Family index of LDO types: ultra-low-noise, wideband high-PSRR, ultralow-IQ, high-current/low-VDO, wide-VIN, tracking/programmable, negative and dual-rail variants; plus DDR/AFE/RF/display/battery use cases and design hooks.
Core LDO Families
General-Purpose LDO
PMOS/NPN topologies; tens–hundreds of mA, solid line/load regulation with OTP/OCP.
Ultra-Low-Noise LDO (RF/Audio)
µV-level noise, wideband/high-freq PSRR and NR pins; post-reg for PLL/VCO/ADC/audio refs.
Wideband High-PSRR LDO
Maintains high PSRR into 10 kHz–10 MHz; cleans DC-DC ripple for imaging/sensors/RF analog rails.
Ultralow-IQ / Nanopower LDO
nA–µA quiescent current; trade keep-alive vs. wake-up speed for battery/harvesting nodes.
High-Current, Low-VDO LDO
1–5 A with very low VDO and fast transients; assist rails for CPU/GPU/FPGA or DDR VTT.
Wide-VIN / High-Voltage LDO
40–100 V rating, surge tolerance and linear SOA; industrial/automotive 24/48 V post-reg.
Tracking / Reference-Follow LDO
Soft-start and sequencing with output tracking an upstream reference or rail ratio.
Programmable LDO (I²C/PMBus)
Adjustable VOUT/ILIM/soft-start with telemetry, alarms and event logging.
Inverting / Negative LDO
Generates −0.5…−15 V with low noise and stability tuning for op-amp/ADC/sensor bias.
Dual-Rail / Dual-Output LDO
Shared ref or independent loops with crosstalk isolation for analog/digital split rails.
Automotive / Industrial / Space
Automotive LDO (Cranking/Load Dump)
Wide temp/voltage with cold-crank sustain, reverse-polarity/current protection and ASIL pins.
Industrial / Intrinsic-Safety LDO
Energy limiting, input OV/transient suppression and isolation-friendly hooks.
Rad-Tolerant / Space LDO
TID/SEE hardening with latch-up/SEU protection and wide-temp packaging.
Operating Modes & Combos
LDO with Bypass / Standby Pass
Low-loss pass-through and brownout protection; fast toggling between standby/peak modes.
LDO + Load Switch Combo
Integrated on/off with active discharge, inrush-limited soft-start and downstream rail control.
Post-Reg after DC-DC
Series with buck to suppress ripple/harmonics; balance power loss vs. VDO/efficiency.
Targeted Use Cases
DDR VTT / Vref LDO
Bidirectional current capability with tight accuracy/tempco and rapid transients.
LDO for AFE / Precision References
Ultra-low noise/PSRR, very low tempco and minimal load-step disturbance.
RF Front-End / PA Bias LDO
High-frequency PSRR with phase-noise-friendly design and fast linearity recovery.
Camera / Display Bias LDO
AVDD/OVDD/ISP/VCM rails with sequencing, soft-start and over-voltage clamps.
LED Bias LDO
Reference/bias front-end for constant-current drivers; low-noise with thermal derating.
Portable / Battery LDO
Wide VIN for battery-direct rails, UVLO and ultra-low off leakage.
Design Hooks, Protection & Diagnostics
Stability & Output Capacitors
Minimum COUT and ESR windows; ceramic-stable options and feed-forward caps.
Start-Up & Pre-Bias
Define soft-start slope, avoid sinking pre-bias; sequencing with PG/RESET.
Transient & Line/Load Regulation
Target ΔV and recovery time; optimize CFF/compensation and verify Bode points.
Protection Set
ILIM/foldback, short-circuit, OTP, active discharge and reverse-current/-battery guards.
EMI & Layout
Shortest IN/OUT loops, star grounding, shield sensitive nodes; TVS/π filtering up front.
Supervision & Telemetry
UV/window comparators, temperature sensors, fault IRQs and optional I²C/PMBus.
Thermal Path & Package
D²PAK/QFN big pads; estimate RθJA and leave power/ TJ margin.
Cascading / Paralleling
Series LDOs to cut noise; avoid loop sharing when paralleling—use OR-ing/load-share schemes.
