Linear Technology DC1688B-A Manual

Description
Demonstration circuit 1668B-A is a PolyPhase
ply featuring two
buck µModule regulators. The DC1668B-A 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 30A 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-A 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
Arrow.com.
Downloaded from
LTM 4627 high efficiency synchronous
®
CONDITIONS/NOTES
Remove V
Current Derating May Be Necessary for Certain V
OUT(MAX)
Frequency and Thermal Conditions
V
IN
V
IN
V
IN
Figure 1. LTM4627/DC1668B-A Demo Board
DEMO MANUAL DC1668B-A
High Efficiency PolyPhase
Step-Down Power Supply
power sup- LTC6902 clock generator. The external clock interleaves
®
the paralleled phases to minimize input and output ripple.
DC1668B-A 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.
Specifications are at T = 25°C
A
SEL Jumper for V = 0.6V
OUT OUT
= 12V, V = 1.8V, 500kHz (20MHz BW)
OUT
= 12V, V = 1.8V, 500kHz
OUT
= 12V, V = 1.8V
OUT
LTM4627EV
0.6V , 1V , 1.2V
DC DC DC
, V ,
IN OUT
< 30mV
86.6% at I
OUT
DC1668ba F01
VALUE
20V
4.5V
, 1.5V 1.8V ,
DC DC DC
2.5V , 3.3V
DC DC
30A
DC
500kHz
250kHz to 770kHz
at I = 30A,
P-P OUT
See Figure 6
= 30A, See Figure 3
See Figure 5
dc1668baf
1