1 Features

1• Two-phase, Synchronous Series Capacitor Buck

Converter

• Automatic Current Balancing Between Phases

• 2-MHz to 5-MHz Per Phase Switching Frequency

• 14-ns Minimum On-Time

• 0.51-V to 2-V Output Voltage Range with ±0.5%

Feedback Reference Voltage

• Input Overvoltage Lockout for 17-V Surge

Protection

• Adjustable Current Limit with Auto Restart

(Hiccup)

• Synchronizes to an External Clock

• Fixed Frequency in Steady State

• Adaptive On-Time Control

• Internal Feedback Loop Compensation

• Internal Gate Drive LDO with External Supply

Option

• EN Pin Allowing for Adjustable Input UVLO

• Selectable Soft-Start Time

• Monotonic Startup with Pre-biased Output

• Output Power Good Indicator (Open Drain)

• Output Overvoltage/Undervoltage Protection

2 Applications

• Telecom, base station, and communications

equipment

• Storage, SSD, DDR memory, switches, hubs,

routers, and other networking equipment

• Low profile/Backside board mounting (< 2 mm

height)

3 Description

The TPS54A20 is a two-phase, synchronous series

capacitor buck converter designed for small size, low

voltage applications from a 12-V input rail. This

topology uniquely merges a switched capacitor circuit

with a two phase buck converter. Advantages include

automatic current balancing between the inductors,

lower switching losses which enable high frequency

(HF) operation, and voltage step-down through the

series capacitor. Small, low profile inductors used

with the TPS54A20 significantly reduce total solution

area and height. An adaptive on-time control

architecture provides fast transient response and

accurate voltage regulation at up to 10-MHz operating

frequency. Fixed frequency operation during steady

state is maintained through the use of a phase lock

loop (PLL) to lock switching signals to a reference

oscillator.