A Four-Channel Clocked-Analog Time-Division Multiplexed LDO with Shared Compensation Capacitor for Thermal-Optic Phase Tuning

This paper presents a four-channel clocked-analog time-division multiplexed (TDM) low-dropout regulator (LDO) that shares the controller between different channels. The controller includes an error amplifier with a shared compensation capacitor and a lightweight local generated supply that can support a wide supply range. Implemented in 130 nm CMOS process, the four-channel clocked-analog TDM LDO can simultaneously track four 50 kHz 1V
_pp
sinusoidal signals at 25 Ω loads and 5 MHz clock frequency with negligible crosstalk. The total chip area is only 0.056 mm
²
, which is 67.5% smaller than the conventional solution with four identical LDOs. This chip area reduction effect makes the TDM LDO a very promising choice in applications that require a large number of tunable supplies with small output power, e.g., thermal-optic phase shifters in silicon photonics.