MAX1455EVKIT-NS_技术文档

19-1032; Rev 0; 5/08

MAX1455 Evaluation Kit

Evluates:MAX145

General Description

Features

♦ Proven PCB Layout

The MAX1455 evaluation kit (EV kit) demonstrates resis-

tive element sensor compensation and calibration using

the MAX1455 and a computer. The kit includes an

assembled and tested PCB, which is available with a

factory-calibrated sensor (MAX1455EVKIT-CS) or with-

out a sensor (MAX1455EVKIT-NS). The software and

computer are not required for performing the initial per-

formance evaluation of the sensor option since the EV

kit is already compensated. A 10-pin ribbon cable con-

nects the EV board to a serial-key adapter,

MAX1452KEY, that plugs into a computer serial port,

allowing the board to be evaluated inside an environ-

mental chamber. The software requires a PC compati-

ble with Windows^®95/98/2000/XP.

♦ Convenient On-Board Test Points

♦ Fully Assembled and Tested

♦ Optional Pressure Sensor (MAX1455EVKIT-CS)

♦ Factory-Calibrated Over Temperature

(MAX1455EVKIT-CS)

♦ LabVIEW^®-Based Software

LabVIEW is a registered trademark of National Instruments, Corp.

Ordering Information

PART

TYPE

EV Kit

MAX1455EVKIT-CS

MAX1455EVKIT-NS

MAX1452KEY*

EV Kit

Serial Key Adapter

Windows is a registered trademark of Microsoft Corp.

*MAX1452KEY is also used for MAX1455EVKIT and is included

in MAX1455EVKIT package.

EV Kit Component List

DESIGNATION QTY

DESCRIPTION

470µF 10V electrolytic capacitor

0.1µF X7R ceramic capacitors

1µF X7R ceramic capacitors

5.6V Zener diode

DESIGNATION QTY

DESCRIPTION

C1

C2, C4, C6

C3, C5

D1

1

3

8-pin DIL header, alternate sensor

connector

S3

1

4

Split pads;

2

SP1–SP4

cut tracks to allow connection of

sensor at S3

1

D2

0

Dual diode, not installed

2-pin header, not installed

Split pad;

J1

0

SP5

1

configure on-board op amp as buffer;

cut tracks to allow use of op amp

-CS

-NS

1

0

1

2-pin header, not installed

2-pin header—shorted

J2

U1

1

MAX1455AAE

MAX1455AAP

J3

J4

2-pin header

-CS

-NS

1

0

2-pin header—shorted

2-pin header, not installed

KEY Component List

P1

10-pin header

DESIGNATION QTY

DESCRIPTION

4mm banana sockets;

connect +5V, GND, OUT

220µF 10V electrolytic capacitor

(radial lead)

P2, P3, P4

3

C1

C2, C3, C5

C4

1

3

1

R1

R2

R3

R4

1

10Ω 5ꢀ resistor

4.7kΩ 5ꢀ resistor

10Ω 5ꢀ resistor

30Ω 5ꢀ resistor

NovaSensor (Fremont, CA)

NPH-8-100GH

Panasonic ECE-A1AKA221

Digi-Key P832-ND

0.33µF 10ꢀ, 25V X7R ceramic

capacitors* (1206)

Taiyo Yuden TMK316BJ334KF or

equivalent

S1

S2

1

0

Murata GRM319R71E334K

(8-pin TO package, 100kPa gauge)

0.047µF 10ꢀ, 50V X7R ceramic

capacitor (1206)

KEMET C1206C473K5RACTU

Digi-Key 399-1246-1-ND

Unused, alternate sensor site

________________________________________________________________ Maxim Integrated Products

1

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.

MAX1455 Evaluation Kit

KEY Component List (continued)

DESIGNATION QTY

DESCRIPTION

DESIGNATION QTY

DESCRIPTION

10µF 10V tantalum capacitor (R case)

Panasonic ECS-T1AX106R

Digi-Key PCS2106CT-ND

npn transistors

Panasonic UN5214 or UN5215CT

Q3, Q5, Q6

3

1

C6

1

pnp differential transistor

Panasonic XP2401

Q4

Q7

0.1µF 10ꢀ, 25V ceramic

capacitors* (0805)

Murata GRM21BR71E104K or

equivalent

n-channnel MOSFET

Zetex ZVN4106F

C7–C12

6

R1

R2, R3

R4

1

2

1

2

1

2

1Ω 1W resistor (2512)

Switching diode 30V, 0.2A

Panasonic MA715-(TX)

Digi-Key MA715CT-ND

110Ω 1/8W resistors (1206)

470Ω 1/8W resistor (1206)

47kΩ 1/8W resistors (1206)

390kΩ 1/8W resistor (1206)

10kΩ 1/8W resistor (1206)

2.2kΩ 1/8W resistors (1206)

Ultra-reed relays

Hamlin HE3621A0510

Digi-Key HE207-ND

D1

D2

1

R5, R6

R7

Diode BAR74

Zetex BAR74ZX

R8

2-pin headers, gold (0.1in centers)

(cut from 36-pin strip)

Sullins PZC36SAAN

R9, R10

J1, J2, J4

3

1

Digi-Key S1011-36-ND

RL1, RL2

U1

2

1

Evluates:MAX145

3-pin header, gold (0.1in center)

(cut from 36-pin strip)

Sullins PZC36SAAN

Op amp (SOT23)*

Maxim MAX4490AUK

J3

Digi-Key S1011-36-ND

IC, hex inverter (14 SO)

Texas Instruments SN74HC04DR

Digi-Key 296-1189-1-ND

Shunts (J1 = open, J2 = shorted, J3

pins = 2/3 shorted (lower two pins),

J4 = shorted)

Sullins SSC024AN

Digi-Key S9002-ND

U2

J1–J4

P1

4

1

Quad 2 input (14 SO)

Texas Instruments SN74HC00DR

Digi-Key 296-1187-1-ND

U3

1

Low-profile header 2 x 5 0.1 centers

3M 2510-6002UB

Digi-Key MHB10K-ND

RS-232 +5V driver/receiver*

Maxim MAX3387ECUG

U4

—

1

MAX1452KEY serial board, PCB

9-pin D-subconnector

AMP 747905-2

Digi-Key A2047-ND

*Indicates that part is normally consigned by Maxim.

P2

1

2

Power MOSFETs (8-pin SO)

Fairchild NDS8958

Q1, Q2

Component Suppliers

SUPPLIER

PHONE

WEBSITE

www.digikey.com

Digi-Key Corp.

KEMET Corp.

800-344-4539

864-963-6300

770-436-1300

626-333-5858

www.kemet.com

Murata Electronics North America, Inc.

Quest Components

www.murata-northamerica.com

www.questcomp.com

2

_______________________________________________________________________________________

!

WARNING!

Do NOT interconnect the EV board and the

KEY while jumper J4 is in place, as this will permanently damage

the KEY when power is applied to the EV board.

MAX1455 Evaluation Kit

Evluates:MAX145

•

Printout of compensation test data (MAX1455EVKIT-CS

only)

Quick Start

Required Equipment

Precision-regulated +5V power supply

Multimeter with at least five significant digits

Sensor pressure source

•

Five samples of the MAX1455

•

Straight-connected serial cable for connecting the

KEY and PC

•

Overview

Procedure

The objective of the EV kit is to allow the user to learn

how to program the ASIC using a hands-on approach.

To do this, users are encouraged to compensate their

own sensors using the EV kit along with the provided

software. This kit is intended to be used by engineers

familiar with resistive element sensors and their com-

pensation techniques.

Use the following quick-start procedure to operate and

evaluate the factory calibration accuracy of a MAX1455

EV board with sensor option.

1) Download and install the MAX1455 EV kit software

on your PC.

2) Run Port98nt.exe (from the START menu or

MAX1455 folder) to load the device driver for PC IO

communication.

The purpose of the MAX1455EVKIT-CS is to demonstrate

the capabilities of the MAX1455 in compensating a typi-

cal resistive element sensor. To assist the user in quickly

evaluating the ASIC, the board has been precompensat-

ed using a generic, low-pressure sensor such as the

NovaSensor NPH8-100G.

3) Connect a 5V power supply to the +5V and GND

terminals on the EV kit.

4) Connect a DVM between OUT and GND.

5) Determine whether the EV board will run in analog

or digital mode:

In the case of the MAX1455EVKIT-CS, the test data print-

out included in the EV kit is specific to the particular EV

board enclosed in the kit. Both the test data and the EV

board contain a serial number for identification.

Factory setting of the -CS type is analog mode.

Factory setting of the -NS type is digital mode.

6) For analog mode, make sure jumper J2 is removed

and jumper J4 is present. Note: It is not possible to

communicate with the MAX1455 while in analog

mode.

Initial Setup

See the MAX1455 EV board (Figure 1). Four configura-

tion jumpers, J1–J4, are provided to make the EV board

adaptable to a wide range of applications. J1 bypasses

the VOUT isolation resistor and is not normally fitted. J2

unlocks the MAX1455 digital interface and places the

part in digital mode. J3 connects DIO to VOUT for single-

pin programming. J4, when fitted, supplies power direct-

ly to the MAX1455. J4 must be removed when operating

in digital mode as control of the power line is then provid-

ed by the serial-adapter board. Two rows of test points

are provided to allow the user to probe the pins of the

MAX1455, including the four sensor nodes. If the user

wishes to connect an alternative sensor, this can be

done using the 8-pin DIL socket, S3. When connecting

an alternative sensor, the user must also cut the four split

pad tracks (SP1–SP4) that connect the resident sensor,

S1/S2. These pads are located on the reverse side of the

board. The 10-way header P1 carries serial data and

power to the serial-adapter board. This must be used

when the MAX1455 is in digital mode and allows the user

to reprogram the ASIC through the computer. Three

4mm banana sockets (P2, P3, and P4) carry the +5V,

OUT, and GND signals to the board. Note that all the

connectors and test pins are labeled on the board.

7) For digital mode, make sure that jumper J2 is present

and jumper J4 is removed before applying power to

the EV board. In addition, make sure that the 10-pin

ribbon cable connects the EV board to the serial com-

munication module and that the 9-pin connector on

the serial module is connected to the PC either directly

or through a straight-connected serial cable.

MAX1455 EV Kit Contents

The MAX1455EVKIT-CS is shipped fully temp-

erature compensated from -40°C to +125°C. The

MAX1455EVKIT-NS version of the EV kit is shipped

without a sensor. Additional material may be included

in your EV kit, which are not listed below.

•

MAX1455 EV board

MAX1452KEY interface adapter

10-pin ribbon cable for connecting the KEY and EV

board

•

Computer interface adapter ribbon interconnect cable

_______________________________________________________________________________________

3

MAX1455 Evaluation Kit

with respect to test point VSS. At this point, there should

be no connection to the sensor pressure port. Since the

sensor supplied is a gauge type, the output voltage at

the analog connector should read about 0.5V.

Carefully remove the plastic sensor protector (if sup-

plied) and connect a silicone pressure tube to the sen-

sor pressure port. Grasp the sensor (not the PCB)

while fitting the tube in place. Perform any required

pressure controller initialization/calibration procedures,

then vent the system. The output voltage should read

0.5V. Perform a few pressure cycles to minimize hys-

teresis effects. Apply full-scale pressure as stated in

the test data or as written on the back of the board, and

confirm that the output reads 4.5V. The user can also

test at other lesser pressures to check for pressure lin-

earity errors.

Extended Temperature Pressure Test

Additional equipment required:

•

Environmental chamber capable of -40°C to +125°C

operation with a noncondensing atmosphere

Evluates:MAX145

The unit can now be tested at any temperature in the

-40°C and +125°C range. It is advisable to first perform

one or two full excursions of temperature and pressure

to minimize hysteresis errors. It is recommended that

the electronics be conformal coated in any application

where condensation of moisture might occur. This was

not done to the EV boards, since the user might wish to

modify the circuit for specific requirements.

Figure 1. Evaluation (EV) Board Layout

Room Temperature Bench Test

(MAX1455EVKIT-CS)

The board output is ratiometric to the supply, and there-

fore, a very accurate setting of the supply voltage is

required to minimize measurement errors. Also, the

board contains a Zener diode, which helps protect

against overvoltage and reverse voltage. The protection

circuit enables if the supply becomes less than approx-

imately -0.7V or more than approximately +5.6V. The

initial electrical connections should be made as follows:

Since the PCB is not conformal coated, it is important

that the environmental chamber not allow condensation

to take place. If this should happen, a bake-out at

+125°C (with no power applied) for a minimum of 1hr is

recommended. Note that the circuit might behave errat-

ically if moisture is allowed to condense on the PCB

since weak ionic paths affect some high-impedance

nodes on the board.

1) Connect the negative terminal of the power supply

to the 4mm banana socket labeled GND.

2) Connect the positive terminal of the power supply to

the 4mm banana socket labeled +5V.

Most of the errors after compensation are due to the sen-

sor’s drift and nonrepeatable behavior. The EV board

compensation printout includes the raw sensor output that

was measured during compensation at each temperature.

Users might wish to compare this data with their measure-

ments of the sensor output in order to separate sensor

errors from ASIC errors. This can be performed at the sen-

sor connector. To avoid attenuating the sensor output sig-

nal, it is recommended to use a multimeter with an input

impedance greater than 10MΩ for this measurement.

3) Connect the DVM to the 4mm banana socket

labeled OUT; the ground return should be connect-

ed to the 4mm banana socket labeled GND.

IMPORTANT! To avoid problems with ground loops,

noise, and to prevent possible damage to the

MAX1452KEY adapter, connect all equipment

including the computer (used later) to the same AC

circuit and use one common earth ground.

If the power supply has a programmable current limit,

set it to approximately 100mA. Adjust the supply volt-

age to +5V and measure the voltage at test point VDD

Important Note: Download factory-compensated coef-

ficients into a file for future reference before overwrit-

ing flash content.

4

_______________________________________________________________________________________

MAX1455 Evaluation Kit

Evluates:MAX145

Table 1. I/O Connector S3 Signals Sensor

Interface

Computer Requirements

and Connections

The next logical step after checking the module perfor-

mance is to actually edit and reprogram the module

using the same sensor. To do so, configure the EV kit

for digital operation and connect the digital interface to

the computer first. Below is a list of the computer

requirements:

SIGNAL

OUT+

IN+

DESCRIPTION

1

Positive output sensor

2

Top of Wheatstone bridge

Positive output sensor

3

OUT+

IN-

4

Bottom of Wheatstone bridge

Negative sensor output

Bottom of Wheatstone bridge

Negative sensor output

Top of Wheatstone bridge

5

OUT-

IN-

•

IBM-compatible PC

6

Windows 95/98/2000/XP

One unused serial port

7

OUT-

IN+

8

Detailed Hardware Description

The MAX1455 (U1) performs analog temperature com-

pensation on piezo-resistive sensors. The MAX1455

contains the temperature compensation coefficients in

its internal EEPROM.

and the software before attempting to remove the sen-

sor supplied with the board and replacing it with the

user sensor. The MAX1455 works with 4-wire closed

Wheatstone bridge-configured sensors. An 8-pin DIL

socket is provided for alternative sensor mounting. The

pinout for this connector is given in Table 1.

Figure 2 shows the circuit diagram of the EV board.

Figures 3–6 illustrate the PCB component placement

and wiring details.

Alternatively, the user can test the ASIC using an artifi-

cial bridge consisting of four discrete resistors. Some

general knowledge of the user’s sensor parameters

must be known in order to set the initial coefficients.

This way, the ASIC is not overloaded (i.e., output satu-

rated). It is recommended that the sensor wires be kept

as short as possible to minimize system noise. At this

point, refer to the Compensation Procedure section in

the MAX1455 user manual for a step-by-step procedure

for compensating the sensor.

The MAX1455 has a single-wire digital interface that can

be connected to the output to maintain a true 3-wire sys-

tem. The MAX1452KEY interface adapter converts and

buffers the outputs from the computer serial port to com-

municate with the ASIC. The adapter also controls power

to the EV board when in digital mode. This configuration

allows power resets to be performed under software

control.

The adapter operates internally at 5V. The ratiometricity

tests of the evaluation board should be limited to 4.5V

to 5.5V while the digital connector is in place. This

requirement is to prevent logic-level mismatch and the

activation of any biasing protection diodes in the front

end of the digital circuits.

Calibrate the new sensor in a temperature-controlled

environmental chamber.

EV Kit Software

An unused serial port on the host PC is required to

allow software control of the MAX1455 EV board.

Figure 7 shows the adapter circuit diagram and Figures

8, 9, and 10 provide PCB component placement and

wiring information.

The MAX1455 EV kit software is an executable file

developed using National Instrument’s LabVIEW soft-

ware. LabVIEW application is not required to run the EV

kit software. The software is a high-level interface that

calls a low-level serial.dll.

Replacing the Sensor

(MAX1455EVKIT-CS)

The factory-calibrated sensor can be replaced by a

user-provided sensor. It is recommended to become

fully familiarized with the basic operation of the ASIC

Note: The MAX1455 software tools can be down-

loaded and installed from the Maxim website at

www.maxim-ic.com.

_______________________________________________________________________________________

5

MAX1455 Evaluation Kit

Table 2. I/O Connector P1 Signal Digital

Interface

MAX1455 EV Kit Files

The software allows editing the contents of the ASIC’s

registers and EEPROM, as well as observing the effects

of changes to the DAC on the output. Once desired

results are obtained, the EEPROM can be programmed

with the register contents.

SIGNAL

DESCRIPTION

Ground return (screen)

Switched +5V return from serial board

1

GND

2

VDDIN

Consult the MAX1455 reference manual for a more

complete description of software operation and usage.

3

VDDOUT Switched +5V out to serial board

4

GND

+5V

Ground return (screen)

5V power input

Below is a listing of the main files included in the EV kit

software tools.

5

6

GND

+5V

Ground return

MAX1455 EV Kit Files

7

5V power input

8

GND

DI/O

GND

Ground return

FILE

FUNCTION

9

Serial digital communications

Ground return

MAX1455.exe Communication program

10

Comp55.exe

read.me

Compensation program

Optional file containing last-minute additions

Low-level functional routines

serial.dll

port98nt.exe

Device driver for PC IO communication

Evluates:MAX145

6

_______________________________________________________________________________________

MAX1455 Evaluation Kit

Evluates:MAX145

Figure 2. MAX1455 EV Kit Schematic Diagram

_______________________________________________________________________________________

7

MAX1455 Evaluation Kit

Evluates:MAX145

Figure 3. MAX1455 EV Kit Top Silk

Figure 4. MAX1455 EV Kit—Bottom Silkscreen

Figure 5. MAX1455 EV Kit—Top Copper

Figure 6. MAX1455 EV Kit—Bottom Copper

8

_______________________________________________________________________________________

MAX1455 Evaluation Kit

Evluates:MAX145

XM490UAK

Figure 7. MAX1452KEY Adapter Schematic Diagram

_______________________________________________________________________________________

9

MAX1455 Evaluation Kit

Evluates:MAX145

Figure 8. Adapter Circuit PWB—Top Silkscreen

Figure 9. Adapter Circuit PWB—Top Copper

Figure 10. Adapter Circuit PWB—Bottom Copper

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.

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

is a registered trademark of Maxim Integrated Products, Inc.


型号：	MAX1455EVKIT-NS
厂家：	MAXIM INTEGRATED PRODUCTS
描述：	Fully Assembled and Tested
文件：	总10页 (文件大小：281K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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