Linear Technology DC252 Demo Manual

DESCRIPTIO
Demonstration Circuit DC252 is designed for mobile 5-bit
VID-programmed notebook CPU applications using the
®
LTC 1736 switching regulator controller. A high perfor-
mance, constant frequency current mode architecture
generates a precise low voltage CPU core supply. Protec-
tion features include an externally defeatable overcurrent
latchoff and internal current foldback for overload condi-
tions. A soft-latched crowbar monitors the output voltage
for overvoltage protection. OPTI-LOOP
allows the transient response to be optimized over a wide
range of output capacitance and ESR values. The circuit
was designed for a 5V to 24V input range but allows a 4.5V
to 28V range (limited by the external MOSFETs). Strong
output drivers easily handle large power MOSFETs effi-
PERFOR A CE SU
PARAMETER
Input Voltage Range
Output
V
IN
TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTOS
Efficiency
100
EXTV = 5V
CC
90
V = 5V
IN
80
70
V = 15V
IN
V = 24V
IN
60
50
40
10mA 100mA 1A
LOAD CURRENT (A)
Frequency Synchronous DC/DC Converter
TM
compensation
ARY
CONDITIONS
(Maximum Input Voltage Limited By External MOSFET and Input Capacitor)
Output Voltage (Programmed with a 5-Bit Mobile VID Code)
Max Output Current (Continuous)
Max Output Current (Peak)
Typical Output Ripple Measured with 10MHz Bandwidth (Burst Mode Operation) I
Typical Output Ripple Measured with 10MHz Bandwidth (Continuous) I
Line Regulation 5V to 24V
Component Side
10A
252 TA01
DEMO MANUAL DC252
DESIGN-READY SWITCHER
LTC1736 5-Bit VID Constant
ciently. Output voltages can be configured according to
Intel mobile VID standards of 0.9V to 2.0V. An internal
power-good circuit monitors the output voltage for out-of-
regulation conditions. External frequency synchronization
is provided, as are three modes of operation: Burst Mode
operation to reduce switching losses and maintain high
operating efficiencies, burst inhibit/forced continuous
mode and a low noise pulse-skipping mode that provides
constant frequency operation down to 1% maximum load
currents with low quiescent current. This results in a
power supply that has very high efficiency, low ripple and
fast transient response. Gerber files for this circuit board
are available. Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation.
= 5A
O
VALUE
5V to 24V
0.9V to 2.0V
11.0A
12A
= 100mA 45mV
O
20mV
0.002%/V
Solder Side
1
TM
P-P
P-P