Performance Summary; Board Photo - Linear Technology DC1668B-C Demo Manual

DESCRIPTION
Demonstration circuit 1668B-C is a PolyPhase
ply featuring four LTM ® 4627
buck µModule ® regulators. The DC1668B-C input voltage
range is between 4.5V to 20V with a jumper programmable
output voltage from 0.6V to 3.3V. The demo circuit can
deliver up to 50A of load with excellent current-sharing.
Current derating may be necessary under certain operat-
ing conditions.
The LTM4627 can be synchronized to an external clock be-
tween 250kHz to 770kHz. The default switching frequency
for the DC1668B-C is set to 500kHz through the onboard

PERFORMANCE SUMMARY

PARAMETER
Maximum Input Voltage
Minimum Input Voltage
Output Voltage V
OUT
Maximum Continuous Output Current I
Default Operating Frequency
External Clock Synchronous Frequency Range
Output Voltage Ripple (Typical)
Efficiency
Load Transient

BOARD PHOTO

® power sup-
high efficiency synchronous
Specifications are at T
CONDITIONS/NOTES
Remove V SEL Jumper for V
OUT
Current Derating May Be Necessary for Certain V
OUT(MAX)
V , Frequency and Thermal Conditions
OUT
V = 12V, V = 1.8V, 500kHz (20MHz BW)
IN OUT
V = 12V, V = 1.8V, 500kHz
IN OUT
V = 12V, V = 1.8V
IN OUT
Figure 1. LTM4627/DC1668B-C Demo Board
DEMO MANUAL DC1668B-C
High Efficiency PolyPhase
Step-Down Power Supply
LTC6902 clock generator. The external clock interleaves
the paralleled phases to minimize input and output ripple.
DC1668B-C demonstrates that paralleling LTM4627 mod-
ules is easy and reliable. These features and the availability
of the LTM4627 in a compact thermally enhanced 15mm
× 15mm × 4.32mm LGA package make the circuit ideal for
use in high density point of load regulation applications.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology, PolyPhase, µModule and the Linear logo are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
= 25°C
A
= 0.6V
OUT DC
,
IN
DC1668bc F01
LTM4627EV
VALUE
0.6V , 1V , 1.2V , 1.5V
DC DC DC
1.8V , 2.5V , 3.3V
DC DC
50A
500kHz
250kHz to 770kHz
< 10mV at I = 50A, See Figure 6
P-P OUT
87.7% at I = 50A, See Figure 3
OUT
See Figure 5
dc1668bcf
20V
4.5V
,
DC
DC
DC
1