VESTEL 17MB11, Service Manual

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Plasma TV Service Manual 05/01/2006
compensation and a fixed-frequency oscillator. The LM2576 series offers a high efficiency replacement
for popular three-terminal adjustable linear regulators. It substantially reduces the size of the heat sink,
and in many cases no heat sink is required. A standard series of inductors available from several
different manufacturers are ideal for use with the LM2576 series. This feature greatly simplifies the
design of switch-mode power supplies. The feedback voltage is guaranteed to
±
2% tolerance for
adjustable versions, and the output voltage is guaranteed to
±
3% for fixed versions, within specified
input voltages and output load conditions. The oscillator frequency is guaranteed to
±
10%. External
shutdown is included, featuring less than 200
⎧
A standby current. The output switch includes cycle-
bycycle current limiting and thermal shutdown for full protection under fault conditions.
12.31.2. Features
• 3.3V, 5V, 12V, and adjustable output versions
• Voltage over specified line and load conditions:
Fixed version:
±
3% max. output voltage
Adjustable version:
±
2% max. feedback voltage
• Guaranteed 3A output current
• Wide input voltage range:
4V to 40V
• Wide output voltage range
1.23V to 37V
• Requires only 4 external components
• 52kHz fixed frequency internal oscillator
• Low power standby mode I
Q
typically < 200
⎧
A
• 80% efficiency (adjustable version typically > 80%)
• Uses readily available standard inductors
• Thermal shutdown and current limit protection
• 100% electrical thermal limit burn-in
12.31.3. Pin Descriptions