Are the ICM-45686 and the LSM6DSV the Same Footprint?

Yes, to within 0.02 mm in height - and no, in every way that matters to your firmware. Both are 14-pad land grid arrays on a 2.5 × 3.0 mm outline, both run from 1.71 to 3.6 V, and both cover the same temperature range.

What does not match is the part your firmware talks to. The ICM-45686 puts its identity register at 0x72 and returns 0xE9; it also has no bank-select register, reaching internal registers indirectly through a three-address path at 0x7C, 0x7D and 0x7E.

The LSM6DSV puts its identity register at 0x0F and returns a fixed 0x70. There is no indirect access path, because the part does not need one.

Two parts that occupy the same square of copper and have no register address in common. That is the whole reason this comparison exists.

Which Specifications Actually Differ?

Each part wins on a different axis, and neither wins overall. The table below puts the published figures side by side; the notes after it matter as much as the numbers.

The noise figures are the LSM6DSV's strongest card, and they are the reason someone would move. Lower noise density on both axes is the one advantage that shows up directly in a control loop.

Read those two bars as separate comparisons, because they are scaled separately. On buffering the ICM-45686 is nearly twice the size; on current it draws about two thirds as much. Both of those are the opposite direction from the noise result.

And the accelerometer range is a hard boundary rather than a preference. The ICM-45686 reaches ±32 g; the LSM6DSV stops at ±16 g. If your application needs the higher range, the comparison is over before the other rows are read.

Which One Should You Choose?

Start with the requirement that cannot be traded, then work down. Four questions decide it, and three of them are hard limits rather than preferences.

Question 4 is the one that gets skipped. Both parts are 14-pad devices on the same outline, which creates an expectation that changing them is a sourcing exercise. It is a firmware project, and the driver work is the cost - not the part.

What Changes in Firmware If You Switch?

Everything that touches the register map, which is most of a driver. The two parts do not share an identity register, an addressing model or an interface to the internal configuration.

The practical consequence is that a driver written for one will compile and fail on the other, and usually it fails late. An identity read that returns an unexpected value is the cheap failure; a configuration write that lands on a different register is the expensive one.

The habit that avoids it is the same one that applies to any IMU port: read the identity register and compare it rather than merely succeeding at the read.

When Should You Stay With the ICM-45686, and When Switch?

Stay when range, buffering or current is the constraint. Move when noise is. That is the honest summary of the table above.

Stay with the ICM-45686 when:

• The design needs acceleration range beyond ±16 g. It reaches ±32 g and the LSM6DSV does not.
• You are buffering a lot of samples between host reads. 8 KB against 4.5 KB is a large difference for a high-rate logger.
• Power budget is tight. 0.42 mA against 0.65 mA in the comparable high-performance mode.
• The driver already exists and works. There is no register overlap to reward a switch.
• You need the wider VDDIO options - this part supports 1.2, 1.8 and 3.0 V IO levels.

Switch to the LSM6DSV when:

• Gyroscope noise is the limiting factor in your loop. 2.8 against 3.8 mdps/√Hz is a real improvement and it is the part's clearest advantage.
• Accelerometer noise matters more than range. 60 against 70 µg/√Hz, with the trade that you lose the ±32 g setting.
• You want a dedicated EIS channel and an auxiliary SPI for OIS data alongside the main interface.
• The firmware is being rewritten anyway, so the register map cost is already paid.

Both parts carry a 20,000 g shock rating and the same 1.71 to 3.6 V supply range, so neither of those decides anything.

Why Buy IMUs from ICMASS?

Because on these two parts the datasheet is where the decision lives, and reading it properly is what we do before a quote goes out.

Both are 14-pad devices in the same 2.5 × 3.0 mm outline, which makes them look interchangeable on a sourcing sheet and anything but interchangeable in firmware. We keep DS-000577 Rev 1.0 and DS13476 Rev 5 together and read the specification tables, not the feature bullets.

Tell us the range you need, whether gyro or accelerometer noise is the binding constraint, and whether the driver is being written fresh. We'll confirm what we can supply and quote it - and if the other part is the right answer for your design, we'll say so.

Frequently Asked Questions About ICM-45686 vs LSM6DSV

Q1: Are the ICM-45686 and LSM6DSV pin-compatible?

A: They share a package size and pin count, but not a register map. Both are 14-pad parts on a 2.5 × 3.0 mm outline - 0.81 mm and 0.83 mm tall respectively. The firmware, however, shares no register addresses at all.

Q2: Which one has lower noise?

A: The LSM6DSV, on both axes. 2.8 mdps/√Hz against 3.8 for the gyroscope, and 60 µg/√Hz against 70 for the accelerometer.

Q3: Which one has the wider measurement range?

A: The ICM-45686 on the accelerometer. It reaches ±32 g where the LSM6DSV stops at ±16 g. Both reach ±4000 dps on the gyroscope.

Q4: Which one uses less power?

A: The ICM-45686 in the comparable high-performance mode - 0.42 mA against 0.65 mA. The LSM6DSV's advantage is noise, not current.

Q5: Can I move a driver from one to the other?

A: Not without a register port. The ICM-45686 identifies itself at register 0x72 returning 0xE9 and reaches internal registers indirectly through 0x7C, 0x7D and 0x7E. The LSM6DSV identifies at 0x0F returning 0x70 and has no indirect path.

Q6: How much FIFO does each part have?

A: 8 KB on the ICM-45686 and 4.5 KB on the LSM6DSV. For a high-rate logger reading the buffer between host cycles, that gap is usually the deciding number.

Q7: Do both parts have the same shock rating?

A: Yes - 20,000 g on both. The LSM6DSV specifies it as acceleration for 0.2 ms. This row does not separate them.

Q8: What supply voltages do they need?

A: The same main rail, different IO options. Both run from 1.71 to 3.6 V. The ICM-45686 supports 1.2, 1.8 and 3.0 V IO; the LSM6DSV has an independent IO supply from 1.08 to 3.6 V.

Q9: Which is better for a flight controller?

A: It depends on which constraint binds. If the loop needs the lowest gyro noise, the LSM6DSV. If it needs ±32 g, deeper buffering or lower current, the ICM-45686. Real designs have swapped in both directions.

Q10: Do the interface options differ?

A: Both offer SPI, I²C and I3C. The ICM-45686 specifies I3C at 12.9 MHz, I²C at 1 MHz and SPI at 24 MHz. The LSM6DSV supports MIPI I3C v1.1 alongside SPI and I²C.

Q11: What is the auxiliary channel for?

A: Offloading image stabilisation and secondary sensor traffic. The ICM-45686 offers an SPI slave for OIS or an I²C master. The LSM6DSV offers an auxiliary SPI for OIS output plus a dedicated EIS channel on the primary interface.

Q12: Should I expect a drop-in swap between these two?

A: No, despite the matching footprint. They occupy the same board area and have nothing in common in the register map. Treat the change as a firmware project that happens to reuse the land pattern.

Q13: Which documents do these numbers come from?

A: The ICM-45686 datasheet DS-000577 Rev 1.0 and the ST LSM6DSV datasheet DS13476 Rev 5. Every figure in the comparison table was read from those two specification tables.