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.