MAXIM Integrated MAX42403 Evaluation Kit User Manual

: June 13, 2024
: maxim integrated

MAX42403 Evaluation Kit

Evaluates: MAX42402/MAX42403

General Description

The MAX42403 evaluation kit (EV kit) provides a proven design to evaluate the MAX42402/MAX42403, high inputvoltage, mini buck converter in a 15-pin, FC2QFN package. Various test points and jumpers are included for evaluation. The MAX42403 EV kit comes with the MAX42403AFLB+ installed (3.3V, 1.5MHz). This EV kit can be used to evaluate all variants of the MAX42402/MAX42403 with minimal component changes.

Benefits and Features

4.5V to 36V Input Supply Range
Adjustable Output Between 0.8V and 12V
Delivers up to 3.5A Output Current (up to 2.5A for the MAX42402)
Frequency Synchronization Input
99% Duty Cycle Operation with Low Dropout
Voltage-Monitoring PGOOD Output with UV/OV Feature
Proven PCB Layout
Fully Assembled and Tested

Ordering Information appears at end of data sheet.

Quick Start

Required Equipment

MAX42403 EV Kit
Power Supply
Voltmeter
Electronic Load

Procedure

The EV kit is fully assembled and tested. Follow the steps below to verify board operation:

While observing safe ESD practices, carefully remove the MAX42403 EV kit board out of its packaging. Quickly inspect the board to ensure that no damage occurred during shipment. Jumpers/shunts are preinstalled prior to testing and packaging.
Verify that all jumpers are in their default positions, as shown in Table 1.
Connect the positive and negative terminals of the power supply to the VSUP and GND2 test pads, respectively.
Connect the positive terminal of the voltmeter to VOUT, and the negative terminal to GND3.
Set the power supply to 14V and 3A current limit. Turn on the power supply.
The voltmeter should display an output voltage of 3.3V.
Connect an electronic load to VOUT and GND3 terminals and set it to 1A.
Turn on the electronic load and increase the current to 3.5A. The voltmeter should display the output voltage of 3.3V.

319-101021; Rev 0; 9/23 DOCUMENT FEEDBACK TECHNICAL SUPPORT

Board Photos

MAXIM Integrated MAX42403 Evaluation Kit A1

Figure 1. MAX42403 EV Kit Board Photo–Top

MAXIM Integrated MAX42403 Evaluation Kit A2 Figure 2. MAX42403 EV Kit Board Photo–Bottom

Detailed Description

This evaluation kit should be used with the following documents:

MAX42402/MAX42403 data sheet
MAX42403 EV kit data sheet (this document)

The MAX42403 EV kit provides a proven layout for all variants of the MAX42402/MAX42403 synchronous buck converter. The device accepts input voltages as high as 36V and delivers up to 3.5A (2.5A for the MAX42402). The EV kit can handle an input-supply transient up to 42V.

Switching Frequency/External Synchronization

The device can operate in two modes: forced PWM or skip. Skip mode has better efficiency for light-load conditions. When SYNC is pulled low, the device operates in skip mode for light loads and in PWM mode for larger loads. When SYNC is pulled high, the device is forced to operate in PWM across all load conditions. Use jumper J2 to switch modes.

SYNC can also be used to synchronize with an external clock. The device operates in FPWM mode when SYNC is connected to an external clock. To do this, uninstall the J2 shunt and connect an external clock at the SYNC pin.

Buck Output Monitoring (PGOOD)

The EV kit provides a power-good output test point (PGOOD) to monitor the status of the buck output. PGOOD is high impedance when the output voltage is in regulation. PGOOD is low impedance when the output voltage drops below 7% (typ) or exceeds 4% (typ) of its nominal regulated voltage. To obtain a logic signal, pull up PGOOD to VBIAS by installing a shunt on jumper J3.

Programming Buck Output Voltage

The MAX42402/MAX42403 has an adjustable 0.8V to 12V output. An external divider connected between the buck output (FB) and GND is used to set the output voltage. To program the output voltage, place the appropriate resistors in the positions of R4 and R5 according to the following equation:

R4 = R5 * [[VOUT/VFB] – 1]

Where VFB = 0.8V and R5 = 10kΩ-50kΩ and replace the output capacitors C12-C17 with appropriate capacitors according to the adjustable tables in the data sheet.

A feedforward capacitor, C19, in parallel with R4 is also recommended to improve loop stability and bandwidth. Refer to the MAX42402/MAX42403 IC data sheet for C19 value.

Evaluating Other Variants

The MAX42403 EV kit comes installed with the 3.3V/1.5MHz, 3.5A variant (MAX42403AFLB+). Additionally, a 400kHz variant with inductor for 3.3V output is also available. The other MAX42402/MAX42403 variants can be installed with minimal component changes.

Evaluation Data

EFFICIENCY vs. OUTPUT CURRENT MAX42403AFLB+

OUTPUT LOAD REGULATION MAX42403AFLB+

OUTPUT LINE REGULATION MAX42403AFLB+

THERMAL IMAGE MAX42403AFLB+
MAXIM Integrated MAX42403 Evaluation Kit A6

Table 1. Default Jumper Settings

JUMPER	SHUNT POSITION	FUNCTION
J1_EN	Pin 1-2	Buck controller enabled
J2_SYNC	Pin 1-2	Forced-PWM mode
J3_PGOOD	Installed	PGOOD is pulled up to BIAS when OUT is in regulation
J4_SPS	Pin 1-2	Spread spectrum disabled

Ordering Information

PART

| TYPE
---|---
MAX42403EVKIT#|

3.3V Output, 1.5MHz EV Kit

MAX42403 EV Kit Bill of Materials

PART	MFG PART #	MANUFACTURER	VALUE	DESCRIPTION
BIAS, EN, PGOOD, SYNC	5012	KEYSTONE	N/A	Test Point Pin Diameter 0.125

MAX42403 EV Kit Schematic

MAXIM Integrated MAX42403 Evaluation Kit
A7

MAX42403 EV Kit PCB Layout

MAXIM Integrated MAX42403 Evaluation Kit A8
MAX42403 EV Kit Layout–Top Silk Layer

MAXIM Integrated MAX42403 Evaluation Kit A9
MAX42403 EV Kit Layout–Top Layer

MAXIM Integrated MAX42403 Evaluation Kit A10
MAX42403 EV Kit Layout–Bottom Silk Layer

MAXIM Integrated MAX42403 Evaluation Kit A11
MAX42403 EV Kit Layout–Bottom Layer

MAXIM Integrated MAX42403 Evaluation Kit A12
MAX42403 EV Kit Layout–Internal Layers are Ground Planes

MAXIM Integrated MAX42403 Evaluation Kit A13
MAX42403 EV Kit Layout–Internal Layer

Revision History

REVISION NUMBER

| REVISION DATE| DESCRIPTION| PAGES CHANGED
---|---|---|---
0|

9/23

| Initial Release|

–

Evaluation Board User Guide

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