Feedback Resistor Divider Standard-value feedback resistors for adjustable regulators and DC/DC converters: Vout = VFB·(1 + R1/R2), the best E12/E24/E96 pairs, the output-voltage error, the FB bias-current effect and the worst case with resistor tolerance.
Related power supply tools All calculators Signal integrity Impedance Calculator – Single-ended and differential microstrip, coated and embedded microstrip, stripline and coplanar lines, solved with a 2D field solver.Propagation Delay, εeff & Timing – Propagation delay, length matching from skew, rise time to bandwidth, critical length and wavelength.Trace Loss (Insertion Loss) Calculator – Insertion loss in dB/in and over the full length: conductor loss with copper roughness and dielectric loss from the field solver, with laminate Dk/Df across frequency.Crosstalk Calculator – Near- and far-end crosstalk between parallel traces from the field solver, with a sweep over the spacing (3W rule check).Differential Via – Via-pair differential impedance through the plane clearance from a 2D field solution, antipad sizing for a target, stub resonance and delay.Via Stitching & Via Fence Spacing – Stitching and fence via pitch from the wavelength (λ/10, λ/20), via-grid cell resonance, leakage between vias and plane-pair cavity resonances.Stackup Stackup Advisor – Enter board thickness, layer count and impedance requirements; the field solver ranks every matching fab stackup and gives the trace widths.Layer Stack Manager – 178 fab stackups from 2 to 12 layers, editable, with any signal layer sent to the impedance calculator.PCB Laminate Materials (Dk / Df) – Datasheet Dk and Df of FR-4, low-loss and RF laminates (Isola, Panasonic, Rogers, Shengyi…) at any frequency, plus solder masks and copper foil roughness.Thermal Junction Temperature – Junction temperature from power and the thermal-resistance chain (θJA or θJC + θCS + θSA), and the maximum power for a Tj limit.Thermal Via Array – Thermal resistance of a via array under a hot pad, with plugged or filled vias, and the temperature drop through the board.Copper Area for Heat Spreading – How much copper a hot part needs: copper-pour thermal resistance by convection and radiation, junction temperature and the smallest pour for a Tj limit.Power & conductors Trace Width, Current & Temperature Rise – IPC-2221: width for a current, current for a width, or temperature rise of a trace, with resistance, voltage drop and loss.Via Calculator – Via current capacity, resistance, thermal resistance, capacitance, inductance and rise-time impact.Skin Effect & AC Resistance – Skin depth in copper and the AC resistance of a trace across frequency.Fusing Current – Current that melts a trace in a given time (Onderdonk), for fault and surge analysis.Wire Gauge & Voltage Drop – AWG diameter, area and resistance, cable voltage drop and loss, the smallest gauge for a drop limit, and Preece fusing current.Conductor Spacing (IPC-2221) – Minimum electrical clearance between conductors from IPC-2221 Table 6-1: internal, external, coated, high altitude, assemblies.Creepage & Clearance (IEC 60664-1) – Minimum clearance and creepage per IEC 60664-1: impulse voltage from mains and overvoltage category, pollution degree, CTI material group, reinforced insulation, altitude.Power integrity PDN Impedance Calculator – Target impedance, plane-pair capacitance, decoupling-capacitor resonance and the number of capacitors needed, with a log-log |Z|(f) plot.Power supply Buck Converter Calculator – Step-down converter power stage: duty cycle, inductor and ripple current, peak switch current, input and output capacitors (TI SLVA477B).Boost Converter Calculator – Step-up converter power stage: duty cycle, inductor, peak switch current, maximum output current of the IC and output capacitor (TI SLVA372D).LDO Regulator Power Dissipation – Linear regulator dissipation, junction temperature, efficiency and dropout headroom, with the maximum load for a Tj limit.Feedback Resistor Divider – Standard-value R1/R2 for adjustable regulators: the best E12/E24/E96 pairs, output error, FB bias current and worst case with tolerance.Components Planar Spiral Inductor – Inductance of square, hexagonal, octagonal and circular PCB spirals (modified Wheeler and current-sheet models), with DC resistance and Q.Through-Hole Padstack Calculator – Plated through-hole sizing per IPC-7251 / IPC-2221 / IPC-2222: hole, outer and inner pads, antipad, thermal relief and annular ring for levels A/B/C.BGA Land Pattern – IPC-7351 land diameter for collapsing and non-collapsing BGA balls, with tolerance and courtyard, and escape-routing capacity between lands.Electronics Ohm's Law & Power – Enter any two of voltage, current, resistance and power to get the other two.Reactance & LC Resonance – XL and XC at a frequency, LC resonance, the L or C for a target frequency, and series/parallel LC impedance with Q.Crystal Load Capacitors & PPM – Crystal load capacitors with the nearest E12/E24 values and resulting CL, plus frequency error ↔ ppm and clock drift.Resistor Tools – Voltage divider with best E12/E24/E96 pairs, LED series resistor with power rating, and series/parallel R, C and L.Attenuator Pads – Matched Pi, T and bridged-T pads with the nearest standard values, their actual loss and return loss, and resistor power.Utilities Unit Converter – Length, copper weight, temperature, power (dBm/W/V) and frequency/wavelength.Reference Charts – Drill sizes (number, letter, fractional, metric), ISO metric and Unified threads with tap and clearance drills, and the AWG wire table.