Analog Devices DC2874A-A Demo Manual

5V, Multiphase (40A, 30A, 20A), Synchronous
DESCRIPTION
Demonstration Circuit DC2874A shows the
10A, Low Voltage, Synchronous Step-Down Silent
Switcher operating as a multiphase 2.0MHz, 3.3V to 1.2V
buck regulator. The DC2874A has three build options to
provide a two phase 20A, three phase 30A, or four phase
40A output solution. The LTC3310S supports adjustable
output voltages from 0.5V to V
cies from 500kHz up to 2.25MHz in multiphase operation.
DC2874A operates in pulse skip mode and allows the
slave phases to stop switching first before the master
starts skipping pulses for better low current efficiency.
The DC2874A also has an EMI filter to reduce conducted
EMI. This EMI filter can be included by applying the input
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
SYMBOL PARAMETER
V /V EMI DC2874A Input Voltage Range
IN IN
V DC2874A V Voltage Range*
OUT OUT
I DC2874A Output Current
OUT
f Switching Frequency
SW
Efficiency
*With 1% resistors. Accuracy will impprove to within 1% using 0.1% resistors.
BOARD PHOTO
DEMO MANUAL DC2874A-A/
LTC 3310S
®
and operating frequen-
IN
Specifications are at T
CONDITIONS
−A, 4 phase build option
−B, 3 phase build option
−C, 2 phase build option
V greater than V
IN
2, 3, or 4 phase
DC2874A-B/DC2874A-C
Step-Down Silent Switcher 2
voltage at the VIN EMI terminal. The EMI performance of
the board is shown in the EMI TEST RESULTS section.
The red lines in the EMI performance graphs illustrate
the CISPR25 Class 5 peak limits for the conducted and
radiated emission tests.
The Efficiency vs. Load graph shows the efficiency of the
circuit with a 3.3V input for the 2-, 3-, 4-phase circuits.
The LTC3310S datasheet gives a complete description of
the device, operation and application information. The data
sheet must be read in conjunction with this demo manual.
The LTC3310S is assembled in a 3mm x 3mm LQFN pack-
age with exposed pads for low thermal resistance.
Design files for this circuit board are
= 25°C
A
OUT
LTC3310S
available.
MIN TYP MAX
2.25 5.5
1.176 1.2 1.224
40
30
20
1.8 2 2.2
92.5
UNITS
V
V
A
A
A
MHz
%
Rev. 0
1