TEMPERATURE LIMIT SWITCH
TC626*
TC626
* PATENTED
TEMPERATURE LIMIT SWITCH
FEATURES
s
s
s
s
s
Requires No External Components
On-Chip Temperature Sensing
TO-220 package for "Hot Spot" Mounting
50mA Output Signal TO-220 Package (TC626VAB)
TO-92 Package for Direct Circuit Board Mounting
GENERAL DESCRIPTION
The TC626 is a temperature limit detector that notifies
the system when measured temperature is above the fac-
tory-programmed setting. It is designed to replace mechani-
cal (bimetal) temperature limit switches and offers increased
ruggedness, higher reliability and greater setpoint accuracy.
It requires no external components.
The TC626 operates over a – 55°C to +125°C tempera-
ture range. It is available in a TO-92 package, which is ideal
for ambient temperature sensing applications. It is also
available in a TO-220-3 package for heatsink temperature
measurement applications.
APPLICATIONS
s
s
s
s
s
Vibration-Immune Temperature Sensing
Fan Speed Control Circuits
System Overtemperature Shutdown
Advanced Thermal Warning
Consumer Products
SYSTEM OVERTEMPERATURE PROTECTION
5V TO 18V
PIN 1 SWITCHES 'HIGH' IF
TEMPERATURE GOES ABOVE
THE PRESET VALUE.
NC
1
TC626
RELAY
3
SYSTEM POWER
ORDERING INFORMATION
Part Number*
TC626xxxVAB
TC626xxxVZB
Package
TO-220-3
TO-92-3
Temperature
Range
– 55°C to +125°C
– 55°C to +125°C
2
*xxx is trip-point temperature, available in 5°C increments, from +10°C
to +120°C (a 50°C part would be TC626050CAB).
NC = NORMALLY CLOSED
PIN CONFIGURATIONS
TO-220-3
TO-92-3
1 2 3
TC626xxxVAB
1 2 3
TC626xxxVZB
1 2 3
OUTPUT
V
DD
GROUND
TC626-6
OUTPUT
V
DD
GROUND
8/23/96 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices.
1
TEMPERATURE LIMIT SWITCH
TC626
ABSOLUTE MAXIMUM RATINGS*
Power Dissipation (TO-92)................................... 440mW
(TO-220) ...............................1600mW
Supply Voltage ............................................................20V
Input Voltage Any Input ...... (GND – 0.3V) to (V
DD
+ 0.3V)
Operating Temperature ......................... – 55°C to +125°C
Maximum Junction Temperature ........................... +150°C
Storage Temperature ............................ – 65°C to +150°C
Lead Temperature (Soldering, 10 sec) ................. +300°C
*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.
ELECTRICAL CHARACTERISTICS:
V
DD
= +5V and T
A
= – 55°C to +125°C, unless otherwise specified.
Parameter
Supply Voltage
Supply Current
Output Resistance
Output Current
Absolute Accuracy
Trip Point Hysteresis
Test Conditions
Min
4.5
—
—
—
—
T–3
3.5
Typ
—
300
—
—
—
T
5
Max
18
600
75
25
10
T+3
6.5
Units
V
µA
Ω
mA
mA
°C
°C
Output High or Low
Source/Sink, V
CC
= 18V
Source/Sink, V
CC
= 4.5V
At trip point
TelCom Semiconductor reserves the right to make changes in the circuitry or specifications detailed in this manual at any time without notice. Minimums
and maximums are guaranteed. All other specifications are intended as guidelines only. TelCom Semiconductor assumes no responsibility for the use of
any circuits described herein and makes no representations that they are free from patent infringement.
DETAILED DESCRIPTION
The TC626 output maintains a logic low state when
measured temperature is below the factory-programmed
setting. As temperature rises, the output is driven active to
a high level [V
DD
– (I
OUT
)(R
OUT
)] when temperature equals
the setpoint value
±3°C.
Built-in hysteresis prevents output "chattering" when
measured temperature is at (or near) the trip point (Figure 1).
As temperature falls through the trip point, hysteresis main-
tains the output high until measured temperature is 5°C
lower than the trip point setting.
The TC626VZB (TO-92 package) has a maximum out-
put current of 10mA while the TC626VAB has a maximum
output current of 50mA. Care must be taken to observe
these output current limits as output currents in excess of
those stated will cause device self-heating resulting in
erroneous temperature measurements.
SET POINT
(SET POINT – 5°C)
OUTPUT
Figure 1. TC626 Operation
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