APPLICATION HINTS (CONT.)
2. For Set Temperatures < 25 °C
R1 =
Vref x TSH
(TSET + TSH) x ISH - TSET x IIB
(9)
(10)
R2 =
TSET x TC x R1
Vref - R1 x ISH - TSET x TC
Example:
R1 and R2 when set temperature is -25 °C (TSET = 248 °K)
and temperature hysteresis (TSH) is 5 °C.
1.6 x 5
R1 = (248 + 5) x 1.25 µ - 248 x 0.1 µ
R1 = 27.45 k = 27 kΩ
R2 =
248 x 4 m x 27.45 k
1.6 - 27.45 k x 1.25 µ - 248 x 4 m
R
2
=
47.47
k
=
47
kΩ
PACKAGE POWER DISSIPATION (PD)
The power dissipation rating of 200 mW represents the
amount of power the device can dissipate without damage
to the IC. Power dissipation should be kept to a minimum
to reduce temperature errors due to self-heating.
TK11051
January 1999 TOKO, Inc.
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