MAX1452 sensor signal conditioner: specs and pinout
An analog sensor signal conditioner IC (Maxim, now Analog Devices) for resistive bridge sensors. It provides amplification, offset and span calibration and temperature compensation. This is a bare SMD chip, not a module.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage VDD | 4.5 V min, 5.0 V typ, 5.5 V max | source Electrical Characteristics, General (p.2) |
| Supply current IDD | 2.0 mA typ, 2.5 mA max | source Electrical Characteristics (p.2) |
| Operating temperature (AAE grade) | -40 C to +125 C | source Absolute Maximum Ratings and Ordering Information (p.1-2) |
| Absolute maximum supply VDD to VSS | -0.3 V to +6 V | source Absolute Maximum Ratings (p.2) |
| Accepted sensor sensitivity | 4 mV/V to 60 mV/V | source Benefits and Features (p.1); Electrical Characteristics (p.2) |
| Differential signal gain range | 39 to 234 V/V in 16 steps | source Electrical Characteristics, Analog Output (p.2) |
| Output options | 0 to 5 V rail-to-rail; 0.5 V to 4.5 V ratiometric; +/-2.5 V | source General description / features (p.1) |
| Calibration resources | 16-bit DACs for offset and span, 768-byte internal EEPROM, uncommitted op amp, on-chip temperature sensor | source General Description (p.1) |
| Programming interface | Single-pin digital input/output (DIO) | source Pin Description (p.6); Detailed Description |
| Oscillator frequency | 0.85 MHz min, 1 MHz typ, 1.15 MHz max | source Electrical Characteristics (p.2) |
Power
| Value | Source | |
|---|---|---|
| Supply | 4.5-5.5 V (5.0 V typ) | source Electrical Characteristics (p.2) |
| Current | 2.0 mA typ, 2.5 mA max (EEPROM erase/write up to 30 mA) | source Electrical Characteristics (p.2) |
Pinout
Pin numbers are for the 16-pin SSOP package from the maker sheet. The part is a bare SMD chip and needs a breakout board or custom PCB.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1 ISRC | Bridge drive current mode setting | source Pin Description (p.5) | ||
| 2 OUT | High ESD and scan path output signal | May need a 0.1 uF capacitor in noisy environments; may be parallel connected to DIO. | source Pin Description (p.5) | |
| 3 VSS | Negative supply voltage | source Pin Description (p.5) | ||
| 4 INM | Bridge negative input | Can be swapped to INP by the configuration register. | source Pin Description (p.5) | |
| 5 BDR | Bridge drive | source Pin Description (p.5) | ||
| 6 INP | Bridge positive input | Can be swapped to INM by the configuration register. | source Pin Description (p.5) | |
| 7 VDD | Positive supply voltage | Connect 0.1 uF from VDD to VSS. | source Pin Description (p.5) | |
| 8 TEST | Internally connected; connect to VSS | source Pin Description (p.5) | ||
| 9 VDDF | Positive supply voltage for EEPROM | Connect 1 uF from VDDF to VSS; connect VDDF to VDD. | source Pin Description continued (p.6) | |
| 10 UNLOCK | Secure-Lock disable; allows communication to the device | source Pin Description continued (p.6) | ||
| 11 DIO | Digital input/output; allows communication with the device | source Pin Description continued (p.6) | ||
| 12 CLK1M | 1 MHz clock output; controllable by a configuration bit | source Pin Description continued (p.6) | ||
| 13 AMPOUT | Uncommitted amplifier output | source Pin Description continued (p.6) | ||
| 14 AMP- | Uncommitted amplifier negative input | source Pin Description continued (p.6) | ||
| 15 AMP+ | Uncommitted amplifier positive input | source Pin Description continued (p.6) | ||
| 16 FSOTC | Full span TC buffered output | source Pin Description continued (p.6) |
Build with it
Project ideas for the MAX1452 sensor signal conditioner. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Conditioner output readout with a 16-bit ADC: The conditioner runs from 5 V and its output can swing 0.5-4.5 V (ratiometric), within the 5 V Uno and ADS1115 range. The SMD chip needs a breakout board, and calibration is done through its single DIO pin as the datasheet describes. Learning project; the bridge sensor itself is not part of this idea (see gaps).
- Conditioned output recorder: Read the conditioned voltage with the ADS1115 over I2C and plot it on the OLED. Power the chip at 4.5-5.5 V; add the 0.1 uF and 1 uF capacitors the datasheet asks for.
- Breadboard sensor conditioning test bench: Use the Uno's 5 V supply for the chip and the Uno's analog input to read OUT (0 to 5 V rail-to-rail). The chip accepts bridge sensors of 4 to 60 mV/V, so check your sensor against that range.
Common mistakes
- Powering it from 3.3 V: the supply range is 4.5-5.5 V (source: link, p.2)
- Leaving out the bypass capacitors: connect 0.1 uF from VDD to VSS and 1 uF from VDDF to VSS (source: link, Pin Description pp.5-6)
- Connecting a sensor outside the input range: it accepts bridge outputs of 4 mV/V to 60 mV/V (source: link, p.1)
Not covered by the official source
- analog.com could not be reached from this machine; the LCSC copy of the Maxim/Analog Devices Rev 5 sheet was used.
- Calibration procedure and DIO protocol were not read in detail.
- No bridge sensor is included in the ideas: load cells and strain gauge parts have no maker sheet in this set to check against the MAX1452 input range (4-60 mV/V), and modules with built-in amplifiers do not need this chip. The ideas are kept as learning ideas for the conditioner's supply and output; pick and verify a bridge sensor (excitation from the BDR pin, supply 4.5-5.5 V) before building a full transducer.
Sources
- link (Maxim MAX1452 Low-Cost Precision Sensor Signal Conditioner datasheet, 19-1829 Rev 5, 4/15; Maxim is now part of Analog Devices; copy hosted by LCSC)