MAX1463 Datasheet, PDF (12/49 Pages) Maxim Integrated Products – Low-Power Two-Channel Sensor Signal Processor

Low-Power Two-Channel Sensor
Signal Processor
t_CS
CS
t_CSI
t_CSS
t_SC
t_CL t_CH
t_CSS
t_CL t_CH
t_CSH
t_SC
t_CSH
SCLK
t_DS
t_DH
t_DS
t_DH
DI
t_DV
DO
t_DO
t_TR
t_DV
t_DO
t_TR
Figure 1. Serial Interface Timing Diagram
Typical Application Circuit
Analog ratiometric output configuration (Figure 2) pro-
vides an output that is proportional to the power-supply
voltage. Ratiometricity is an important consideration for
automotive, battery-operated instruments, and some
industrial applications.
Detailed Description
The MAX1463 is a highly integrated, low-power, two-
channel sensor signal processor optimized for industri-
al and process control applications, such as pressure
sensing and compensation, RTD and thermal-couple
linearization, weight sensing and classification, and
remote process monitoring with limit indication.
The MAX1463 incorporates a 16-bit CPU, user-pro-
grammable 4kB of FLASH memory, 128 bytes of
FLASH user information, 16-bit ADC, two 16-bit DACs,
two 12-bit PWM digital outputs, four rail-to-rail op amps,
SPI interface, two GPIOs, and one on-chip temperature
sensor.
Each sensor signal can be amplified, compensated for
temperature, linearized, and the offset and full scale
can be adjusted to the desired value. The MAX1463
can provide outputs as analog voltage (DAC) or digital
(PWM, GPIOs), or simple on/off alarm indication
(GPIOs). The uncommitted op amps can be used to
provide 4–20mA outputs or for additional gain and fil-
tering. Each DAC output is routed to either a small or
large op amp. Large op amps are capable of driving
heavier external loads. The unused circuit functions
can be turned off to save power.
All sensor linearization and on-chip temperature com-
pensation is done by a user-defined algorithm stored in
FLASH memory. The user-defined algorithm is pro-
grammed over the serial interface and stored in 4kB of
integrated FLASH memory.
The MAX1463 uses an internal 4MHz oscillator or an
externally supplied 4MHz clock. CPU code execution
and ADC operation is fully synchronized to minimize
the noise interference of a CPU-based sensor proces-
sor system. The internal clock can be routed off chip for
driving external circuit components to maintain system
synchronization and to avoid clock-beat noise often
found in multiclock systems. The CPU sequentially exe-
cutes instructions stored in FLASH memory.
Sensor Input
The MAX1463 provides two differential signal inputs,
INP1-INM1 and INP2-INM2. These inputs can also be
configured as four singled-ended signals. Each input
can have a common-mode range from V_DD to V_SS and
a programmable gain range of 0.94V/V to 240V/V. The
differential input signals are summed with the output of
the coarse offset DAC (CO DAC) for offset correction
prior to being amplified by the programmable gain
amplifier (PGA). The resulting signal is applied to the
differential input of the ADC for conversion.
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