
1
Motorola, Inc. 1995
±
250g Amplified
The MMAS250G family of silicon capacitive, micro–machined accelerome-
ters features integral signal amplification, signal conditioning, a 4–pole
low–pass filter and temperature compensation. Zero–G offset, full scale span
and filter roll–off are factory set and require no external passives. A calibrated
self–test feature mechanically displaces the seismic mass with the application
of a digital self–test signal. The device is offered in either of two plastic
packages, thereby accommodating various axis orientation requirements.
The MMAS250G incorporates a single polysilicon seismic mass, suspended
between two fixed polysilicon plates (G–cell). The forces of acceleration move
the seismic mass, thereby resulting in a change in capacitance. The G–cell is
sealed at the die level, creating a particle–free environment. The G–cell
features built–in damping and over–range stops to protect it from mechanical
shock.
MMAS250G accelerometers are ideally suited for automotive crash detection
and recording, vibration monitoring, automotive suspension control, appliance
control systems, etc.
Features
Full Scale Measurement
±
250g
Calibrated, True Self–Test
Standard 16–Pin Plastic DIP
Integral Signal Conditioning and 4–Pole Filter
Linear Output
Robust, High Shock Survivability
SIMPLIFIED BLOCK DIAGRAM
g
4
SELF–TEST
+
+
8
VS
+
A
LOW–PASS FILTER
6
BYPASS
TEMPERATURE
COMPENSATION
5
OUTPUT
7
GND
G–CELL
This document contains information on a product under development. Motorola reserves the right to change or discontinue this product without notice.
Order this document
by XMMAS250G/D
SEMICONDUCTOR TECHNICAL DATA
PIN NUMBER
MICROMACHINED
ACCELEROMETER
±
250g AMPLIFIED
1
N/C (1)
9
N/C (1)
2
N/C (1)
10
N/C (1)
3
N/C (1)
11
N/C (1)
4
Self–Test
12
N/C (1)
5
Output
13
N/C (1)
6
Bypass (2)
14
N/C (1)
7
GND
15
N/C (1)
8
VS (2)
16
N/C (1)
NOTES:
1. Internal connections. All N/C must
remain floating, except DIP’s pin
11 which must be tied to pin 8.
2. Bypass to ground with 0.1
μ
F ceramic
capacitor to improve noise performance.
DIP PACKAGE
CASE 648C–03
SIP PACKAGE
CASE 447–01