Linear Technology DC2548A Demo Manual

Description
Demonstration circuit 2548A is an active rectifier with
reverse protection featuring the
board is designed for 5A load current. The input volt-
age range of the LT8672 is –40V to +42V. Two clamping
diodes, D1 and D2, are used on the board to protect the
IC from overvoltage spikes at the input, thus limiting the
application's DC input voltage range to –15V and +35V.
The voltage drop on the MOSFET is 20mV in regulation.
The LT8672 can rectify input ripple with an amplitude of
6V and a frequency of up to 50kHz, or with an ampli-
P-P
tude of 2V and a frequency of up to 100kHz. High fre-
P-P
quency ripple should not be applied at full load current
for more than a few minutes, otherwise C5 may overheat.
JP1 can be used to set the LT8672 in shutdown mode.
It can be turned on by connecting the EN/UVLO to V
V . A digital signal can also be applied at the EN/UVLO
OUT
turret to control the part. Due to the presence of the exter-
nal MOSFET's body diode, the load is not disconnected
from the input if the part is shut down.
performance summary
SYMBOL PARAMETER
V DC Operating Input Voltage Range
IN
f (AC) Maximum Frequency of AC Input Signal to
Be Rectified
I Max Output Current
OUT
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The PG pin on the demo board can be easily by applying
LT 8672. The demo a voltage source between VEXT and GND. VEXT must not
®
exceed 5V.
The demo board allows installation of an EMI filter at the
output. To use the EMI filter, install L2, C7, and remove
C5 on the board. In addition, multiple MOSFET footprints
are provided on the backside of the board, making it con-
venient to use other MOSFETs.
The LT8672 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 demo circuit 2548A. The LT8672 is assembled in a
10-lead MSOP package. Proper board layout is essential
for maximum thermal and electrical performance. See the
or data sheet sections for details.
IN
Design files for this circuit board are available at
http://www.linear.com/demo/DC2548A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog
Devices, Inc. All other trademarks are the property of their respective owners.
Specifications are at T
CONDITIONS
V < 6V, C
P-P GATE-SOURCE
V < 2V, C
P-P GATE-SOURCE
V =12V
IN
DEMO MANUAL DC2548A
Active Rectifier Controller
with Reverse Protection
= 25°C
A
MIN
–15
= 10nF 50
= 10nF 100
LT8672
TYP MAX UNITS
35
kHz
kHz
5
dc2548af
1
V
A