.