®
TOP100-4
TOPSwitch® Family
Three-terminal Off-line PWM Switch
Product Highlights
Low Cost Replacement for Discrete Switchers
• 20 to 50 fewer components - cuts cost, increases reliability
• Source-connected tab and Controlled MOSFET turn-on
reduce EMI and EMI filter costs
• Allows for a 50% smaller and lighter solution
• Cost competitive with linears above 5 W
Up to 90% Efficiency in Flyback Topology
• Built-in start-up and current limit reduce DC losses
• Low capacitance 350 V MOSFET cuts AC losses
• CMOS controller/gate driver consumes only 6 mW
• 70% maximum duty cycle minimizes conduction losses
Simplifies Design - Reduces Time to Market
• Supported by many reference designs
• Integrated PWM Controller and 350 V MOSFET in a
industry standard three pin TO-220 package
• Only one external capacitor needed for compensation,
bypass and start-up/auto-restart functions
System Level Fault Protection Features
• Auto-restart and cycle by cycle current limiting functions
handle both primary and secondary faults
• On-chip latching thermal shutdown protects the entire
system against overload
AC
IN
DRAIN
SOURCE
CONTROL
TOPSwitch
PI-1704112995
Figure 1. Typical Application.
TOPSwitch SELECTION GUIDE
OUTPUT POWER RANGE
ORDER
PART
NUMBER
PFC/
BOOST
FLYBACK
100/110 V
VAC
48 V
DC
100/110
VAC
TOP100YAI*
0-20 W
0-6.8 W
0-30 W
TOP101YAI*
15-35 W
6-12 W
25-50 W
Description
TOP102YAI*
20-45 W 8.5-17 W
35-70 W
The TOPSwitch family implements, with only three pins, all
functions necessary for an off-line switched mode control
system: high voltage N-channel power MOSFET with controlled
turn-on gate driver, voltage mode PWM controller with
integrated 100 kHz oscillator, high voltage start-up bias circuit,
bandgap derived reference, bias shunt regulator/error amplifier
for loop compensation and fault protection circuitry. Compared
to discrete MOSFET and controller or self oscillating (RCC)
switching converter solutions, a TOPSwitch integrated circuit
can reduce total cost, component count, size, weight and at the
same time increase efficiency and system reliability. These
TOP103YAI*
25-55 W
11-22 W
45-90 W
TOP104YAI*
30-60 W
12-25 W
55-110 W
Highly Versatile
• Implements Buck, Boost, Flyback or Forward topology
• Easily interfaces with both opto and primary feedback
• Supports continuous or discontinuous mode of operation
• Specified for operation down to 16 V DC input
* Package Outline: Y03A
devices are intended for 100/110 VAC off-line Power Supply
applications in the 0 to 60 W range and power factor correction
(PFC) applications in the 0 to 110 W range. They are also well
suited for Telecom, Cablecom and other DC to DC converter
applications in the 0-25 W range (see Design Note DN-16).
July 1996
