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Description
Demonstration circuit 1878A features the LTC3789EGN,
a high efficiency switching step-up/down controller. The
input range has been extended to 75V by using a LTC4444-
5 MOSFET driver on the input side. The minimum input
voltage is 8V. The output voltage is 12V. The board is
capable of delivering up to 5A of output current over the
input voltage range.
The LTC3789EGN is a high performance switching regula-
tor controller designed to regulate the output using input
voltages above, below or equal to the output voltage.
Synchronous operation provides very high efficiency, up
to 97%. Constant frequency current mode architecture
allows phase-lockable frequency from 200kHz to 600kHz.
performance summary
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
Output Voltage V
Regulation
OUT
Maximum Continuous Output Current
Default Operating Frequency
External Clock Synchronous Frequency Range
Efficiency
Load Transient
DEMO MANUAL DC1878A
An accurate output current limit provides support for bat-
tery charging. A wide input and output range with smooth
transfer function through all operating modes makes the
product ideal for automotive, telecom and battery systems.
The MODE/PLLIN pin can select between pulse-skipping
mode and forced continuous mode operation and allows
the IC to be synchronized to an external clock. A power
good output pin indicates when the output is within 7.5%
of its set point.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(T
= 25°C)
A
CONDITIONS
V
= 8V – 75V, I
= 0A – 5A
IN
OUT
Some Airflow May Be Needed at High Input Voltage and
Continuous Full Load
R3 = 0Ω
V
= 8V to 75V, I
= 5A
IN
OUT
LTC3789EGN
8V to 75V
IN
DC/DC Converter
VALUE
8V
75V
12V ± 2%
5A
200kHz
200kHz – 600kHz
90.5% to 97%. See Figures 3 and 6
See Figure 5
Buck/Boost
dc1878af
1
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Related Manuals for Linear Technology DC1878A
Summary of Contents for Linear Technology DC1878A
- Page 1 97%. Constant frequency current mode architecture allows phase-lockable frequency from 200kHz to 600kHz. L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
-
Page 2: Quick Start Procedure
TINP). By setting BOOST1 to 3.0V, the LTC3789 will issue narrow refresh pulses on BG1 which keeps the top gate driver powered also in BOOST mode. In addition, DC1878A demo board has layout for an optional 4. Turn on the power at the input. Increase V to between bias supply intended for a future monolithic high voltage 8V and 75V. - Page 3 DEMO MANUAL DC1878A Quick start proceDure Figure 1. Proper Measurement Equipment Setup dc1878af...
- Page 4 DEMO MANUAL DC1878A Quick start proceDure INPUT VOLTAGE (V) Figure 2. Input Current at Full Load (12V at 5A Output) η% LOSS INPUT VOLTAGE (V) Figure 3. Efficiency and Power Loss at Full Load. The Power Loss is Highest at High Input...
- Page 5 DEMO MANUAL DC1878A Quick start proceDure 100mV Figure 4. Output Ripple Voltage Measured Across C OUT1 dc1878af...
- Page 6 DEMO MANUAL DC1878A Quick start proceDure Figure 5. Load Transient Response dc1878af...
- Page 7 DEMO MANUAL DC1878A Quick start proceDure LOAD (A) Figure 6. Efficiency at Various Input Voltages dc1878af...
- Page 8 DEMO MANUAL DC1878A Quick start proceDure LOAD (A) Figure 7. Output Current Limit (The Easiest Way to Do This Test Is with an Active Load in Voltage Mode) dc1878af...
-
Page 9: Parts List
DEMO MANUAL DC1878A parts List ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP , 0603 470pF 10% 50V NPO AVX 06035A471KAT CAP , 0603 0.01µF 10% 50V X7R AVX 06035C103KAT2A CF1, C31, C32, C37, CF CAP , 0603 OPTION OPTION CIN1, COUT11, CIN11, COUT21, CIN21... - Page 10 DEMO MANUAL DC1878A parts List ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER XSTR, FDC2512 N-CHANNEL MOSFET FAIRCHILD FDC2512 XSTR, MOSFET N-CHANNEL 100V VISHAY SiR870DP Q3, Q5 XSTR, MOSFET N-CHANNEL 20V VISHAY SiR496DP-T1-GE3 XSTR, MOSFET N-CHANNEL 100V VISHAY SiR882DP XSTR, SMALL SIGNAL NPN SOT-23 DIODES INC.
- Page 11 DEMO MANUAL DC1878A parts List ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER TP4, TP5, TP8, TP10, TP11-TP13 TURRET MILL-MAX 2501-2-00-80-00-00-07-0 XFMR, LOW POWER FLYBACK TRANS PULSE PA0648NL IC, VOLT REG. LINEAR TECH. LTC3789EGN IC, HIGH VOLTAGE SYNCHRONOUS LINEAR TECH. LTC4444EMS8E-5 N-CHANNEL MOSFET DRIVER IC, CONSTANT FREQ.
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Page 12: Schematic Diagram
DEMO MANUAL DC1878A schematic Diagram dc1878af... - Page 13 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
- Page 14 Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods.
- Page 15 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Analog Devices Inc. DC1878A...
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