TOP242-250
M Pin
X Pin
I
REM(N)
(Enabled)
Output
MOSFET
Switching
I
UV
L Pin
I
OV
(Disabled)
Disabled when supply
output goes out of
regulation
I
LIMIT
(Default)
I
Current
Limit
I
DC
MAX
(78.5%)
Maximum
Duty Cycle
I
V
BG
+ V
TP
-22
µA
-27
µA
V
BG
Pin Voltage
-250
-200
-150
-100
-50
0
50
100
150
200
250
300
350
400
I
X and L Pins (Y, R or F Package) and M Pin (P or G Package) Current (µA)
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.
PI-2636-010802
Figure 11. MULTI-FUNCTION (P or G package), LINSE-SENSE, and EXTERNAL CURRENT LIMIT (Y, R or F package) Pin Characteristics.
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 DC
MAX
. Line feed-forward with
DC
MAX
reduction lowers maximum duty cycle from 78% at I
M(DC)
(+60
µA
typical) to 38% at I
OV
(+225
µA).
External current
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.
12
M
12/04
POWERINT [ POWER INTEGRATIONS, INC. ]
