MAX1452_09 Datasheet, PDF (10/25 Pages) Maxim Integrated Products – Low-Cost Precision Sensor Signal Conditioner

Low-Cost Precision Sensor
Signal Conditioner
SENSOR
5
BDR
6 _INP
7
V_{DD VDDF 9}
FSOTC ¹⁶
MAX1452
4 _INM
ISRC ¹
OUT ²
13
AMPOUT
AMP- ¹⁴
AMP+ ¹⁵
RSTC
RISRC ^4.99MΩ
499kΩ
0.1μF
TEST V_SS
83
100kΩ
2N4392
G
D 100Ω
S
1
IN
Z1
MAX15006B
8 _OUT
GND
30Ω
5
V_IN+
+12V TO +40V
1.0μF
2.2μF
0.1μF
4.99kΩ
0.1μF
2N2222A
100kΩ
47Ω
V_IN-
Figure 4. Basic 4–20mA Output, Loop-Powered Configuration
• Registers CONFIG, OTCDAC, and FSOTCDAC are
refreshed from EEPROM.
• Registers ODAC and FSODAC are refreshed from
the temperature indexed EEPROM locations.
Calibration Operation, Registers Updated by Serial
Communications
• The MAX1452 has not had the Secure-Lock byte
set (CL[7:0] = 00hex) or UNLOCK is high.
• Power is applied to the device.
• The power-on-reset functions have completed.
• The registers can then be loaded from the serial
digital interface by use of serial commands. See the
section on Serial I/O and Commands.
Internal EEPROM
The internal EEPROM is organized as a 768 by 8-bit
memory. It is divided into 12 pages, with 64 bytes per
page. Each page can be individually erased. The mem-
ory structure is arranged as shown in Table 1. The look-
up tables for ODAC and FSODAC are also shown, with
the respective temp-index pointer. Note that the ODAC
table occupies a continuous segment, from address
000hex to address 15Fhex, whereas the FSODAC table
is divided in two parts, from 200hex to 2FFhex, and
from 1A0hex to 1FFhex. With the exception of the gen-
eral purpose user bytes, all values are 16-bit wide
words formed by two adjacent byte locations (high byte
and low byte).
The MAX1452 compensates for sensor offset, FSO, and
temperature errors by loading the internal calibration
registers with the compensation values. These compen-
sation values can be loaded to registers directly through
the serial digital interface during calibration or loaded
automatically from EEPROM at power-on. In this way the
device can be tested and configured during calibration
and test and the appropriate compensation values
10 ______________________________________________________________________________________