TOP250 datasheet(40/54 Pages) POWERINT

40 / 54 page

Rev. R 10/20

TOP242-250

www.power.com

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

The following precautions should be followed when

testing TOPSwitch-GX by itself outside of a power

supply. The schematic shown in Figure 53 is suggested

for laboratory testing 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 (drain active state) so that the

continuous drain voltage waveform 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-2653-033015

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

05K

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