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DEMO MANUAL DC237/DC238
NO-DESIGN SWITCHER
LT1506 Monolithic 4A Switcher
5V to 15V Input
3.3V Output
DESCRIPTIO
U
Demonstration circuits DC237/DC238 are complete
DC/DC step-down regulators using the LT
®
1506, constant
frequency, high efficiency converter in 7-pin DD (DC238)
and SO-8 (DC237) packages. These circuits are primarily
used in personal computers, disk drives, portable
handheld devices and, in larger systems, as local onboard
regulators. High frequency switching allows the use of
small inductors, making this all surface mount solution
ideal for space conscious systems.
, LTC and LT are registered trademarks of Linear Technology Corporation.
BOARD PHOTOS
DC237 Component Side DC238 Component Side
PERFORmANCE SU ARY
UW
WW
T
A
= 25°C, V
IN
= 12V, I
LOAD
= 2A, V
OUT
= 3.3V, SHDN and SYNC pins open, unless otherwise specified.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Note 1) 3.23 3.3 3.42 V
Maximum I
LOAD
(Note 2) 4 A
Input Voltage Range 4.5 15 V
Switching Frequency 460 500 540 kHz
Output Ripple Voltage 70 mV
P-P
Line Regulation 5V to 15V 2 mV
Load Regulation I
LOAD
= 10mA to 4A 14 mV
SHDN Lockout Threshold 2.3 2.38 2.46 V
SHDN Shutdown Threshold 0.15 0.37 0.6 V
Synchronization Range DC237 Only 580 1000 kHz
Supply Current SHDN = 0V 20 µA
Note 1: Output voltage variations include ±1% tolerance of feedback
divider network. For tighter voltage range, use lower tolerance resistors or
fixed 3.3V output device, LT1506-3.3.
Note 2: For DC237, additional thermal restrictions apply.
