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MAX2511 Evaluation Kit

_______________General Description

The MAX2511 Evaluation Kit (EV kit) simplifies testing of

the MAX2511 low-power IF transceiver. The EV kit pro-

vides 50Ω SMA connectors for all RF inputs and out-

puts. A varactor-tuned tank circuit is provided for the

MAX2511 VCO, and it can be tuned by applying a con-

trol voltage to the EV kit.

____________________________Features

+2.7 to +5.5V Single-Supply Operation

SMA Connectors for Signal Ports Compatible

with 50Ω Test Equipment

Allows Individual and Cascade Evaluation of

Circuit Blocks

10.7MHz Receive Filter Included

On-Board Jumpers Allow Testing of Advanced

System Power Management (four modes)

Includes VCO Tank Circuit (435.7MHz nominal)

Fully Assembled and Tested

Evaluates: MAX2511

______________Component Suppliers

SUPPLIER

Alpha

Industries

AVX

Coilcraft

Murata

PHONE/

FAX

(617) 935-5150/

(617) 933-0159

(803) 946-0690/

(803) 626-3123

(847) 639-6400/

(847) 639-1469

(814) 237-1431/

(814) 238-0490

INTERNET

http://www.alphaind.com

http://www.avxcorp.com

______________Ordering Information

http://www.coilcraft.com

http://www.murata.com

PART

MAX2511EVKIT-SO

TEMP. RANGE

-40°C to +85°C

BOARD TYPE

Surface Mount

_____________________________________________________________Component List

DESIGNATION

C1, C3

C4, C8, C10,

C11, C13, C14,

C15, C20, C22,

C25, C26

C6, C7

C9, C16, C17,

C18, C19

C12

C21, C23

C24

C27, C28

QTY

DESCRIPTION

10nF ceramic capacitors

100pF ceramic capacitor

47nF ceramic capacitors

(C11 not supplied)

10pF ceramic capacitor

47pF ceramic capacitors

470pF capacitors

47nF ceramic capacitor

(not installed)

100nF ceramic capacitors

10µF tantalum capacitor

AVX TAJC106K016

47pF ceramic capacitors

(not installed)

Dual varactor diode

Alpha SMV1204-199

DESIGNATION

IF,

LIMIN,

LIMOUT,

MIXOUT, OSCOUT,

TXIN,

TXIN

L2, L3

LOP, LON

R1, R10

R2, R4

R5, R6

R7, R8, R11, R13

JU5

None

QTY

DESCRIPTION

50Ω edge-mount SMA connectors

(TXIN connector not installed)

8.2nH inductor

Coilcraft 0805CS-080XMBC

220nH inductors

Coilcraft 0805CS–221XMBC

50Ω top-mount SMA connectors

(not installed)

270Ω resistors

1kΩ resistors

10kΩ resistor

953Ω, 1% resistors

51Ω resistors

MAX2511EEI (28 QSOP)

10.7MHz ceramic bandpass filter

Murata SFE10.7MA5-A

Shunts

2-pin headers

3-pin headers

________________________________________________________________

Maxim Integrated Products

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

For small orders, phone 408-737-7600 ext. 3468.

MAX2511 Evaluation Kit

Evaluates: MAX2511

_________________________Quick Start

The following section provides instructions for operat-

ing the MAX2511 evaluation kit (EV kit) as an IF trans-

ceiver. The differential IF port (IF,

IF)

is a bidirectional

port configured for operation over a wide range of fre-

quencies (200MHz to 440MHz). The high-side oscillator

is configured for nominal 435.7MHz operation, with

approximately 100MHz total span. The TXIN,

TXIN,

LIMOUT, and

LIMOUT

ports are configured for

10.7MHz operation.

VCC and GND terminals on the EV kit. Set one

voltage source to 2V, and connect it to the gain-

control terminal (labeled GC). Connect the other

voltage source to the FADJ pin and set it to 1.75V.

2) Enable Tx mode by putting 3-pin jumper TXEN in

the “1-2” position and jumper RXEN in the “2-3”

position. This sets TXEN to V

and RXEN to GND.

The supply current should be about 40mA. (See

Table 1.)

3) Connect the spectrum analyzer to OSCOUT. Set the

analyzer to 435.7MHz center frequency with a

100MHz total span. Adjust the FADJ voltage source

to center the LO frequency at or near 435.7MHz. The

OSCOUT output power should be around -9dBm.

4) Remove the SMA cable from the OSCOUT port.

Connect the spectrum analyzer to IF. Terminate the

other output (IF(J9)) with a 50Ω SMA terminator.

Optionally, IF and

can be combined using a 180°

balun. With no TXIN signal applied, the LO leakage

is the only transmitter signal observable.

5) Connect an RF generator to the TXIN input and set

it to 10.7MHz at -16dBm of output power. The spec-

trum analyzer should show an image-rejected out-

put spectrum with the desired signal at 425MHz,

the suppressed LO at 435.7MHz, and the image at

446.4MHz. You may need to fine tune the FADJ

voltage to keep the LO at the correct frequency.

Because the Tx output is loaded by the Rx input

(approximately 200Ω differential), the single-ended

Tx output power will be near -8.5dBm into the 50Ω

spectrum analyzer. If the Tx output were loaded with

100Ω differential, this would correspond to -2dBm.

6) Test the GC function by slowly lowering the voltage

on the GC pin from 2V to 0V. You will see at least a

40dB change in fundamental output power over this

voltage range. Note the decreasing supply current

draw with reduced output power due to the

MAX2511’s unique biasing scheme.

7) When the transmitter is set up properly, you may

wish to test other features, such as shutdown mode

(both TXEN and RXEN jumpers set to “2-3”) (see

Table 1). The image rejection of the MAX2511 over

frequency can be checked by varying the TXIN and

LO frequencies.

Test Equipment Required

This section lists the test equipment recommended for

verifying operation of the MAX2511. It is intended only

as a guide; some substitutions may be possible.

•

One (optionally two) RF signal generator capable of

delivering at least 0dBm of output power in the

10MHz to 500MHz frequency range (HP8656B,

HP8648A, or equivalent). One generator is required

to test the Rx and Tx signal paths; the other is used

optionally as an external LO source if the on-chip

oscillator is overdriven.

An RF spectrum analyzer that can cover the trans-

mitter’s output frequency range, as well as a few

harmonics (HP8560E, for example)

A voltmeter for measuring the RSSI output voltage

An oscilloscope for observing the limiter output

signals

A power supply that can provide at least 100mA at

+2.7V to +5.5V

Two voltage sources for providing the gain-control

(GC) pin voltage and the oscillator frequency-adjust

voltage (FADJ)

Two 50Ω SMA terminators

Optional:

An RF 180° hybrid combiner or balun

(Anzac H-9 or equivalent). This is used for differen-

tial coupling into the IF and

connectors on the

transceiver. If a hybrid is not available, these inputs

and outputs can be evaluated in a single-ended

configuration at a slight performance cost.

•

Connections and Setup

This section provides step-by-step instructions for get-

ting the EV kit up and running in both Tx and Rx modes.

Tx Mode

Perform the following steps to evaluate the MAX2511 in

Tx mode:

1) Make the DC connections: set the power supply to

3V with a 100mA current limit, and connect it to the

Rx Mode

This section describes how to connect and use the

MAX2511’s receiver section.

1) Verify that DC connections have been made, per

step 1 in the

Tx Mode

section.

_______________________________________________________________________________________

MAX2511 Evaluation Kit

Table 1. Operating Modes

MODE

Shutdown

Transmit

Receive

Standby

JUMPER SETTING

RXEN

2–3

1–2

TXEN

2–3

1–2

2–3

1–2

putting the part in shutdown mode and reducing supply

current to around 0.1µA.

To enter standby mode, bring both TXEN and RXEN

jumpers to the “1-2” position, so that TXEN = RXEN =

. This reduces the supply current to about 9.5mA

while leaving the oscillator and other circuitry active (for

fast switching into either Rx or Tx mode).

Evaluates: MAX2511

_______________Detailed Description

The following section covers the EV kit’s circuit blocks

in detail (see the MAX2511 data sheet for additional

information).

2) Switch the part into Rx mode by moving the RXEN

jumper to the “1” position and the TXEN jumper to the

“3” position (Table 1). Verify that the GC voltage is 2V.

3) Connect the spectrum analyzer to the OSCOUT

pin, and verify that LO is still at the correct fre-

quency (435.7MHz). Adjust the FADJ pin voltage, if

necessary. Set the RF generator to 425MHz at

-30dBm. Connect the generator to the IF connector.

Terminate the

with a 50Ω SMA terminator.

Optionally, the RF generator’s signal can be split

using a 180° balun connected to IF and

IF.

This

connection is the same as the optional balun con-

nection for Tx mode, but the balun is used in the

reverse direction.

4) Connect an oscilloscope to the limiter output

LIMOUT, and set its input impedance to 50Ω. The

signal level observed on the oscilloscope should be

around 28mVp-p, which corresponds to 550mVp-p

at the device pin. Note that R5 and the 50Ω oscillo-

scope load impedance form a 20:1 voltage divider.

The limiter’s output voltage range can be adjusted

by varying the GC voltage.

Note:

Ensure that the LO frequency is maintained

at 435.7MHz to keep the IF output centered within

the Rx 10.7MHz filter’s passband.

5) Connect a voltmeter to the RSSI test pad in the

upper-left corner of the EV kit to monitor the RSSI

output voltage. For -30 dBm of RXIN power, the

RSSI voltage should be approximately 750mV.

Lower the input power in 10dBm steps, observing

the decrease in RSSI output voltage of about

100mV per 10dB change in input power. Increase

RXIN power above -30dBm to verify compression

performance. Return the power to -30dBm.

6) Observe that the signal at LIMOUT remains con-

stant over the RXIN power range.

Tx Inputs

The TXIN and

TXIN

pins are differential inputs to the

MAX2511’s image-reject transmitter. The EV kit is

shipped configured for single-ended operation at the

TXIN connector. To convert to differential operation,

populate C12 with a 47nF capacitor, and install an SMA

connector. The input impedance of these pins is set by

pull-up resistors R7 and R8. This input is typically a

10.7MHz signal at 100mVp-p.

Tx Outputs

The MAX2511’s Tx output pins (TXOUT and

TXOUT)

are high-impedance open collectors; therefore, external

inductors are used for proper biasing. DC-blocking

capacitors are used to connect to these outputs.

TXOUT and

TXOUT

are connected to the SMA connec-

tors IF and

IF.

Consult the schematic diagram for more

information. C18, C19, L2, and L3 act only to provide

biasing and DC blocking; they do not set the output

impedance. Refer to the MAX2511 data sheet for more

information on designing a matching network for this

port.

Rx Input

The Rx input pins (RXIN and

RXIN)

do not require

external DC biasing. Capacitors C16 and C17 provide

DC blocking. On the EV kit, they are connected in a

shared configuration with the Tx outputs, at the IF and

SMA connectors (see Figure 2 for more information).

Rx Output and Limiter Input

The receive downconverter mixer’s output appears at

the MIXOUT pin—a current source that can drive a

165Ω load to 2Vp-p. The MIXOUT pin is terminated with

330Ω (R10 + R11) for proper match to the bandpass fil-

ter (Z

= 330Ω). Therefore, the net load at MIXOUT is

330Ω



330Ω = 165Ω.

The EV kit design allows separate testing of the Rx

mixer and limiter sections of the MAX2511. Coupling

capacitor C20 is used to connect the node between

R10 and R11 to an external SMA connector. This

System Power-Management Features

Besides the Tx/Rx modes previously mentioned, the

MAX2511 supports two other operating modes: shut-

down and standby. Bring both TXEN and RXEN

jumpers to the “2-3” position (TXEN = RXEN = GND),

_______________________________________________________________________________________

MAX2511 Evaluation Kit

Evaluates: MAX2511

network has some attenuation, but presents the correct

impedance to the MIXOUT pin and provides a nearly

50Ω output impedance for measurement. The voltage

attenuation is 21.4dB.

The limiter input pin (LIMIN) requires a DC bias level

set by the VREF pin. To present this bias level, resistors

R10 + R11 and R1 + R13 and are connected to VREF

and not to ground. To minimize noise, this voltage is

bypassed with capacitor C21 to ground.

C5, and D1. Add capacitors C27 and C28 (both 47pF

SMT capacitors). Add J2 and J3 (top-mount SMA con-

nectors). Replace C6 and C7 with 0Ω shorts and L1

with a 100Ω resistor. These modifications allow a differ-

ential LO source to be AC coupled into the TANK and

TANK

pins. The circuit can then be driven from a differ-

ential LO source at LO and

with a power level of

-3dBm per side (0dBm total). The external signal

source used can be split into LO and

with an addi-

tional 180° balun of the same type as mentioned in the

Test Equipment Required

section. For optimum LO

suppression and image rejection, a differential LO

source is recommended if overdriving LO.

Oscillator Tank

The oscillator tank shipped with the EV kit is configured

for operation at a 425MHz IF frequency, with a

10.7MHz second IF. This places the desired oscillator

frequency at 435.7MHz. The oscillation frequency can

be controlled over approximately a 100MHz range by

adjusting the FADJ voltage from 0V to 3V. Do not apply

voltages higher than 10V to the FADJ connector.

If this frequency range does not cover your target IF

frequency, it is fairly simple to retune the oscillator by

adjusting capacitor C5 and inductor L1 (see the

MAX2511 data sheet for more information on oscillator

tank design).

Layout Issues

A good PC board is an essential part of an RF circuit

design. The EV kit PC board can serve as a guide for

laying out a board using the MAX2511.

Remove the ground plane directly under LO tank com-

ponents, IF port coupling components, and limiter out-

puts (Figure 5).

LO Overdrive

The MAX2511 EV kit can be operated from an external

LO source with a few modifications (Figure 1). The fol-

lowing components must be removed entirely: R2, R4,

Rx Inputs and Tx Outputs

The RXIN and

RXIN

input coupling network should be

symmetrical to provide the best input balance if used

as a differential input. The TXOUT and

TXOUT

biasing

networks should also be symmetrical to present an

equivalent load on each pin.

PIN = -3dBm SMA

C28

47pF

(REPLACE WITH

0Ω SHORT)

100Ω

(REPLACE L1

WITH 100Ω)

1kΩ

(REMOVE)

FADJ

(REMOVE)

C26

47nF

10k

(REMOVE)

TANK

MAX2511

TANK

(REPLACE WITH

0Ω SHORT)

PIN = -3dBm SMA

C27

47pF

ADD C27 AND C28 47pF CAPACITORS, J2 AND J3 SMA CONNECTORS.

REMOVE R2, R4, C5, AND D1. REPLACE C6 AND C7 WITH 0Ω SHORTS.

REPLACE L1 WITH A 100Ω RESISTOR.

Figure 1. LO Overdrive Circuit

_______________________________________________________________________________________

10.7MHz

MURATA

CERAMIC FILTER SFE10.7MA5-A

= 330Ω

JU5

270Ω

R13

51Ω

C20

C22

47nF

C21

100nF

MIXOUT

SMA

J11

R11

51Ω

LIMIN

SMA

R10

270Ω

LIMIN

MIXOUT

RXIN

TXOUT

RXIN

470pF

C16

22OnH

470pF

22OnH

C17

VCC

RSSI

TANK

C19

470pF

VREF

10nF

1kΩ

D1 ALPHA

47pF

10pF

SMV1204-199

8.2nH

100pF

10nF

RSSI

TXIN

RXEN

TXEN

LIMOUT

C23

100nF

TXIN

(NOT

SUPPLIED)

51Ω

C12

47nF

(NOT

SUPPLIED)

LIMOUT

Figure 2. MAX2511 EV Kit Schematic

SMA

J10

C25

47nF

LOP

SMA

C28

(NOT SUPPLIED)

FADJ

10kΩ

TANK

GND

OSCOUT

GND

47pF

VCC

47nF

VCC

47nF

470pF

VCC

GND

C26

47nF

MAX2511

C18

470pF

VCC

SMA

1kΩ

OSCOUT

SMA

C14

47nF

LON

SMA

C15

47nF

C27

(NOT SUPPLIED)

VCC

51Ω

C24

10µF

953Ω

VCC

JU1

2 1

VCC

C11

47nF

C10

47nF

GND

VCC

LIMOUT

SMA

TXIN

SMA

C13

47nF

LIMOUT

SMA

Evaluates: MAX2511

_______________________________________________________________________________________

GND

RXEN

TXEN

JU2

MAX2511 Evaluation Kit

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