EN2342QI Evaluation Board User Guide
Instructions
The numbers in the instructions below correspond
to the numbers in Figure 1. By following the number
sequence below, the device can be turned on by
step 7.
1)
ENABLE
– The jumper on the left two pins
of J3 enables the device through the
resistor divider R21 and R22). Remove this
jumper to disable the device. Leave J3 open
and use an external signal to TP1 to toggle
the enable on (>1.25V) and off (<0.95V).
2)
AVINO to AVIN Connection (J1)
-
Connection from AVINO to AVIN pin. Add
Jumper to J1 for Single Supply
Mode. Remove Jumper for Dual Supply
Mode.
3)
Output Voltage Settings (J5)
- As shown,
output voltage is set to 1.2V. The jumper
may be switched to change the output
voltage. From left to right R5, R8, R7, R6
(3.3V, 2.5V, 1.8V, 1.2V).
4)
PVIN (J7)
- Connect 4.5V to 14V supply on
J7. Do not turn on until everything is
connected correctly.
5)
Ground (J10 and J11)
- Connect the input
supply ground to J11 and the output ground
to J10.
6)
AVIN (J9)
- This is the power for the internal
controller. For Dual Supply Mode, connect
the 3.3V to AVIN on J9. Be sure to remove
J1. For Single Supply Mode, leave AVIN
open and be sure J1 has a jumper.
7)
VOUT (J6)
- Connect the load to J6. If the
instructions were followed up to this point,
the device may be powered to turn on.
8)
RCLX Resistor (R16)
- Current limit resistor
setting. Follow the table below for
recommended values based on output
voltage. See Datasheet for details.
PVIN
V
OUT
R
CLX
R
FS
4.5V
to
14V
5.0V
68.1k
30k
3.3V
61.9k
22k
2.5V
56.2k
10k
1.8V
54.9k 4.87k
1.5V
53.6k 3.01k
1.2V
46.4k 3.01k
≤1.0V 38.3k 3.01k
9)
RFS Resistor (R10)
- Frequency setting
resistor. Follow the table below for
recommended values based on output
voltage. See Datasheet for details.
PVIN VOUT
R
FS
Typical fsw
4.5V
to
14V
5.0V
30k
1.48 MHz
3.3V
22k
1.38 MHz
2.5V
10k
1.3 MHz
1.8V
4.87k
1.15 MHz
1.5V
3.01k
1.0 MHz
1.2V
3.01k
1.0 MHz
<1.0V 3.01k
1.0 MHz
10)
External Compensation (R3 = Ra), C7 =
Ca, R4 = Rca)
– The on board values are
designed to work with a variety of input and
output voltage ranges. For optimization,
follow the Datasheet recommendations.
11)
S_IN and S_OUT
- Connect an external
clock signal to S_IN to use an external clock
as the switching frequency
(0V ≤ S_IN ≤
2.5V). Be sure the frequency is within 10%
of the recommended typical switching
frequency. The S_OUT pin can be used to
“daisy chain” other EN2342 devices so they
have the same operating frequency. See
Datasheet for details on Frequency
Synchronization.
12)
POK
- This is the open drain POK flag,
which is pulled up to AVIN by R1. When
VOUT is over 90% of regulation, POK will
be pulled high to AVIN.
13)
Soft Start Capacitor (C2)
– The soft start
capacitor is by defaulted 47nF and can be
between 10nF to 68nF. See Datasheet for
details.
14)
Input Protection
– The EN2342QI
evaluation board comes with some input
polarity protection and PVIN slew rate
protection on the backside of the evaluation
board. Be sure to follow input voltage
specifications based on the Datasheet.
www.altera.com/enpirion
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10592 December 16, 2014 Rev A
