 2002 Microchip Technology Inc.

DS21447C-page 9

TC647

5.0

TYPICAL APPLICATIONS

Designing with the TC647 involves the following:

(1) The temp sensor network must be configured to

the temperature range to be regulated.

(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 TC647 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 TC647 should consult the documen-

tation for both TC642EV and (DS21403) and

TC642DEMO (DS21401). Figure 5-1 shows the base

schematic for the TC642DEMO.

FIGURE 5-1:

Typical Application Circuit.

FAULT

SENSE

NTC

R1

R2

R3

R4

GND

Fan Fault

Shutdown

Shutdown

(Optional)

Note: *See cautions regarding latch-up considerations in Section 5.0, "Typical Applications".

Q1

+12V

+5V*

VOUT

1 µF

TC647

Fan

1

8

6

7

5

4

2

3

CB

1 µF

CB

0.01 µF

CB

0.01 µF