MAX4208EVKIT+ - Maxim Integrated Products, Inc.

General Description

The MAX4208 evaluation kit (EV kit) simplifies evalua-

tion of the MAX4208 ultra-low offset/drift, adjustable

gain, precision instrumentation amplifier in a µMAX®

package. The MAX4208 features high-impedance dif-

ferential inputs optimized for small voltages (±100mV

max) and provides rail-to-rail output. The MAX4208 EV

kit is configured for a gain of 148V/V. The EV kit oper-

ates from a single-supply voltage between 2.85V and

5.5V, or dual supplies providing ±1.425V to ±2.75V.

The MAX4208 EV kit can also be used to evaluate the

MAX4209 fixed-gain amplifiers. The MAX4208 IC tem-

perature range is -40°C to +125°C.

The MAX4209 EV kit, available separately, evaluates the

100V/V fixed-gain MAX4209 amplifier without external

gain-setting resistors.

Note: To evaluate a MAX4209 IC featuring internal

gain-setting resistors, order a MAX4209EVKIT+ or

request a free sample of the MAX4209 IC along with the

MAX4208EVKIT+. See the

Part Selection Table

for IC

ordering information.

Features

oSingle- or Dual-Supply Operation

2.85V to 5.5V Single-Supply Operation

±1.425V to ±2.75V Dual-Supply Operation

oAdjustable Voltage Gain Configured to 148V/V

oRail-to-Rail Output

oConfigurable Reference Voltage: Externally or

Internally Buffered

oOptional Current-Sense Mode

oFully Assembled and Tested

Evaluates: MAX4208/MAX4209

MAX4208 Evaluation Kit

________________________________________________________________

Maxim Integrated Products

19-0997; Rev 0; 9/07

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim's website at www.maxim-ic.com.

Component List Ordering Information

Part Selection Table

PART TYPE

MAX4208EVKIT+ EV Kit

PART GAIN (V/V)

MAX4208AUA+ Adjustable

MAX4209TAUA+ 10

MAX4209HAUA+ 100

MAX4209KAUA+ 1000

DESIGNATION QTY DESCRIPTION

C1, C3 2

10µF ±10%, 10V X5R ceramic

capacitors (0805)

Murata GRM21BR61A106K

KEMET C0805C106K8PAC

C2, C4, C5 3

0.1µF ±10%, 10V X5R ceramic

capacitors (0402)

Murata GRM155R61A104K

KEMET C0402C104K8RACTU

C6, C7 0 Not installed, capacitors (0603)

C8 1

1000pF ±10%, 16V X5R ceramic

capacitor (0402)

Murata GRM155R61C102K

JU1 1 4-pin header

JU2, JU3 2 2-pin headers

R1 1 1kΩ ±0.1% resistor (0805)

IRC PCF-W0805LF-03-1001-B

R2 1 147kΩ ±0.1% resistor (0805)

IRC PCF-W0805LF-03-1473-B

R3, R4 2 4.99kΩ ±1% resistors (0603)

R5, R6 0 Not installed, resistors—short (0603)

R7 0 Not installed, resistor (1206)

U1 1 MAX4208AUA+ (8-pin µMAX)

— 3 Shunts

— 1 PCB: MAX4208 Evaluation Kit+

Denotes lead-free and RoHS-compliant

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Evaluates: MAX4208/MAX4209

MAX4208 Evaluation Kit

2 _______________________________________________________________________________________

Quick Start

Recommended Equipment

Before beginning, the following equipment is needed:

• 5V, 1A-rated DC power supply

• Function generator

• Oscilloscope

Procedure

The MAX4208 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 completed.

1) Verify that a shunt is installed across pins 1-4 of

jumper JU1 (on-board buffered-reference mode).

2) Verify that a shunt is installed on jumper JU2 (single-

supply operation).

3) Verify that a jumper is not installed on jumper JU3

(buffered-reference mode).

4) Set the DC power-supply output to 5V and disable

the output.

5) Set the function generator output to a 10mVP-P,

200Hz, 0V DC offset sine wave. Terminate the func-

tion generator as needed.

6) Connect the power-supply positive output to the

VDD PCB pad on the EV kit.

7) Connect the power-supply ground to the GND PCB

pad next to VDD on the EV kit.

8) Connect the function generator output across the

differential input PCB pads, IN+ and IN-.

9) Connect the IN- PCB pad to the GND PCB pad with

a wire.

10) Connect the oscilloscope to the OUT PCB pad and

the oscilloscope ground clip to the GND PCB pad.

11) Enable the DC power supply and the function gen-

erator.

12) Verify that the oscilloscope measures a 1.48VP-P,

200Hz, 2.5V DC offset sine wave.

Detailed Description

The MAX4208 EV kit evaluates the MAX4208 instrumenta-

tion amplifier that features adjustable gain with gain-

setting resistors R1 and R2, low offset voltage, and low

offset voltage drift. The output-voltage range is from VSS

+ 100mV, to VDD - 100mV. The MAX4208 EV kit voltage

gain is configured to 148V/V. The EV kit operates from a

single-supply voltage between 2.85V and 5.5V or from

a dual-supply voltage providing ±1.425V to ±2.75V.

The MAX4208 EV kit can evaluate the fixed-gain

MAX4209 ICs in the 8-pin µMAX package by replacing

the MAX4208 IC U1 and removing resistors R1 and R2.

Power Supply

The MAX4208 EV kit jumper JU2 must be configured

properly for single-supply or dual-supply operation. For

single-supply operation, a single power supply is con-

nected to VDD and GND. For dual-supply operation,

connect a positive supply to VDD, a negative supply to

VSS, and supply ground to GND. See Table 1 to config-

ure jumper JU2.

Component Suppliers

Table 1. Power-Supply Configuration

(Jumper JU2)

Note: Indicate that you are using the MAX4208 or MAX4209 when contacting these component suppliers.

SUPPLIER PHONE WEBSITE

IRC 361-992-7900 www.irctt.com

KEMET Corp. 864-963-6300 www.kemet.com

Murata Mfg. Co., Ltd. 770-436-1300 www.murata.com

SHUNT

POSITION VSS PIN EV KIT FUNCTION

Installed Connected to

GND

Single-supply operation.

Power only VDD.

Not installed Not connected Dual-supply operation.

Power VDD and VSS.

REFIN/MODE Operation Modes

The EV kit jumper JU1 configures the MAX4208 for direct

reference, buffered reference, or shutdown mode. The

reference voltage at REF sets the output voltage DC sig-

nal, OUT, when the differential input signal VIN+ - VIN-

equals zero. In direct-reference-mode operation, con-

nect a user reference voltage directly to the REF PCB

pad. In buffered-reference-mode operation, connect a

user reference voltage to the REFIN/MODE input PCB

pad or use the resistor-divider network R3 and R4 to

provide a reference voltage for REFIN/MODE, scaled

from VDD. The network is configured to scale the volt-

age at REFIN/MODE to one-half of VDD. Replace resis-

tors R3 and R4 to modify the voltage applied to

REFIN/MODE using the following equation:

where VDD is the input supply voltage to the EV kit.

In buffered-reference mode, the MAX4208 internally

buffers the REFIN/MODE voltage onto REF.

Note: Do not connect an external source to the REF PCB

pad in buffered-reference mode. See Table 2 for jumper

JU1 configurations.

REF Input

The EV kit’s jumper JU3 must be configured properly

for appropriate reference-voltage operation. In direct

reference mode, install a shunt on jumper JU3 to con-

nect REF to the on-board ground (GND), or remove the

shunt to connect a user reference voltage to the REF

input PCB pad. For either buffered-reference mode,

REF must not be connected to a reference voltage;

thus, the shunt on jumper JU3 must not be installed.

See Table 2 for jumper JU3 configurations.

Optional capacitor C6 can be used for reference-volt-

age stability/filtering. Choose an appropriate value as

needed.

On-Board Current Sensing

The MAX4208 EV kit can be configured for on-board

current sensing by installing a surface-mount 1206

sense resistor at R7, located between the IN+ and IN-

PCB pads. Use the following equation to select the

value for resistor R7:

where IIN is the maximum current flowing across resis-

tor R7 and 30mV is a suggested sense voltage. 30mV x

148V/V gives a 4.4V output swing. Refer to the

R7 30mV

IIN

V VDD x R4

R3 R4

REFIN/MODE =+

⎛

⎝

⎜⎞

⎠

⎟

Evaluates: MAX4208/MAX4209

MAX4208 Evaluation Kit

_______________________________________________________________________________________ 3

Table 2. Jumpers JU1 and JU3 Configurations

MODE JU1 SHUNT

POSITION

REFIN/MODE

JU3 SHUNT

POSITION REF PIN EV KIT FUNCTION

Installed Connected to

GND

JU1 disables the internal REF buffer.

JU3 sets the REF voltage to GND.

Direct-reference-mode

operation 1-2 Connected to

VSS

Not installed

Connected to

user reference

voltage

JU1 disables the internal REF buffer.

JU3 allows the user to set the REF

voltage directly. Apply a user reference

voltage to the REF PCB pad in the 0V

and VDD - 1.6V range.

Shutdown mode 1-3 Connected to

VDD — — Entire IC is in shutdown. ICC < 5µA.

Buffered-reference-

mode operation

(on-board reference)

1-4 Connected to

VDD / 2 Not installed Not connected

The IC buffers the on-board VDD / 2

onto REF. Do not install JU3 or connect

an external source to the REF PCB pad.

Buffered-reference-

mode operation (user

reference)

Not installed

Connected to

user reference

voltage

Not installed Not connected

The IC buffers a user reference voltage

onto REF. Apply a user reference

voltage to the REFIN/MODE PCB pad in

the range of VSS + 200mV and VDD -

1.6V. Do not install JU3 or connect an

external source to the REF PCB pad.

Evaluates: MAX4208/MAX4209

MAX4208/MAX4209 IC data sheet for application

details. Verify that the selected resistor is rated for the

appropriate current and power levels.

For high-power applications, use the IN+ and IN- PCB

pads as sense connections to an off-board current-

sense resistor.

Differential Input Filter

The MAX4208 EV kit features an optional balanced-dif-

ferential resistor-capacitor filter across the MAX4208

IN+ and IN- input pins. Use the surface-mount 0603

PCB pads for installing resistors R5, R6, and capacitor

C7, which form the filter. Before installing resistors R5

and R6, cut open the shorting PCB trace located at the

respective pads.

Gain Setting

The MAX4208 EV kit gain is configured to 148V/V by

resistors R1 and R2. Replacing these resistors with

high-precision, surface-mount 0805 resistors can

change the gain. Tolerance of ±0.1% or better is rec-

ommended for optimum performance. Use the follow-

ing equation to select values for resistors R1 and R2:

R2 = R1 x (Gain - 1)

where R1 ≤1kΩand the sum of R1 + R2 is 10kΩ≤(R1 +

R2) ≤500kΩ.

Evaluating the MAX4209

The MAX4208 EV kit can be used to evaluate the fixed-

gain MAX4209 IC in the 8-pin µMAX package by replac-

ing the MAX4208 IC U1 and removing resistors R1 and

R2. The MAX4209 IC features fixed gains of 10V/V,

100V/V, or 1000V/V. See the

Part Selection Table

for

ordering information.

The MAX4209 EV kit is also available separately.

MAX4208 Evaluation Kit

4 _______________________________________________________________________________________

0.1μF

1000pF

147kΩ

0.1%

1kΩ

0.1%

OUT

GND

REF

JU3

OPEN

VDD

OUT

REF

REFIN/MODE

IN-

IN+

VSS

0.1μF

OPEN

0.1μF

10μF

JU2

GND

VSS

SHORT

IN+

IN-

OPEN

REFIN/MODE

GND

JU1

4.99kΩ

VSS

10μF

MAX4208

VDD

GND

Figure 1. MAX4208 EV Kit Schematic

Evaluates: MAX4208/MAX4209

MAX4208 Evaluation Kit

_______________________________________________________________________________________ 5

Figure 2. MAX4208 EV Kit Component Placement Guide—

(Component Side)

Figure 3. MAX4208 EV Kit PCB Layout—Component Side

Evaluates: MAX4208/MAX4209

MAX4208 Evaluation Kit

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

Figure 4. MAX4208 EV Kit PCB Layout—Solder Side