Smartphone Cooling Rounds Out Parade of Advanced MEMS
MEMS technology allows embedded computing designs to carry out physical tasks necessary to bridge the gap between the world of ones and zeros, and the universe where action is required. MEMS measure inertial energy and provide precise guidance and measurement in semiconductor-scale packaging. Here are the latest microphones, accelerometers, pressure sensors, and fans available for new system development.
Everyone loves a cool micromachine. They are a marvel of miniaturization, and it’s always fun to ponder what’s possible when the world of semiconductor design and manufacturing merges with the universe of tiny gyros, pressure sensors, and inertial measurement units. One could almost imagine minuscule mice running in very tiny wheels affixed to pulleys that do things that are very important in the world of embedded design.
This month’s datasheet explores some of the latest innovations from MEMS suppliers worldwide. Although advancements in this space may be less astounding than those in 2-D ICs, the feats they perform are no less amazing.
One of the coolest innovations to come across Circuit Cellar’s editorial attention is a microcooling MEMs device for mobile devices. Yep, it’s like a CPU fan but in an ultra-slim package, one that could fit into a smartphone. According to the manufacturer, the rise in AI applications in mobile computing devices creates the need for chips inside to require active cooling. When you are creating parody images of the least desirable political figures of the day, this tiny fan will make sure the chip doesn’t overheat and crap out before the final product is ready to post to a social media platform. Presumably.
The one caveat before readers jump ahead and focus solely on the µcooling machine is that the manufacturer does not provide a data sheet. Circuit Cellar must have a data sheet for a MEMS product to get featured in a regular column called “Datasheet”. Otherwise, how can an embedded designer discern whether the product was just hype or an actual product available to ship for production volumes?
But it is so cool and new that this Circuit Cellar editor decided to throw caution to the wind and include it here. Many embedded system designers are intelligent; therefore, they can use their judgment and experience when applying the sniff test to this so-called product.
But don’t let one slip stop you from reviewing the other ultra-fantastic MEMS profiled here. There are accelerometers, tire-pressure sensors, microphones, and inertial measurement units. Have you witnessed the latest advances in MEMS microphone technology? As it happens, some notable features make a seemingly mundane category jump out and beg for attention. There are two microphones profiled here in the pages that follow.
What still has yet to happen to advance MEMS technology are tiny internal combustion engines to retrofit that matchbox-sized replica of a 1969 Detroit-issued muscle car. Yes, this editor has kept a remnant of his childhood around for 50-plus years because it still inspires dreams of endless summer nights filled with drag-strip heroics and 12-second triumphs. But, as it turns out, the little plastic piece representing a real engine fell out decades ago. Since then, I’ve been waiting for MEMS manufacturers to warm up to create a replacement for this plastic piece. Let’s say a miniaturized replica of a 426-cubic-inch displacement V-8, double pumped. Imagine the possibilities. Still, there are no signs of that even being possible, especially in the data sheet department. This project must also coincide with a miniature drag parachute to be deployed after the checkered flag.
HIGH VIBES-LOW NOISE
For audio active noise cancellation, robotics, wearables, and low-power motion detection, Analog Devices provides the ADXL380, a low-noise, low-power, wide bandwidth 3-Axis MEMS Accelerometer supporting the ±4 g, ±8 g, and ±16 g ranges. Low noise and low power enable accurate measurements of audio signals or heart sounds even in high vibration environments.
- Ultralow noise density: 20 μg/√Hz (XY) and 27 μg/√Hz (Z)
- High performance: 340 μA
- Ultra-low power: 33 μA
- Wide bandwidth: 4 kHz
- Low latency: group delay
STYLISH AND WEARABLE
Bosch Sensortec offers the BMA530 for stylish and minimalistic wearables that offer little space for powerful components. The accelerometer provides an advanced feature set in combination with world’s smallest acceleration sensor – only 1.2 x 0.8 x 0.55 mm³. It is designed for compact devices such as wearables and toys requiring less sensor size, especially lower height. BMA530 includes integrated functionalities like step-counter and generic interrupts for easy use.
- Dimensions – 1.2 x 0.8 x 0.55 mm³
- Wafer level chip scale package
- 16-bit digital resolution
- ±2, ±4, ±8, ±16 g measurement ranges
- ~1.56 Hz … 6.4 kHz output data rate
- ±75 mg offset soldered
- ±0.75 mg/K TCO
- Sensitivity Error 1%
- 120 µg/√Hz noise density
- 125 µA current consumption
- 18 µA low power current consumption @ 100 Hz
- 4.75 µA current consumption suspend mode, data retention
- I³C, I²C and SPI interface
- 2 Interrupt Pins (I²C, I³C)
- 1 Interrupt Pin (3-wire SPI)
- High perf. mode,
- Low power mode (LPM)
- 1 KB FIFO
- Data-ready interrupt
- 3 generic interrupts
- Step Counter
- Android Features
DUST-WIND-DUDE
Infineon offers the IM73A135V01IP57 dust- and water-resistant analog XENSIV microphone for conference systems, cameras, camcorders, Voice User Interface (VUI) devices, smart speakers, home automation and IoT devices. Applications which require a microphone with high SNR (low self-noise), low distortion (high AOP), which is also IP57 qualified to withstand environmental conditions. Best-in-class Signal to Noise Ratio (SNR) of 73dB(A) enables far field and low volume audio pick-up.
- Component level IP57 water and dust resistant
- 73dB signal-to-noise ratio
- 135dBSPL acoustic overload point
- 20Hz flat frequency response with low frequency roll off
- Active Noise Cancellation
- Power optimized modes determined by VDD level
- Package dimensions: 4mm x 3mm x 1.2mm
- Omnidirectional pickup pattern
- Audio pattern detection
- Extremely low noise preamplifier
- 170 uA operating supply current
- 2.3 V to 3 V operating supply
- Temperature Range:- 40-to-85 C
- Length: 4 mm
- Width: 3 mm
- Depth: 1.2 mm
- Directional Properties: Omnidirectional
- Mounting Style: SMD/SMT
- Package: LGA-5
MELEXIS IS YOUR LEXIS
The Melexis MLX90830 MEMS pressure sensor handles gas and liquid measurement from 2 to 70 bar and is designed for electric vehicle thermal management systems. With a novel physical design called Triphibian technology, the factory-calibrated device measures the absolute pressure and delivers a proportional analog output signal. The MLX90830 strives to reduce module cost by simplifying system integration. EV thermal management applications include standalone sensors, and embedded sensors in expansion valves, e-compressors, and pumps.
- Triphibian technology
- +/-0.5% full scale lifetime accuracy
- Ratiometric analog output
- Minimum 0.4ms fast response time
- System in a package
- MEMS
- Analog front-end circuitry
- 16-bit microcontroller
- Voltage regulators
- Analog ratiometric back-end
- Automotive temperature range
- (-40°C to 150°C)
- Robust in gas and liquid media
- Qualified according to AEC-Q100 and
- AEC-Q103-002
- Configurable diagnostic features
- PTC04 programming tool
- Customized calibration curves
- Extended over (+40V) and reverse (-40V)
- ASIL compliant developed as an
- ASIL A SEooC as per ISO 26262
MAGNETIC PERSONALITY
For electronic compass and navigation, position sensing and general purpose magnetic field measurements, Memsic offers the MMC5983MA, an high performance automotive grade AMR Magnetometer. This part differentiates itself by offering dynamic range and accuracy: ±8G FSR, 18bits operation,0.4mG total RMS noise and a heading accuracy of 0.5º. With an operating temperature range from -40ºC to +105ºC, this part is AEC-Q100 qualified.
- Integrated 3-axis magnetic sensor and electronic circuits
- Minimize external components
- ± 8G FSR dynamic range and accuracy:
- 18-bit operation
- 0.4mG total RMS noise
- 0.5º heading accuracy
- 1000Hz max output data rate
- Size – 3.0mm x 3.0mm x 1.0mm
- Industrial standard low-profile package
- Degaussing with built-in SET/RESET function
- Eliminates thermal variation induced offset error
- On-chip sensitivity compensation
- On-chip temperature sensor
- Data-ready Interrupt
- Low power consumption
- 1µ A power down current
- I2C Slave,
- FAST(≤400KHz) mode
- 3.0V single low power supply
- SPI interface available
PRESSURE DROP
For integrated tire pressure monitoring sensors (TPMS), NXP offers the NTM88 family in a small 4 mm x 4 mm x 1.98 mm package. The device family provides low transmitting power consumption, large customer memory size, and single- or dual-axis accelerometer architecture. The NTM88Hxx5S TPMS solution integrates an 8-bit MCU, pressure sensor, accelerometers in four ranges, programmable RF transmitter and flexible LF receiver. The sensor supports a 2-channel timer/pulse-width module.
- Transducer measurement interfaces with low-power AFE
- 10-bit compensated pressure sense element
- 10-bit compensated accelerometers
- 8-bit compensated internal device temperature measurement 8-bit compensated internal device voltage measurement
- Two I/O pins for external signals
- 8-bit S08 compact instruction set controller:
- 64 bytes NVM parameter registers
- 512 bytes SRAM
- 16 kB flash memory (512 bytes reserved for NXP coefficients)
- NXP firmware libraries
- Programmable RF transmitter
- Characterized for baud rate examples of 9.6 kbp/s, 19.2 kbp/s, and 38.4 kbp/s
- Flexible 125 kHz LF receiver
- Client SPI to support host access
- AEC-Q100, Rev. H
ROCK AND ROLL IMU
ST Micro offers the ISM330BX system-in-package inertial measurement unit (IMU) with a 3-axis digital accelerometer and a 3-axis digital gyroscope provides optimal motion experience with triple channels for processing acceleration and angular rate data for motion tracking and vibration measurements. Qvar sensing offers three channels with configuration, processing, and filtering in a compact 2.5 x 3.0 x 0.71-mm package. Dedicated features and data processing for motion processing are designed for finite state machine (FSM), sensor fusion low power (SFLP), adaptive self-configuration (ASC), and machine learning core (MLC) filters for IoT applications.
- 0.6 mA motion tracking
- Always-on low-power features
- 6-axis IMU sensor
- 3-axis accelerometer with selectable full scale: ±2/±4/±8 g
- 3-axis gyroscope
- With extended selectable full scale: ±125/±250/±500/±1000/±2000/±4000 dps
- 3-axis accelerometer
- low noise 70 μg/√Hz over SPI/I²Cd/I3C interface
- SPI / I²C / MIPI I3C v1.1 serial interface
- TDM controller interface
- Embedded sensor fusion algorithm
- Programmable finite state machine
- Qvar sensor data processing @ 960 Hz
- Machine learning core
- AI application features and filters
- Analog supply voltage: 1.71 V to 3.6 V
- Size: 2.5 mm x 3 mm x 0.71 mm
MIC’D UP
TDK’s T5848 is a multi-mode, low noise digital MEMS microphone in a .5 × 2.65 × 0.98-mm surface-mount package for wearables, smart televisions, remote controls, IoT devices, teleconferencing, gaming controls and security systems. Unique to this design is an Acoustic Activity Detector (AAD) which processes the ambient environment and sends an interrupt signal to the host processor, allowing the processor to power down other energy-hungry parts of the system to preserve system level power. The T5848 consists of a MEMS microphone element and an impedance converter amplifier and an analog-to-digital converter.
- Digital I²S interface with high precision 20-bit data
- 3.5 × 2.65 × 0.98 mm surface-mount package
- 9 µA Sleep Mode
- 20uA AAD Analog Mode
- Sn/Pb and Pb-free solder
- Impedance converter amplifier
- I²S connects with DSPs and MCUs
- Low Power (AlwaysOn) mode
- Acoustic Activity Detect(AAD) Analog and Digital.
- High SNR in all modes.
- 133 dB SPL AOP in HighQuality mode
- 19 dB SPL AOP in Low Power Mode
- Temperature range: -40°C to +85°C
- Sensitivity range −37 dB FS ±1 dB −26 dB FS ±1 dB
- SNR range: 68 dBA to 64 dBA
- Current range: 310 µA to 120 µA
- Clock range: 2.0 MHz to 3.7 MHz 600 kHz to 800 kHz
FAN-ON-A-CHIP
What if you could take a bulky CPU fan from a 1997 PC and reduce it to the 1-mm thin MEMS package for smartphones, tablets and other mobile devices. That’s what xMEMs is trying to do with a solid-state XMC-2400 uCooling chip, but without the noise and vibration of those ancient relics.
AI has been implicated as the reason why these fans are needed now after decades of pervasive mobile device use which appeared to operate just fine without active cooling. xMEMS CEO and Co-Founder Joseph Jiang, explains in a press release:
“Thermal management in ultramobile devices, which are beginning to run even more processor-intensive AI applications, is a massive challenge for manufacturers and consumers. Until XMC-2400, there’s been no active-cooling solution because the devices are so small and thin.” Sampling is expected in Q1 CY 2025.
- Package size – 9.26 x 7.6 x 1.08-mm
- 2.67% or 1/39th of package volume compared to competitive part
- Weight – 150 milligrams
- 96% smaller and lighter than non-silicon alternatives
- 39 Cubic cm per second air movement
- 1,000Pa back pressure
- Semiconductor reliability
- IP58 rated
- Top and side-venting options
- MEMS and piezo thin film process
- Qualified to IEC & JEDEC standards
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • OCTOBER 2024 #411 – Get a PDF of the issue
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Tom Murphy has been plying his trade as a technology journalist for more than 25 years, first as an editor/writer/reporter and then as a communications professional. He has earned industry recognition for both journalistic endeavors and technology campaigns. Before joining Circuit Cellar magazine as editor-in-chief (2024), Tom wrote tech briefs, newsletters, blogs, press releases, white papers, and technical articles for numerous clients, primarily in the semiconductor industry. His introduction into the industry came as an editor for “Electronic News” covering microprocessor companies, the fabless semiconductor phenomena, communication chips, and many others. When he’s not tapping away at the keyboard, Tom learns Dungeons and Dragons terminology from his 10-year-old daughter and walks his bulldog (slowly) around the block.
