2-26

TELCOM SEMICONDUCTOR, INC.

Maximum Chip Temperature ................................. +150

°C

Storage Temperature ............................ – 65

°C to +150°C

Lead Temperature (Soldering, 10 sec) ................. +300

°C

*Static-sensitive device. Unused devices must be stored in conductive

material. Protect devices from static discharge and static fields. Stresses

above those listed under "Absolute Maximum Ratings" may cause perma-

nent damage 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.

Exposure to absolute maximum rating conditions for extended periods may

affect device reliability.

ABSOLUTE MAXIMUM RATINGS*

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

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

Derating Factors

Plastic DIP .................................................... 8mW/

°C

SOIC ............................................................. 6mW/

°C

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

Operating Temperature

V Version ........................................ – 40

°C to +125°C

E Version .......................................... – 40

°C to +85°C

C Version ............................................... 0

°C to +70°C

Figure 1. TC623 Sense Resistors vs. Trip Temperature

DETAILED DESCRIPTION

TC623 Operation

The TC623 consists of a positive temperature coeffi-

cient (PTC) temperature sensor and dual threshold detec-

tor. Temperature set point programming is easily accom-

plished with external programming resistors from the HIGH

LIMIT outputs remain inactive (low) as long as the measured

temperature is below setpoint values. As temperature in-

creases, the LOW LIMIT is driven high when temperature

equals the LOW LIMIT setpoint (

±3°C). If temperature

continues to climb, the HIGH LIMIT output is driven high

when temperature equals the HIGH LIMIT setpoint (

±3°C).

Figure 1 shows the relationship between the sense resis-

tance values and trip point temperature.

The CONTROL output is driven high when the HIGH

LIMIT output goes high, and is reset low when the LOW

LIMIT output goes low. This output provides the logic for

simple ON/OFF fan control. Figure 2 shows overall TC623

operation.

Figure 2. TC623 Temperature vs. Output

Parameter

Conditions

Min

Typ*

Max

Unit

Supply Voltage Range

2.7

—

4.5

V

Supply Current

2.7V

—

150

250

µA

Absolute Accuracy

T = Programmed Temperature

T – 3

T

±1

T +3

°C

——

V

—

—

V

—

—

V

—

—

V

Hysteresis

Falling Temperature

—

—

– 2

°C

* Measured at 25

°C

TEMPERATURE (

°C)

-55

-35

-15

5

25

45

65

85

105

125

50

100

150

200

250

LOW SET POINT

HIGH SET POINT

LOW LIMIT OUTPUT

HIGH LIMIT OUTPUT

CONTROL OUTPUT (COOL OPTION)

TEMPERATURE

TC623

3V, DUAL TRIP POINT

TEMPERATURE SENSOR