MODEL 1525 HIGH-END INDUSTRIAL/INERTIAL
MEMS SURFACE MOUNT ACCELEROMETERECCN 7A994•••••••••••

Excellent In-Run Bias Stability
Zero Cross Coupling by Design
Allan Variance from 5 μg
-40 to +85°C Operation±4V Differential Output+5 VDC, 5 mA Power (Typical)
Internal Temperature Sensor
Nitrogen Damped
Hermetically Sealed
Serialized for Traceability
9 mm sq. J-Lead LCC-20 Package

STANDARD G-RANGESFULL SCALE
ACCELERATION±2g±5g± 10 g± 25 g± 50 g20 PINJLCC
1525J-002
1525J-005
1525J-0101525J-025
1525J-050

PositiveAcceleration

0.165"

0.350""J" SUFFIXPACKAGE

0.350"DESCRIPTION
The Model 1525 is the best in class, low-cost, integrated accelerometer for use in high-end industrial,
inertial, and zero to medium frequency instrumentation applications requiring high repeatability and lownoise. Each miniature, hermetically sealed package combines a MEMS capacitive sense element and acustom integrated circuit that includes a sense amplifier and differential output stage. It is relatively
insensitive to temperature changes and gradients. Each device is marked with a serial number on its
top and bottom surfaces for traceability. A calibration test report is supplied with each unit showing themeasured bias, scale factor, linearity, operating current, & frequency response.

ZERO (DC) TO MEDIUM FREQUENCY APPLICATIONSPERFORMANCE*
Unless otherwise specified VDD=VR=5.0 VDC, TC=25°C, Differential Output, J-lead package
PERFORMANCEINPUT RANGE:In Run Bias Stability (Allan Variance Min) (μg)
Bias Calibration Error, Typical (mg)1Long Term Bias Repeatability (mg (1σ))4Bias Temperature Coefficient (mg/°C (max))1
Long Term Scale Factor Repeatability (PPM (1σ))4
Scale Factor Temperature Coefficient (PPM/°C)1Long Term Scale Factor Stability (% of scale)4Input Axis Misalignment (mrad (1σ))
Vibration Rectification, 100 Hz (μg/g2 rms)
Output Noise, Differential, Typical (μg/√Hz rms)
Velocity Random Walk (m/s√Hr)
Temperature Sensor Sensitivity (uA/°C) (Nominal)±2G
Typ (Max)±5G
Typ (Max)±10G
Typ (Max)±25G
Typ (Max)±50G
Typ (Max)

5<501.50.5400500.03610070.005
1.6

10
<50
1.50.540050
0.036100100.005
1.6

20<50
1.50.5400500.03
6100
180.0071.6

50<1253.75
1.25
40050
0.03
675
250.012
1.6

100
<250
7.5
2.5
40050
0.03
675
50
0.025
1.6

*

Specified -40° TO +85°C
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446

www.silicondesigns.com[page 1]15-July-2020

A

MODEL 1525 INERTIAL ACCELEROMETERPERFORMANCEINPUT RANGE:

Frequency Response, Nominal, 5% (Hz)Frequency Response, Nominal, 3 dB (Hz)Frequency Response, Minimum, 3 dB (Hz)Sensitivity (Scale Factor), Differential (mV/g)±2G
Typ (Max)±5G
Typ (Max)±10G
Typ (Max)±25G
Typ (Max)±50G
Typ (Max)0 – 250
0 – 250
0 – 250
2000

0 – 300
0 – 300
0 – 300
800

0 – 420
0 – 420
0 – 420
400

0 – 660
0 – 660
0 – 660
160

0 – 1050
0 – 1050
0 – 1050
80

PARAMETERͲůůǀĞƌƐŝŽŶƐMIN

RMS Model Residual (+/- 1g, -30° to +80°C) (PPM of FS)
Non-Linearity (% of FS)3
Bias Calibration Error, Typical (% Full Scale)
Scale Factor Calibration Error (%, Nominal)
Bias Temperature Coefficient (PPM Full Scale/C°)
Turn-On Transient (in less than 0.5 ms) (PPM of FS)
Output Impedance (ohms)
Operating Voltage (volts)
Operating Current (IDD+IVR) (mA)
Case Operating Temperature (°C)2
Storage Temperature (°C)2
Voltage on VDD to GND (Volts)
Voltage on Any Pin (except DV) to GND (Volts)4
Voltage on DV to GND (Self-Test) (Volts)
Mass, J-Lead Package (grams)
Mechanical Shock (0.1 ms) (g - peak)••

4.75TYPMAX100
0.2

200
0.5
0.50.550

150
90
5.05.5-55-55-0.5-0.5

5.25
6.5+125+1256.0
VDD+0.5±150.68
5000Output Span = ±4V differential output = 8000 mVScale = measured value; FS = Full Scale = absolute output = 4000 mV

Note 1: (TC= -40° to +85°C) Tighter tolerances may be available on special order.
Note 2: Voltages on pins other than DV, GND or VDD may exceed 0.5 volt above or below the supply voltages provided
the current is limited to 1 mA.
Note 3: Additional versions in 100g, 200g, and 400g are available by special order and are tested and specified
from -65 to +65g.
Note 4: Tested as: Power cycle 100x, Shock 500g all axis, storage at -45°C and 85°C, temperature cycle 10x -40 to120C, vibration 90%FS 125—1000Hz band.
Note 5: Measured from -30°C to +80°C
Note 6: Recommended Models:•Applied Acceleration = Bias + BiasTC * T+ BiasTC2*T**2+ (5.00/VR)*(SF+ SFTC*T+ k2*Vout)*(Vout), whereparameters are the least squares fit with T = (Measured Temp – 25C) and Vout = (Vaop-Vaon).

•The term (5.00/VR) can be ignored if calibrated in a production IMU with a repeatable reference or if the A/D
reference and the VR voltage are derived from the same source.

•When the internal Temp Sensor is used, a recommended model is T = TBias + TSens*Vit + TSens2 * Vit**2,
where the temperature parameters are the least squares fit to (oven temperature-25C) and Vit is a voltage
proportional to the current out of IT.

* NOTICE: Stresses greater than those listed above may cause permanent damage to the device. These aremaximum stress ratings only. Functional operation of the device at or above these conditions is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability and lifespan.
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 2]15-July-2020

MODEL 1525 INERTIAL ACCELEROMETEROPERATIONThe model 1525 sensitive axis is perpendicular to thebottom of the package, with positive acceleration
resulting from a positive force pushing on the bottom ofthe package. The seismic center is located on acenterline through the dual sense elements andhalfway between them.
The Model 1525 produces a differential +/-4 volts output
voltage, the value of which varies with acceleration asshown in figure 1. The seismic center is located on acenterline through the dual sense elements halfway
between them. Any errors due to rotation about thispoint are effectively cancelled by the internalelectronics
Two reference voltages, +5.0 and +2.5 volts (nominal),
are required; scale factor is ratiometric to the +5.0 volt
reference voltage relative to GND, and both outputs atzero acceleration are nominally 80 mV below the +2.5volt input.

The 1525 should not be used inSingle Ended mode

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





'9 JQG



JQG



7239,(: $21 9'',7  

$23

YGG

DV (input): Pin 4. Deflection Voltage. Connect to the 2.5 Volt pin for best

JQG 9YGG

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.

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

SIGNAL DESCRIPTIONS

repeatability. A test input that applies an electrostatic force to the sense element, simulating a positiveacceleration. The nominal voltage at this pin is ½ VDD. DV voltages higher than required to bring the output topositive full scale may cause device damage to 2g, 5g, and 10g devices. See app note.
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. VR 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. VR current is less than 50 μA.
IT (output)/ClkIn (Input): Pin 8. Temperature dependent current source or optional external clock input. Tie to VDD
if not used. See application note for details on ClkIn.
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
and should remain unused. See application notes for possible special use of these pins.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 3]15-July-2020

MODEL 1525 INERTIAL ACCELEROMETERRECOMMENDED CONNECTIONSDEFLECTION VOLTAGE (DV) TEST INPUT: This test input applies an electrostatic force to the sense element,simulating a positive acceleration of up to +10g. It has a nominal input impedance of 32 kΩ and a nominal open
circuit voltage of ½ VDD. For best accuracy during normal operation, this input should be left unconnected orconnected to a voltage source equal to ½ of the VDD supply.
The 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 byapplying voltage to the DV input. When voltage is applied to the DV input on 2g, 5g, or 10g devices, it should beapplied gradually to avoid damage. The application of DV voltages greater than required to bring the output topositive full scale may cause device damage. The proportionality constant (k) varies for each device and is notcharacterized.
The 2.5V input (pin 17) may be driven from a resistive divider.
ESD and LATCH-UP CONSIDERATIONS: The model 1525 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 comingin contact with the device. Although the 1525 is resistant to latch-up, inserting a 1525 into or removing it from apowered socket may cause damage.
+ 5V
REF

+ 5V
Po w er

3
VR

14
VD D

5K
TES T IN P U T( O P TION A L )40 .1 u F
17Δ ( AOP − AON

111525

AON2 .5 VIT0 .1 u F

5K25GN D
196©

22¹0 .1 u F

9AOPDV) ≈ k §¨ V DV − 1 V DD ·¸

1216OU TP U T ( P O S ITIV E)
O U TP U T ( N EG A TIVE)

818

RT2K

TEM P ERA TU RE
VO L TA G E O U T( OP TIO N A L )INTERNAL CLOCK
The model 1525 contains an internal clock than runs at approximately 900 KHz. The internal clock is powered byVDD. Like other synchronous sensors, it is subject to clock “lock-in” with other accelerometers driven by the same
VDD. To avoid possible lock-in and small bias jumps, it is recommended that the VDD power to each accelerometerbe supplied by separately buffered sources or filtered from a common well bypassed source by a LC filter with aminimum of 20 dB loss at 800 KHz. Alternatively, multiple accelerometers can be driven by the same external clockwith a frequency in the range of 0.5 to 1 MHz, Contact SDI for more information on using an external clock.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 4]15-July-2020

MODEL 1525 INERTIAL ACCELEROMETERINTERNAL TEMPERATURE SENSING
The model 1525 accelerometer outputs a temperaturedependent current source on pin 8. This signal is useful formeasuring the internal temperature of the accelerometer sothat any previously characterized bias and scale factor
temperature dependence, for a particular accelerometer, can becorrected. The nominal output current at 25°C is ≈500 (±200) μA
and the nominal sensitivity is 1.5 (±0.5) μA/°C. 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.
If a greater voltage change versus temperature or lower signal
source impedance is needed, add the amplifier as shown on theright 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 a sensitivity of ≈ -29 mV/°C. Figure 3 shows thevoltage 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.

VT ≈ RT [(500μA) + [(1.5μA)(T − 25)]]
Δ VT
Δ T
ROFF == R T (1 . 5 μ A )− VOFF§VT·¨ R ¸ + (500 μA) + [(1.5μA)(T − 25)]
G¹©

ªVºVT ≈ − RG « OFF + (500μA) + [(1.5μA)(T − 25)]» ¬ ROFF
¼ΔV− ΔVT= − RG (1.5μA)  RG =ΔT(1.5μA)(ΔT )Keep Pin 8 voltage in 0 to +3V range for proper readings.
Temperature Sensor White Noise (1-1000 Hz):MIN
TYPMAXUNITS
0.25
0.25
0.25°C rms

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 5]15-July-2020

MODEL 1525 INERTIAL ACCELEROMETERPACKAGE DIMENSIONS
1.
2.
3.
4.

5.

*Dimensions “M,” “T,” and “U” locate sensing element’s center of mass.
Lid is electrically tied to terminal 19 (GND).
Controlling dimension: Inch.
Terminals are plated with 60 microinches min gold over 80 microinches
min nickel. This plating specification does not apply to the Pin-1 identifier
mark on the bottom of the J-lead package version.
Package: 90% min alumina (black), lid: solder sealed kovar.
*TR

K

F

*UNDimA
B
DFK
*M
NPR
*T*UPBATERMINAL 20PositiveAccelerationATERMINAL 1Inches
MinMax
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
MinMax
8.69
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 TYP

DIM
AB
C
DE
F
Gmm
5.84
10.92
2.54
0.84
1.27
0.33
3.05

*M
DSOLDERING RECOMMENDATIONSRoHS Compliance:
The model 1525 does not containelemental lead and is RoHS compliant.

FGF

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.

EAC
D

Soldering:
Solder reflow should not exceed 239°C,exceeding this temperature may result in permanentdamage.

B

Inch.230
.430
.100
.033
.050
.013
.120

J-LCC Solder Contact Plating Information: The plating composition and thickness for the solder pads andcastellations on the J-Lead package top layer is 100 to 225 micro inches thick of 99.7% gold (Au) over 80 to 350
micro inches thick of electroplated nickel (Ni).
The aforementioned dimensions are recommendations only and may or may not be optimal for your soldering
process.

Do not use ultrasonic cleaners. Ultrasonic cleaning voids the warranty and may break internal
wire bonds.

COMPANION ACCESSORY
The Model EB-J Analog Test Sets provide a convenient means of testing andevaluating SDI Model 1525 surface mount accelerometers in the JLCC package
format. The zero-insertion-force socket is pre-fitted to the board, which
includes set jumpers for advanced features of SDI accelerometers. A 10-pin
connector and ribbon cable provide connections to the user's test equipment.
The EB-J Set and SDI Surface Mount Accelerometers are each sold separately.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 6]15-July-2020



MODEL 1525 INERTIAL ACCELEROMETERTEST REPORT EXAMPLES:
LINEARITY, PHASE & FREQUENCY RESPONSE BY G-LEVEL
The included 1525-TST test reports provide additional information about the linearity, output, phase, andfrequency response as tested for each individual unit. The following are examples of the graphical data
supplied on test reports, by G-level.
NOTE: Frequency response is specified as performance once soldered. Frequency response on test
reports, as reported by simulating frequency response with the DV pin, will indicate lower values than
the actual performance once soldered.

EXAMPLE 2G: 1525J-002

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 7]15-July-2020



MODEL 1525 INERTIAL ACCELEROMETEREXAMPLE 5G: 1525J-005



SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 8]15-July-2020



MODEL 1525 INERTIAL ACCELEROMETEREXAMPLE 10G: 1525J-010

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 9]15-July-2020



MODEL 1525 INERTIAL ACCELEROMETEREXAMPLE 25G: 1525J-025

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 10]15-July-2020



MODEL 1525 INERTIAL ACCELEROMETEREXAMPLE 50G: 1525J-050

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
Silicon Designs, Inc. • 13905 NE 128th Street, Kirkland WA 98034 • Phone: 425-391-8329 • Fax: 425-391-0446
www.silicondesigns.com[page 11]15-July-2020