19-5757; Rev 0; 2/11
MAX44264 Evaluation Kit
Evaluates: MAX44264
General Description
The MAX44264 evaluation kit (EV kit) is a fully assembled
and tested circuit board that contains all the compo-
nents necessary to evaluate the MAX44264 IC, offered
in a space-saving 0.9mm x 1.3mm, 6-bump wafer-level
package (WLP). The device is a rail-to-rail micropower
op amp, drawing only 750nA of supply current. The EV
kit operates from a single 1.8V to 5.5V DC power supply.
S
1.8V to 5.5V Single-Supply Operation
S
Jumper Selectable for Inverting, Noninverting,
Features
Differential, and Buffer Op-Amp Configurations
S
Demonstrates Super-Capacitor Charge Balancing
Using the Op-Amp Buffer Configuration
S
Evaluates the Device in a 6-Bump WLP
S
Proven PCB Layout
S
Fully Assembled and Tested
Ordering Information
appears at end of data sheet.
Component List
DESIGNATION
C1, C2
QTY
2
DESCRIPTION
0.22F -20% to +80%, 3.3V super
capacitors (6.8mm)
1FF
Q10%,
6.3V X5R ceramic
capacitor (0603)
Murata GRM188R60J105K
0.1FF
Q10%,
16V X5R ceramic
capacitor (0603)
Murata GRM188R61C104K
0.01FF
Q10%,
16V X7R ceramic
capacitor (0603)
Murata GRM188R71C103K
Not installed, ceramic capacitor
(0603)
2-pin headers
DESIGNATION
JU2
R1, R6
R2
R3, R4
R5
U1
—
—
QTY
1
0
1
2
1
1
3
1
DESCRIPTION
3-pin header
Not installed, resistors (0603)
R1 is short (PC trace) and
R6 is open
0I
Q5%
resistor (0603)
2MI
Q5%
resistors (0603)
10I
Q5%
resistor (0603)
Rail-to-rail op amp (6 WLP)
Maxim MAX44264EWT+
(Top Mark: +CB)
Shunts (JU1, JU2, JU3)
PCB: MAX44264 EVALUATION
KIT
C3
1
C4
1
C5
1
C6
JU1, JU3
0
2
Component Supplier
SUPPLIER
Murata Electronics North America, Inc.
PHONE
770-436-1300
WEBSITE
www.murata-northamerica.com
Note:
Indicate that you are using the MAX44264 when contacting this component supplier.
_________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX44264 Evaluation Kit
Evaluates: MAX44264
Quick Start
•
•
•
MAX44264 EV kit
Voltmeter
Required Equipment
1.8V to 5.5V, 100mA DC power supply
The EV kit is fully assembled and tested. Follow the steps
below to verify board operation.
Caution: Do not turn on
the power supply until all connections are completed.
1) To configure the EV kit as an op-amp buffer to
balance super capacitors C1 and C2 charge, set
jumpers JU1, JU2, and JU3 in their default positions,
as shown in Table 1.
2) Set the power supply to provide 5V and then disable
the power supply.
3) Connect the power-supply positive terminal to the
VDD PCB pad.
4) Connect the power-supply ground to the GND PCB
pad (nearest the VDD PCB pad).
5) Enable the power supply.
6) Verify that the OUT PCB pad is at 2.5V.
Procedure
The EV kit comes preconfigured as a buffer used in a
super-capacitor charge-balancing circuit. Super capaci-
tors offer exceptional charge storage density and are
widely used to prolong the life of weak batteries sub-
ject to high current-load pulses, or to buffer a weak
energy source to a high-power load in energy-harvesting
devices. In such applications, it is common to have a
stack of super capacitors connected in series to achieve
the desired working voltage. The EV kit demonstrates
an active, super-capacitor charge-balancing circuit that
distributes the charge equally across two series-connected
super capacitors (C1 and C2), ensuring identical voltage
across each capacitor. This circuit prevents overvoltage
conditions from occurring across either of the super
capacitors due to a difference in leakage currents and
tolerance in the capacitor values. The IC’s ultra-low power
consumption of 750nA and CMOS inputs allow a power-
efficient solution to the super-capacitor charge-balancing
problem.
While super-capacitor charge balancing is the featured
application, the EV kit also provides flexibility to easily
reconfigure the op amp into any of the four common
circuit topologies: inverting amplifier, noninverting ampli-
fier, differential amplifier, or buffer. Table 2 lists the JU1,
JU2, and JU3 jumper settings for the various op-amp
configurations. The configurations are described in the
next few sections.
Important Note:
Remove super capacitors C1 and
C2 when not demonstrating super-capacitor charge
balancing in the four configurations detailed in the
Noninverting Amplifier, Inverting Amplifier, Differential
Amplifier,
and
Buffer Amplifier
sections.
Default Application Circuit
Op-Amp Configurations
Detailed Description of Hardware
The MAX44264 EV kit contains the MAX44264 IC, which
is a rail-to-rail micropower op amp with an ultra-low
750nA supply current designed in a 6-bump WLP. The
EV kit operates from a single 1.8V to 5.5V DC power
supply.
Table 1. Default Shunt Positions
JUMPER
JU1
JU2
JU3
SHUNT
POSITION
Not installed
2-3
Installed
DESCRIPTION
IN- = OUT (through resistor R2)
IN+ = VDD/2
Table 2. JU1, JU2, JU3 Jumper Functions
(IN-, IN+, REF)
OP-AMP
CONFIGURATION
Inverting
Differential
Noninverting
Buffer
Super-capacitor
buffer
SHUNT POSITION
JU1
Installed
Not
installed
Not
installed
1-2
JU2
JU3
Not
installed
2-3
Installed
_________________________________________________________________
Maxim Integrated Products
2
MAX44264 Evaluation Kit
Evaluates: MAX44264
Noninverting Amplifier
To configure the device as a noninverting amplifier,
replace R2 and R6 with suitable resistors. Replace
R3 with a short and remove C5 (follow the jumper set-
tings listed in Table 2). The output voltage (V
OUT
) for
the noninverting configuration is given by the following
equation:
R2
V
OUT
=
1
+
(
V
IN
+
+
V
OS
)
R6
where:
V
OS
= Input-referred offset voltage.
V
IN+
= Input voltage applied at the IN+ PCB pad.
Inverting Amplifier
To configure the device as an inverting amplifier, cut open
the shorted PCB trace on R1. Replace R3 with a short and
remove C5. Replace R1 and R2 with suitable gain resistors
(follow the jumper settings listed in Table 2). An appropri-
ate DC voltage (V
DC
) should be applied to the IN+ PCB
pad to level shift the output voltage of the op amp if the
applied input voltage (V
IN-
) at the IN- PCB pad is positive:
R2
R2
V
OUT
= −
V
IN
−
+
1
+
(
V
OS
+
V
DC
)
R1
R1
Differential Amplifier
To configure the device as a differential amplifier, cut
open the shorting PCB trace on R1. Replace R1–R4 with
appropriate resistors. Remove C5 (follow the jumper
settings listed in Table 2). Apply a reference voltage
(V
REF
) to the REF PCB pad to level shift the output volt-
age of the op amp, if required. When R1 = R3 and R2 =
R4, the CMRR of the differential amplifier is determined
by the matching of ratios R1/R2 and R3/R4:
R2
V
OUT
=
GAIN(V
IN
+
−
V
IN
−
)
+
1
+
V
OS
+
V
REF
R1
where:
GAIN
=
R2 R4
=
R1 R3
Buffer Amplifier
To configure the device as a standard unity-gain buffer,
replace R3 with a short and remove C5:
V
OUT
=
V
IN
+
+
V
OS
Important Note:
Remove super capacitors C1 and C2
when not demonstrating super-capacitor charge balancing
for the four configurations just listed.
_________________________________________________________________
Maxim Integrated Products
3
MAX44264 Evaluation Kit
Evaluates: MAX44264
Figure 1. MAX44264 EV Kit Schematic
_________________________________________________________________
Maxim Integrated Products
4
MAX44264 Evaluation Kit
Evaluates: MAX44264
1.0”
Figure 2. MAX44264 EV Kit Component Placement Guide—
Component Guide
1.0”
Figure 3. MAX44264 EV Kit PCB Layout—Component Side
1.0”
Figure 4. MAX44264 EV Kit PCB Layout—Solder Side
_________________________________________________________________
Maxim Integrated Products
5
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