4.096V fixed reference in a breadboard-friendly TO-92
The MCP1541-I/TO is a series voltage reference from Microchip Technology that outputs a fixed 4.096 V with ±1% initial accuracy. That 4.096 V is a deliberate number — it maps cleanly to a 12-bit ADC's LSB at 1 mV per count, making it a natural bias for microcontrollers sampling analog sensors. Housed in a TO-92-3 through-hole package, it fits standard breadboards and perfboards without needing a breakout. The three leads — input, output, ground — are spaced at 0.1-inch pitch, so you can drop it into a solderless breadboard for a weekend prototype or solder it onto a stripboard for a permanent build.
For a 10-bit ADC with a 4.096 V reference, the LSB is 4 mV — the noise floor sits well below one LSB, so the reference itself won't limit resolution. A 12-bit ADC (1 mV LSB) sees about 0.7 LSB of noise from the reference, which is acceptable for most sensor readouts. Temperature drift is 50 ppm/°C typical. If your design spans a wide temperature swing, budget that drift into the system accuracy, or consider a lower-drift reference for sub-mV precision.
Supply current and output drive — battery-friendly
The reference draws 120 µA quiescent supply current and can source up to 2 mA to the load. That 120 µA is low enough to leave on continuously in a battery-powered sensor node — it adds about 1 mAh per year of standby drain. The 2 mA output can bias an op-amp front-end or a microcontroller's reference input without an external buffer. Below 4.3 V the output drops out of regulation — don't feed it from a 3.3 V bus or a dying lithium cell below 3.6 V.