2
dc2397af
DEMO MANUAL DC2397A
QUICK START PROCEDURE
Figure 2. DC2397A Step Load Response. V
IN
= 12V,
V
OUT
= 12V, Load Step is from 100mA to 400mA.
Figure 1: DC2397A Typical Efficiency vs Load. V
OUT
= 12V.
V
IN
= 5V, PWM MODE
V
IN
= 5V, Burst Mode OPERATION
V
IN
= 24V, Burst Mode OPERATION
V
IN
= 24V, PWM MODE
LOAD CURRENT (A)
1.0E-04 1.0E-03
1.0E-02
1.0E-01
1.0E+00
0
10
20
30
40
50
60
70
80
90
100
EFFICIENCY (%)
DC2397A F01
I
OUT
: 200mA/DIV
V
OUT
: 500mV/DIV
200μs/DIV
Using short twisted pair leads for any power connections
and with all loads and power supplies off, refer to Figure 4
for the proper measurement and equipment setup. The
power supply (PS1) should not be connected to the circuit
until told to do so in the procedure below.
When measuring the input or output voltage ripple, care
must be taken to avoid a long ground lead on the oscil-
loscope probe. Measure the input or output voltage ripple
by touching the probe tip directly across the V
IN
or V
OUT
and GND terminals (see Figure 5), or by using an oscil-
loscope probe tip jack.
1. Jumper and PS1 settings to start:
PS1:
OFF
JP1:
MODE
FIXED FREQ
JP2:
VS1
V
CC
JP3:
VS2
V
CC
JP4:
MPPC
OFF
JP5:
RUN
ON
JP6:
EXTV
CC
INT
2. With power OFF connect the power supply (PS1) as
shown in Figure 4. If accurate current measurements
are desired (for efficiency calculation for example)
then connect ammeters in series with supplies as
shown. The ammeters are not required however.
3. Connect a 50mA load (240Ω) to V
OUT
as shown in
Figure 4.
4. Turn on PS1 and slowly increase the voltage until
the voltage at V
IN
is 3V.
5. Verify V
OUT
is ~12V.
6. V
IN
can now be varied between 2.4V and 25V. The
load may need to be reduced for V
IN
< 3V for V
OUT
to remain in regulation.
7. The load can be varied. The maximum load is a
function of V
IN
and the device current limit. Consult
the data sheet for more information on output cur-
rent vs V
IN
.
8. V
OUT
can be varied by setting jumpers JP2 and JP3
in accordance with the “V
OUT
JUMPER CONFIGU-
RATION” table on the front of the DC2397A demo
board.
9. For operation in Burst Mode, move jumper JP1 to
“Burst Mode” position. See the data sheet for more
information on Burst Mode operation.
10. For operation with V
CC
powered from V
OUT
, move
JP6 to “EXT”.
NOTE:
If V
OUT
drops out of regulation, check to be
sure the maximum load has not been exceeded, and
that V
IN
is not below the minimum value for regula-
tion (see data sheet).
