Rev. R 10/20

12

TOP242-250

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through a resistor. However, this function is not necessary

in most applications since the internal current limit of the

P and G package devices has been reduced, compared

to the Y, R and F package devices, to match the thermal

dissipation capability of the P and G packages. It is there-

fore recommended that the MULTI-FUNCTION pin is used

for line sensing as described above and not for external

current limit reduction. The same pin can also be used

as a remote ON/OFF and a synchronization input in both

modes. Please refer to Table 3 for possible combinations

of the functions with example circuits shown in Figure 30

through Figure 40. A description of specific functions in

terms of the MULTI-FUNCTION pin I/V characteristic is

shown in Figure 11. The horizontal axis represents MULTI-

FUNCTION pin current with positive polarity indicating

currents flowing into the pin. The meaning of the vertical

axes varies with functions. For those that control the ON/

OFF states of the output such as UV, OV and remote ON/

OFF, the vertical axis represents the enable/disable states

of the output. UV triggers at I

UV (+50 µA typical) and OV

triggers at I

OV (+225 µA typical with 30 µA hysteresis).

Between the UV and OV thresholds, the output is enabled.

For external current limit and line feed- forward with DC

MAX

reduction, the vertical axis represents the magnitude

of the I

LIMIT and DCMAX. Line feed-forward with DCMAX

reduction lowers maximum duty cycle from 78% at I

M(DC)

-250

-200

-150

-100

-50

050

100

150

200

250

300

350

400

PI-2636-010802

Output

MOSFET

Switching

(Enabled)

(Disabled)

ILIMIT (Default)

DCMAX (78.5%)

Current

Limit

M Pin

L Pin

X Pin

Maximum

Duty Cycle

VBG

-22 A

-27 A

VBG + VTP

I

I

I

I

IUV

IREM(N)

IOV

Pin Voltage

Note: This figure provides idealized functional characteristics with typical performance values. Please refer to the parametric

table and typical performance characteristics sections of the data sheet for measured data.

X and L Pins (Y, R or F Package) and M Pin (P or G Package) Current ( A)

Disabled when supply

output goes out of

regulation

Figure 11. MULTI-FUNCTION (P or G package), LINSE-SENSE, and EXTERNAL CURRENT LIMIT (Y, R or F package) Pin

Characteristics.