Datasheet
Evaluates: MAX9924U/MAX9925
MAX9924U Evaluation Kit
2 _______________________________________________________________________________________
Component List (continued) Component Suppliers
SUPPLIER PHONE WEBSITE
Murata
E l ectr oni cs N or th
America, Inc.
770- 436- 1300 w ww .m ur ata- nor tham er ica.com
Panasonic Corp. 800- 344- 2112 www.panasonic.com
Note: Indicate that you are using the MAX9924U or MAX9925
when contacting these component suppliers.
Quick Start
Required Equipment
Before beginning, the following equipment is needed:
• One 5V, 100mA power supply
• One voltmeter
• One oscilloscope
Procedure
The MAX9924U EV kit is fully assembled and tested.
Follow the steps below to verify board operation. See
Tables 1–4 for a description of the jumpers detailed in
the procedure below. Caution: Do not turn on the
power supply until all connections are completed.
1) Connect a voltmeter to TP3 (VCC/2) and TP4 (GND)
test points.
2) Verify that a shunt is not installed across the pins of
jumpers JU1 and JU3.
3) Verify that a shunt is installed across pins 1-2 of
jumpers JU2, JU4, and JU5 (MODE A1 operation).
4) Verify that a shunt is installed across the pins of
jumpers JU7 and JU10 and that no shunt is
installed across jumpers JU8 and JU9 (on-board
triangle-wave generator, 2.5kHz).
5) Connect the V_PULL PCB pad to the VCC pad to
pull the COUT signal up to VCC.
6) Connect the 5V power supply to the VCC pad.
Connect the power supply’s ground to the GND pad.
7) Turn on the power supply and verify that the volt-
meter reads approximately 2.5V.
8) Using an oscilloscope, measure the signal at the
COUT and GND pads, which should be a 2.5kHz
square waveform with amplitude of 5V.
9) The EV kit circuit is ready for further evaluation using
a VR or magnetic pickup sensor. See the
Jumper
Selection
section for configuring the EV kit circuit.
Detailed Description of Hardware
The MAX9924U EV kit features a differential VR sen-
sor interface circuit using a MAX9924U IC in a 10-pin
µMAX surface-mount package. The EV kit’s single-
channel interface circuit evaluates signals from both
differential and single-ended sensors. The interface
circuit provides a fixed gain of 1V/V and evaluates
sensor-signal amplitudes of 40mV
P-P
to 300V
P-P
with
a frequency range of 5Hz to 25kHz. Power for the EV
kit circuit can be supplied by a 4.5V to 5.5V DC
source that provides at least 100mA.
The MAX9924U EV kit circuit can be configured to
demonstrate the MAX9924U MODE A1, A2, B, or C
operation. Resistors R3, R4 and capacitor C10 pro-
vide a VCC/2 source for evaluating MODE B or C. For
MODE C operation, surface-mount resistor pads (R1,
R2) are provided to configure the high- and low-
threshold voltage. Refer to the
Mode Selection
sec-
tion in the MAX9924/MAX9925 IC data sheet for addi-
tional information on the modes of operation.
Lowpass sensor input filtering is provided by resistors
R5, R6 on the SENSE+ input, and resistors R7, R8,
and capacitor C5 on the SENSE- input. PCB pads
provide access to the MAX9924U square-wave open-
drain output signal at COUT.
Additionally, PCB pads are provided for interfacing with
a user-supplied microcontroller PWM signal when eval-
uating MODE B of the MAX9924U, which enables the
MAX9924U threshold voltage to be set externally.
Resistor R13 and capacitor C4 provide a lowpass filter
for the PWM input signal connected to the FILTER PCB
pad. Refer to the
Adaptive Peak Threshold
section in
the MAX9924/MAX9925 IC data sheet for additional
information.
The MAX9924U EV kit provides a configurable on-
board triangle-wave generator using a MAX9000 IC for
evaluating the MAX9924U without a sensor. Capacitors
C6, C7, resistors R15, R16, and jumpers JU8, JU9 con-
DESIGNATION QTY DESCRIPTION
TP3, TP5 2 PC mini test points, red
TP4, TP6 2 PC test points, black
U1 1
VR sensor interface (10 µMAX)
Maxim MAX9924UAUB+
U2 1
High-speed op amp comparator
reference (8 SO)
Maxim MAX9000ESA+
— 9 Shunts (JU1–JU5, JU7–JU10)
— 1 PCB: MAX9924U Evaluation Kit+