TPS65257RHAR 4.5-V TO 16-V INPUT,HIGH CURRENT, SYNCHRONOUS STEP DOWN THREE DC-DC CONVERTER VQFN-40 spot stock

Product Descriptions

TPS65257 is a power management IC with three step-down buck converters. Both high-side and low-side MOSFETs are integrated to provide fully synchronous conversion with higher efficiency. 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- or 15-V systems. The output voltage can be set externally using a resistor divider to any value between 0.8 V and the input supply minus the resistive drops on the converter path. 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 (RLIM) pin that enables designer to adjust current limit by selecting an external resistor and optimize the choice of inductor. All converters operate in ‘hiccup mode’: Once an over-current lasting more than 10 ms is sensed in any of the converters, they will shut down for 10 ms and then the start-up sequencing will be tried again. If the overload has been removed, the converter will ramp up and operate normally. If this is not the case the converter will see another over-current event and shuts down again repeating the cycle (hiccup) until the failure is cleared. If an overload condition lasts for less than 10 ms, only the relevant converter affected will shut-down and re-start and no global hiccup mode will occur.

The switching frequency of the converters is set by an external resistor connected to ROSC pin. The switching regulators are designed to operate from 300 kHz to 2.2 MHz. The converters operate with 180° phase between then to minimize the input filter requirements.

All converters have peak current mode control which simplifies external frequency compensation. The device has a built-in slope compensation ramp. The slope compensation can prevent sub harmonic oscillations in peak current mode control. A traditional type II compensation network can stabilize the system and achieve fast transient response. Moreover, an optional capacitor in parallel with the upper resistor of the feedback divider provides one more zero and makes the crossover frequency over 100 kHz.

All converters feature an automatic low power pulse PFM skipping mode which improves efficiency during light loads and standby operation, while guaranteeing a very low output ripple, allowing for a value of less than 2% at low output voltages.​

Product Features

• Wide Input Supply Voltage Range:4.5 V - 16 V

• 0.8-V, 1 PERCENT Accuracy Reference

• Continuous Loading:3 A (Buck1), 2 A (Buck2 and 3)

• Maximum Current:3.5 A (Buck 1), 2.5 A (Buck2 and 3)

• Synchronous Operation, 300-kHz – 2.2-MHz Switching Frequency Set By External Resistor

• External Enable Pins With Built-In Current Source for Easy Sequencing

• External Soft Start Pins

• Adjustable Cycle-by-Cycle Current Limit Set by External Resistor

• Current-Mode Control With Simple Compensation Circuit

• Automatic Low Pulse Skipping (PSM) Power Mode, Allowing for an Output Ripple Better than 2 PERCENT

• Support Pre-Biased Outputs

• Power Good Supervisor and Reset Generator

• 1-A USB Power Switch With Overcurrent and Thermal Protection

• Push Button (10-kV ESD Rated Pin for PB_IN) Control for Intelligent System Power-On/Power-Off Operation

• Small, Thermally Efficient 40-Pin 6-mm x 6-mm RHA (QFN) package

• -40°C to 125°C Junction Temperature Range

Product Specification

Product Photos

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