Microchip Technology TC623CVOA, TC623CEPA, TC623CEOA, TC623CCPA, TC623CCOA Datasheet

TC623

3V, Dual Trip Point Temperature Sensor

Features

• Integrated Temp Sensor and Detector Operate
from a SupplyVoltage as Low as 2.7V

• Replaces Mechanical Thermostats and Switches

• On-Chip Temperature Sense

• 8-Pin DIP or SOIC for Direct PCB Mounting

• 2 User Programmable Temperature Set Points

• 2 Independent Temperature Limit Outputs

• Heat/Cool Regulate Output

Applications

• CPU Thermal Management

• System Over or Under TemperatureShutdown

• Advanced Thermal Warning

• Fan Speed Control Circuits

• Accurate Appliance Temperature Sensing

• Environmental Control

Device Selection Table

Part Number Package Temp. Range

TC623CCOA 8-Pin SOIC 0°C to +70°C

TC623CCPA 8-Pin PDIP 0°C to +70°C
TC623CEOA 8-Pin SOIC -40°C to +85°C
TC623CEPA 8-Pin PDIP -40°C to +85°C
TC623CVOA 8-Pin SOIC -40°C to +125°C

NOTE: Latch Output (C option), is a Standard Device. Con­tact Factory for Latch Q Output (H option).

Functional Block Diagram

Package Type

SOIC

NC

LOW SET

HIGH SET

GND

1

2

TC623CCOA
TC623CEOA

3

TC623CVOA

4

8

7

6

5

V

CC

LOW LIMIT

HIGH LIMIT

CONTROL

PDIP

V

NC

LOW SET

HIGH SET

GND

1

2

TC623CCPA
TC623CEPA

3

4

8

CC

LOW LIMIT

7

6

HIGH LIMIT

5

CONTROL

General Description

The TC623 is a 3V solid-state, programmable temper­ature sensor designed for use in thermal management
applications. It f eatures dual thermal interrupt outputs
(LOW LIMIT and HIGH LIMIT) each of which are set
with an external resistor. The HIGH LIMIT and LOW
LIMIT outputs are driven active (high) when measured
temperature equals the user programmed limits. The
CONTROL output is driven active (high) when t emper­ature equals the HIGH LIMIT set point and turned off
when temperaturefallsbelow the LOW LIMITset point.
TheCONTROLoutputcanbeusedtoprovidesimple
ON/OFF control to a cooling fan if so desired.

Low voltage operation, easy set point programming,
small size and low cost make the TC623 an ideal
choice for many thermal management applications.

Latch

8

V

CC

7

LOW LIMIT

6

HIGH LIMIT

5

SR

CONTROL

Q

1

2

3

4

Temperature

To Voltage

Converter

V

REF

Gen.

V

REF

V

REF

Gen.

R < R

LOW

TC623

+

–

+

–

HIGH

NC

LOW SET

HIGH SET

GND



2002 Microchip TechnologyInc. DS21441B-page 1

TC623

1.0 ELECTRICAL
CHARACTERISTICS

Absolute Maximum Ratings*

Supply Voltage......................................................5.5V

Input Voltage Any Input..(GND – 0.3V) to (V
Package Power Dissipation (T

≤ 70°C)

A

DD

+0.3V)

*Stresses above those listed under "Absolute Maximum Rat­ings"maycause permanentdamage to the device.These are
stress ratings only and functional operation of the device at
these or any other conditions above those indicated in the
operation sections of the specifications is not implied. E xpo­sure to Absolute Maximum R ating conditions for extended
periodsmay affectdevice reliability.

Plastic DIP.............................................730mW

SOIC......................................................470mW

Derating Factors

Plastic DIP ............................................8mW/°C

SOIC.....................................................6mW/°C

Operating Temperature

V Version .................................-40°C to +125°C

E Version ...................................-40°C to +85°C

C Version ...................................... 0°C to +70°C

Storage Temperature..........................-65°C to +150°C

TC623 ELECTRICAL SPECIFICATIONS

Electrical Characteristics: Over Operating Temperature Range, VDD= 2.7V to 4.5V, unlessotherwise specified.

Symbol Parameter Min Typ. Max Unit Test Conditions

V

DD

I

DD

T

SET

V

OH

V

OL

HYS Hysteresis — — -2 °C Falling Te mperature

SupplyVoltage Range 2.7 — 4.5 V
Supply Current — 150 250 µA2.7V≤ VDD≤ 4.5V
Absolute Accuracy T - 3 T ±1 T + 3 °C T = ProgrammedTemperature
Output Voltage High 0.9 x V

0.8 x V

OutputVoltage Low —

—

DD
DD

—
—

—
—

—
—

0.1 x V

0.2 x V

DD
DD

V
V

V
V

IOH=250µA
I

=500µA

OH

IOL=500 µA
I

=1mA

OL

DS21441B-page 2



2002 Microchip TechnologyInc.

2.0 PIN DESCRIPTION

ThedescriptionsofthepinsarelistedinTable2-1.

TABLE 2-1: PIN FUNCTION TABLE

Pin No.

(8-Pin SOIC)

(8-Pin PDIP)

1 NC No Internal Connection.
2 LOW SET Low temperature set point. Connect an external 1% resistorfrom LOW SET to V

3 HIGH SET High temperature set point. Connect an external 1% resistor from HIGH SET t o

4 GND Ground Terminal.
5 CONTROL Control output.
6 HIGH LIMIT High temperature push/pull output.
7 LOW LIMIT Low t emperature push/pull output.
8V

Symbol Description

to set trip point.

V

to set trip point.

DD

CC

Power supply input.

TC623

DD



2002 Microchip TechnologyInc. DS21441B-page 3

TC623

p

)

3.0 DETAILED DESCRIPTION

3.1 TC623 Operation

The TC623 has a positive temperature coefficient
(Silicon)temperature sensor and dual threshold detec­tor. Temperature set point programming is accom­plished with external resistors from the HIGH SET and
LOW SET inputs to V
LIMIT outputs remain inactive (low) as long as the
measured temperature is below set point values. As
temperature increases, the LOW LIMIT is driven high
when temperature equals t he LOW LIMIT set point
(±3°C). If temperature continues to climb, the HIGH
LIMIT output is driven high when temperature equals
the HIGH LIMIT set point (±3°C).

Figure 3-1 shows the relationship between the sense
resistance values and trip point t emperature.

FIGURE 3-1: TC623 SENSE

250

200

(kΩ)

TRIP

150

100

RESISTANCE, R

50

-55 -35 -15 5 25 45 65 85 105 125

. The HIGH LIMIT and LOW

CC

RESISTORS VS. TRIP
TEMPERATURE

TEMPERATURE (˚C)

The CONTROL output is driven high when the HIGH
LIMIT output goes high and is RESET low when t he
LOW LIMIT output goes low. This output provides the
logic f or simple ON/OFF fan control. Figure 3-2 shows
overall TC623 operation.

FIGURE 3-2: TC623 TEMPERATURE

VS. OUTPUT

High Set Point

Temperature

Control Out

Low Set Point

Low Limit Output

High Limit Output

ut (Cool Option

To prevent output "chattering" when measuredtemper­ature is at (or near) the trip point values, the LOW SET
and HIGH SET inputseachhave a built-in hysteresis of

-2°Cmax.As a result, the HIGH LIMIT and LOW LIMIT
outputs remain active until the measured temperature
falls a maximum of 2°C below the programmed HIGH
SET and LOW SET thresholds as shown in Figure 3-3.
The programmedsettingthreshold of Figure 3-3 is user
programmed temperature trip points of either the LOW
SET or HIGH SET inputs. T he LOW LIMIT or HIGH
LIMIT output is driven active when temperatureequals
the set point value (to within 3°C). The output remains
active until the temperature falls an additional 2°C
below the set point due to hysteresis.

FIGURE 3-3: HIGH SE T AND LOW SET

THRESHOLDS

DS21441B-page 4

Programmed Setpoint

-2˚C Hysteresis

High Limit or Low Limit Ouput



2002 Microchip TechnologyInc.