TOP242-250
27
K
9/03
Table 4 (cont). Comparison Between TOPSwitch-II and TOPSwitch-GX.
*Not available **Current limit set to internal maximum
Function
TOPSwitch-FX
TOPSwitch-GX
TOPSwitch-GX
Advantages
Light Load Operation
Cycle skipping
Frequency and Duty Cycle
reduction
Line sensing and externally
set current limit possible
simultaneously
(functions split onto
L and X pins)
100-30%
Improves light load efficiency
Reduces no-load consumption
Additional design flexibility allows all
features to be used simultaneously
Line Sensing/Externally Line sensing and
Set Current Limit
(Y, R and F Packages)
externally set
current limit
mutually
exclusive (M pin)
100-40%
Current Limit
Programming
Range
Minimizes transformer core size
in highly continuous designs
TOPSwitch-FX
vs.
TOPSwitch-GX
Table 5 compares the features and performance differences
between
TOPSwitch
-
GX
and
TOPSwitch-FX
. Many of the new
features eliminate the need for additional discrete components.
Other features increase the robustness of design allowing cost
savings in the transformer and other power components.
Function
TOPSwitch-II
TOPSwitch-GX
Figures
TOPSwitch-GX
Advantages
Remote ON/OFF
N/A*
Single transistor
or optocoupler
interface or manual 25, 26, Low consumption in remote off state
switch
27, 29, Active-on control for fail-safe
36, 37, Eliminates expensive in-line on/off
38, 39,
switch
40
Allows processor controlled turn
on/off
Permits shutdown/wake-up of
peripherals via LAN or parallel port
Single transistor
Synchronization to external lower
or optocoupler
frequency signal
interface
Starts new switching cycle on
demand
Hysteretic 130
°
C
Automatic recovery from thermal
min. Shutdown (with
fault
75
°
C hysteresis)
Large hysteresis prevents circuit
board overheating
±
7% (@25
°
C)
10% higher power capability due to
-8% (0
°
C to100
°
C) -4% Typical
(0
°
C to 100
°
C)**
0.037" / 0.94 mm
0.137" / 3.48 mm
0.037" / 0.94 mm
0.137" / 3.48 mm
TO-220 0.046" / 1.17 mm
0.068" / 1.73 mm
DRAIN Creepage at
0.045" / 1.14 mm
0.113" / 2.87 mm
PCB for Y, R and F
(R and F
(preformed leads)
Packages
Package N/A*)
11, 22, Fast on/off (cycle by cycle)
23, 24, Active-on or active-off control
Synchronization
N/A*
Thermal Shutdown
125
°
C min.
Latched
Current Limit Tolerance
±
10% (@25
°
C)
tighter tolerance
DRAIN
Creepage
at Package
DIP
SMD
Greater immunity to arcing as a
result of build-up of dust, debris and
other contaminants
Preformed leads accommodate
large creepage for PCB layout
Easier to meet Safety (UL/VDE)
Table 5. Comparison Between TOPSwitch-FX and TOPSwitch-GX.
(continued on next page)