MS5540C Datasheet, PDF (15/18 Pages) Intersema Sensoric SA – MINIATURE BAROMETER MODULE

DECOUPLING CAPACITOR
Particular care must be taken when connecting the device to power supply. A 47 µF tantalum capacitor must be
placed as close as possible of the MS5540C's VDD pin. This capacitor will stabilise the power supply during data
conversion and thus, provide the highest possible accuracy.
APPLICATION EXAMPLE: ALTIMETER SYSTEM USING MS5540C
MS5540C is a circuit that can be used in connection with a microcontroller in mobile altimeter applications. It is
designed for low-voltage systems with a supply voltage of 3 V, particularly in battery applications. The MS5540C
is optimised for low current consumption as the AD-converter clock (MCLK) can use the 32.768 kHz frequency of
a standard watch crystal, which is supplied in most portable watch systems.
For applications in altimeter systems Intersema can deliver a simple formula to calculate the altitude, based on a
linear interpolation, where the number of interpolation points influences the accuracy of the formula.
3V-Battery
LCD-Display
MS5540C
XTAL1
32.768 kHz
VDD
VDD
MCLK
DIN
DOUT
SCLK
GND
47µF
Tantal
XTAL2
4/8bit-Microcontroller
GND
Keypad
EEPROM
optional
Figure 7: Demonstration of MS5540C in a mobile altimeter.
RECOMMENDED PAD LAYOUT
Pad layout for bottom side of MS5540C soldered onto printed circuit board
DA5540C_003
June 16th, 2008
15
0005540C1193 ECN 1118