Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 1 of 8
Enpirion Confidential
Preliminary
Enpirion EP53x8xQI DC/DC Converter
Module Evaluation Board
Introduction
This application note describes how to test the following EP53x8xQI converters using the
Enpirion 3x3 Module EVAL BOARD shown in Fig. 1: EP5368LQI, EP5368HQI,
EP5388LQI, EP5388HQI, EP53A8LQI, and EP53A8HQI. In addition to this document
you will also need the device datasheet.
The EP53x8xQI converters are part of a new class of DC/DC converter products, a
complete power system on silicon:
• These devices are complete modules including magnetics, and require only
ceramic input and output capacitors.
• The evaluation board is designed to offer a wide range of engineering evaluation
capabilities. This includes the base configuration of an 0603 input capacitor and
an 0805 output capacitor.
• Pads are available to add up to one additional input capacitor and up to two
additional output capacitors to allow for evaluation of performance over a wide
range of input/output capacitor combinations.
• Pads are available to populate an external divider if desired.
• Easy jumpers are provided for the following signals:
o Enable
o VS0-VS3 output voltage select
• Numerous test points are provided as well as clip leads for input and output
connections
• The board comes with input decoupling, and input reverse polarity protection to
safeguard the device from common setup mishaps.
Quick Start Guide
STEP 1: Set the “ENABLE” jumper to the Disable Position.
CAUTION: the signal pins ENA, VS0, VS1, VS2, and VS3 must
be connected to a logic “high”, jumper to the lef t, or a logic
“low”, jumper to the right. If left floating the state is
indeterminate.
STEP 2: Connect a power supply to the input test points, TP8 (+) and TP5 (-) as
indicated in Figure 1. The same test points can also be used to measure the input voltage.
Ou tput Disabled
Jumper
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 2 of 8
Enpirion Confidential
Preliminary
CAUTION: be mindful of the polarity and the voltage magnitude. If VIN is
greater than 6V, the board may get damaged. If the input voltage polarity is
wrong, diode D1 will conduct, and draw excessive input current.
STEP 3: Set the output voltage select pins for the desired output voltage. Refer to Tables
1 and 2 to determine the setting.
CAUTION: the external resistor divider is not populated in
the standard board configuration. Choosing the “EXT” option
for the EP53x7LQI without the external resistors R1 and R2
will result in unpredictable behavior.
STEP 4: Connect the load to the output connectors TP7 (+) and TP6 (-), as indicated in
Figure 1.The same test points are also used to measure the DC output voltage.
Figure 1. Evaluation Board Layout.
STEP 5: Move the ENABLE jumper to the enabled position, and power up the board.
The EP53x8xQI should now be operational.
“0”
“1”
CIN
COUT
Decou pling Ca p
(to decouple supply cables)
Reverse polarity diode
Output Volta
g
e Select
Output Enable
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 3 of 8
Enpirion Confidential
Preliminary
Output Voltage Select
Table 1. EP53x8LQI Output Voltage Select Truth Table
VS3 VS2 VS1 VS0 VOUT
0 0 0 0 1.50
0 0 0 1 1.45
0 0 1 0 1.40
0 0 1 1 1.35
0 1 0 0 1.30
0 1 0 1 1.25
0 1 1 0 1.20
0 1 1 1 1.15
1 0 0 0 1.10
1 0 0 1 1.05
1 0 1 0 1.00
1 0 1 1 0.95
1 1 0 0 0.90
1 1 0 1 0.85
1 1 1 0 0.80
1 1 1 1 EXT
Table 2. EP53x8HQI Output Voltage Select Truth Table
VS3 VS2 VS1 VS0 VOUT
0 0 0 0 3.3
0 0 0 1 3.2
0 0 1 0 3.1
0 0 1 1 3.0
0 1 0 0 2.9
0 1 0 1 2.8
0 1 1 0 2.7
0 1 1 1 2.6
1 0 0 0 2.5
1 0 0 1 2.4
1 0 1 0 2.3
1 0 1 1 2.2
1 1 0 0 2.1
1 1 0 1 2.0
1 1 1 0 1.9
1 1 1 1 1.8
The EP53x8xQI utilizes a 4 pin output voltage select scheme. The output voltage is
programmed by setting the VSx jumpers to either a logic “1” or a logic “0” as described
in the Quick Start section
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 4 of 8
Enpirion Confidential
Preliminary
Tables 1 and 2 show the truth table for VOUT selection. There are fifteen preset output
voltage levels for the EP53x8LQI, and sixteen preset levels for the EP53x8HQI.
Test Recommendations
Recommendations
To guarantee measurement accuracy, the following precautions should be observed:
1. Make all input and output voltage measurements at the board using the test
points provided. This will eliminate voltage drop across the line and load
cables that can produce false readings.
2. Measure input and output current with series ammeters or accurate shunt
resistors. This is especially important when measuring efficiency.
3. Use a balanced impedance probe tip as shown in Figure 2, and through-hole
test point pair TP2 to measure the output voltage ripple to avoid noise
coupling into the probe ground lead.
Using The External Voltage Divider
The EP53x8xQI evaluation board is designed to provide a great deal of flexibility in
evaluating the performance of the Enpirion DC/DC module.
Pre-tinned pads are provided to place 0805 sized 1% resistors on the board to implement
an external resistor divider for the EP53x8LQI to choose an output voltage other than one
of the pre-set voltages available on the VID. See Figure 3 for the basic circuit.
Figure 2: Balanced-impedance oscilloscope probe. Wrap bare wire around
the ground shaft and bring the wire close to the probe tip. This minimizes
probe loop inductance and stray noise pickup by the probe.
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 5 of 8
Enpirion Confidential
Preliminary
VIN VSense
Vin
VS1
VS2
VS0
EP53x8LQI
10µF
2.2uF
VOUT
Vout
GND
ENABLE
R1
R2
VFB
VS3
Figure 3. External divider schematic for the EP53x8LQI.
The output voltage is selected by the following formula:
()
2
1
16.0 R
R
OUT VV +=
R1 must be chosen as 237kΩ to maintain control loop stability. Then R2 is given as:
Ω
−
=6.0
102.142 3
2OUT
Vx
R
The external voltage divider option is chosen by setting the jumpers VS0 – VS3 to a logic
“high”.
Dynamically Adjustable Output
The EP53x8xQI is designed to allow for dynamic switching between the predefined
voltage levels by toggling the VID pins. The inter-voltage slew rate is optimized to
prevent excess undershoot or overshoot as the output voltage levels transition. The slew
rate is defined in the datasheet.
This feature can be tested by connecting the VSx jumper center pins to logic driver to
toggle between the various VOUT states.
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 6 of 8
Enpirion Confidential
Preliminary
Input and Output Capacitors
The input capacitance is a single 0603 X5R MLCC. Please see the part datasheet for the
exact value. There are pre-tinned pads that allows for one additional 0603 capacitor to
experiment with input filter performance.
The output capacitance requirement is a single X5R MLCC. Please see the datasheet for
the exact value. The board has pre-tinned pads for up to 2 additional 0805 output
capacitors.
NOTE: Capacitors must be X5R or X7R dielectric formulations. Do not use Y5V
or any similar dielectric.
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 7 of 8
Enpirion Confidential
Preliminary
C3
C4 N/U
C10
FB1
C5 N/U
TP2
1
2
TP1
1
2
0805
0603
J1
ASP12192002
1
2
3
5
6
7
9
10
11
13
14
15
17
18
19
Vin
Vout
Vin
TP6 1
TP81
TP51
ENABLE
VS0
VS1
VS2
R1
N/U
R2
N/U
J3
1
2
3
LLM
+
C8
U2
N/U
Vin
TP71
D1
C1 N/U
C2
0805
0805 0805
0603
0805
U1
Enpirion 3x 3 Module
NC(SW)
1
PGND
2
LLM
3
Vfb
4
Vsense
5
AGND
6
VOUT
7
VOUT
8
VS3 9
VS2 10
VS1 11
VS0 12
Enable 13
Vin 14
NC(SW) 15
NC(SW) 16
C9
N/U
0805
0805
VS3
Input Protection
Figure 4: 3x3 Module Evaluation Board Schematic
Application Note EP53x8xQI Eval Board
May 2008 V0.1
Page 8 of 8
Enpirion Confidential
Preliminary
Contact Information
Enpirion, Inc.
685 Route 202/206
Suite 305
Bridgewater, NJ 08807
Phone: 908-575-7550
Fax: 908-575-0775
Enpirion reserves the right to make changes in circuit design and/or specifications at any
time without notice. Information furnished by Enpirion is believed to be accurate and
reliable. Enpirion assumes no responsibility for its use or for infringement of patents or
other third party rights, which may result from its use. Enpirion products are not
authorized for use in nuclear control systems, as critical components in life support
systems or equipment used in hazardous environment without the express written
authority from Enpirion.
