pling to AC. The scope now displays a lowpass-fil-

tered square wave at TP3 (filtered analog base-

band data). Use the RF generator’s LF OUTPUT

(modulation output) to trigger the oscilloscope.

7) Monitor the DATA_OUT terminal and verify the pres-

ence of a 2kHz square wave.

Additional Evaluation

1) With the modulation still set to AM, observe the

effect of reducing the RF generator’s amplitude on

the DATA_OUT terminal output. The error in this

sliced digital signal increases with reduced RF sig-

nal level. The sensitivity is usually defined as the

point at which the error in interpreting the data (by

the following embedded circuitry) increases

beyond a set limit (BER test).

2) With the above settings, a 315MHz-tuned EV kit

should display a sensitivity of about -114dBm (0.2%

BER) while a 433.92MHz kit displays a sensitivity of

about -112dBm (0.2% BER). Note: The above sensi-

tivity values are given in terms of average.

3) Capacitors C5 and C6 are used to set the corner

frequency of the 2nd-order lowpass Sallen-Key

data filter. The current values were selected for bit

rates up to 3kbps. Adjusting these values accom-

modates higher data rates (refer to the MAX7033

data sheet for more details).

Layout Issues

A properly designed PC board is an essential part of

any RF/microwave circuit. On high-frequency inputs

and outputs, use controlled-impedance lines and keep

them as short as possible to minimize losses and radia-

tion. At high frequencies, trace lengths that are on the

order of

λ/10 or longer can act as antennas.

Keeping the traces short also reduces parasitic induc-

tance. Generally, 1in of a PC board trace adds about

20nH of parasitic inductance. The parasitic inductance

can have a dramatic effect on the effective inductance.

For example, a 0.5in trace connecting a 100nH induc-

tor adds an extra 10nH of inductance or 10%.

To reduce the parasitic inductance, use wider traces

and a solid ground or power plane below the signal

traces. Also, use low-inductance connections to ground

on all GND pins, and place decoupling capacitors

close to all VDD connections.

The EV kit PC board can serve as a reference design for

laying out a board using the MAX7033. All required com-

can be directly “inserted” in the application circuit.

Detailed Description

Power-Down Control

The MAX7033 can be controlled externally using the

SHDN connector. The IC draws approximately 2.5µA in

shutdown mode. Jumper JU1 is used to control this

mode. The shunt can be placed between pins 2 and 3

for continuous shutdown, or pins 1 and 2 for continuous

operation. Remove JU1 shunt for external control. See

Table 1 for the jumper function descriptions.

MAX7033 Evaluation Kit

_______________________________________________________________________________________

3

Note: Indicate that you are using the MAX7033 when contact-

ing these component suppliers.

SUPPLIER

PHONE

FAX

Coilcraft

800-322-2645

847-639-1469

Crystek

800-237-3061

941-561-1025

Hong Kong Crystal

852-2412 0121

852-2498 5908

Murata

800-831-9172

814-238-0490

Component Suppliers

Table 1. Jumper Function

JUMPER

STATE

FUNCTION

1-2

Normal operation

2-3

Power-down mode

JU1

N.C.

External power-down control

1-2

Crystal divide ratio = 32

JU2

2-3

Crystal divide ratio = 64

1-2

Mixer output to MIX_OUT

2-3

External IF input

JU3

N.C.

Normal operation

1-2

Uses PDOUT for faster receiver startup

JU4

2-3

GND connection for peak detector filter

1-2

Disable AGC

2-3

Enable AGC

JU5

N.C.

External control of AGC lock function

1-2

IR centered at 433MHz

2-3

IR centered at 315MHz

JU6

N.C.

IR centered at 375MHz

1-2

Connect VDD to +3.3V supply

JU7

N.C.

Connect VDD to +5.0V supply