Digital pot for calibration and trim
The MAX5161LEZT+T is a single-channel digital potentiometer from Maxim Integrated, configured as a rheostat with 50kΩ end-to-end resistance and 32 equally spaced taps. The linear taper means each step changes resistance by roughly 1.56 kΩ — predictable for voltage-divider or adjustable-reference loops where the transfer function stays linear across the sweep. The 400 Ω wiper resistance (typical) adds a small offset at the low end — budget that into the minimum-resistance calculation if the design uses the bottom end of the range.
Interface and control logic
The digital interface uses three lines — U/D, INC, and CS — to increment or decrement the wiper position. This up/down protocol is common on Maxim digital pots and frees up pins compared to an I²C or SPI bus. The wiper setting is volatile; it defaults to midscale (tap 16) at power-up and resets on loss of supply.
Housed in a 6-pin TSOT-23-6 (thin SOT-23), the part occupies minimal board area — roughly 2.9 mm × 2.8 mm. The thin profile suits height-constrained assemblies like PCIe cards or compact sensor modules. The ±25% tolerance on the end-to-end resistance means two production lots could land at 37.5 kΩ or 62.5 kΩ — the wiper step scales proportionally, so the ratio accuracy between taps is tighter than the absolute value.