QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 993
500MA, 2.25 MHZ SYNCHRONOUS STEP-DOWN REGULATOR
1
LTC3542
DESCRIPTION
Demonstration circuit 993A is a step-down converter,
using the LTC3542 monolithic synchronous buck regula-
tor. The DC993A has an input voltage range of 2.5V to
5.5V, and is capable of delivering up to 500 mA of output
current in a small 2x2 mm DFN package. The output
voltage of the DC993A can be set as low as 0.6V, the
reference voltage of the LTC3542. At low load currents,
the DC993A can operate in either noise sensitive applica-
tions, due to the capability of the LTC3542 to operate in
pulse-skipping mode, or in high efficiency applications,
because the LTC3542 can also operate in Burst Mode.
Of course, in continuous mode, or large load current
applications, the DC993A is a high efficiency circuit -
over 90% in some cases. The DC993A consumes only
27 uA during sleep mode operation, and during shut-
down, it consumes at less than 1 uA. Because of the
high switching frequency of the LTC3542 – nominal 2.25
MHz - the DC993A uses low profile surface mount com-
ponents. These features, plus the LTC3542 coming in a
either a tiny 2x2 mm 6-Lead DFN package or a small 6-
Lead SOT package, make the DC993A an ideal circuit for
use in battery-powered, hand-held applications.
Gerber
files for this circuit are available. Call the LTC Fac-
tory.
Table 1. Performance Summary (TA = 25°C)
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage
2.5V
Maximum Input Voltage
5.5V
GND = Shutdown
Run/Shutdown
VIN = Run
1.2V ±4% (1.152V – 1.248V)
1.5V ±4% (1.44V - 1.56V)
Output Voltage VOUT
VIN = 2.5V to 5.5V, IOUT = 0A to 500 mA
1.8V ±4% (1.728V – 1.872V)
Typical Output Ripple VOUT
VIN = 5V, IOUT = 500 mA (20 MHz BW)
< 20mVP–P
Line
±1%
Output Regulation
Load
±1%
Nominal Switching Frequency
2.25 MHz
Burst Mode - VIN = 3.6V, VOUT = 1.8V
~60 mA ± 10 mA
Operation Modes
Pulse-Skip - VIN = 3.6V, VOUT = 1.8V
~60 mA ± 10 mA
