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 permanent 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*
Package Power Dissipation (TA ≤ 70°C)
Plastic DIP ......................................................730mW
SOIC...............................................................470mW
Derating Factors
Plastic DIP .................................................... 8mW/°C
SOIC............................................................. 6mW/°C
Supply Voltage ...........................................................5.5V
Input Voltage Any Input....... (GND – 0.3V) to (VDD +0.3V)
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 coefficient (PTC) temperature sensor and dual threshold detector. Temperature set point programming is easily accomplished with external programming resistors from the HIGH
SET and LOW SET inputs to VCC. The HIGH LIMIT and LOW
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 resistance 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
ELECTRICAL CHARACTERISTICS
Over Operating Temperature Range) VDD = 2.7V to 4.5V, unless otherwise specified.
Parameter Conditions Min Typ* Max Unit
Supply Voltage Range 2.7 — 4.5 V
Supply Current 2.7V ≤ VDD ≤ 4.5V — 150 250 µA
Absolute Accuracy T = Programmed Temperature T – 3 T ±1 T +3 °C
V
OH
I
OH =
250µA 0.9 x V
DD
—— V
I
OH =
500µA 0.8 x V
DD
— — V
V
OL
I
OL =
500µA — — 0.1 x V
DD
V
I
OL =
1mA — — 0.2 x V
DD
V
Hysteresis Falling Temperature — — – 2 °C
* Measured at 25°C
TEMPERATURE (°C)
RESISTANCE (kΩ)
-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