Schematic text block for hv_input_*_terminal_*_protected (TPS1HTC100-Q1). Paste the block between the rule lines into a KiCad schematic text item next to the placed design block, the same way the TMC5130 sense-resistor note travels with that block. Values derived from tps1htc100-q1.pdf (SLVSHZ1A, rev July 2025); K_SNS = 800 A/A, K_CL = 46-53 A*kOhm. KiCad's default stroke font is not monospaced, so the columns will look slightly ragged. Either accept that, set the text item to a monospace font, or rebuild the two tables as KiCad 10 schematic tables. -------------------------------------------------------------------------------- TPS1HTC100-Q1 SMART HIGH-SIDE SWITCH - PER-BOARD RESISTOR SELECTION R_ILIM sets the current limit. R_SNS sets the ADC sense scaling. They do independent jobs, but R_SNS has a ceiling that depends on I_CL - see below. PREREQUISITES, or neither resistor does anything: DIAG_EN must be driven HIGH. Left floating (internal pulldown) the analog sense, open-load and short-to-battery diagnostics are all disabled. ILIM must NEVER float. Floating selects the internal default limit AND is "considered a fault state for the device" (datasheet Table 4-2). --- R_ILIM (single resistor to GND) -> CURRENT LIMIT ------------------------- I_CL = K_CL / R_ILIM Transient peak allowance: I_CL_LINPK = 1.5 x I_CL R_ILIM I_CL min typ max source 49.9k / 50k 0.73 A 0.92 A 1.11 A datasheet 40k 0.9 A 1.2 A 1.4 A computed 25k 1.5 A 1.96 A 2.3 A datasheet 20k 1.9 A 2.5 A 2.9 A computed 16.7k 2.3 A 3.0 A 3.5 A datasheet 10k 4.0 A 5.3 A 6.3 A datasheet open or GND 6.1 A 7.3 A 8.6 A datasheet - do not use Adjustable range is 1 A to 5 A, or 7.3 A with ILIM at GND. Pick a limit that clears the board's worst-case load AND passes the inrush into the downstream bulk capacitance, since charging above ~10 uF is current-limited. --- R_SNS (single resistor to GND) -> SENSE SCALING ------------------------- V_SNS = (I_OUT / 800) * R_SNS TWO CEILINGS, BOTH MUST HOLD: 1. FAULT LEVEL - does NOT depend on I_CL. In fault the pin sources I_SNSFLT = 5.2-6.4 mA into R_SNS. R_SNS <= V_ADC_MAX / 6.4 mA 3.3 V ADC -> 515 ohm absolute; use <= 470 ohm for margin. Reducing R_SNS is the only fix. The alternative clamp level V_SNSFH is 3.3-4.4 V at DIAG_EN = 3.3 V and 4.5-5.8 V at DIAG_EN = 5 V, both of which exceed a 3.3 V ADC input. 2. CURRENT RANGE - scales with I_CL. R_SNS <= V_ADC_MAX * 800 / (1.5 * I_CL) 3.3 V ADC -> R_SNS <= 1760 / I_CL(A) ohm CONSEQUENCE: ceiling 1 binds up to I_CL = 3.4 A, so for any limit at or below that, R_SNS DOES NOT NEED TO CHANGE when R_ILIM changes. Above 3.4 A, scale R_SNS down per ceiling 2. I_CL R_SNS max, 3.3 V ADC which ceiling binds 1 A 515 ohm fault level 2 A 515 ohm fault level 3 A 515 ohm fault level 3.4 A 515 ohm crossover 5 A 350 ohm current range 7.3 A 240 ohm current range 249 ohm satisfies both ceilings across the part's entire adjustable range and is a safe single value for every board: 0.311 V/A, full scale 10.6 A, fault level 1.29-1.59 V. At I_CL = 7.3 A a 1.5x transient peak reads 3.41 V - the reading saturates, nothing is damaged. Larger R_SNS buys ADC amplitude, not accuracy. I_SNS accuracy is +-5 to 6% above ~0.5 A but +-25 to 30% below 60 mA regardless of R_SNS, so this is a coarse supply monitor by construction. For a 5 V ADC, ceiling 1 becomes 781 ohm and ceiling 2 becomes 2670/I_CL. --- ADC INPUT --------------------------------------------------------------- RP2040 absolute maximum on an ADC pin is VDD + 0.3 V = 3.6 V. Size both ceilings against 3.0-3.3 V, not 3.6 V. SNS also reports a fault by driving high, so the fault level - not the maximum current - is usually what sets R_SNS. -------------------------------------------------------------------------------- Worked example, mouse-joystick-pcb: one 0.67 A/phase stepper on a 36 V rail draws roughly 0.2-0.3 A while holding. R_ILIM = 40k gives I_CL ~1.2 A, about 4x headroom. That is below the 3.4 A crossover, so R_SNS is chosen purely by the fault ceiling: 249 ohm, the largest stocked value comfortably under 470 ohm. Stocked combinations at the time of writing, for the values not available as a single resistor: 25k = 2 x 49.9k in parallel (OW-PASS-RC0402FR-0749K9L) 20k = 2 x 40k in parallel (OW-PASS-SCR0603F40K) 249R = single (OW-PASS-CRCW0402249RFKED) Re-check stock rather than trusting this list; the two tables above do not depend on it.