Look up a use, then a part
Byuse is a small map of electronics applications. Open a use to see why it exists and a few starting MPNs. Live distributor results appear only if you set a key.
Sensing
Measure the world: motion, temperature, light, current.
Barometric altitude
Relative height for drones, weather stations, or indoor floors. You want a pressure sensor with a documented noise floor, not a generic “pressure” search.
BMP390 · LPS22HH
High-side current sense
Measure rail current without breaking the ground. A digital or analog current-sense amplifier plus a Kelvin sense resistor from the passives list.
INA219 · INA228
Humidity in a sealed box
Condensation and desiccant checks. A combined RH + temperature sensor on I2C, with a filter cap if the box is dirty or outdoors.
HDC2010 · SHT40-AD1B-R2
IMU for a drone
A 6-axis IMU for attitude and vibration-aware flight control. Look for a usable gyro range, SPI or I2C that your FC already speaks, and a package you can actually reflow on a small board.
BMI270 · ICM-42688-P · LSM6DSO
Temperature sensor for an enclosure
Watch the air or a wall inside a box so a fan, heater, or logger has a trustworthy number. Prefer a digital sensor with a defined accuracy and a package you can keep off a hot regulator.
MCP9808-E/MS · TMP102 · TMP117
Compute
MCUs, FPGAs, and on-board memory as you actually use them.
FPGA for glue logic
Replace a pile of level shifters, counters, and one-off timing with a small FPGA you can still afford. Not an SoC hunt — a handful of LUTs and I/O.
ICE40UP5K-SG48ITR · LCMXO2-1200HC-4TG144C
MCU for a battery device
Sleep current and wake sources matter more than MHz. Look for a stop/standby number you believe, enough flash for your stack, and a package you can hand-assemble.
MSP430FR2433 · nRF52840-QIAA · STM32L432KCU6
MCU for a USB gadget
A small board that enumerates without a second chip. Native USB device, enough endpoints for HID or CDC, and a bootloader story you will actually use.
ATMEGA32U4-AU · RP2040
SPI NOR flash for firmware
A place to put a second-stage image, assets, or a little filesystem. Standard SPI NOR with a footprint you have already laid out.
AT25SF081-SSHD-B · W25Q128JVSIQ
Power
Charge, regulate, switch, and gauge energy.
Buck regulator for a digital rail
3.3 V or 1.8 V from a battery or 5 V brick. You want a datasheet efficiency plot at your load, not a generic “switching regulator” browse.
AP63203WU-7 · TPS62130ARGTR
Li-ion charger
A single-cell USB or barrel charger with a termination you trust. Prefer a part with a published JEITA or timer story over a mystery module.
BQ24074RGTR · MCP73831T-2ACI/OT
Quiet LDO for an analog rail
After the buck, a low-noise LDO for the ADC, IMU, or microphone. PSRR and noise density matter; dropout at your current is the other number.
ADP151AUJZ-3.3-R7 · TPS7A4701RGWR
Single-cell fuel gauge
A remaining-capacity number that does not lie after the first week. Impedance-track or a ModelGauge part, not a voltage divider and hope.
BQ27441DRZR-G1A · MAX17048G+T10
Wireless
Radios and location: BLE, Wi-Fi, LoRa, GNSS.
BLE for a wearable
A radio + MCU you can ship with a coin cell or a tiny LiPo. SoftDevice or Zephyr already exists; pick the SoC that matches your antenna budget.
nRF52832-QFAA · nRF52840-QIAA
GNSS fix for a tracker
A position that converges outdoors without a science project. A module with a documented antenna and a backup-current number you can live with.
MAX-M10S-00B · SAM-M10Q-00B
LoRa for long range
A few kbps across a field or a building. Transceiver plus your own MCU, or a module if you do not want to certify the radio.
RFM95W-915S2 · SX1262IMLTRT
Wi-Fi for an IoT node
Join a home AP, speak MQTT or HTTP, and still have GPIOs left. Modules are often the right answer; these are the chips underneath.
ESP32-C6-WROOM-1-N8 · ESP32-S3-WROOM-1-N16R8
Actuation
Move or light something: motors, solenoids, LEDs.
Brushed DC motor driver
A small motor, two directions, maybe current limit. An H-bridge with a voltage and current you will not exceed, and a sleep pin.
DRV8833PWP · TB6612FNG
RGB LED matrix driver
A face, a badge, or a status wall. An I2C LED matrix driver so the MCU is not bit-banging sixty PWM channels.
IS31FL3731-QFLS2-TR · LP5009PWR
Silent stepper driver
A 3D-printer or camera slide axis that should not whine. UART or STEP/DIR, stealthChop or equivalent, and a sense-resistor story.
A4988SETTR-T · TMC2209-LA
Interface
Talk to a host or a human: USB-C, level shift, displays.
I2C / UART level shifter
1.8 V sensor, 3.3 V MCU. An auto-bidirectional translator, not a pile of MOSFET tricks you will forget to bias.
PCA9306DCTR · TXB0108PWR
Small OLED for a panel
A 0.96" or 1.3" status display. The controller is the part; the glass is whatever your mechanicals allow.
SSD1306Z · ST7789V
USB-C PD sink
Ask a charger for 9 V or 15 V without a full PD stack on your MCU. A controller that speaks PD and exposes a voltage you can then buck.
FUSB302BMPX · STUSB4500QTR
Passives as used
Not a catalog of every 0402 — the parts you reach for on purpose.
Current-sense resistor
The shunt in front of an INA. Kelvin pads if you care; a 4-terminal part if you care more. Value from the drop you can afford.
CRF2512-FZ-R010ELF · WSHP2818R0100FEA
Decoupling capacitor as used
The 100 nF you put on every VDD pin, plus a bulk cap at the regulator. This is a use, not a tour of every C0G value.
CL10B104KB8NNNC · GRM188R71C104KA01D
TVS for an I/O or USB line
Clamp a connector before the MCU dies. Low capacitance for USB/HDMI; a slightly slower part is fine on a button.
PESD5V0S1BA,115 · USBLC6-2SC6