AK8996/W

Pressure Sensor control IC

(Detector×1ch, Second order temperature compensation, SPI I/F)

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Description

The AK8996 is a pressure sensor interface IC that features compensation for temperature drift and sensor variation. It is designed to excite and interface to a bridge sensor. Variations in the sensor can be corrected via compensation values stored in integrated non-volatile memory (EEPROM). Compensation values are obtained from measurement results for a set of offset voltages and temperature drift, along with a set of bridge voltages and temperature drift, including characteristics of the AK8996.

The internal compensation circuit is accomplished through DACs, with 4-bit and 7-bit resolution to adjust offset voltage of the sensor, and the secondary characteristics compensator for the associated temperature drift, coupled with 9-bit resolution to adjust the span voltage and another secondary characteristics compensator for its associated temperature drift. Depending on the application, the internal EEPROM values can be pre-configured to enable adjustment of the reference sensitivity and the output reference voltage.

Depending on the application, the AK8996’s internal EEPROM values can be preconfigured to enable adjustment of the reference sensitivities and output reference voltages. Sampling frequencies can be switched between 100Hz, 1kHz, 2kHz and 10.24kHz using the internal EEPROM data.

The AK8996 is provided with a pressure detection circuit. If the applied pressure exceeds the defined voltage threshold at the PTH terminal, a high-level signal is output on the DET pin. The threshold can be adjusted by the internal EEPROM data. The AK8996 is also provided with a self-diagnostic function. Upon power-up or at initial operation immediately after exiting standby mode, this self-test feature checks for the required value at the output (VOUT pin), and if an expected value is not available, the output is assumed to be anomalous and a high-level signal is output on the DET pin, in the same manner as with the pressure detection.

Key Features

• Pressure sensor compensation and excitation IC (Analog output)

• Low power consumption: 350µA typ. @ 100Hz sampling

• Standby function: 1µA max.

• Low-voltage operation: 2.2 to 3.6V, 5V±10%

• Operating temperature range: -40 to 105℃

• Integrated span voltage switching function (by a factor of 5, typ.)

- Resolution: Gain Amp. 1: 3-bits; Gain Amp. 2:1-bit

Adjustment step: factor of 1/step (by a factor of 2 to 9);

factor of 1/step (by a factor of 1 and 2)

• Integrated sensor output compensation

• Offset voltage adjustment

- Resolution: Rough: 4-bits; Fine: 7-bits

- Adjustment step: Rough: 7.5%/step; Fine 0.125%/step @VDD: 5.0V

• Offset voltage temperature drift adjustment (1st/2nd order coefficient)

- Resolution: 10-bits; 8-bits

- Adjustment step: 0.196%/step; 0.787%/step

• Output span voltage adjustment

- Resolution: 9-bits

- Adjustment value: 100/[100+0.25*N](%) N: -256 to +255

• Sensitivity temperature drift adjustment (1st/2nd order coefficient)

- Resolution: 10-bits; 8-bits

- Adjustment step: 0.196%/step; 0.787%/step

• Integrated output reference voltage switching function

- Resolution: Rough 5-bits; Fine 6-bits

- Adjustment step: 0.0005*VDD/step (0.0785*VDD to 0.9215*VDD) @VO

• Integrated criteria adjustment function for determining positive/negative pressure

- Resolution: 10-bits

- Adjustment step: 0.001*VDD/step (0.05*VDD to 0.95*VDD)

• Integrated output gain (buffer gain) switching function (by a factor of 4, typ.)

- Resolution: 3-bits

- Adjustment step: factor of 0.5/step (by a factor of 2 to 4)

• Integrated sampling frequency switching function: 100Hz, 1kHz, 2kHz, 10.24kHz

• Ratiometric voltage output

• Integrated constant voltage source for pressure sensor

: 2.0V @VDD: 2.2 to 3.6V; 4.0V @VDD: 5.0V±10%

• Integrated reference voltage & reference current generator

- VREF voltage adjustment control

- Resolution: 3-bits

- Adjustment step: 1%/step

- IREF current adjustment control

- Resolution: 4-bits

- Adjustment step: 2.7%/step typ.

• Integrated temperature sensor

- Temperature range: -40 to 105℃

- Temperature sensor output voltage adjustment control

- Resolution: 6-bits

- Adjustment step: 0.2%/step

• Integrated timer oscillator for intermittent operation (1024 kHz typ.)

- Oscillating frequency adjustment control

- Resolution: 4-bits

- Adjustment step: 5%/step

• Integrated EEPROM for compensation values and control data storage

- Size: 157 bits

- Endurance: 1,000 times or more

- Retention time: 10 years or more @Ta: 105℃

• Integrated pressure detection/self-diagnosis function

• Supply type: Wafer PKG (UQFN16)

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Block Diagram

Block Diagram

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