Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsMAX1452AAE+

General Description

The MAX1452 is a highly integrated analog-sensor sig-

nal processor optimized for industrial and process con-

trol applications utilizing resistive element sensors. The

MAX1452 provides amplification, calibration, and temper-

ature compensation that enables 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 trim-

ming with the integrated 16-bit DACs. Offset and span are

calibrated using 16-bit DACs, allowing sensor products to

be truly interchangeable.

The MAX1452 architecture includes a programmable

sensor excitation, a 16-step programmable-gain ampli-

fier (PGA), a 768-byte (6144 bits) internal EEPROM, four

16-bit DACs, an uncommitted op amp, and an onchip

temperature sensor. In addition to offset and span com-

pensation, the MAX1452 provides a unique temperature

compensation strategy for offset TC and FSOTC that was

developed to provide a remarkable degree of flexibility

while minimizing testing costs.

The MAX1452 is packaged for the commercial, industrial,

and automotive temperature ranges in 16-pin SSOP/

TSSOP and 24-pin TQFN packages.

Customization

Maxim can customize the MAX1452 for high-volume

dedicated applications. Using our dedicated cell library

of more than 2000 sensor-specific functional blocks,

Maxim can quickly provide a modified MAX1452 solution.

Contact Maxim for further information.

Applications

● Pressure Sensors

● Transducers and Transmitters

● Strain Gauges

● Pressure Calibrators and Controllers

● Resistive Elements Sensors

● Accelerometers

● Humidity Sensors

Outputs Supported

● 4–20mA

● 0 to +5V (rail-to-rail)

● +0.5V to +4.5V Ratiometric

● +2.5V to ±2.5V

Features

● Provides Amplification, Calibration, and Temperature

Compensation

● Accommodates Sensor Output Sensitivities from

4mV/V to 60mV/V

● Single Pin Digital Programming

● No External Trim Components Required

● 16-Bit Offset and Span Calibration Resolution

● Fully Analog Signal Path

● On-Chip Lookup Table Supports Multipoint

Calibration Temperature Correction

● Supports Both Current and Voltage Bridge Excitation

● Fast 150μs Step Response

● On-Chip Uncommitted Op Amp

● Secure-Lock™ Prevents Data Corruption

● Low 2mA Current Consumption

Detailed Block Diagram and Pin Configurations appear at

the end of data sheet.

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

**Dice are tested at T

= +25°C, DC parameters only.

19-1829; Rev 4; 10/14

Secure-Lock is a trademark of Maxim Integrated Products, Inc.

PART TEMP RANGE PIN-PACKAGE

MAX1452CAE+ 0°C to +70°C 16 SSOP

MAX1452EAE+ -40°C to +85°C 16 SSOP

MAX1452AAE+ -40°C to +125°C 16 SSOP

MAX1452AUE+ -40°C to +125°C 16 TSSOP

MAX1452ATG+ -40°C to +125°C 24 TQFN-EP*

MAX1452C/D 0°C to +70°C Dice**

MAX1452 Low-Cost Precision Sensor

Signal Conditioner

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (25 pages)

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EVALUATION KIT AVAILABLE MAX1452 General Description The MAX1452 is a highly integrated analog-sensor signal processor optimized for industrial and process control applications utilizing resistive element sensors. The MAX1452 provides amplification, calibration, and temperature compensation that enables an overall performance approaching the inherent repeatability of the sensor.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Absolute Maximum Ratings Supply Voltage, VDD to VSS.........................................-0.3V, +6V Supply Voltage, VDD to VDDF................................-0.5V to +0.5V All Other Pins...................................(VSS - 0.3V) to (VDD + 0.3V) Short-Circuit Duration, FSOTC, OUT, BDR, AMPOUT................................................................
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Electrical Characteristics (continued) (VDD = VDDF = +5V, VSS = 0V, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS Output-Voltage Low IOUT = 1mA sinking, TA = TMIN to TMAX Output-Voltage High IOUT = 1mA sourcing, TA = TMIN to TMAX MIN 4.75 Output Impedance at DC Output Offset Ratio Output Offset TC Ratio TYP MAX UNITS 0.100 0.20 V 4.87 V 0.1 Ω ΔVOUT/ ΔOffset 0.90 1.05 1.20 V/V ΔVOUT/ ΔOffset TC 0.9 1 1.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Electrical Characteristics (continued) (VDD = VDDF = +5V, VSS = 0V, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL Current-Source Reference Resistor Temperature Coefficient ΔRISRC 1300 ppm/°C RFTC 75 kΩ ΔRFTC 1300 ppm/°C 8 Bits FSOTC Resistor FSOTC Resistor Temperature Coefficient CONDITIONS MIN TYP MAX UNITS TEMPERATURE-TO-DIGITAL CONVERTER Temperature ADC Resolution Offset P3 LSB Gain 1.45 °C/bit Nonlinearity P0.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Typical Operating Characteristics (VDD = +5V, TA = +25°C, unless otherwise noted.) MAX1452 toc01 OUTPUT ERROR FROM STRAIGHT LINE (mV) DNL (mV) 2.5 0 -2.5 -5.0 0 10k 20k 30k 40k 50k 60k 70k 5.0 MAX1452 toc02 AMPLIFIER GAIN NONLINEARITY OFFSET DAC DNL 5.0 ODAC = 6250hex OTCDAC = 0 FSODAC = 4000hex FSOTCDAC = 8000hex PGA INDEX = 0 IRO = 2 2.5 0 -2.5 -5.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Pin Description (continued) PIN NAME FUNCTION SSOP/TSSOP TQFN-EP 9 11 VDDF 10 12 UNLOCK 11 14 DIO 12 15 CLK1M 13 17 AMPOUT 14 18 AMP- Uncommitted Amplifier Negative Input 15 19 AMP+ Uncommitted Amplifier Positive Input 16 21 FSOTC — — EP Positive Supply Voltage for EEPROM. Connect a 1µF capacitor from VDDF to VSS. Connect VDDF to VDD or for improved noise performance connect a 30Ω resistor to VDD. Secure-Lock Disable.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Offset Correction VDD VDD IRO DAC BIAS GENERATOR MAX1452 OSCILLATOR CLK1M TEST INP ∑ PGA OUT INM BDR CURRENT SOURCE TEMP SENSOR 8-BIT ADC VDDF DIO UNLOCK INTERNAL EEPROM 6144 BITS ANAMUX 16 BIT DAC - FSO (176) POINT 16 BIT DAC - OFFSET (176) 16 BIT DAC - OFFSET TC 16 BIT DAC - FSO TC ISRC 416 BITS FOR USER VDD A=1 176 TEMPERATURE LOOK UP POINTS FOR OFFSET AND SPAN. BDR AMP+ FSOTC OP-AMP AMPOUT AMPVSS Figure 1.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Linear and Nonlinear Temperature Compensation For high accuracy applications (errors less than 0.25%), the first-order offset and FSO TC error should be compensated with the offset TC and FSOTC DACs, and the residual higher order terms with the lookup table. The offset and FSO compensation DACs provide unique compensation values for approximately 1.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner G 2N4392 IN 1 S D VPWR +12V TO +40V MAX15006B 8 7 5 6 BDR VDD INP OUT 5 30Ω VDDF GND 9 OUT 2 OUT MAX1452 FSOTC SENSOR 4 16 INM RSTC ISRC TEST VSS 8 1 RISRC 1.0µF 2.2µF 0.1µF 0.1µF 3 GND Figure 3. Basic Nonratiometric Output Configuration Typical Nonratiometric Operating Circuit (12VDC < VPWR < 40VDC) Nonratiometric output configuration enables the sensor power to vary over a wide range.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner 2N4392 G VIN+ +12V TO +40V D 100Ω S IN 1 Z1 MAX15006B 8 7 5 6 BDR VDDF FSOTC 9 16 MAX1452 SENSOR 4 1.0µF RSTC ISRC GND 5 30Ω VDD INP OUT 1 INM 2.2µF 0.1µF RISRC 4.99MW OUT AMPOUT AMPAMP+ TEST VSS 8 2 499kW 0.1µF 13 14 15 2N2222A 4.99kΩ 0.1µF 100kΩ 3 100kΩ 47Ω VIN- Figure 4. Basic 4–20mA Output, Loop-Powered Configuration ● Registers CONFIG, OTCDAC, and FSOTCDAC are refreshed from EEPROM.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 1.
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MAX1452 The ODAC and FSODAC are loaded from the EEPROM lookup tables using an index pointer that is a function of temperature. An ADC converts the integrated temperature sensor output to an 8-bit value every 1ms. This digitized value is then transferred into the temp-index register. The typical transfer function for the temp-index is as follows: temp-index = 0.6879 Temperature (°C) + 44.0 where temp-index is truncated to an 8-bit integer value.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner THREE-STATE NEED WEAK PULLUP DRIVEN BY TESTER DIO 11111 0 1 0 0 11 0 1 0 11 1 THREE-STATE NEED WEAK PULLUP DRIVEN BY MAX1452 1 1 1 1 1 1 1 0 0 0 0 0 1 0 0 0 111111 1 1 1 11 STOP-BIT MSB LSB START-BIT STOP-BIT MSB LSB START-BIT Figure 5. DIO Output Data Format 3) Write the load internal calibration register (LdICR) command to CRIL[3:0].
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MAX1452 Low-Cost Precision Sensor Signal Conditioner THREE-STATE NEED WEAK PULLUP DRIVEN BY TESTER DIO 11111 0 1 0 0 11 0 1 0 11 1 THREE-STATE 2ATIM +1 BYTE TIMES THREE-STATE NEED WEAK PULLUP 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 11 STOP-BIT MSB LSB START-BIT HIGH IMPEDANCE OUT VALID OUT Figure 6. Analog Output Timing The analog signal driven onto the OUT pin is determined by the value in the ALOC register. The signals are specified in Table 15.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner DIO[1:N] DATA DATA VOUT +5V DVM VDD MODULE N MAX1452 MODULE 2 MAX1452 MODULE 1 DION DIO2 DIO1 MAX1452 DIGITAL MULTIPLEXER VSS VOUT VDD VSS VOUT VDD VSS VOUT TEST OVEN Figure 7. Automated Test System Concept MAX1452 Evaluation Kit To expedite the development of MAX1452 based transducers and test systems, Maxim has produced the MAX1452 evaluation kit (EV kit).
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MAX1452 Low-Cost Precision Sensor Signal Conditioner RAW SENSOR OUTPUT TA = +25∞C 30.0 ERROR (% FSO) VOUT (mV) 80 60 40 6 0 0 20 40 60 UNCOMPENSATED SENSOR TEMPERATURE ERROR 80 100 FSO 20.0 OFFSET 10.0 0.0 -10.0 -20.0 -50 0 -0.1 -0.15 FSO 100 150 COMPENSATED TRANSDUCER TA = +25∞C 5.0 OFFSET 4.0 VOUT (V) ERROR (% FSO) COMPENSATED TRANSDUCER ERROR 0.15 0.1 0.05 0 -0.05 50 TEMPERATURE (∞C) PRESSURE (kPs) 3.0 2.0 1.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 3. Configuration Register (CONFIG[15:0]) FIELD NAME 15:13 OSC[2:0] 12 REXT DESCRIPTION Oscillator frequency setting. Factory preset, do not change. Logic ‘1’ selects external RISRC and RSTC. 11 CLK1M EN Logic ‘1’ enables CLK1M output driver. 10 PGA Sign Logic ‘1’ inverts INM and INP polarity. 9 IRO Sign Logic ‘1’ for positive input referred offset (IRO). Logic ‘0’ for negative input referred offset (IRO).
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 5. PGA Gain Setting (PGA[3:0]) PGA[3:0] PGA GAIN (V/V) 0000 0001 Table 6. Temp-Index Typical Values TEMP-INDEX[7:0] 39 TEMPERATURE (°C) DECIMAL HEXADECIMAL 52 -40 20 14 0010 65 25 65 41 0011 78 85 106 6A 0100 91 125 134 86 0101 104 0110 117 Table 7. Oscillator Frequency Setting 0111 130 OSC[2:0] OSCILLATOR FREQUENCY 1000 143 100 -37.5% 1001 156 101 -28.1% 1010 169 110 -18.8% 1011 182 111 -9.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 9. Control Location (CL[15:0]) FIELD NAME DESCRIPTION 15:8 CL[15:8] Reserved 7:0 CL[7:0] Control Location. Secure-Lock is activated by setting this to FFhex which disables DIO serial communications and connects OUT to PGA output. Table 10.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 11. CRIL Command Codes CRIL[3:0] NAME DESCRIPTION 0000 LdICR Load internal calibration register at address given in ICRA with data from DHR[15:0]. 0001 EEPW EEPROM write of 8 data bits from DHR[7:0] to address location pointed by IEEA[9:0]. 0010 ERASE Erase all of EEPROM (all bytes equal FFhex). 0011 RdICR Read internal calibration register as pointed to by ICRA and load data into DHR[15:0].
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 13. IRSP Decode IRSP[3:0] RETURNED VALUE 0000 DHR[7:0] 0001 DHR[15:8] 0010 IEEA[7:4], ICRA[3:0] concatenated 0011 CRIL[3:0], IRSP[3:0] concatenated 0100 ALOC[3:0], ATIM[3:0] concatenated 0101 IEEA[7:0] EEPROM address byte 0110 IEED[7:0] EEPROM data byte 0111 TEMP-Index[7:0] 1000 BitClock[7:0] 1001 Reserved. Internal flash test data. 1010-1111 11001010 (CAhex). This can be used to test communication. Table 14.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Table 15. ALOC Definition ALOC[3:0] ANALOG SIGNAL DESCRIPTION 0000 OUT PGA Output 0001 BDR Bridge Drive 0010 ISRC Bridge Drive Current Setting 0011 VDD Internal Positive Supply 0100 VSS Internal Ground 0101 BIAS5U 0110 AGND 0111 FSODAC 1000 FSOTCDAC 1001 ODAC 1010 OTCDAC 1011 VREF Internal Test Node Internal Analog Ground. Approximately half of VDD.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Detailed Block Diagram EEPROM (LOOKUP PLUS CONFIGURATION DATA) VDD EEPROM ADDRESS USAGE 000H + 001H VDD 16-BIT FSO DAC ISRC : 15EH + 15FH 160H + 161H 162H + 163H 164H + 165H VSS VDD RISRC 75kΩ 16-BIT OFFSET DAC RSTC 75kΩ 166H + 167H 168H + 169H 16AH + 16BH 16CH + 16DH : INP 16-BIT FSOTC DAC PHASE REVERSAL MUX VSS ∑ VSS TEST CLK1M VDDF FSO DAC LOOKUP TABLE (176 x 16-BITS) BANDGAP TEMP SENSOR 8-BIT LOOKUP ADDRESS ∑∆ DIGITAL INTERFA
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MAX1452 Low-Cost Precision Sensor Signal Conditioner OUT 2 INM 4 BDR 5 MAX1452 13 AMPOUT VSS 3 INM 4 BDR 5 INP 6 12 CLK1M INP 6 11 DIO VDD 7 10 UNLOCK TEST 8 9 SSOP/TSSOP VDDF N.C. FSOTC N.C. AMP+ 21 20 19 + MAX1452 7 8 9 10 11 12 UNLOCK 14 AMP- VSS 3 22 VDDF 1 15 AMP+ 23 TEST ISRC OUT 2 24 N.C. 16 FSOTC N.C. + N.C. ISRC 1 VDD TOP VIEW N.C. Pin Configurations TQFN Chip Information SUBSTRATE CONNECTED TO: VSS www.maximintegrated.
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MAX1452 Low-Cost Precision Sensor Signal Conditioner Revision History REVISION NUMBER REVISION DATE PAGES CHANGED DESCRIPTION 4/09 Added TQFN and TSSOP package information, changed packages to lead free, changed all occurrences of ASIC to MAX1452, changed VDDF RC filter values, recommended a more suitable voltage reference for non-ratiometric application circuits, corrected MAX1452 input range, and added typical EEPROM current requirements to EC table, and added gain nonlinearity graph.