The Silicon Designs Model 1521 is a low-cost, general-purpose integrated MEMS accelerometer optimized for zero to medium frequency industrial applications requiring extremely low noise and reliable long-term stability.
Each hermetically-sealed package integrates a MEMS capacitive sense element with a custom IC that includes a precision sense amplifier and differential output stage. Available in ±2g through ±400g ranges, in both 20-pin LCC (leadless) and JLCC (J-lead) ceramic packages.
7 µg/√Hz @ ±2g
0 Hz to 2000+ Hz
Or 0.5–4.5V single-ended
Ratiometric output
Pin 8 current source
5000g @ 0.1ms
Full operating range
Top & bottom marked
| Full Scale | Sensitivity (mV/g) | Noise (µg/√Hz) | BW 5% Typ (Hz) | BW 3dB Typ (Hz) | Max Shock (g pk) | JLCC Model | LCC Model |
|---|---|---|---|---|---|---|---|
| ±2g | 2000 | 7 | 0–250 | 0–525 | 2000 | 1521J-002 | 1521L-002 |
| ±5g | 800 | 12 | 0–400 | 0–800 | 2000 | 1521J-005 | 1521L-005 |
| ±10g | 400 | 18 | 0–700 | 0–1100 | 2000 | 1521J-010 | 1521L-010 |
| ±25g | 160 | 25 | 0–1300 | 0–1750 | 5000 | 1521J-025 | 1521L-025 |
| ±50g | 80 | 50 | 0–1600 | 0–2100 | 5000 | 1521J-050 | 1521L-050 |
| ±100g | 40 | 100 | 0–1700 | 0–3000 | 5000 | 1521J-100 | 1521L-100 |
| ±200g | 20 | 200 | 0–1900 | 0–3600 | 5000 | 1521J-200 | 1521L-200 |
| ±400g | 10 | 400 | 0–2000 | 0–4200 | 5000 | 1521J-400 | 1521L-400 |
| Parameter | Min | Typ | Max | Units | Notes |
|---|---|---|---|---|---|
| Bias Calibration Error | — | 16 | 40 | ±mV | |
| Bias Calibration Error (Span) | — | 0.2 | 0.5 | ±% span | |
| Bias Temperature Shift (−55 to +125°C) | −200 | 0 | +200 | PPM/°C | ¹ |
| Scale Factor Calibration Error | — | 0.5 | 1 | ±% | ² |
| Scale Factor Temperature Shift (−55 to +125°C) | −200 | 0 | +200 | PPM/°C | ¹ |
| Non-Linearity (−90 to +90% FS) | — | 0.15 | 0.5 | ±% span | ¹² |
| Long Term Bias Stability | — | 1000 | 2000 | ±PPM span | |
| Long Term Scale Factor Stability | — | 500 | 1000 | ±PPM | |
| Cross Axis Sensitivity | — | 2 | 3 | ±% | ² |
| Input Axis Misalignment | — | 5 | 10 | ±mrad | |
| Turn-On Transient | — | 75 | — | ±PPM FS | <0.5ms |
| Output Impedance | — | 90 | — | Ω | |
| Operating Voltage | 4.75 | 5.0 | 5.25 | V | ³ |
| Operating Current (IDD+IVR) | — | 5.5 | 6.5 | mA | |
| Power Dissipation | — | 35 | — | mW | |
| Mass (L package; J adds 0.06g) | — | 0.62 | — | grams | |
| Case Operating Temperature | −55 | — | +125 | °C | |
| Max Reflow Solder Temperature | — | — | +239 | °C |
² For 2g–50g only; 100g+ versions tested from −65 to +65g.
³ Pins other than DV/GND/VDD may exceed ±0.5V above supply if limited to 1mA. DV (self-test) ±15V max.
| Parameter | Limit |
|---|---|
| Voltage on VDD to GND | −0.5 to +6.0V |
| Voltage on any Pin (except DV) to GND | −0.5 to VDD+0.5V |
| Voltage on DV to GND (Self-Test) | ±15V |
| Storage Temperature | −55 to +125°C |
| Max Reflow Solder Temp | +239°C |
CMOS device susceptible to ESD damage. Diode protection provided but observe standard ESD precautions. Ground personnel and tools before contact. Do not insert/remove from powered sockets. Do NOT use ultrasonic cleaners — may break internal wire bonds (voids warranty).
Differential (AOP−AON) varies linearly from −4V to +4V across the full ±FS range.
At zero acceleration AOP = AON = +2.5V, giving 0V differential.
Single-ended (AOP) spans 0.5V to 4.5V centered at 2.5V — half the sensitivity of differential mode.
AOP = 2.5 + k·a(g)
AON = 2.5 − k·a(g)
AOP−AON = 2k·a(g)
DV Self-Test:
Δ(AOP−AON) ≈ k(VDV − ½VDD)²
Reference: Pin 17 (2.5V) via 5kΩ ÷ 5kΩ resistor divider + 0.01µF
Bypass: 0.1µF on VR (pin 3/9)
DV (pin 4): Leave open or tie to ½VDD for normal operation
GND: Pins 2, 5, 6, 18, 19
Outputs: AOP (pin 12), AON (pin 16), IT (pin 8)
The sensitive axis is perpendicular to the package bottom. Positive acceleration results from a positive force pushing on the bottom of the package. Device experiences +1g with lid facing up in Earth's gravitational field.
The seismic center is located on a centerline through the dual sense elements. Internal electronics cancel rotation errors. Scale factor is ratiometric to VR — voltages can be measured ratio-metrically for good repeatability without a separate precision reference.
Single-Ended Mode: AOP only, 0.5V to 4.5V, half sensitivity
| Dim | Min (in) | Max (in) | Min (mm) | Max (mm) |
|---|---|---|---|---|
| A | 0.342 | 0.358 | 8.69 | 9.09 |
| B | 0.346 | 0.378 | 8.79 | 9.60 |
| C | 0.055 TYP | 1.40 TYP | ||
| D | 0.095 | 0.115 | 2.41 | 2.92 |
| E | 0.085 TYP | 2.16 TYP | ||
| F | 0.050 BSC | 1.27 BSC | ||
| G | 0.025 TYP | 0.64 TYP | ||
| H | 0.050 TYP | 1.27 TYP | ||
| *M | 0.066 TYP | 1.68 TYP | ||
| N | 0.050 | 0.070 | 1.27 | 1.78 |
| *T | 0.085 TYP | 2.16 TYP | ||
| *U | 0.175 TYP | 4.45 TYP | ||
Pre-Tinning: Recommended to prevent gold migration embrittlement
LCC Plating: 60–225 µin Au over 80–350 µin Ni over refractory
J-Lead Plating: 100–225 µin Au (99.7%) over 80–350 µin electroplated Ni
RoHS: Compliant — no elemental lead
Ultrasonic cleaning may break internal wire bonds and voids the warranty.
Recommended Solder Pad (inches):
A=0.230, B=0.430, C=0.100, D=0.033, E=0.050, F=0.013, G=0.120
| Application | Recommended Range | Key Reason |
|---|---|---|
| Seismic / Tilt | ±2g | Lowest noise (7µg/√Hz) |
| Inclination / Platform Level | ±2g to ±5g | DC response, high sensitivity |
| Structural / Vibration | ±5g to ±25g | Balanced BW & sensitivity |
| Machine Health / Robotics | ±10g to ±50g | Wide BW, industrial range |
| Automotive Crash / Safety | ±50g to ±200g | High g survivability |
| Impact / Shock Recording | ±200g to ±400g | Max shock range (5000g) |
| Pyrotechnic / Ballistic | ±400g | Highest dynamic range |
Use AOP−AON differentially for maximum CMRR, lowest noise, and best accuracy. Single-ended is acceptable for low-cost ADC interfaces.
Temperature Compensation:
Use IT (pin 8) current output with a known resistor to measure internal die temperature, then correct for bias and scale factor drift vs. characterized temperature coefficients.
Ratiometric ADC Interface:
Connect VR (pin 3) to ADC VREF for inherently ratiometric reading — supply variations cancel.
Seismic / Low-Frequency:
Model 1521 responds to DC (0 Hz). Excellent for tilt sensing where output at rest = 1g (gravity component on sensitive axis).
| Range | Sensitivity | Noise µg/√Hz |
BW 5% (Hz) | BW -3dB (Hz) | BW Min (Hz) |
Shock (g pk) | JLCC | LCC |
|---|---|---|---|---|---|---|---|---|
| ±2g | 2000 mV/g | 7 | 0–250 | 0–525 | 0–300 | 2000 | 1521J-002 | 1521L-002 |
| ±5g | 800 mV/g | 12 | 0–400 | 0–800 | 0–420 | 2000 | 1521J-005 | 1521L-005 |
| ±10g | 400 mV/g | 18 | 0–700 | 0–1100 | 0–660 | 2000 | 1521J-010 | 1521L-010 |
| ±25g | 160 mV/g | 25 | 0–1300 | 0–1750 | 0–1050 | 5000 | 1521J-025 | 1521L-025 |
| ±50g | 80 mV/g | 50 | 0–1600 | 0–2100 | 0–1400 | 5000 | 1521J-050 | 1521L-050 |
| ±100g | 40 mV/g | 100 | 0–1700 | 0–3000 | 0–1700 | 5000 | 1521J-100 | 1521L-100 |
| ±200g | 20 mV/g | 200 | 0–1900 | 0–3600 | 0–2100 | 5000 | 1521J-200 | 1521L-200 |
| ±400g | 10 mV/g | 400 | 0–2000 | 0–4200 | 0–2400 | 5000 | 1521J-400 | 1521L-400 |
Section 1 — What is this AID AI Datasheet™?
This AID AI Datasheet™ is a fully self-contained, interactive engineering tool created by Analog Intelligent Design Inc. (AID). It transforms the static Silicon Designs Model 1521 PDF datasheet into a live, interactive reference that delivers:
- Physics-anchored interpolation models derived from digitized manufacturer data
- Real-time calculators for output voltage, temperature sensing, noise/SNR, and DV self-test
- An interactive model selector that recommends the optimal 1521 variant for your application
- Accurate chart renderings from verified digitized data (4 G-ranges: ±2g, ±10g, ±100g, ±400g)
- A built-in offline Engineering Assistant (knowledge base, no API required)
Section 2 — Navigating the Tabs
- Overview — Part summary, key specs, and g-range model table
- Performance — Full spec table with all parameters and absolute max ratings
- Charts — Linearity, differential output, frequency response, and phase — select ±2g, ±10g, ±100g, or ±400g
- Calculators — Output voltage, temperature sensor, noise/SNR, and DV self-test calculators
- Pinout & Connections — Full 20-pin description, recommended circuit, operation principle
- Package — L-suffix (LCC) and J-suffix (JLCC) dimensions, soldering notes
- Applications — Application domains, model selection guide, tilt calculator
- Model Selector — Interactive selector: enter your g-range, bandwidth, and get the right model
- User Guide — This document
- AI Assistant — Ask engineering questions about the 1521
Section 3 — Using the Output Voltage Calculator
Select your model and enter the applied acceleration in g. The calculator computes AOP and AON voltages and the differential output, all based on the formula:
AON = 2.5 − (Sensitivity_mV_per_g × g_applied / 1000)
Differential = AOP − AON
All calculations are ratiometric — if you change VDD, the sensitivity scales accordingly. Never exceed ±FS acceleration to keep outputs within 0.5–4.5V (single-ended) or ±4V (differential).
Section 4 — Temperature Sensor Usage (Pin 8)
The IT pin (pin 8) outputs a temperature-proportional current. Use a resistor RT to ground to convert to voltage. Keep the pin 8 voltage between 0 and +3V for correct operation.
Sensitivity ≈ +3 mV/°C with RT = 2kΩ
For better dynamic range, add an op-amp stage (Figure 2 in the datasheet). With VOFF=−5V, RG=15kΩ, ROFF=7.32kΩ, you get ≈−29 mV/°C over the full −55 to +125°C range.
Section 5 — DV Self-Test Input
The DV pin (pin 4) applies an electrostatic force to the sense element, simulating positive acceleration. For normal operation, leave DV open or tie to ½VDD (+2.5V). The output shift follows:
Section 6 — Chart Data Provenance
All chart data in this AID AI Datasheet™ was extracted from the Silicon Designs Model 1521 datasheet (29-July-2020) using calibrated digitization at high resolution. The four G-ranges represented (±2g, ±10g, ±100g, ±400g) are the ranges with digitized data in the verified source dataset. Charts for ±5g, ±25g, ±50g, and ±200g use specified datasheet curves but were not independently digitized in this version.
Section 7 — Important Application Warnings
- Minimize exposure above 125°C for maximum lifespan
- Avoid ultrasonic cleaning — voids warranty and may break wire bonds
- ESD-sensitive CMOS device — use standard ESD precautions
- Do not insert or remove from powered socket
- Pre-tin leads to prevent gold migration embrittlement in solder joints
- Optional calibration test report (1521-TST) available for each unit
- Frequency response tested via DV pin — actual mounted performance is higher
Ask any engineering question about the Silicon Designs Model 1521. Built-in knowledge base — no internet required.