Quick Start Procedure - Linear Technology DC1668A-C Demo Manual

DEMO MANUAL DC1668A-C
PERFORMANCE SUMMARY
PARAMETER
Input Voltage Range
Output Voltage V
OUT
Maximum Continuous Output Current I
Default Operating Frequency
External Clock Synchronous Frequency Range
Output Voltage Ripple (Typical)
Efficiency
Load Transient

QUICK START PROCEDURE

Demonstration circuit 1668A-C is easy to set up to evaluate
the performance of paralleled LTM4627 modules. Please
refer to Figure 1 for proper measurement equipment setup
and follow the procedure below:
1. With power off, connect the input power supply, load,
meters and V BNC cable as shown in Figure 1.
OUT
Preset the load to 0A and V
jumpers in the following positions for a typical 1.8V
application:
JP2
V Select
OUT
1.8V
2. Turn on the power at the input. Increase V
(Do not hot-plug the input supply or apply more than
the rated maximum voltage of 20V to the board or the
modules may be damaged).
2
CONDITION
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
IN OUT
500kHz (20MHz BW)
V = 12V, V
IN OUT
500kHz
V = 12V, V
IN OUT
supply to be 0V. Place
IN
JP7 JP6
RUN TRACK/SS
OFF SOFT-START
to 12V
IN
= 0.6V
OUT DC
= 1.8V
= 1.8V
= 1.8V
3. Set the RUN pin jumper (JP7) to the ON position. The
output voltage should be regulated. The output voltage
meter should read 1.8V ±2% (1.76V to 1.84V).
4. Vary the input voltage from 5V to 20V and adjust the
load current from 0A to 50A. V
regulated at 1.8V ±2%. Observe the load regulation,
output voltage ripple, efficiency and other parameters.
Output voltage ripple should be measured at J6 with
OUT
a BNC cable and oscilloscope. The probe channel for
V should be set at 50Ω termination resistance to
OUT
match the BNC cable.
5. For optional load transient testing apply an adjustable
positive pulse signal between IOSTEP CLK and GND
pins. The pulse amplitude sets the load step current
amplitude. The pulse width should be short (< 1ms)
and pulse duty cycle should be low (< 15%) to limit the
thermal stress on the load transient circuit. The load
step current can be monitored with a BNC connected
to J5 (5mV/A).
VALUE
4.5V to 20V
0.6V , 1V , 1.2V , 1.5V
DC DC DC
2.5V , 3.3V
DC DC
, 50A
IN DC
500kHz
250kHz to 770kHz
< 10mV at I = 50A, See Figure 5
P-P OUT
87.7% at I = 50A, See Figure 2
OUT
See Figure 4
should remain
OUT
, 1.8V ,
DC DC
dc1668acf