MODEL 1531 HIGH TEMPERATUREANALOG SURFACE MOUNT ACCELEROMETER•••••••••••___Low Noise: 12 μg/√Hz typical for 5g Full Scale Version-55 to +175°C Operation
Responds to frequencies from zero (DC) to 2000+ Hz
High Stability and Durability±4V Differential Output+5 VDC, 5 mA Power (Typical)
Integrated Sensor & Amplifier
Internal Temperature Sensor
Nitrogen Damped & Hermetically Sealed
Serialized for Traceability
RoHS Compliant

AVAILABLE G-RANGESFULL SCALE
ACCELERATION±5g

20 PINJLCC
1531J-005± 10 g1531J-010± 25 g

1531J-025± 50 g

1531J-050± 100 g

1531J-100± 200 g

1531J-200± 400 g

1531J-400

The Model 1531 is a low-cost, general-purpose integrated MEMS accelerometer for use in zero to medium frequency
industrial applications that require extremely low noise and reliable long-term stability in high-temperatureenvironments. The Model 1531 accelerometers are individually tested, programmed, calibrated and verified in aclimate chamber to ensure the greatest accuracy in even high temperature conditions.
Each miniature, hermetically sealed package combines a MEMS capacitive
sense element and a custom integrated circuit that includes a sense amplifierand differential output stage. Each device is marked with a serial number on
its top and bottom surfaces for traceability. A calibration test report (1531TST) is provided with every unit showing the measured bias, scale factor,linearity, operating current, & frequency response.

"J" SUFFIXPACKAGE

0.350

Positive
Acceleration

0.350

0.165

ZERO (DC) TO MEDIUM FREQUENCY APPLICATIONSPERFORMANCEINPUTRANGEg±5±10±25±50±100±200±400

SENSITIVITY,DIFFERENTIALFREQUENCYRESPONSE(TYPICAL, 5%)

mV/g
Hz800
0 – 400
4000 – 700
160
0 – 1300
800 – 1600
400 – 1700
200 – 1900
100 – 2000
By Model: VDD=VR=5.0 VDC, TC=25°C
FREQUENCYRESPONSE(TYPICAL, 3 DB)Hz
0 – 800
0 – 1100
0 – 1750
0 – 2100
0 – 30000 – 3600
0 – 4200

FREQUENCYRESPONSE(MINIMUM, 3 DB)

OUTPUT NOISE,DIFFERENTIAL(RMS, TYPICAL)MAX.
MECHANICALSHOCK (0.1 MS)

Hzμg/(root Hz)
g (peak)0 – 4201220000 – 660
180 – 1050
250 – 1400
5050000 – 1700
1000 – 2100
2000 – 2400
400Single ended sensitivity is half of values shown.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETERPERFORMANCE - ALL VERSIONSAll Models: Unless otherwise specified VDD=VR=5.0 VDC, TC=25°C, Differential. Span = ±g range = 8000 mVPARAMETERMINTYPMAXUNITS

Bias Calibration Error (mV)
1640± mV
Bias Calibration Error (Span)0.20.5± % of span
Bias Temperature Shift (TC= -55 to +125°C) 1-200
0+200(PPM of span)/°C
Scale Factor Calibration Error 2
0.5
1±%
1
Scale Factor Temperature Shift (TC= -55 to +125°C)
-200
0+200
PPM/°C
Non-Linearity (-90 to +90% of Full Scale) 1, 20.15
0.5± % of spanLong Term Bias Stability
1000
2000
± PPM of spanLong Term Scale Factor Stability
500
1000± PPM
Cross Axis Sensitivity
23±%Input Axis Misalignment
510± mrad
Turn-On Transient (in less than 0.5ms)
75± PPM of FS
Output Impedance
90OhmsOperating Voltage 34.75
5.05.25
volts
Operating Current (IDD+IVR)
5.5
6.5mA
Mass
0.68
grams
Case Operating Temperature-55 to +175°C
Voltage on VDD to GND-0.5V to 6.0V
Storage Temperature-55 to +175°C
Voltage on any Pin (except DV) to GND3 -0.5V to VDD+0.5V
Max Reflow Solder Temperature+239°C
Voltage on DV to GND (Self-Test)±15V
Power Dissipation 50 mW
Note 1: Tighter tolerances are available on other SDI accelerometers.
Note 2: For 5g thru 50g only; 100g and greater versions are tested and specified from -65 to +65g.
Note 3: Voltages on pins other than DV, GND or VDD may exceed 0.50 volt above or below the supply voltages provided
the current is limited to 1 mA.
NOTICE: Minimize exposure above 155°C for maximum lifespan. Stresses greater than those listed above may cause permanent
damage to the device. These are maximum stress ratings only. Functional operation of the device at or above these conditions isnot implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability and lifespan.

OPERATION
The Model 1531 produces a differential output voltage of +/-4 volts full scale, the value of which varies with acceleration
as shown in the figure below. The sensitive axis is perpendicular to the bottom of the package, with positive
acceleration resulting from a positive force pushing on the bottom of the package. The seismic center is located on acenterline through the dual sense elements and halfway between them. The internal electronics effectively cancel
any errors due to rotation. Two reference voltages, +5.0 and +2.5 volts (nominal), are required; scale factor isratiometric to the +5.0 volt reference voltage relative to GND, and both outputs at zero acceleration are nominally thesame as the +2.5 volt input.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETERJQGground.



*1'

VDD and GND (power): Pins (14) and (19) respectively. Power (+5 Volts DC) and95

SIGNAL DESCRIPTIONS

AOP and AON (output): Pins 12 and 16 respectively. Analog output voltages

'9 



proportional to acceleration. The AOP voltage increases (AON decreases) withpositive acceleration; at zero acceleration both outputs are nominally equal tothe +2.5 volt reference. The device experiences positive (+1g) acceleration with
its lid facing up in the earth’s gravitational field. Use of differential mode isstrongly recommended for both lowest noise and highest accuracy operation.
Voltages can be measured ratio-metrically to VR for good repeatability without
requiring a separate precision reference voltage for an A/D.

JQG 9JQG



7239,(: $21,7 



$23

YGG



YGG

 9''DV (input): Pin 4. Deflection Voltage. Connect to the 2.5 Volt pin for bestJQG

repeatability. A test input that applies an electrostatic force to the sense element, simulating a positive acceleration.
The nominal voltage at this pin is ½ VDD. DV voltages higher than required to bring the output to positive full scale may
cause device damage to 5g and 10g devices.
VR (input): Pin 3. Voltage Reference. Tie to a good reference (not directly to VDD) for best scale factor repeatability.
A 0.1μF bypass capacitor is recommended at this pin. The current is less than 100 μA.
2.5 Volt (input): Pin 17. Sets internal and output common mode value. Tie to a resistive voltage divider from +5 volts.
A 0.1μF bypass capacitor is recommended at this pin. The current is less than 50 μA.
IT (output): Pin 8. Temperature dependent current source. May be tied to VDD or left disconnected if not used.
Special Use Pins: Pins 9 and 11 should be tied to VDD, Pins 2, 5, 6, and 18 to GND.

** Pins 1, 7, 10, 13, 15, and 20 are reserved for future use and should remain unused **RECOMMENDED CONNECTIONSDEFLECTION VOLTAGE (DV) TESTINPUT: This test input applies anelectrostatic force to the senseelement, simulating a positive
acceleration of up to +10g. It has anominal input impedance of 32 kΩ
and a nominal open circuit voltage of½ VDD. For best accuracy during
normal operation, this input shouldbe left unconnected or connected toa voltage source equal to ½ of the VDD
supply.

+ 5V
115K
TEST INPUT(OPTIONAL)

143

0.1 uF

9VDD VR
417

AOP

DV

AON
2.5V
IT

0.01uF

5K
2GND
5196

12168

OUTPUT (POSITIVE)OUTPUT (NEGATIVE)
TEMPERATURE DEPENDENTCURRENT SOURCE

181§·Δ ( AOP − AON ) ≈ k ¨ V DV − V DD ¸2©
¹The change in differential output voltage (AOP - AON) is proportional to the square of the difference between thevoltage applied to the DV input (VDV) and ½ VDD. Only positive shifts in the output voltage may be generated by applying
voltage to the DV input. When voltage is applied to the DV input on 5g or 10g devices, it should be applied gradually toavoid damage. The application of DV voltages greater than required to bring the output to positive full scale may cause
device damage. The proportionality constant (k) varies for each device and is not characterized.
ESD and LATCH-UP CONSIDERATIONS: The model 1531 accelerometer is a CMOS device subject to damage fromlarge electrostatic discharges. Diode protection is provided on the inputs and outputs, and it is not easily damaged,
but care should be exercised during handling. However, individuals and tools should be grounded before coming incontact with the device. Although the 1531 is resistant to latch-up, inserting a 1531 into or removing it from a powered
socket may cause damage.
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
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www.silicondesigns.com[page 3]29-Aug-2021

2

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

MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEROPTIONAL INTERNAL TEMPERATURE SENSING
The model 1531 accelerometer contains a temperature
VT ≈ RT [(500 μA ) + [(1.5μA )(T − 25)]]
dependent current source that is output on pin 8. This signal isuseful for measuring the internal temperature of theΔVT= RT (1.5μA)
accelerometer so that any previously characterized bias andΔTscale factor temperature dependence, for a particularªVºaccelerometer, can be corrected.
VT ≈ − RG « OFF + (500 μA) + [(1.5μA)(T − 25)]»¬ ROFFThe nominal output current at 25°C is ≈500 (±200) μA and thenominal sensitivity is 1.5 (±0.5) μA/°C. Fluctuations in VDD & VR
have little effect on the temperature reading. A reduction of 0.10
V to both VDD & VR will reduce the current about 1 μA, whichcorresponds to less than a 1°C change in reading. With a single
resistor RT = 2K between IT (pin 8) and GND the output voltage VT
will vary between +0.76 and +1.3 volts from -55 to +125°C, which
equates to a sensitivity of ≈+3 mV/°C.

ROFF =RG =¼− VOFFV§ T·¨ R ¸ + (500 μA) + [(1.5μA)(T − 25)]
G¹
©

− ΔVT
(1.5μA)(ΔT )ΔV= − RG (1.5μA)
ΔT

If a greater voltage change versus temperature or lower signal source impedance is needed, add the amplifier
as shown on the right side in Figure 2. With offset voltage VOFF = -5V, gain resistor RG = 15.0K and offset resistor
ROFF = 7.32K, the output voltage VT will vary between +4.5 and +0.5 Volts from -55 to +125°C, which equates to asensitivity of ≈ -29 mV/°C.
Figure 3 shows the voltage compliance of the temperature dependent current source (IT) at room temperature.
The voltage at pin 8 must be kept in the 0 to +3V range in order to achieve proper temperature readings.
+ 5V
RG
115K
417

14VDD

3VR

0.1 uF

9+ 5 to + 15VITDVAOP
2.5V
AON.01uF

5K
25GND198VT

1216R OFFFigure 2

- 5 to - 15 V
618VOFFSPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETERPACKAGE DIMENSIONS
1. *Dimensions “M,” “T,” and “U” locate sensing element’s center of mass.
2. Lid is electrically tied to terminal 19 (GND).
3. Controlling dimension: Inch.
4. Terminals are plated with 60 micro inches min gold over 80 micro inches
min nickel. This plating specification does not apply to the Pin-1 identifier
mark on the bottom of the J-lead package version.
5. Package: 90% min alumina (black), lid: solder sealed kovar.
*T

N

K

F

*UR

P
B

A

TERMINAL 20

PositiveAcceleration

Dim
A
B
DFK
*M
NP
R
*T
*UInchesMin
Max
0.342 0.358
0.346 0.378
0.095 0.115
0.050 BSC
0.010 R TYP
0.066 TYP
0.050 0.070
0.017 TYP
0.023 R TYP
0.085 TYP
0.175 TYP

Millimeters
MinMax8.69
9.09
8.79
9.60
2.41
2.92
1.27 BSC
0.25 R TYP
1.68 TYP
1.27
1.78
0.43 TYP
0.58 R TYP
2.16 TYP
4.45 TYPTERMINAL 1*MDASOLDERING RECOMMENDATIONSRoHS Compliance: The model 1531 does not contain elemental lead and is RoHS compliant.
Soldering: Solder reflow should not exceed 239°C, exceeding this temperature may result in permanent damage.
Pre-Tinning of Accelerometer Leads is Recommended: To prevent gold migration embrittlement of the solder joints,
it is best to pre-tin the accelerometer leads.
LCC Solder Contact Plating Information: The plating composition and thickness for the solder pads and castellations
on the J-Lead package top layer is 100 to 225 microinches thick of 99.7% gold (Au) over 80 to 350 microinches thick ofelectroplated nickel (Ni).
Recommended Solder Pad Pattern: The recommended solder pad size and shape for the J-Lead packages is shownin the diagram and table. These dimensions are recommendations only and may or may not be optimum for yourparticular soldering process.

FG

Do not use ultrasonic cleaners.
Ultrasonic cleaning may break internal wire bonds and will voidthe warranty.

FE
ACDDIM
ABCDEFGInch.230.430.100.033.050.013.120mm
5.84
10.92
2.540.84
1.27
0.33
3.05

B

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETERTEST REPORT EXAMPLES:LINEARITY, PHASE & FREQUENCY RESPONSE BY G-LEVEL
The included 1531-TST calibration test reports provide additional information about the linearity, output,phase, and frequency response as tested for each individual unit. The following are examples of thegraphical data supplied on test reports, by G-level.
NOTE: Frequency response on test reports is documented by simulating frequency response with the DV
pin. This will indicate lower values than the actual performance once soldered or otherwise permanently
installed upon a board.

EXAMPLE 5G: 1531L-005

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29-Aug-2021

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEREXAMPLE 10G: 1531L-010

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETER

EXAMPLE 25G: 1531L-025

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEREXAMPLE 50G: 1531L-050

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEREXAMPLE 100G: 1531L-100SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEREXAMPLE 200G: 1531L-200

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MODEL 1531 ANALOG SURFACE MOUNT ACCELEROMETEREXAMPLE 400G: 1531L-400

COMPANION ACCESSORY
The Model EB-J Analog Test Sets provide a convenient means of testingand evaluating SDI Model 1531 surface mount accelerometers in theJLCC package formats. The zero-insertion-force socket is pre-fitted tothe board, which includes set jumpers for advanced features of SDIaccelerometers. A 10-pin connector and ribbon cable provide
connections to the user's test equipment. The EB-J Sets and SDI
Surface Mount Accelerometers are each sold separately.

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