TOP243YN datasheet(40/52 Pages) POWERINT

40 / 52 page

TOP242-250

12/04

Figure 54a. Current Limit vs. X or M Pin Current (see Figures 55a and 56a for TOP245P and TOP246P).

The following precautions should be followed when testing

TOPSwitch-GX

by itself outside of a power supply. The

schematicshowninFigure53issuggestedforlaboratorytesting

of TOPSwitch-GX.

When the DRAIN pin supply is turned on, the part will be

in the auto-restart mode. The CONTROL pin voltage will be

oscillating at a low frequency between 4.8 V and 5.8 V and

the drain is turned on every eigth cycle of the CONTROL pin

oscillation. If the CONTROL pin power supply is turned on

while in this auto-restart mode, there is only a 12.5% chance

that the CONTROL pin oscillation will be in the correct state

(drainactivestate)sothatthecontinuousdrainvoltagewaveform

may be observed. It is recommended that the V

C power supply

be turned on ﬁrst and the DRAIN pin power supply second if

continuous drain voltage waveforms are to be observed. The

12.5% chance of being in the correct state is due to the divide-

by-8 counter. Temporarily shorting the CONTROL pin to the

SOURCE pin will reset TOPSwitch-GX, which then will come

up in the correct state.

BENCH TEST PRECAUTIONS FOR EVALUATION OF ELECTRICAL CHARACTERISTICS

Typical Performance Characteristics

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

100

120

140

160

180

200

-250

-200

-150

-100

-50

IX or IM (µA)

PI-2653-031904

Scaling Factors:

TOP242 P/G/Y/R/F: .45

TOP243 P/G:

.75

TOP243 Y/R/F:

.90

TOP244 P/G:

TOP244 Y/R/F:

1.35

TOP245 Y/R/F:

1.80

TOP246 Y/R/F:

2.70

TOP247 Y/R/F:

3.60

TOP248 Y/R/F

4.50

TOP249 Y/R/F:

5.40

TOP250 Y/R/F:

6.32

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

100

120

140

160

180

200

10K

15K

20K

25K

30K

35K

40K

External Current Limit Resistor RIL (Ω)

PI-2652-042303

45K

Maximum and minimum levels

are based on characterization.

Minimum

Typical

Maximum