TOP242-250

M

12/04

12

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

pincurrentwithpositivepolarityindicatingcurrentsflowinginto

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

30 µA hysteresis). Between the UV and OV thresholds, the

output is enabled. For external current limit and line feed-

forward with DC

magnitude of the I

DC

(+60 µA typical) to 38% at I

limit is available only with negative MULTI-FUNCTION

pin current. Please see graphs in the Typical Performance

Characteristics section for the current limit programming

range and the selection of appropriate resistor value.

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

400

PI-2636-010802

Output

MOSFET

Switching

(Enabled)

(Disabled)

Current

Limit

M Pin

L Pin

X Pin

Maximum

Duty Cycle

-22

µA

-27

µA

I

I

I

I

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 (

µA)

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.