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MAX38889A Evaluation

Kit

Evaluates: MAX38889

319-100736; Rev 0; 4/21

General Description

The MAX38889A evaluation kit (EV kit) evaluates the

MAX38889 supercapacitor backup regulator, which is

designed to transfer power between a supercapacitor and

a system supply rail. When the main battery is present and

above the minimum system voltage for charging, the

MAX38889 charges the supercapacitor with an average

current of 1.5A.

Once the supercapacitor is charged, the circuit draws only

4

μA of current while it maintains the supercapacitor in its

ready state. When the main battery is removed, the

MAX38889 draws power from the supercapacitor and

regulates the system voltage to the set backup voltage with

a programmed maximum peak inductor current of 3A. The

MAX38889 is externally programmable for maximum

supercapacitor voltage, system backup voltage, peak

charging, and peak backup inductor currents.

Features and Benefits

• 2.5V to 5.5V System Output Voltage Range

• 0.5V to 5.5V Supercapacitor Voltage Range

• 3A Peak Charging and Backup Inductor Currents

• Resistor-Adjustable VSYS, VCAP Voltages

• Resistor-Adjustable Charging and Backup Currents

• Proven Two-Layer, 2oz Copper PCB Layout

• Demonstrates Compact Solution Size

• Fully Assembled and Tested

MAX38889A EV Kit Files

FILE

DESCRIPTION

MAX38889A EV BOM

EV Kit Bill of Materials

MAX38889A EV PCB Layout

EV Kit Layout

MAX38889A EV Schematic

EV Kit Schematic

Ordering Information appears at end of data sheet.

Quick Start

Required Equipment

• MAX38889A EV Kit

• 6V, 4A DC Power Supply

• Two Digital Multimeters (DMM)

Procedure

The EV kit is fully assembled and tested. Use the following

steps to verify board operation.

Caution: Do not turn on the power supply until all

connections are completed.

1)

Verify that a shunt is installed onto pins 1 and 2,

jumper ENC (charging enabled).

2)

Verify that a shunt is installed onto pins 1 and 2,

jumper ENB (backup enabled).

3)

Verify that jumper LOAD is opened. (No load is

connected across VSYS and PGND.)

4)

Set the power supply output to 3.4V and disable the

power supply.

5)

Connect the power supply between the VSYS and

PGND terminal posts.

6)

Connect the DMM between the VSYS and PGND

terminal posts.

7)

Connect the DMM between the VCAP and PGND

terminal posts.

8)

Enable the

power

supply and

verify that

the

supercapacitor voltage at VCAP is ramping up and

stops at about 2.7V.

9)

Disable and disconnect the power supply from the

VSYS and PGND terminal posts.

10) Verify

that

VSYS

regulates

to

3V

and

the

supercapacitor starts to discharge.

11) Install jumper JU2. (This connects a 4.02

Ω load

across VSYS and PGND.)

12) Verify that VSYS regulates to 3V while VCAP is

ramping down to 1V.

13) Verify that VSYS is 0V when VCAP drops below 1V.