bmp280 datasheet

Bosch
Sensortec | BMP280 Data sheet
11 |
48
Modifications reserved | Data subject to change without notice
Document number: BST-BMP280-DS001-23 Revision_1.23_11202
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3.1 Block Diagram
Figure 1 shows a simplified block diagram of the BMP280:
Figure 1: Block diagram of BMP280
3.2 Power management
The BMP280 has two separate power supply pins
• V
DD
is the main power supply for all internal analog and digital functional blocks
• V
DDIO
is a separate power supply pin, used for the supply of the digital interface
A power-on reset generator is built in which resets the logic circuitry and the register values after the
power-on sequence. There are no limitations on slope and sequence of raising the V
DD
and V
DDIO
levels. After powering up, the sensor settles in sleep mode (see 3.6.1).
Warning. Holding any interface pin (SDI, SDO, SCK or CSB) at a logical high level when V
DDIO
is
switched off can permanently damage the device due caused by excessive current flow through the
ESD protection diodes.
If V
DDIO
is supplied, but V
DD
is not, the interface pins are kept at a high-Z level. The bus can therefore
already be used freely before the BMP280 V
DD
supply is established.
3.3 Measurement flow
The BMP280 measurement period consists of a temperature and pressure measurement with
selectable oversampling. After the measurement period, the data are passed through an optional IIR
filter, which removes short-term fluctuations in pressure (e.g. caused by slamming a door). The flow is
depicted in the diagram below.
Logic
OSC
NVM
ADC
Pressure/
temperature
sensing
element
Voltage
reference
Voltage
regulator
(analog &
digital)
V
DDIO
GND
I
n
t
e
r
f
a
c
e
SDI
SDO
SCK
CSB
V
DD
POR
Analog
front-end