AK8998 Datasheet, PDF (3/59 Pages) Asahi Kasei Microsystems – Preliminary

[AK8998/W/D]
Overview
The AK8998 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 AK8998.
The internal compensation circuit is accomplished through a 12-bit resolution DAC (Rough: 4bits, Fine:
8bits) to adjust offset voltage, and the primary characteristics compensator for the associated temperature
drift, coupled with 13-bit resolution (G1&G2 Gain adjustment: 5bits, G3 Gain adjustment: 8bits) to adjust
the span voltage and another primary characteristics compensator for its associated temperature drift.
The output stage, with an internal resistor of 146kΩ, is band-limited with a combination of external
capacitors, providing a low impedance output. And the EEPROM data, if used, enables the internal SCF
and SMF. In this case, the band limitation is performed by the internal LPF (fc: 1kHz, 500Hz, 250Hz),
eliminating the need for the external capacitors.
EEPROM data can be preconfigured to enable a setup of output reference voltage, designation of the
external temperature sensor (when a pressure sensor and AK8998 are separated), selection of a
sampling frequency (1kHz or 10kHz), the input polarity, and AGND pin validation.
Two sets of the pressure detectors are provided. When the pressure exceeding the detection threshold
stored in the EEPROM is applied, the DET 1 and/or DET2/PTH pins go high (the polarity change is
possible by EEPROM). And the detection threshold can be specified externally by EEPROM. In that case,
the Pressure Detectors 2 is disabled, and the detection threshold for the Pressure Detectors 1 can be
defined by DET2/PTH pin.
It can access to the EEPROM and control register (volatile memory) by a two-wire serial interface of
CSCLK and VOUT (at the time of SDI/O mode) pin.
MSxxxxx-E-00
-3-
2012/11