MAX9921 Evaluation Kit

2

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Quick Start

Recommended Equipment

Before beginning, the following equipment is needed:

•

MAX9921 EV kit

•

One 6V to 18V DC power supply

•

A magnet

Procedure

The MAX9921 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 made.

1) Verify that all jumpers are in the default positions, as

shown in Table 1.

2) Connect the DC power supply between the

MAX9921 EV kit’s VBAT and GND pads.

3) Turn on the DC power supply.

4) Move the magnet in front of S1 and S2. Observe the

light change of the OUT1 and OUT2 LEDs on the

EV kit board.

Detailed Description of Hardware

The MAX9921 EV kit board provides a proven layout for

evaluating the MAX9921. The EV kit comes with

MAX9921AUB+ installed.

External Power Supply

The MAX9921 is powered by a user-supplied 6V to

18V DC power supply connecting between VBAT and

GND. The MAX9921 EV kit board is not reverse-

battery protected.

During the emulation of the Hall input shorted to GND,

the MAX9921 will draw substantial shorting current until

the MAX9921 turns off the shorted input. The shorting

current can reach a peak of 60mA to 70mA and the

entire event may last 0.5µs. Many common regulated-

lab power supplies will overshoot in response to a

large, short-term current pulse. When evaluating the

short-to-GND fault, an unregulated supply is recom-

mended, such as a wet-cell battery.

Hall-Effect Sensors and Related Jumpers

The MAX9921 EV kit has two Hall-effect sensors

(A1140EUA). JU1 and JU2 provide a convenient way to

evaluate the MAX9921 with different Hall-effect sensors

and emulate different failure conditions, as shown in

Table 1.

DIAG and OE Configuration

The MAX9921 EV kit uses JU3 and JU4 to configure the

MAX9921 DIAG and OE inputs, as shown in Table 1.

Refer to the MAX9921 IC data sheet for a detailed

description of the MAX9921 diagnostic information.

Outputs, Related LEDs, and Jumpers

The MAX9921 EV kit has three outputs: OUT1, OUT2,

and

ERR. Each output has an LED to indicate its cur-

rent status. All three outputs can be individually pulled

up with a 100kΩ resistor, as shown in Table 1. Refer to

the MAX9921 IC data sheet for a detailed description of

OUT1, OUT2, and

ERR outputs.

Table 1. MAX9921 EV KIT Jumper

Descriptions (JU1-JU7)

JUMPER

POSITION

DESCRIPTION

1-2

Emulates Hall input shorted to

battery

1-3*

Demonstrates normal operation

with on-board Hall sensor

1-4

Emulates Hall input shorted to GND

1-5

Evaluates other Hall sensors

JU1, JU2

Open

Emulates the open-circuit failure

1-2*

Outputs enabled

JU3

Open

Outputs disabled

1-2

Outputs reflect diagnostic

information

JU4

Open*

Outputs reflect Hall sensor

information

1-2*

OUT1 with 100k

Ω pullup

JU5

Open

OUT1 without pullup

1-2*

OUT2 with 100k

Ω pullup

JU6

Open

OUT2 without pullup

1-2*

ERR with 100k

Ω pullup

JU7

Open

ERR without pullup

*

Default position.