Linear Technology DC2565A Demo Manual

Description
Demonstration Circuit 2565A is a 42V, 0.75A micropower
synchronous step-down regulator featuring the
The demo board is designed for 5V output from a 5.5V
to 42V input. The wide input range allows a variety of
input sources, such as automotive batteries and indus-
trial supplies. The LT8607 is a compact, high efficiency,
high speed synchronous monolithic step-down switch-
ing regulator that consumes less than 3μA of quiescent
current when output is regulated at 5V. Top and bottom
power switches, compensation components and other
necessary circuits are inside of the LT8607 to minimize
external components and simplify design.
The SYNC pin on the demo board is grounded by default
for low ripple Burst Mode
SKIPPING position can change the operation mode to
pulse-skipping operation. Once JP1 is on SPREAD SPEC-
TRUM position, V is applied to the SYNC pin for low
CC
EMI spread spectrum operation. To synchronous to an
external clock, move JP1 to SYNC and apply the external
clock to the SYNC turret. Figure 1 shows the efficiency
of the circuit.
performance summary
SYMBOL PARAMETER
V Input Voltage Range
IN
V Output Voltage
OUT
I Maximum Output Current
OUT
f Switching Frequency
SW
EFE Efficiency at DC
42V, 0.75A Micropower Synchronous
LT
operation. Move JP1 to PULSE
®
Specifications are at T
CONDITIONS
V = 12V, I
IN
DEMO MANUAL DC2565A
Step-Down Regulator
The demo board has an EMI filter installed. The radiated
8607. EMI performances of the board (with EMI filter) are shown
®
in Figure 2 and Figure 3. The red lines in Figure 2 and
Figure 3 are CISPR25 Class 5 peak limit. To use the EMI
filter, the input should be tied to V
tor L2, which is a 0Ω jumper on the board by default
now, can be added in the EMI filter to further reduce the
conducted emission.
The LT8607 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this demo manual
for DC2565A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2565A
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Analog Devices, Inc. All other trademarks are the property of their respective owners.
= 25°C
A
= 0.75A
OUT
LT8607
, not V
EMI IN
MIN TYP MAX
5.5 42
4.8 5 5.2
0.75
1.85 2 2.15
92.4
. An induc-
UNITS
V
V
A
MHz
%
dc2565af
1