 2002 Microchip Technology Inc.

DS21449C-page 9

TC649

5.0

TYPICAL APPLICATIONS

Designing with the TC649 involves the following:

(1) The temperature sensor network must be

to 100% of the temperature range to be regulated.

(2) The auto-shutdown temperature must be set

(3) The output drive transistor and associated circuitry

must be selected.

be designed for maximum efficiency while

delivering adequate signal amplitude.

(5) If shutdown capability is desired, the drive require-

ments of the external signal or circuit must be

considered.

The TC642 demonstration and prototyping board

(TC642DEMO) and the TC642

Evaluation

Kit

(TC642EV) provide working examples of TC649 cir-

cuits and prototyping aids. The TC642DEMO is a

printed circuit board optimized for small size and ease

of inclusion into system prototypes. The TC642EV is a

larger board intended for benchtop development and

analysis. At the very least, anyone contemplating a

design using the TC649 should consult the documen-

tation for both TC642EV (DS21403) and TC642DEMO

(DS21401).Figure 5-1 shows the base schematic for

the TC642DEMO.

FIGURE 5-1:

Typical Application Circuit.

FAULT

SENSE

NTC

R3

GND

*See cautions regarding Latch-up Considerations in Section 5.0, "Typical Applications".

**Optional. See Section 5.0, "Typical Applications" for details.

Notes:

Fan Fault

Shutdown

Shutdown**

+12V

+5V*

1 µF

TC649

Fan

0.01 µF

0.01 µF

1 µF

+

+5V