placed close to the pressure sensor, can cause exces-

sive errors. Of particular concern is an extremely long

sensor-output settling time.

Nonlinearity Compensation

RFTC to compensate for sensor nonlinearity. For more

information on this application, refer to the MAX1459

Reference Manual.

Test System Configuration

The MAX1459 is designed to support an automated

production pressure-temperature test system with inte-

grated calibration and temperature compensation.

Figure 15 shows the implementation concept for a low-

cost test system capable of testing multiple transducer

modules connected in parallel. Three-state outputs on

the MAX1459 allow for parallel connection of transduc-

ers. A digital multiplexer controls the chip-select signal

for each transducer. The test system shown in Figure

15 includes a dedicated test bus consisting of five

wires:

• Two power-supply lines

• One analog output voltage line from the transducers

to a system DVM

• Two serial-interface lines: DIO (input/output) and

SCLK (clock)

MAX1459 Evaluation

____________________________________Development Kit

To expedite the development of MAX1459-based trans-

ducers and test systems, Maxim has produced the

MAX1459 evaluation kit (EV kit). First-time users of

the MAX1459 are strongly encouraged to use this

kit. The MAX1459 EV kit is designed to facilitate manu-

al programming of the MAX1459 and includes the fol-

lowing:

1) Evaluation Board with a silicon pressure sensor.

2-Wire, 4–20mA

Smart Signal Conditioner

20

______________________________________________________________________________________

MAX1459

1µF

AUXILIARY OP AMP

(INTERNAL TO MAX1459)

0.1µF

MAX875

GND

5V

G

S

D

100

Ω

PN4391

0.1µF

1µF

GND

50

Ω

B

E

C

2N2222

Q1

TransZorb™

4–20mA

12V–40V

Ci

Figure 14. 2-Wire, 4–20mA Circuit

TransZorb is a trademark of General Semiconductor Industries,

Inc.