DA6503.005
14 December 2016
BLOCK DIAGRAM
TE3
OSC
VREG
VDD
EEPROM
VREFP
ADC
PI
P
SDA/MOSI
T
I2C/
SPI
MISO
CONTROL
NI
P
SCL/SCLK
XCS
T
VDD
COMMON
VREFN
XCLR
EOC
R3
R1
XSPI
R4
R2
TEST
MAS6503
T
P
T
TE1 TE2
GND
Figure 1. MAS6503 block diagram
FUNCTIONAL DESCRIPTION
MAS6503 has one input channel suitable for a
piezoresistive pressure sensor. There are four input
signal conversion ranges and eight offset values
selectable to meet various sensor signal ranges.
MAS6503 has an internal clock oscillator making an
external clock unnecessary. To save power the
clock oscillator and the optional voltage regulator
are turned on only when a conversion is running.
The oscillator frequency is factory trimmed to 500
kHz using a 6-bit register. The converter runs from
a system clock which is half of the oscillator
frequency. In a specific test mode an external clock
signal can be also used when connected to the
OSC pin.
In addition the device can be configured for
temperature measurement. The temperature is
typically needed for temperature compensation and
indication purposes. The device supports eight
different sensor bridge resistance values from
2.0kΩ up to 10kΩ.
Communication with MAS6503 is handled by the
MAS6503 also features VDD level monitoring which
is useful especially in battery operated systems.
The VDD level information could be used for battery
energy capacity indication, switching between
different power modes in the system and also for
VDD dependency compensation purposes. In the
VDD level monitoring mode the on-chip regulator
need to be disabled.
serial interface compatible with either
a
bi-
directional 2-wire I2C bus or a 4-wire SPI bus. The
XSPI pin is for selecting which bus type is used.
In addition to a fixed I2C device address the
MAS6503 has also
a
programmable device
address. It has been factory programmed to same
value as the fixed device address of MAS6503.
When unique device address is needed it can be
programmed to EEPROM address (DE/5EHEX)..
The AD-converter is ratiometric offering possibility
to run measurements at varying supply voltage
conditions. However the device has also an
optional voltage regulator with four selectable
output voltage options 1.8V, 2.2V, 2.6V and 2.9V.
The on-chip voltage regulator offers additional
regulation against supply noise and variations. Note
that in the VDD level monitoring mode the on-chip
voltage regulator needs to be disabled.
Note: The 2-wire I2C bus of MAS6503 supports
only basic I2C bus communication protocol but not
for example 10-bit addressing, arbitration and clock
stretching features of the I2C bus specification.
The 256-bit EEPROM memory is available for
storing trimming and calibration data on chip. Two
of the EEPROM bytes are reserved for dedicated
function. One is for internal clock oscillator trimming
value and the another one for programmable I2C
address value but the remaining 240 bits are free
for storing calibration and other information.
The AD-converter resolution is selected by the over
sampling ratio (OSR) setting. Higher OSR
corresponds to higher resolution but also longer
conversion time.
2 (34)
MAS [ MICRO ANALOG SYSTEMS ]
