ADXRS300EB - Analog Devices

±300°/s Single Chip Yaw Rate

Gyro with Signal Conditioning

ADXRS300

FEATURES

Complete rate gyroscope on a single chip

Z-axis (yaw rate) response

High vibration rejection over wide frequency

2000 g powered shock survivability

Self-test on digital command

Temperature sensor output

Precision voltage reference output

Absolute rate output for precision applications

5 V single-supply operation

Ultrasmall and light (< 0.15 cc, < 0.5 gram)

APPLICATIONS

Vehicle chassis rollover sensing

Inertial measurement units

Platform stabilization

GENERAL DESCRIPTION

The ADXRS300 is a complete angular rate sensor (gyroscope)

that uses Analog Devices’ surface-micromachining process to

make a functionally complete and low cost angular rate sensor

integrated with all of the required electronics on one chip. The

manufacturing technique for this device is the same high

volume BIMOS process used for high reliability automotive

airbag accelerometers.

The output signal, RATEOUT (1B, 2A), is a voltage proportional

to angular rate about the axis normal to the top surface of the

package (see Figure 4). A single external resistor can be used to

lower the scale factor. An external capacitor is used to set the

bandwidth. Other external capacitors are required for operation

(see Figure 5).

A precision reference and a temperature output are also

provided for compensation techniques. Two digital self-test

inputs electromechanically excite the sensor to test proper

operation of both sensors and the signal conditioning circuits.

The ADXRS300 is available in a 7 mm × 7 mm × 3 mm BGA

chip-scale package.

FUNCTIONAL BLOCK DIAGRAM

2G 1F

7F 6A 7D7C7B

4A 5A 7E 6G

PDD

12V

ADXRS300

47nF

22nF

100nF

22nF

CP2 CP1 PGND CP4 CP3 CP5

CHARGE PUMP/REG.

TEMP

PTAT

RATEOUT

2.5V

π DEMOD

RATE

SENSOR

SELF

TEST

100nF 100nF

CMID

AGND

AVCC

ST1

ST2 CORIOLIS SIGNAL CHANNEL

SEN1

SEN2

OUT

SUMJ

OUT

2.5V REF

≈

Ω

35%

≈

Ω

35%

180k

Ω

RESONATOR LOOP

–

Figure 1.

Rev. B

Information furnished by Analog Devices is believed to be accurate and reliable.

However, no responsibility is assumed by Analog Devices for its use, nor for any

infringements of patents or other rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and

registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700 www.analog.com

ADXRS300

Rev. B | Page 2 of 8

TABLE OF CONTENTS

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 4

Rate Sensitive Axis........................................................................ 4

ESD Caution.................................................................................. 4

Pin Configuration and Function Descriptions............................. 5

Theory of Operation ........................................................................ 6

Supply and Common Considerations ....................................... 6

Setting Bandwidth ........................................................................ 7

Increasing Measurement Range ..................................................7

Using the ADXRS300 with a Supply-Ratiometric ADC ..........7

Null Adjust .....................................................................................7

Self-Test Function .........................................................................7

Continuous Self-Test.....................................................................7

Outline Dimensions..........................................................................8

Ordering Guide .............................................................................8

REVISION HISTORY

3/04—Data Sheet Changed from Rev. A to Rev. B

Updated Format..................................................................Universal

Changes to Table 1 Conditions....................................................... 3

Added Evaluation Board to Ordering Guide................................ 8

3/03—Data Sheet Changed from Rev. 0 to Rev. A

Edit to Figure 3.................................................................................. 5

ADXRS300

Rev. B | Page 3 of 8

SPECIFICATIONS

@TA = 25°C, VS = 5 V, Angular Rate = 0°/s, Bandwidth = 80 Hz (COUT = 0.01 µF), ±1g, unless otherwise noted.

Table 1.

ADXRS300ABG

Parameter Conditions Min1 Typ Max1 Unit

SENSITIVITY Clockwise rotation is positive output

Dynamic Range2 Full-scale range over specifications range ±300 °/s

Initial @25°C 4.6 5 5.4 mV/°/s

Over Temperature3 V

S = 4.75 V to 5.25 V 4.6 5 5.4 mV/°/s

Nonlinearity Best fit straight line 0.1 % of FS

NULL

Initial Null 2.3 2.50 2.7 V

Over Temperature3 V

S = 4.75 V to 5.25 V 2.3 2.7 V

Turn-On Time Power on to ±½°/s of final 35 ms

Linear Acceleration Effect Any axis 0.2 °/s/g

Voltage Sensitivity VCC = 4.75 V to 5.25 V 1 °/s/V

NOISE PERFORMANCE

Rate Noise Density @25°C 0.1 °/s/√Hz

FREQUENCY RESPONSE

3 dB Bandwidth (User Selectable)4 22 nF as comp cap (see the Setting Bandwidth section) 40 Hz

Sensor Resonant Frequency 14 kHz

SELF-TEST INPUTS

ST1 RATEOUT Response5 ST1 pin from Logic 0 to 1 –150 –270 –450 mV

ST2 RATEOUT Response5 ST2 pin from Logic 0 to 1 +150 +270 +450 mV

Logic 1 Input Voltage Standard high logic level definition 3.3 V

Logic 0 Input Voltage Standard low logic level definition 1.7 V

Input Impedance To common 50 kΩ

TEMPERATURE SENSOR

VOUT at 298°K 2.50 V

Max Current Load on Pin Source to common 50 µA

Scale Factor Proportional to absolute temperature 8.4 mV/°K

OUTPUT DRIVE CAPABILITY

Output Voltage Swing IOUT = ±100 µA 0.25 VS – 0.25 V

Capacitive Load Drive 1000 pF

2.5 V REFERENCE

Voltage Value 2.45 2.5 2.55 V

Load Drive to Ground Source 200 µA

Load Regulation 0 < IOUT < 200 µA 5.0 mV/mA

Power Supply Rejection 4.75 VS to 5.25 VS 1.0 mV/V

Temperature Drift Delta from 25°C 5.0 mV

POWER SUPPLY

Operating Voltage Range 4.75 5.00 5.25 V

Quiescent Supply Current 6.0 8.0 mA

TEMPERATURE RANGE

Specified Performance Grade A Temperature tested to max and min specifications –40 +85 °C

1 All minimum and maximum specifications are guaranteed. Typical specifications are not tested or guaranteed.

2 Dynamic range is the maximum full-scale measurement range possible, including output swing range, initial offset, sensitivity, offset drift, and sensitivity drift at

5 V supplies.

3 Specification refers to the maximum extent of this parameter as a worst-case value of TMIN or TMAX.

4 Frequency at which response is 3 dB down from dc response with specified compensation capacitor value. Internal pole forming resistor is 180 kΩ. See the Setting

Bandwidth section.

5 Self-test response varies with temperature. See the Self-Test Function section for details.

ADXRS300

Rev. B | Page 4 of 8

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Acceleration (Any Axis, Unpowered, 0.5 ms) 2000 g

Acceleration (Any Axis, Powered, 0.5 ms) 2000 g

+VS –0.3 V to +6.0 V

Output Short-Circuit Duration

(Any Pin to Common)

Indefininte

Operating Temperature Range –55°C to +125°C

Storage Temperature –65°C to +150°C

Stresses above those listed under the Absolute Maximum

Ratings may cause permanent damage to the device. This is a

stress rating only; functional operation of the device at these or

any other conditions above those indicated in the operational

section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect

device reliability.

Applications requiring more than 200 cycles to MIL-STD-883

Method 1010 Condition B (–55°C to +125°C) require underfill

or other means to achieve this requirement.

Drops onto hard surfaces can cause shocks of greater than

2000 g and exceed the absolute maximum rating of the device.

Care should be exercised in handling to avoid damage.

RATE SENSITIVE AXIS

This is a Z-axis rate-sensing device that is also called a yaw rate

sensing device. It produces a positive going output voltage for

clockwise rotation about the axis normal to the package top, i.e.,

clockwise when looking down at the package lid.

2.5V

RATE

AXIS RATEOUT

RATE IN

GND

4.75V

0.25

LATERAL AXIS

ABCDEFG

A1 1

LONGITUDINAL

AXIS

= 5V

Figure 2. RATEOUT Signal Increases with Clockwise Rotation

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the

human body and test equipment and can discharge without detection. Although this product features

proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy

electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance

degradation or loss of functionality.

ADXRS300

Rev. B | Page 5 of 8

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

AGND

TEMP

ST2

ST1

PGND

AVCC

CP1

CP2

CP4

RATEOUT

GFEDCBA

CP5 CP3

PDD

CMID SUMJ

2.5V

Figure 3. 32-Lead BGA (Bottom View)

Table 3. Pin Function Descriptions

Pin No. Mnemonic Description

6D, 7D CP5 HV Filter Capacitor—47 nF

6A, 7B CP4

6C, 7C CP3

Charge Pump Capacitor—22 nF

5A, 5B CP1

4A, 4B CP2

Charge Pump Capacitor—22 nF

3A, 3B AVCC + Analog Supply

1B, 2A RATEOUT Rate Signal Output

1C, 2C SUMJ Output Amp Summing Junction

1D, 2D CMID HF Filter Capacitor—100 nF

1E, 2E 2.5V 2.5 V Precision Reference

1F, 2G AGND Analog Supply Return

3F, 3G TEMP Temperature Voltage Output

4F, 4G ST2 Self-Test for Sensor 2

5F, 5G ST1 Self-Test for Sensor 1

6G, 7F PGND Charge Pump Supply Return

6E, 7E PDD + Charge Pump Supply

ADXRS300

Rev. B | Page 6 of 8

THEORY OF OPERATION

The ADXRS300 operates on the principle of a resonator gyro.

Two polysilicon sensing structures each contain a dither frame,

which is electrostatically driven to resonance. This produces the

necessary velocity element to produce a Coriolis force during

angular rate. At two of the outer extremes of each frame,

orthogonal to the dither motion, are movable fingers that are

placed between fixed pickoff fingers to form a capacitive pickoff

structure that senses Coriolis motion. The resulting signal is fed

to a series of gain and demodulation stages that produce the

electrical rate signal output. The dual-sensor design rejects

external g-forces and vibration. Fabricating the sensor with the

signal conditioning electronics preserves signal integrity in

noisy environments.

The electrostatic resonator requires 14 V to 16 V for operation.

Since only 5 V is typically available in most applications, a

charge pump is included on-chip. If an external 14 V to 16 V

supply is available, the two capacitors on CP1–CP4 can be

omitted and this supply can be connected to CP5 (Pin 7D) with

a 100 nF decoupling capacitor in place of the 47 nF.

After the demodulation stage, there is a single-pole low-pass

filter consisting of an internal 7 kΩ resistor (RSEN1) and an

external user-supplied capacitor (CMID). A CMID capacitor of

100 nF sets a 400 Hz ±3 5% low-pass pole and is used to limit

high frequency artifacts before final amplification. The band-

width limit capacitor, COUT, sets the pass bandwidth (see Figure 5

and the Setting Bandwidth section).

AGND

TEMP

ST2

ST1

CP1

CP2

RATEOUT

CP4 PDD

CMID

SUMJ 2.5V

1B 1C 1D 1E 1F

7B 7C 7D 7E 7F

CP5

CP3

100nF

OUT

= 22nF

22nF

AVCC

100nF

PGND

22nF

47nF

NOTE THAT INNER ROWS/COLUMNS OF PINS HAVE BEEN OMITTED

FOR CLARITY BUT SHOULD BE CONNECTED IN THE APPLICATION.

Figure 4. Example Application Circuit (Top View)

SUPPLY AND COMMON CONSIDERATIONS

Only power supplies used for supplying analog circuits are

recommended for powering the ADXRS300. High frequency

noise and transients associated with digital circuit supplies may

have adverse effects on device operation.

Figure 4 shows the recommended connections for the ADXRS300

where both AVCC and PDD have a separate decoupling capacitor.

These should be placed as close to the their respective pins as

possible before routing to the system analog supply. This mini-

mizes the noise injected by the charge pump that uses the PDD

supply.

It is also recommended to place the charge pump capacitors

connected to the CP1–CP4 pins as close to the part as possible.

These capacitors are used to produce the on-chip high voltage

supply switched at the dither frequency at approximately

14 kHz. Care should be taken to ensure that there is no more

than 50 pF of stray capacitance between CP1–CP4 and ground.

Surface-mount chip capacitors are suitable as long as they are

rated for over 15 V.

–

SELF

TEST

AVCC

ST1

ST2

ADXRS300

CP2 CP1

PDD

4A 5A 7E 6G

CHARGE

PUMP/REG.

12V

PTAT

7F 6A 7B 7C 7D

47nF

CP4 CP3 CP5

RATE

SENSOR

2G 1F 1D

CORIOLIS

SIGNAL CHANNEL

AGND CMID

1CSUMJ

RATE-

OUT

2.5V

3G TEMP

OUT

180kΩ1%

RESONATOR LOOP

DEMOD

2.5V REF

≈7kΩ±35%

100nF

22nF

100nF 100nF C

OUT

SEN1

SEN2

22nF

PGND

Figure 5. Block Diagram with External Components

ADXRS300

Rev. B | Page 7 of 8

SETTING BANDWIDTH

External capacitors CMID and COUT are used in combination

with on-chip resistors to create two low-pass filters to limit the

bandwidth of the ADXRS300’s rate response. The –3 dB

frequency set by ROUT and COUT is

()

OUTOUTOUT CR/f ×××= π21

and can be well controlled since ROUT has been trimmed during

manufacturing to be 180 kΩ ± 1%. Any external resistor applied

between the RATEOUT (1B, 2A) and SUMJ (1C, 2C) pins

results in

()()

EXTEXTOUT R/RR ××= kΩ180kΩ180

The –3 dB frequency is set by RSEN (the parallel combination

of RSEN1 and RSEN2) at about 3.5 kΩ nominal; CMID is less well

controlled since RSEN1 and RSEN2 have been used to trim the rate

sensitivity during manufacturing and have a ±35% tolerance. Its

primary purpose is to limit the high frequency demodulation

artifacts from saturating the final amplifier stage. Thus, this pole

of nominally 400 Hz @ 0.1 µF need not be precise. Lower

frequency is preferable, but its variability usually requires it to

be about 10 times greater (in order to preserve phase integrity)

than the well-controlled output pole. In general, both –3 dB

filter frequencies should be set as low as possible to reduce the

amplitude of these high frequency artifacts and to reduce the

overall system noise.

INCREASING MEASUREMENT RANGE

The full-scale measurement range of the ADXRS300 can be

increased by placing an external resistor between the RATEOUT

(1B, 2A) and SUMJ (1C, 2C) pins, which would parallel the

internal ROUT resistor that is factory-trimmed to 180 kΩ. For

example, a 330 kΩ external resistor will give ~50% increase in

the full-scale range. This is effective for up to a 4× increase in

the full-scale range (minimum value of the parallel resistor

allowed is 45 kΩ). Beyond this amount of external sensitivity

reduction, the internal circuitry headroom requirements

prevent further increase in the linear full-scale output range.

The drawbacks of modifying the full-scale range are the

additional output null drift (as much as 2°/sec over temperature)

and the readjustment of the initial null bias (see the Null Adjust

section).

USING THE ADXRS300 WITH A SUPPLY-

RATIOMETRIC ADC

The ADXRS300’s RATEOUT signal is nonratiometric, i.e.,

neither the null voltage nor the rate sensitivity is proportional to

the supply. Rather they are nominally constant for dc supply

changes within the 4.75 V to 5.25 V operating range. If the

ADXRS300 is used with a supply-ratiometric ADC, the

ADXRS300’s 2.5 V output can be converted and used to make

corrections in software for the supply variations.

NULL ADJUST

Null adjustment is possible by injecting a suitable current to

SUMJ (1C, 2C). Adding a suitable resistor to either ground or to

the positive supply is a simple way of achieving this. The

nominal 2.5 V null is for a symmetrical swing range at

RATEOUT (1B, 2A). However, a nonsymmetric output swing

may be suitable in some applications. Note that if a resistor is

connected to the positive supply, then supply disturbances may

reflect some null instabilities. Digital supply noise should be

avoided, particularly in this case (see the Supply and Common

Considerations section).

The resistor value to use is approximately

)()00018052( NULL1NULL0NULL V– V/, . R

VNULL0 is the unadjusted zero rate output, and VNULL1 is the target

null value. If the initial value is below the desired value, the

resistor should terminate on common or ground. If it is above

the desired value, the resistor should terminate on the 5 V

supply. Values are typically in the 1 MΩ to 5 MΩ range.

If an external resistor is used across RATEOUT and SUMJ, then

the parallel equivalent value is substituted into the preceding

equation. Note that the resistor value is an estimate since it

assumes VCC = 5.0 V and VSUMJ = 2.5 V.

SELF-TEST FUNCTION

The ADXRS300 includes a self-test feature that actuates each of

the sensing structures and associated electronics in the same

manner as if subjected to angular rate. It is activated by standard

logic high levels applied to inputs ST1 (5F, 5G), ST2 (4F, 4G), or

both. ST1 causes a voltage at RATEOUT equivalent to typically

–270 mV, and ST2 causes an opposite +270 mV change. The

self-test response follows the viscosity temperature dependence

of the package atmosphere, approximately 0.25%/°C.

Activating both ST1 and ST2 simultaneously is not damaging.

Since ST1 and ST2 are not necessarily closely matched,

actuating both simultaneously may result in an apparent null

bias shift.

CONTINUOUS SELF-TEST

The one-chip integration of the ADXRS300 gives it higher

reliability than is obtainable with any other high volume

manufacturing method. Also, it is manufactured under a mature

BIMOS process that has field-proven reliability. As an additional

failure detection measure, power-on self-test can be performed.

However, some applications may warrant continuous self-test

while sensing rate. Application notes outlining continuous self-

test techniques are also available on the Analog Devices website.

ADXRS300

Rev. B | Page 8 of 8

OUTLINE DIMENSIONS

BOTTOM

VIEW

76543

TOP VIEW

3.65 MAX SEATING

PLANE

DETAIL A

BALL DIAMETER

7.00 BSC SQ

4.80 BSC

0.60

0.55

0.50

3.20

2.50 0.44

0.25 0.15 MAX

COPLANARITY

0.80

BSC

BALL A1

INDICATOR

A1 CORNER

INDEX AREA

DETAIL A

Figure 6. 32-Lead Chip Scale Ball Grid Array [CSPBGA]

(BC-32)

Dimensions shown in millimeters

ORDERING GUIDE

Model Temperature Range Package Description Package Outline

ADXRS300ABG –40°C to +85°C 32-Lead BGA BC-32

ADXRS300ABG-Reel –40°C to +85°C 32-Lead BGA BC-32

ADXRS300EB Evaluation Board

registered trademarks are the property of their respective owners.

C03227–0–3/04(B)