The ISOTMP35R device is also evaluated by means of a "directional" temperature response test, where only

the thermally connected, high-voltage pins of the device are exposed to the elevated temperature, while the

remaining low-voltage pins remain in free air at a standard room temperature condition of 25°C. The objective of

this form of thermal response test is to more properly evaluate the thermal conductivity of the device under test,

even though a slight error can persist from the reference temperature.

Figure 6-4. Directional Thermal Response Test

T = TA = 25°C

Additional thermal

gradient from lower

temperature side

T = TTEST

Heat sourced

through 2oz.

Copper plane

ISOTMP35R

This is demonstrated in Figure 6-5, where ISOTMP35R is shown alongside a standard negative temperature

coefficient (NTC) thermistor, as well as the same NTC adhered via non-conductive thermal epoxy to the high

voltage copper, placed at a clearance distance of 8mm from the temperature source. The resulting responses

demonstrate the excellent response time as well as the accuracy of the ISOTMP35R device. The reference

temperature in this test is 75°C.

Time (s)

-4

0

4

8 12 16 20 24 28 32 36 40 44 48 52 56 60

20

25

30

35

40

45

50

55

60

65

70

75

80

ISOTMP35R

NTC with Epoxy

NTC without Epoxy

Figure 6-5. ISOTMP35R Directional Thermal Response

6.4 Device Functional Modes

The singular functional mode of the ISOTMP35R is an analog output directly proportional to temperature.

ISOTMP35R

SNIS244 – SEPTEMBER 2025

www.ti.com

12

Submit Document Feedback

Copyright © 2025 Texas Instruments Incorporated

Product Folder Links: ISOTMP35R