LTC1504A
500mA Low Voltage
Step-Down Synchronous
Switching Regulator
FEATURES
s
s
s
s
s
s
s
s
s
s
DESCRIPTION
The LTC
®
1504A is a self-contained, high efficiency syn-
chronous buck switching regulator. It includes a pair of
on-chip 1.3Ω power switches, enabling it to supply up to
500mA of load current. Efficiency peaks at 92%, minimiz-
ing heat and wasted power. The synchronous buck archi-
tecture allows the output to source or sink current as
required to keep the output voltage in regulation. 100%
duty cycle operation minimizes dropout voltage.
The LTC1504A is available in adjustable and fixed 3.3V
output versions. An adjustable current limit circuit pro-
vides protection from overloads. The internal 1% refer-
ence combined with a sophisticated voltage feedback loop
provides optimum output voltage accuracy and fast load
transient response. The LTC1504A is specified to operate
with input voltages between 4V and 10V. Contact the LTC
factory for guaranteed specifications at 2.7V supply.
The LTC1504A is a pin-compatible, functional upgrade to
the LTC1504.
The LTC1504A is available in a plastic SO-8 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
500mA Output Current at 3.3V Output
Up to 92% Peak Efficiency
100% Maximum Duty Cycle
Internal Reference Trimmed to 1%
Output Can Source or Sink Current
Requires as Few as Four External Components
Input Voltage Range: 4V to 10V
Adjustable Current Limit
Small SO-8 Package
200kHz Switching Frequency Can Typically be
Synchronized Up to 500kHz
APPLICATIONS
Daisy-Chained Control Outputs
s
s
s
s
Small Portable Digital Systems
Active Termination
Auxiliary Output Voltage Supplies
Minimum Part Count/Size Switchers
TYPICAL APPLICATION
Minimum Part Count 5V to 3.3V Regulator
NC
I
MAX
5V
SHUTDOWN
SHDN
SW
L
EXT
50µH
3.3V AT 500mA
EFFICIENCY (%)
5V to 3.3V Efficiency
100
90
80
70
60
50
40
30
20
1504A • TA01
+
V
CC
C
IN
22µF
LTC1504A-3.3
GND
SS
SENSE
COMP
1000pF
+
C
OUT
47µF
C
IN
: AVX TPSC226M016R0375
C
OUT
: AVX TAJC476M010
L
EXT
: COILTRONICS CTX50-1P
NC
10
0
10
100
LOAD CURRENT (mA)
500
1504 • TA02
U
U
U
1
LINER [ LINEAR TECHNOLOGY ]
