19-1032; Rev 0; 5/08
MAX1455 Evaluation Kit
General Description
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.
♦
Proven PCB Layout
♦
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.
Features
Evaluates: MAX1455
Ordering Information
PART
MAX1455EVKIT-CS
MAX1455EVKIT-NS
MAX1452KEY*
TYPE
EV Kit
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
C1
C2, C4, C6
C3, C5
D1
D2
J1
J2
J3
J4
P1
P2, P3, P4
R1
R2
R3
R4
S1
S2
QTY
1
3
2
1
0
0
-CS
-NS
1
-CS
-NS
1
3
1
1
1
1
1
0
DESCRIPTION
470µF 10V electrolytic capacitor
0.1µF X7R ceramic capacitors
1µF X7R ceramic capacitors
5.6V Zener diode
Dual diode, not installed
2-pin header, not installed
0
1
1
0
2-pin header, not installed
2-pin header—shorted
2-pin header—shorted
2-pin header, not installed
DESIGNATION
QTY
U1
U1
1
1
SP5
1
SP1–SP4
4
DESIGNATION
S3
QTY
1
DESCRIPTION
8-pin DIL header, alternate sensor
connector
Split pads;
cut tracks to allow connection of
sensor at S3
Split pad;
configure on-board op amp as buffer;
cut tracks to allow use of op amp
MAX1455AAE
MAX1455AAP
2-pin header
KEY Component List
DESCRIPTION
220µF 10V electrolytic capacitor
(radial lead)
Panasonic ECE-A1AKA221
Digi-Key P832-ND
0.33µF ±10%, 25V X7R ceramic
capacitors* (1206)
Taiyo Yuden TMK316BJ334KF or
equivalent
Murata GRM319R71E334K
0.047µF ±10%, 50V X7R ceramic
capacitor (1206)
KEMET C1206C473K5RACTU
Digi-Key 399-1246-1-ND
10-pin header
4mm banana sockets;
connect +5V, GND, OUT
10Ω ±5% resistor
4.7kΩ ±5% resistor
10Ω ±5% resistor
30Ω ±5% resistor
NovaSensor (Fremont, CA)
NPH-8-100GH
(8-pin TO package, 100kPa gauge)
Unused, alternate sensor site
C1
1
C2, C3, C5
3
C4
1
________________________________________________________________
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
Evaluates: MAX1455
KEY Component List (continued)
DESIGNATION
C6
QTY
1
DESCRIPTION
10µF 10V tantalum capacitor (R case)
Panasonic ECS-T1AX106R
Digi-Key PCS2106CT-ND
0.1µF ±10%, 25V ceramic
capacitors* (0805)
Murata GRM21BR71E104K or
equivalent
Switching diode 30V, 0.2A
Panasonic MA715-(TX)
Digi-Key MA715CT-ND
Diode BAR74
Zetex BAR74ZX
2-pin headers, gold (0.1in centers)
(cut from 36-pin strip)
Sullins PZC36SAAN
Digi-Key S1011-36-ND
3-pin header, gold (0.1in center)
(cut from 36-pin strip)
Sullins PZC36SAAN
Digi-Key S1011-36-ND
Shunts (J1 = open, J2 = shorted, J3
pins = 2/3 shorted (lower two pins),
J4 = shorted)
Sullins SSC024AN
Digi-Key S9002-ND
Low-profile header 2 x 5 0.1 centers
3M 2510-6002UB
Digi-Key MHB10K-ND
9-pin D-subconnector
AMP 747905-2
Digi-Key A2047-ND
Power MOSFETs (8-pin SO)
Fairchild NDS8958
DESIGNATION
Q3, Q5, Q6
Q4
Q7
R1
R2, R3
R4
R5, R6
R7
R8
R9, R10
RL1, RL2
QTY
3
1
1
1
2
1
2
1
1
2
2
DESCRIPTION
npn transistors
Panasonic UN5214 or UN5215CT
pnp differential transistor
Panasonic XP2401
n-channnel MOSFET
Zetex ZVN4106F
1Ω 1W resistor (2512)
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
Op amp (SOT23)*
Maxim MAX4490AUK
IC, hex inverter (14 SO)
Texas Instruments SN74HC04DR
Digi-Key 296-1189-1-ND
Quad 2 input (14 SO)
Texas Instruments SN74HC00DR
Digi-Key 296-1187-1-ND
RS-232 +5V driver/receiver*
Maxim MAX3387ECUG
MAX1452KEY serial board, PCB
C7–C12
6
D1
1
D2
1
J1, J2, J4
3
J3
1
U1
1
U2
1
J1–J4
4
U3
1
P1
1
U4
—
1
1
P2
1
*Indicates
that part is normally consigned by Maxim.
Q1, Q2
2
Component Suppliers
SUPPLIER
Digi-Key Corp.
KEMET Corp.
Murata Electronics North America, Inc.
Quest Components
PHONE
800-344-4539
864-963-6300
770-436-1300
626-333-5858
WEBSITE
www.digikey.com
www.kemet.com
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
•
•
•
Printout of compensation test data (MAX1455EVKIT-CS
only)
Five samples of the MAX1455
Straight-connected serial cable for connecting the
KEY and PC
Quick Start
Required Equipment
•
•
•
Precision-regulated +5V power supply
Multimeter with at least five significant digits
Sensor pressure source
Evaluates: MAX1455
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.
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.
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.
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.
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:
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.
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.
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.
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
Evaluates: MAX1455
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
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:
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.
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
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.
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.
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.
Important Note: Download factory-compensated coef-
ficients into a file for future reference before overwrit-
ing flash content.
4
_______________________________________________________________________________________
MAX1455 Evaluation Kit
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:
• IBM-compatible PC
•
•
Windows 95/98/2000/XP
One unused serial port
Table 1. I/O Connector S3 Signals Sensor
Interface
PIN
1
2
3
4
5
6
7
8
SIGNAL
OUT+
IN+
OUT+
IN-
OUT-
IN-
OUT-
IN+
DESCRIPTION
Positive output sensor
Top of Wheatstone bridge
Positive output sensor
Bottom of Wheatstone bridge
Negative sensor output
Bottom of Wheatstone bridge
Negative sensor output
Top of Wheatstone bridge
Evaluates: MAX1455
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.
Figure 2 shows the circuit diagram of the EV board.
Figures 3–6 illustrate the PCB component placement
and wiring details.
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.
Figure 7 shows the adapter circuit diagram and Figures
8, 9, and 10 provide PCB component placement and
wiring information.
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.
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.
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.
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.
Note:
The MAX1455 software tools can be down-
loaded and installed from the Maxim website at
www.maxim-ic.com.
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
_______________________________________________________________________________________
5
PCB设计
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