ADI Linear Regulator LT3073 - Pairing Combination of LDO with VIOC Function and Switching Regulator

Semiconductor Integrated Circuits (ICs)
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Based on the compatibility requirements of the VIOC system (such as FB voltage, power matching, and topology adaptation), this article presents verified pairing combinations of LDOs and switching regulators. The pairing follows two core principles:

  1. Avoid Compatibility Risks: Directly exclude combinations where “the LDO is incompatible with the switching regulator” (e.g., LDOs with VIOC function paired with SS3 switching regulators, or switching regulators with FB voltage > 1V) to reduce trial-and-error costs;
  2. Match Performance Requirements: Ensure the output current of the LDO matches the power supply capability of the switching regulator (e.g., a 3A LDO paired with a switching regulator with ≥3A output) to prevent system overload caused by insufficient upstream power supply.
LDO Model Key LDO Parameters Regulator 1 Regulator 2 Regulator 3 Core Pairing Basis
LT3041 20V input, 1A output, ultra-low noise, ultra-high PSRR, single-input power supply; requires pairing with switching regulators with FB voltage ≤ 1V LT8608 LTC3307A LTC3626 The FB voltages of the three switching regulators are all ≤ 1V (LT8608: 0.778V; LTC3307A: 0.5V; LTC3626: 0.6V), which meet the operating requirements of the VIOC pin of LT3041.
LT3045-1 20V input, 500mA output, ultra-low noise, ultra-high PSRR, single-input power supply; same compatibility requirements as LT3041 LT8608 LTC3307A LTC3626 Consistent with LT3041, it matches switching regulators with FB voltage ≤ 1V; in addition, the efficiency of the three switching regulators is compatible with the low-power requirements of LT3045-1.
LT3073 0.6V~5.5V input, 3A output, 45mV low dropout voltage, ultra-low noise; requires additional low-current BIAS power supply (e.g., 5.5V VBIAS) LT8609A LTC3309A LTC8640 All three switching regulators are high-current types (3A~5A output), which match the 3A high-output current requirement of LT3073; additionally, they do not adopt the SS3 topology (avoiding FB pin incompatibility).
LT3074 5.5V input, 3A output, ultra-low noise, high PSRR; with PMBus communication function; requires BIAS power supply LT8609A LTC3309A LTC8640 It has the same current requirement as LT3073; moreover, the three switching regulators support forced continuous mode, which is compatible with the stable power supply requirements of PMBus systems.
LT3078 5.5V input, 5A output, 55mV low dropout voltage, ultra-low noise; requires BIAS power supply; dedicated for high-current loads LTM4658 LTC3309A LT8642S LTM4658 (10A output) and LT8642S (10A output) match the 5A high current requirement; in addition, LTM4658 adopts μModule packaging, which simplifies PCB layout.

(Table source: ADI)

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