TPS65250_1 Datasheet, PDF (1/38 Pages) Texas Instruments – 4.5-V TO 18-V INPUT, HIGH CURRENT, SYNCHRONOUS STEP DOWN THREE BUCK CONVERTER WITH INTEGRATED FET AND DYING GASP STORAGE AND RELEASE CIRCUIT

TPS65250
www.ti.com
SLVSAA3 – JUNE 2010
4.5-V TO 18-V INPUT, HIGH CURRENT, SYNCHRONOUS STEP DOWN THREE BUCK
CONVERTER WITH INTEGRATED FET AND DYING GASP STORAGE AND RELEASE
CIRCUIT
Check for Samples: TPS65250
FEATURES
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• Wide Input Supply Voltage Range
(4.5 V - 18 V)
• 0.8 V, 1% Accuracy Reference
• Continuous Loading: 3 A (Buck 1),
2 A (Buck 2 and 3)
• Maximum Current: 3.5 A (Buck 1),
2.5 A (Buck 2 and 3)
• Adjustable Switching Frequency
300 kHz - 2.2 MHz Set By External Resistor
• External Synchronization Pin for Oscillator
• External Enable/Sequencing and Soft Start
Pins
• Adjustable Current Limit Set By External
Resistor
• Soft Start Pins
• Current-Mode Control With Simple
Compensation Circuit
• Power Good and Reset Generator
• Storage and Release Circuit Optimized for
Reduction of Storage Capacitance in Dying
Gasp Mode (Option)
• Low Power Mode Set By External Signal
• QFN Package, 40-Pin 6 mm x 6 mm RHA
APPLICATIONS
• xDSL/xPON Modems
• Cable Modems
• Power Line Modem
• Home Gateway and Access Point Networks
• Wireless Routers
• Set Top Box
DESCRIPTION/ORDERING INFORMATION
The TPS65250 features three synchronous wide input range high efficiency buck converters. The converters are
designed to simplify its application while giving the designer the option to optimize their usage according to the
target application.
The converters can operate in 5-, 9-, 12-, 15- and 18-V systems and have integrated power transistors. The
output voltage can be set externally using a resistor divider to any value between 0.8 V and the input supply
minus 1 V. Each converter features enable pin that allows a delayed start-up for sequencing purposes, soft start
pin that allows adjustable soft-start time by choosing the soft-start capacitor, and a current limit (RLIMx) pin that
enables designer to adjust current limit by selecting an external resistor and optimize the choice of inductor. The
COMP pin allows optimizing transient versus dc accuracy response with a simple RC compensation.
The switching frequency of the converters can either be set with an external resistor connected to ROSC pin or
can be synchronized to an external clock connected to SYNC pin if needed. The switching regulators are
designed to operate from 300 kHz to 2.2 MHz. Both Bucks 2 and 3 run in-phase and 180° out of phase with
Buck1 to minimize input filter requirements.
TPS65250 features a unique storage and release circuitry for dying gasp mode. The storage capacitor is
separated from input capacitor during normal operation. The storage and release circuit will charge the storage
capacitor with a controlled circuit to reduce the inrush current from the adaptor supply to a storage voltage of
20 V to accumulate as much energy as possible taking advantage of the ½ CV² feature.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010, Texas Instruments Incorporated