19-5945 Rev 0; 6/11
EVALUATION KIT AVAILABLE
MAX1454
Precision Sensor Signal Conditioner
with Overvoltage Protection
General Description
The MAX1454 is a highly integrated analog sensor
signal conditioner targeted for automotive applications.
The device provides amplification, calibration, and tem-
perature compensation to enable an overall performance
approaching the inherent repeatability of the sensor. The
fully analog signal path introduces no quantization noise
in the output signal while enabling digitally controlled
trimming of the output. Offset and span are calibrated
with integrated 16-bit DACs, allowing sensors to be truly
interchangeable.
The device architecture includes a programmable sen-
sor excitation, a 32-step programmable-gain amplifier
(PGA), a 2K x 8 bits internal flash memory, four 16-bit
DACs, and an on-chip temperature sensor. In addition
to offset and span compensation, the device provides a
unique temperature-compensation method for offset TC
and FSO TC to provide a remarkable degree of flexibility
while minimizing manufacturing costs.
The device is packaged in a 16-pin TSSOP and covers
the automotive AEC-Q100 Grade 1 temperature range of
-40NC to +125NC.
Benefits and Features
S
Complete Signal Conditioning in a Single IC
Package
Provides Amplification, Calibration, and
Temperature Compensation
Accommodates Sensor Output Sensitivities
from 1mV/V to 200mV/V
Overvoltage Protection to 45V
Reverse-Voltage Protection to 45V
S
High-Precision Compensation Reduces
Downstream Circuit Complexity
Fully Analog Signal Path
16-Bit Offset and Span-Calibration Resolution
On-Chip Lookup Table Supports Multipoint
Calibration Temperature Correction
S
Supports Both Current and Voltage-Bridge
Excitation
S
Fast 85µs Step Response
S
Sensor Fault Detection
S
Simple PCB Layout
S
Single-Pin Digital Programming
S
No External Trim Components Required
Applications
Pressure Sensors
Strain Gauges
Pressure Calibrators and Controllers
Resistive Element Sensors
Humidity Sensors
Ordering Information
appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to
www.maxim-ic.com/MAX1454.related.
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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.
MAX1454
Precision Sensor Signal Conditioner
with Overvoltage Protection
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND.)
V
DD
, V
DDF
............................................................-0.3V to +3.0V
V
DDX
.......................................................................-45V to +45V
All Other Pins............................. -0.3V to Min (V
DDX
+ 0.3V, 6V)
Continuous Power Dissipation (T
A
= +70NC)
16-Pin TSSOP (derate 11.1mW/NC above +70NC) ...888.9mW
Operating Temperature Range ........................ -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) .............................. +300NC
Soldering Temperature (reflow) ......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TSSOP
Junction-to-Ambient Thermal Resistance (q
JA
) ..........90NC/W
Junction-to-Case Thermal Resistance (q
JC
) ...............27NC/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(V
DDX
= 5V, V
GND
= 0V, T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
GENERAL CHARACTERISTICS
External Supply Voltage
External Supply Current
Oscillator Frequency
LDO Regulator Output Voltage
Power-On-Reset Threshold
External Supply Voltage-Ramp
Rate
ANALOG INPUT
Input Impedance
Input-Referred Offset-
Temperature Coefficient
Input-Referred Adjustable-
Offset Range
R
IN
(Notes 5, 6)
Offset TC = 0 at gain = 44 (Note 7)
Percent of 4V span, no load, IRO[3:0] =
0000bin, source impedance = 5kI, V
OUT
= 0.5V to 4.5V; measured at V
OUT
= [0.5V,
2.5V, 4.5V] at a gain of 112
CMRR
Specified for common-mode voltages
between GND and V
DDX
(Note 8)
1
-150
1
Q1
+150
MI
FV/NC
mV
V
DDX
I
DDX
f
OSC
V
DD
V
POR
Not to be loaded by external circuitry, must
be connected to a 0.1FF capacitor to GND
Referred to V
DDX
pin
(Note 4)
1
(Note 3)
0.85
2.375
3.0
5.0
2.5
1
2.5
2.4
5.5
3
1.15
2.625
V
mA
MHz
V
V
V/ms
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Nonlinearity of Signal Path
0.01
%
Common-Mode Rejection
Ratio
Input-Referred Adjustable FSO
90
200
dB
mV/V
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Maxim Integrated Products
2
MAX1454
Precision Sensor Signal Conditioner
with Overvoltage Protection
ELECTRICAL CHARACTERISTICS (continued)
(V
DDX
= 5V, V
GND
= 0V, T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
ANALOG OUTPUT
Selectable in 32 steps
PGA[4:0] = 00000bin
PGA[4:0] = 00101bin
PGA[4:0] = 01010bin
PGA[4:0] = 01100bin
Differential Signal Gain
PGA[4:0] = 01101bin
PGA[4:0] = 01110bin
PGA[4:0] = 01111bin
PGA[4:0] = 10000bin
PGA[4:0] = 10110bin
PGA[4:0] = 11100bin
PGA[4:0] = 11111bin
Output-Voltage Swing
Output-Voltage Low
Output-Voltage High
Output Current Drive
Capability
Output Source Current Limit
Output Sink Current Limit
Output Impedance at DC
Output Offset Ratio
Output Offset TC Ratio
Step Response
(63% Final Value)
Maximum Capacitive Load
Gain = 36
Noise at Output Pin
DC to 1kHz, source
impedance = 5kI
Gain = 256
Gain = 512
Gain = 1024
Gain = 2048
DV
OUT
/
DOffset
DAC
DV
OUT
/
DOffset
TC DAC
V
OUT
= 2.5V
0.9
0.9
85
0.01
0.5
1.5
3
6
12
mV
RMS
-8
0.2
1.2
1.2
No load
I
OUT
= 1mA sinking, T
A
= T
MIN
to T
MAX
I
OUT
= 1mA sourcing, T
A
= T
MIN
to T
MAX
Maintain DC output to 2mV error compared
to no load case (Note 4)
V
DDX
-
0.55
Q1
8
5.5
12.5
40
58
72
86
101
130
374
1037
1823
V
GND
+
0.02
6 to 2048
6
14
44
64
80
96
112
144
416
1152
2048
6.5
15.5
48
70
88
106
123
158
458
1267
2253
V
DDX
-
0.32
0.25
V
V
V
mA
mA
mA
I
V/V
V/V
Fs
FF
V/V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated Products
3
MAX1454
Precision Sensor Signal Conditioner
with Overvoltage Protection
ELECTRICAL CHARACTERISTICS (continued)
(V
DDX
= 5V, V
GND
= 0V, T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
BRIDGE DRIVE
Bridge Current
I
BDR
CMRATIO[1:0] = 00
Current-Mirror Ratio
AA
CMRATIO[1:0] = 01
CMRATIO[1:0] = 10
CMRATIO[1:0] = 11
Maximum Bridge Load
Capacitance
FSO DAC Code Range
Output Voltage Range
V
BDR
Voltage excitation mode (Note 4)
(Note 4)
(Note 4)
0.1
4.8
9.6
14.4
24
1
0x4000
0.75
0xC000
V
DDX
-
0.75
16
DV
OUT
/DCode DAC reference = V
DDX
= 5V
DV
OUT
/DCode DAC reference = V
BDR
= 2.5V
DV
BDR
/DCode DAC reference = V
DDX
= 5V
DV
BDR
/DCode DAC reference = V
BDR
= 2.5V
Including sign
DV
OUT
/DCode
Input referred, DAC reference = V
DDX
= 5V
(Note 9)
76
38
76
38
5
3.7
6
12
18
30
2.5
7.2
14.4
21.6
36
nF
Hex
V
A/A
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL-TO-ANALOG CONVERTERS (DACs)
DAC Resolution
Offset DAC Bit Weight
Offset TC DAC Bit Weight
FSO DAC Bit Weight
FSO TC DAC Bit Weight
COARSE-OFFSET DAC
IRO DAC Resolution
IRO DAC Bit Weight
INTERNAL RESISTORS
OUT/DIO Pullup Resistance
Current Source Reference
Resistor
Current Source Reference
Resistor Temperature
Coefficient
FLASH MEMORY
Endurance
Retention
Page Erase Time
Mass Erase Time
(Notes 4, 10)
T
A
= +85NC (Note 4)
(Notes 4, 11)
(Notes 4, 11)
10,000
10
32
32
Cycles
Years
ms
ms
R
PULLUP
R
ISRC
TCR
ISRC
100
10
kI
kI
Bits
mV/bit
Bits
FV/bit
FV/bit
FV/bit
FV/bit
600
ppm/NC
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Maxim Integrated Products
4
MAX1454
Precision Sensor Signal Conditioner
with Overvoltage Protection
ELECTRICAL CHARACTERISTICS (continued)
(V
DDX
= 5V, V
GND
= 0V, T
A
= +25NC, unless otherwise noted.) (Note 2)
PARAMETER
Operating Current
Program/Erase Current
TEMPERATURE-TO-DIGITAL CONVERTER
Temperature ADC Resolution
Offset
Gain
Nonlinearity
Lowest Digital Output
Highest Digital Output
DIGITAL INPUT (OUT/DIO)
Input Low Voltage
Input High Voltage
OVERVOLTAGE PROTECTION
Overvoltage-Protection
Threshold
FAULT DETECTION
IN+/IN- Low Comparator
Threshold
IN+/IN- High Comparator
Threshold
Detection-Threshold Accuracy
Comparator Hysteresis
Output Clip Level During Fault
Conditions
Note
Note
Note
Note
Note
Note
Note
2:
3:
4:
5:
6:
7:
8:
I
OUT
= 1mA sinking
0.2 x
V
BDR
0.8 x
V
BDR
Q25
20
150
250
V
V
mV
mV
mV
5.53
5.75
6.0
V
V
IL
V
IH
0
V
DDX
x
2/3
V
DDX
/3
V
DDX
V
V
8
Q3
1.5
Q0.5
0x00
0xAF
Bits
LSB
NC/Bit
LSB
hex
hex
SYMBOL
(Note 4)
(Note 4)
CONDITIONS
MIN
TYP
MAX
8
7
UNITS
mA
mA
All units are production tested at T
A
= +25NC and +125NC. Specifications over temperature are guaranteed by design.
Excludes sensor or load current. Analog mode with voltage excitation on BDR pin, FSODAC = 0x8000.
Specification is guaranteed by design.
All electronics temperature errors are compensated together with sensor errors.
The sensor and the device must be at the same temperature during calibration and use.
This is the maximum allowable sensor offset.
This is the sensor’s sensitivity normalized to its drive voltage, assuming a desired full-span output of V
DDX
- 1V and a
nominal bridge voltage of V
DDX
/2.
Note 9:
Bit weight is ratiometric to V
DDX
.
Note 10:
Programming of the flash memory at room temperature is recommended.
Note 11:
No commands can be executed until the erase operation has completed. During erase operations, all commands sent to
the device are ignored.
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Maxim Integrated Products
5
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