Motorola MMAS40GWB Datasheet

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SEMICONDUCTOR TECHNICAL DATA

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±40g Amplified

The MMAS40G family of silicon capacitive, micro–machined accelerometers
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 MMAS40G 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 wafer level, creating a particle–free environment. The G–cell
features built–in damping and over–range stops to protect it from mechanical
shock.

MMAS40G accelerometers are ideally suited for automotive crash detection
and recording, vibration monitoring, automotive suspension control, appliance
control systems, etc.

Features

• Minimum Full Scale Measurement ±40g

• Calibrated, True Self–Test

• Senses Parallel to the Printed Circuit Board

• Integral Signal Conditioning and 4–Pole Filter

• Linear Output

• Robust, High Shock Survivability

SIMPLIFIED BLOCK DIAGRAM

+

+

Order this document

by MMAS40GWB/D

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MICROMACHINED

ACCELEROMETER

±40g AMPLIFIED

(Wingback)

1

2

3

4

5

6

WB PACKAGE

CASE 456–03

PIN NUMBER (WB)

1 4

NC (1) V

25

Self–Test GND

36

Output VS (2)

NOTES:

1. Connect to ground.

2. Bypass at pin to ground with 0.1 µF
ceramic capacitor for specified perfor­mance.

ref

(2)

2 SELF–TEST

g

(Replaces XMMAS40GWB)

Motorola Sensor Device Data

 Motorola, Inc. 1997

G–CELL

LOW–PASS FILTER

6V

S

+

A

TEMPERATURE

COMPENSATION

5 GND

4V

ref

3

OUTPUT

1

MMAS40GWB

MAXIMUM RATINGS

Rating Symbol Value Unit

Acceleration (biased each axis) G ±500 g
Acceleration (unbiased each axis) G ±2000 g
Supply Voltage V
Storage Temperature T
Operating Temperature(6) T

Smax

stg

A

–0.3 to +7.0 Vdc
–40 to +105 °C

–40 to +85 °C

OPERATING CHARACTERISTICS (V

Characteristic Symbol Min Typ Max Unit

Acceleration Range G ±40 ±55 — g
Output Drive Capability — –0.2 — 0.2 mA
Supply Voltage V
Supply Current I
Full Scale Output Range V
Sensitivity (over temperature range) (2) (3) ∆V/∆G 36 40 44 mV/g
Zero Acceleration Output (over temperature range) (3) (4) V
Linearity — — 0.5 2.0 %FSO
Transverse Sensitivity — — 1.0 3.0 %FSO
Frequency Bandwidth — 300 400 500 Hz
Noise — — 15 25 mV
Self–Test Output Equivalent (5) G
Self–Test Input Low V
Self–Test Input High V
Self–Test Input Current — 10 70 200 µA

NOTES:

1. The output voltage increases from the Zero Acceleration Output for positive acceleration and decreases for negative acceleration. The
typical sensitivity is 40 mV/g. For example, with VS = 5.0 V , a +20g input will result in a 3.3 V output. (V
input will result in a 1.7 V output.

2. Sensitivity is a ratiometric parameter: ∆V/∆G

3. The compensated temperature operating range is –40 to +85°C.

4. Zero Acceleration Output is a ratiometric parameter: V

5. Equivalent output in response to a Logic Level One on the self–test pin.

6. Additional temperature range available. Consult factory.

= 5.0 Vdc, TA = 25°C unless otherwise noted)

S

S

O

FSO

off

S

STL

STH

(Vs)

= ∆V/∆G

off(Vs)

x (VS/5 V).

(5 V)

= V

off(5 V)

x (VS/5 V).

4.75 5.0 5.25 V
— 5.0 7.0 mA

0.3 — VS – 0.3 V

2.2 2.5 2.8 V

20 25 30 g
— — 1.6 V

3.4 — — V

= 2.5 + 0.040 x 20) and a –20g

output

pk

ORDERING INFORMATION

Device Temperature Range Case No. Package

MMAS40GWB –40 to +85°C 456–03 Plastic Wingback

2

Motorola Sensor Device Data