ADXL180WCPZ-RL Analog Devices Inc, ADXL180WCPZ-RL Datasheet - Page 10

• Manufacturer Part Number: ADXL180WCPZ-RL
• Description: IC ACCELEROMETER CONFIG 16-LFCSP
• Manufacturer: Analog Devices Inc
• Series: iMEMS®r

Specifications of ADXL180WCPZ-RL

• Axis: X or Y
• Acceleration Range: ±50g, 100g, 150g, 200g, 250g, 350g, 500g
• Voltage - Supply: 5 V ~ 14.5 V
• Output Type: Analog
• Bandwidth: 100Hz ~ 800Hz Selectable
• Mounting Type: Surface Mount
• Package / Case: 16-LFQFN, CSP Exposed Pad
• Package Type: LFCSP EP
• Operating Supply Voltage (min): 5V
• Operating Temperature (min): -40C
• Operating Temperature (max): 125C
• Operating Temperature Classification: Automotive
• Product Depth (mm): 5mm
• Product Height (mm): 1.43mm
• Product Length (mm): 5mm
• Mounting: Surface Mount
• Pin Count: 16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sensitivity: -
• Interface: -
• Lead Free Status / Rohs Status: Compliant
• Other names: ADXL180WCPZ-RLCT

ADXL180
THEORY OF OPERATION
OVERVIEW
The ADXL180 is a complete satellite system, including
acceleration sensor, data filtering, digital protocol functionality,
and a 2-wire, high-voltage, current-modulated bus interface
communications port.
ACCELERATION SENSOR
The ADXL180 provides a fully differential sensor structure and
circuit path. This device uses electrical feedback with zero force
feedback. Figure 4 is a simplified view of one of the differential
sensor elements. Each sensor includes several differential capa-
citor unit cells. Each cell is composed of fixed plates attached to the
substrate and movable plates attached to the frame. Displacement
of the frame changes the differential capacitance, which the on-
chip circuitry measures.
Complementary signals drive the fixed capacitor plates. The
relative phasing between the two halves of the differential
MECHANICAL
SPRING
COUPLINGS
ISOLATED
ACCELERATION SENSING AXIS
+X-AXIS SENSOR
–X-AXIS SENSOR
UNIT SENSING
CELL
Figure 4. Simplified View of ADXL180 Sensor Under Acceleration
PLATE
CAPACITORS
Figure 5. Differential Acceleration Sensing
0
0
+
–
MOVING
PLATE
ANCHOR
Rev. A | Page 10 of 60
ANCHOR
FIXED
PLATES
COMMON TO BOTH CHANNELS
EMI DISTURBANCE RESPONSE
ACCELERATION RESPONSE
DIFFERENTIAL BETWEEN CHANNELS
sensor is such that the displacement signal is differential
between the two measurement channels. Using the fully
differential sensor and an antiphase clocking scheme helps
reject electrical environmental noise (see Figure 5).
The ADXL180 acceleration sensor uses two electrically isolated,
mechanically coupled sensors to measure acceleration as shown
in Figure 5. The clock phasing of the readout is such that the
electrical signal due to acceleration is differential between the
channels and environmental disturbances couple in as a common-
mode signal. The following differential amplifier can then extract
the acceleration signal while suppressing the environmental noise.
Electrical feedback adjusts the amplitudes of the fixed capacitor
plates’ drive signals such that the ac signal on the moving plates
is zero. The feedback signal is linearly proportional to the applied
acceleration. This feedback technique ensures that there is no
net electrostatic force applied to the sensor.
MOVABLE
FRAME
UNIT SELF-TEST
FORCING CELL
+
–
AMP
V
OUT