Linear Technology DC164 Demo Manual

U
DESCRIPTIO
Demonstration Circuit 164 is a constant-frequency step-
down (buck) regulator implemented entirely in surface
®
mount, using the LTC 1624 switching regulator controller.
DC164 is usable in a wide range of portable, industrial,
computer and communications applications. The output
voltage is programmable to 2.5V, 3.3V or 5V via a jumper.
The input voltage can range from 4.8V to 28V (limited by the
external MOSFET). The circuit highlights the capabilities of
the LTC1624, which uses a current mode, constant-fre-
quency architecture to switch an N-channel power MOSFET
while providing 95% maximum duty cycle. Operating effi-
ciencies exceeding 90% are obtained.
PERFORMANCE
Input Voltage Range (Maximum Input Voltage Limited by External MOSFET and Input Capacitor)
Output Output Voltage (Jumper Selectable)
Max Output Current (Continuous)
Max Output Current (Peak)
Typical Output Ripple at 10MHz Bandwidth (Burst Mode Operation) I
Typical Output Ripple at 10MHz Bandwidth (Continuous) I
V Line Regulation 4.5V to 20V
IN
I Load Regulation No Load to Full Rated Output
OUT
I Supply Current with No Load (Typical), V
Q
Supply Current in Shutdown (Typical), V
V Run Pin Threshold (Typical)
ITH/RUN
Frequency Operating Frequency (Typical)
TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTO
Efficiency
100
V = 10V
IN
90
V = 5V
OUT
80
70
60
V
OUT
50
1 10
LOAD CURRENT (mA)
8-Pin N-Channel DC/DC Converter
SUMM ARY
Operating Temperature Range 0°C to 50°C.
W U
V = 2.5V
OUT
= 3.3V
100 1000 3000
DC164 • TPC01
DEMO MANUAL DC164
DEMO MANUAL DC164
DESIGN READY SWITCHER
LTC1624 Constant Frequency,
This results in a power supply that has very high
efficiency, low ripple and fast transient response. At
low output currents the LTC1624 automatically switches
TM
to Burst Mode operation to reduce switching losses
and maintain high operating efficiencies. Additionally,
the supply current can be shut down to less than
20µA (V = 10V). This feature is an absolute necessity to
IN
maximize battery life in portable applications. Gerber files
for this circuit board are available. Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
= 100mA
O
= 1A
O
= 10V
IN
= 10V
IN
U
4.8V to 28V
2.5V, 3.3V, 5V
3.0A
3.5A
50 mV
P-P
35mV
P-P
0.002%/V
– 1%
550µA
16µA
0.8V
200kHz
1