1FEATURES

2• Operating Input Voltage 2.25 V to 5.5 V

• Output Voltage as Low as 0.7 V

• 1% Internal 0.7-V Reference

• Predictive Gate Drive™ N-Channel MOSFET

Drivers for Higher Efficiency

• Externally Adjustable Soft-Start and Short

Circuit Current Limit

• Programmable Fixed-Frequency 100-kHz to

1-MHz Voltage-Mode Control

• Source or Sink Current

• Quick Response Output Transient

Comparators With Power Good Indication

Provide Output Status

• 16-Pin PowerPAD™ Package

APPLICATIONS

• Networking Equipment

• Telecom Equipment

• Base Stations

• Servers

• DSP Power

SUPPORTS DEFENSE, AEROSPACE,

AND MEDICAL APPLICATIONS

• Controlled Baseline

• One Assembly and Test Site

• One Fabrication Site

• Available in Military (–55°C to 125°C)

Temperature Range (1)

• Extended Product Life Cycle

• Extended Product-Change Notification

• Product Traceability

(1) Custom temperature ranges available

DESCRIPTION

The TPS40021 is a dc-to-dc controller designed for non-isolated synchronous buck regulators, providing

enhanced operation and design flexability through user programmability.

The device utilizes a proprietary Predictive Gate Drive technology to minimize the diode conduction losses

associated with the high-side and synchronous rectifier N-channel MOSFET transistions. The integrated charge

pump with boost circuit provides a regulated 5-V gate drive for both the high side and synchronous rectifier

N-channel MOSFETs. The use of the Predictive Gate Drive technology and charge pump/boost circuits combine

to provide a highly efficient, smaller and less expensive converter.

Design flexibility is provided through user programmability of such functions as: operating frequency, short circuit

current detection thresholds, soft-start ramp time, and external synchronization frequency. The operating

frequency is programmable using a single resistor over a frequency range of 100 kHz to 1 MHz. Higher operating

frequencies yield smaller component values for a given converter power level as well as faster loop closure.

The short circuit current detection is programmable through a single resistor, allowing the short circuit current

limit detection threshold to be easily tailored to accommodate different size (RDS(on)) MOSFETs. The short circuit

current function provides pulse-by-pulse current limiting during soft-start and short term transient conditions as

well as a fault counter to handle longer duration short circuit current conditions. If a fault is detected the controller

shuts down for a period of time determined by six consecutive soft-start cycles. The controller automatically

retries the output every seventh soft-start cycle.

In addition to determining the off time during a fault condition, the soft-start ramp provides a closed loop

controlled ramp of the converter output during startup. Programmability allows the ramp rate to be adjusted for a

wide variety of output L-C component values.